From Shed to Success: Celebrating Varlowe’s 20th Anniversary

20 Years of Specialist Service

In 2003, a vision bloomed in a rather unconventional setting: a humble 4ft shed. There, Varlowe, a company destined to become a leading provider of industrial services, took its first steps. 

Driven by the idea of offering a comprehensive solution under one roof, Varlowe embarked on a journey that has seen it evolve into a trusted partner for countless facilities managers and businesses across the commercial and industrial sectors.

High-quality service is Our Hallmark

From the beginning, Varlowe’s core mission has been to deliver exceptional service and earn lasting customer satisfaction. This dedication to quality is evident in everything they do, from their specialist services like CNC precision machining, electrical services, steel fabrication, and Class 1 coded welding to their comprehensive pipework services.

Varlowe’s commitment to excellence is further reinforced by its team of highly skilled professionals. As the founder himself says, “I like to bring the very best people into the business. It has been about getting the right men and women.” This focus on building a strong, supportive team fosters a fun and collaborative work environment where employees are passionate about exceeding customer expectations.

A History of Growth and Adaptation

Varlowe’s story is not just about maintaining high standards but also about adapting to changing needs. A prime example is their expansion into CNC machining. Recognising the growing importance of this technology, Varlowe invested in its own state-of-the-art CNC machine shop, equipped with top-of-the-line Hurco turning and milling machines. This commitment to staying at the forefront of its industry ensures it can continue providing its clients with the most relevant and valuable services.

Overcoming challenges is another hallmark of Varlowe’s success. A notable instance was the refurbishment of their impressive 3 million pound headquarters during the COVID-19 pandemic. This accomplishment demonstrates Varlowe’s resilience and unwavering commitment to progress. But it wasnt always easy..

Shed Days…Then Stepping Up

Those early days in the shed were a wild ride – cramped quarters but big dreams! We saw the headaches businesses faced dealing with separate contractors, and we were determined to change that. It took serious hustle to find the right people, the right equipment, and build a reputation. But with each challenge, we got better, stronger, and that problem-solving mindset is what led us to our first proper workshop down Patrick Gregory Road.

Growing Our Capabilities

The first workshop we had was a significant milestone for us. We were able to work on larger projects and offer more services since we had more space. Our reputation started to grow, and it paved the way for our next significant move into our current headquarters.

Giving Back to the Community

Varlowe believes in being a positive force beyond the realm of business. The company actively supports local charities and sports teams, making a valuable contribution to the Wolverhampton community. Additionally, their efforts to refurbish neighbouring buildings and revitalize the street reflect their dedication to the area’s well-being.

Celebrating a Milestone and Looking Ahead

Last month, Varlowe celebrated its 20th anniversary in style, treating the entire team to a fun-filled evening at the dog races in Monmore Green, complete with a magician to add to the merriment. This celebration was a testament to the company’s commitment to its employees, considered the heart and soul of Varlowe’s success.

Varlowe’s vision is clear: continued growth and adding more valued customers. With their unwavering dedication to quality, a skilled and passionate team, and a willingness to adapt, Varlowe is undoubtedly well-positioned for continued success in the years to come.

Congratulations to Varlowe on 20 years of exceptional service!

MIG Vs TIG! Whats the difference? Which one should you use? Whats the pros and cons of each?

MIG and TIG welding are two types of welding that use an electric arc and a shielding gas. 

However, they differ in the type of welding electrodes used to create the arc. 

MIG welding uses a machine-fed solid wire, while TIG welding uses a non-consumable electrode and a hand-held filler rod.

As a result of these differences, each welding process has advantages, disadvantages, and preferred applications. 

To explore this further, let’s look closely at each method.

In The Blue Corner – MIG

Metal inert gas (MIG) welding, formally known as gas metal arc welding (GMAW), employs an automated or semi-automated arc to accomplish the welding process. 

When MIG welding, a wire electrode is used as the filler material, which is consumed during the process. Additionally, a shielding gas is utilised to protect the weld, enhance weld penetration, and reduce the occurrence of weld bead porosity.

The welding gun, which supplies the electrode and shielding gas, plays a crucial role. Typically, a shielding gas blend comprising 75% argon and 25% CO2 is utilised. However, other mixtures may be employed based on the materials and specific factors. 

A continuous, consumable wire electrode and a shielding gas are directed through a lead to the welding gun. The size and material of the wire used for welding can differ based on the type of metals being joined, the thickness of the pieces, and the type of connection needed.

The wire feed speed (WFS) settings determine how fast the electrode is fed into the weld, ensuring an adequate supply of weld metal for the joint.

In The Red Corner – TIG

Gas tungsten arc welding (GTAW), also known as Tungsten inert gas (TIG) welding, is a welding process that uses an arc, similar to MIG welding.

It involves a tungsten electrode (that is not consumed)and a separate filler material fed manually into the weld pool using both hands.

The filler rod’s composition and size depend on the weld type being conducted.

TIG welding employs 100% argon as a shielding gas. CO2 can cause tungsten oxide formation that can contaminate the weld and wear out the electrode prematurely. 

In addition, TIG welding uses a foot pedal that enables the welder to control the amperage, allowing precise control over the heat introduced to the metal during welding.

Advantages and Disadvantages

Comparing the advantages and disadvantages of MIG and TIG welding provides valuable insights into these two popular welding processes.

Knowing the strengths and weaknesses of different welding methods can help welders and fabricators choose the best one for their project, resulting in optimal efficiency and results.

MIG Advantages and Disadvantages

MIG welding is frequently the preferred method when joining large and thick materials. 

This technique uses a consumable wire as both the electrode and filler material. 

MIG welding is faster than TIG welding, meaning production times are shorter and costs are lower.

Additionally, MIG welding is easier to learn and can create welds that require minimal cleaning and finishing. 

It is worth mentioning that MIG welds may not possess the same precision, strength, or visual appeal as those created by an expert TIG welder.

TIG Advantages and Disadvantages

The TIG welding method uses a non-consumable tungsten electrode in combination with a separate filler rod to join small and thin materials. 

This method is adaptable and suitable for various types of materials.

Due to the higher temperatures of the torch, TIG requires less amperage. However, it is slower compared to MIG welding, which can result in longer production times and increased costs. 

TIG welding is more challenging to learn and requires skilled practitioners to produce accurate and precise welds. The larger and bulkier torch also makes it more difficult to see the welding puddle.

Despite these challenges, TIG welding provides greater control over the welding process, resulting in more robust, precise, and aesthetically pleasing welds than MIG welding.

Applications

MIG Applications

MIG welding is an excellent option for those who want to learn to weld. 

It is easy to understand, simple to use, and can join various materials, including aluminium, mild steel, and stainless steel. 

It is a great choice for thicker metals and where the appearance of the weld is not a major concern.

TIG Applications

TIG welding is challenging to master but produces more accurate outcomes than MIG welding. 

It is ideal for welding thinner materials, including aluminium, copper, steel, and titanium. 

TIG welding finds extensive application in jobs that demand precision, such as aerospace, motorsport, industrial structures, production line manufacture, and many more.

The Key Differences

We previously discussed the disparities between MIG and TIG welding techniques. 

MIG is considered more convenient to master and execute, quicker, and ideal for welding thicker materials. 

On the other hand, TIG welding provides better control and accuracy, is suited for thinner materials, and produces tidier welds with minimal finishing required.

Besides these broad distinctions, several differences can be classified based on properties, cost, and ease of learning.

Weld Strength

When it comes to welding, TIG welded joins tend to be stronger than those produced by MIG welding. 

This is because TIG welders create a narrow, focused arc for better metal penetration. 

If applied correctly, TIG weld beads contain very few holes or defects that can weaken the weld. 

However, it’s important to note that MIG welds can still be strong if certain precautions are taken. 

For example, grinding or cutting a V-shaped groove into the joint before welding can increase penetration. 

Good travel speed and torch positioning can also improve the strength of MIG welds.

Weld Speed

MIG welders are known for their faster welding speeds in a production setting. 

This is because they automatically feed filler material into the weld pool, and their rounder and broader arc dissipate heat better. 

This allows welders to move the welding material quicker and complete longer runs without the risk of overheating.

On the other hand, TIG welders can only move the weld puddle slowly, and they need more filler rods to compete with MIG welding speeds. 

Additionally, the air-cooled torches used in TIG welding get too hot during lengthy welding runs, so they need to cool down or be replaced with more expensive water-cooled torches.

Shielding Gas

Shielding gas is used to ensure high-quality welds in both MIG and TIG welding. 

This gas acts as a protective layer for the weld puddle, guarding it against reactive gases in the air that could lead to impurities. 

For TIG welding, pure argon gas is usually employed to shield the weld, as the tungsten electrode is susceptible to reactive gases such as oxygen or CO2. 

On the other hand, MIG welding typically employs a blend of 75% argon and 25% CO2, as the addition of carbon dioxide helps stabilise the arc and improve penetration. 

However, there may be exceptions to these general shielding gas rules, depending on the specific application. 

For instance, TIG welding may sometimes blend argon with helium, hydrogen, or nitrogen. 

When welding aluminium, MIG welding uses 100% pure argon or pure CO2 to save costs and enhance weld penetration.

Additionally, the two methods have different shielding gas flow rates. 

MIG welding usually requires 35 to 50 cubic feet per hour, while TIG welding uses 15 to 25 cubic feet per hour.

Weld Aesthetics

TIG welding typically results in better-looking welds than MIG welding. 

TIG welds produce minimal or no spatter and usually only require light polishing to remove discolouration. 

Welded stacks of “coins” created through TIG welding are considered the most visually appealing and can enhance the look of unpainted welds in materials like steel or aluminium. 

On the other hand, MIG welds have a less attractive appearance, even though skilled welders can still produce aesthetically pleasing MIG weld beads. 

Nevertheless, MIG welding is suitable for applications where appearance is not a major concern or if the welds will be coated, concealing the joint’s appearance.

Process Difficulty

MIG is generally considered easier to learn and master compared to TIG. 

To perform TIG welding, you need to use both hands. One hand is used to move the welding torch, while the other hand is used to feed the filler rod.

Additionally, a foot pedal is often used to control the amperage, making the process more challenging to master. 

TIG welding also requires thorough cleaning and preparation of the metals to be joined. 

On the other hand, MIG welding is simpler as it does not involve a foot pedal, and the welding gun automatically feeds the filler material. 

This means that only one hand is needed to complete the weld.

Cost

TIG welding is more expensive per foot of bead due to lower deposition rates and the need for skilled and costly welders. 

Additionally, TIG welding involves more preparation work, which increases the cost. 

Furthermore, the supplies and machines for MIG welding are typically less expensive than those for TIG welding. 

These factors all contribute to the higher cost of TIG welding.

FAQs

Is TIG Better Than MIG?

Deciding whether TIG or MIG is superior depends on several factors. 

TIG can provide stronger welds and a better appearance when executed correctly by a skilled welder. 

However, if the welder lacks experience, MIG welding may produce a higher-quality weld. 

Additionally, MIG welding is quicker than TIG welding, making it possible to complete longer runs in a shorter time. 

In conclusion, the choice between TIG and MIG depends on the specific circumstances.

Should I Learn MIG Or TIG welding?

The choice between learning MIG or TIG welding depends on your goals. 

• If you prioritise ease of learning and productivity, go for MIG welding.
• If precision and high-quality welds are important, choose TIG welding.

If you are a complete beginner, it’s best to start learning the basics of welding with MIG or Stick. MIG is easier to handle and allows for producing acceptable welds more quickly and efficiently.

Is TIG welding harder than MIG?

TIG welding is generally considered to be more difficult than MIG welding due to the need for precise manual control, coordination of multiple actions, and the use of a non-consumable electrode.

How To Choose The Correct Process

It can be difficult to determine whether to use MIG or TIG welding because of the variances between the two methods.

However, both methods have their unique benefits that can serve as a helpful guide in choosing the appropriate technique.

When to use MIG:

• Thicker materials – MIG welding is more appropriate for joining thicker stock materials.
• Long runs – MIG welding’s continuous wire feed is advantageous for longer runs as it requires fewer stops and starts to replace filler material compared to TIG welding. This results in a reduced risk of weld defects.
• Difficult positions – Using MIG is simple, even in challenging positions, because it only needs one hand to operate.
• High productivity – When it comes to productivity, MIG welding is more efficient than TIG welding because TIG welding takes longer to complete.
• Less experienced welders – MIG welding is more beginner-friendly than TIG welding, making it a better option for welders with less experience.

When to use TIG:

• Thinner materials – TIG welding is perfect for bonding thin materials prone to burn through or warping due to its precision and accuracy.
• Short runs – TIG welding is most suitable for small-scale production.
• Shop or bench work – Managing TIG out of position can be challenging, so it is best to perform this process in a bench or shop setting for optimal results.
• Delicate or fine work – TIG welding is ideal for a visually pleasing final weld. TIG welding is recommended for visible pieces like automotive restoration or artwork. This process enables better control to prevent burning or warping.
• Non-ferrous metals – Professional welders typically use TIG welding for working with materials such as aluminium, copper, stainless steel, and other speciality metals.
• Experienced welders – A skilled welder is a must to fully benefit from TIG welding. Otherwise, it’s best to consider a simpler method like MIG welding.

How Does The Amperage Of MIG And TIG Compare?

The amperage required for MIG welding and TIG welding can vary depending on the specific job requirements, such as the type and thickness of the metal being welded. However, here’s a general comparison:

MIG Welding:

• MIG welding typically uses higher amperage compared to TIG welding.
• The amperage range for MIG welding can vary from around 30 amps for thin materials up to several hundred amps for thicker materials.
• The higher amperage in MIG welding is needed to melt the wire electrode quickly and provide sufficient heat for deep penetration and effective fusion.

TIG Welding:

• TIG welding generally uses lower amperage compared to MIG welding.
• The amperage range for TIG welding can start as low as five amps for thin materials and can go up to a few hundred amps for thicker materials.
• TIG welding requires lower amperage because it relies on precise control of the heat input to create a focused and concentrated arc. It allows for better control over the weld pool and reduces the risk of overheating or distorting the base metal.

It’s important to note that the specific amperage settings for welding jobs should be determined based on factors such as the type and thickness of the metal, joint design, welding position, and desired weld quality. The welding machine and electrode size also play a role in determining the appropriate amperage settings. Welding parameters should be selected based on industry standards, manufacturer recommendations, and the expertise of the welder.

How Do The Welding Puddle And Arc Visibility Differ Between MIG And TIG?

The visibility of the welding puddle and arc differs between MIG (Metal Inert Gas) welding and TIG (Tungsten Inert Gas) welding due to the differences in the welding processes. Here’s how they compare:

MIG Welding:

• Visibility of the Welding Puddle: In MIG welding, the welding puddle is typically less visible due to the wire electrode’s continuous feed and the shielding gas’s presence. The wire electrode is consumed and continuously fed through the welding gun, creating a small welding puddle. The shielding gas around the arc protects the molten metal from atmospheric contamination. As a result, the welding puddle is somewhat obscured by the continuous flow of the wire and the shielding gas.
• Visibility of the Arc: The arc in MIG welding is generally less visible compared to TIG welding. The shielding gas used in MIG welding helps to stabilise the arc, but it also tends to dim the brightness of the arc. The bright arc is typically concentrated at the tip of the welding gun, where the wire electrode makes contact with the base metal.

TIG Welding:

• Visibility of the Welding Puddle: In TIG welding, the welding puddle is more visible compared to MIG welding. Since TIG welding involves manually adding a filler rod to the weld puddle, the welder has a clear view of the molten metal. This visibility allows the welder to closely monitor and control the weld puddle’s size, shape, and penetration.
• Visibility of the Arc: The arc in TIG welding is generally more visible and brighter compared to MIG welding. TIG welding utilises a non-consumable tungsten electrode, which produces a focused and intense arc. During welding, the tungsten electrode remains intact, which provides a clear view of the arc and its interaction with the base metal. The bright and visible arc enables the welder to control the welding process precisely.

In summary, MIG welding tends to have a less visible welding puddle and a slightly dimmed arc due to the continuous wire feed and shielding gas. On the other hand, TIG welding offers better visibility of the welding puddle and a brighter, more visible arc, which allows for greater control and precision during the welding process.

Can You Slow MIG Down Enough That It Is Similar To TIG And You Can Do Very Precise Welds?

While MIG (Metal Inert Gas) welding is generally known for its higher welding speeds and productivity than TIG (Tungsten Inert Gas) welding, it can slow down the MIG process and achieve more precise welds. Here are a few factors to consider:

Welding Technique

By adjusting your welding technique, you can have better control over the MIG process. This includes reducing the travel speed, using shorter arc lengths, and manipulating the welding gun more precisely. Slowing the movement and maintaining a steady hand can help achieve more precise welds.

Wire Size and Type

The wire size and type used in MIG welding can influence the precision of the welds. When using a wire with a smaller diameter, the control over heat input and filler metal deposition becomes more precise. Additionally, selecting a wire with a lower deposition rate can help achieve more precise welds.

Shielding Gas

The choice of shielding gas can also impact weld quality and precision. Some shielding gas mixtures, such as argon-rich blends, provide better control over the arc and produce cleaner welds. Consult with welding experts or refer to manufacturer recommendations to select the appropriate shielding gas for your specific welding application.

Welding Parameters

Adjusting the welding parameters, such as voltage, amperage, and wire feed speed, can help fine-tune the MIG welding process for more precise welds. Lowering the voltage and wire feed speed can reduce heat input and allow for better control over the weld puddle. Experimenting with different parameters and practising on scrap materials can help you find the optimal settings for your desired precision.

While these techniques can help slow down the MIG welding process and improve precision, it’s important to note that TIG welding still offers finer control and is generally better suited for highly precise welds. TIG welding is the preferred option for applications that demand the utmost precision and weld quality due to its manual control over the filler rod and accurate heat input.

Conclusion

When it comes to welding, there are two main methods: MIG and TIG. MIG welding involves using a hand-held torch to feed a continuously-fed electrode wire and shielding gas. On the other hand, TIG welding uses a tungsten electrode and a separate filler rod. 

Shielding gas is fed through a supply line, and a torch-mounted control or foot pedal is used to adjust the amperage.

It’s important to note that neither method is better than the other. Each has its advantages and disadvantages, depending on the situation.

MIG welding is often preferred for its low cost, fast welds, and ease of use. This makes it a good choice for less experienced welders who still need to produce high-quality results. 

TIG welding, on the other hand, is more difficult to master and can be more expensive and slower. However, it can deliver unparalleled accuracy and aesthetic quality that MIG welding can’t match. 

TIG welding is ideal for thinner or more delicate jobs, while MIG welding is better suited for thicker materials.

Coordinate Measuring Machines (CMMs) are efficient and precise measurement systems used in various industries to ensure that manufactured parts meet specific design needs.

CMMs use a range of advanced measurement probes, each with unique capabilities for collecting precise data on a part’s dimensions and geometry.

Specialised software analyses the data to create a detailed 3D model of the part, which can then be compared to the original design to ensure it falls within the acceptable range of variation. These limits refer to the acceptable range of variation or deviation from a specific measurement or specification.

CMMs have revolutionised quality control in manufacturing, allowing for more accurate and efficient inspection processes and reducing the risk of defects and recalls.

Let’s delve into this widely used measurement tool in more detail.

Brief History Of CMM

CMM has come a long way since their inception almost six decades ago. The modern CMM industry produces over 6,000 new machines annually and retrofits tens of thousands more. It’s hard to imagine relying solely on hand measurements for quality control, given how widespread CMM use is today.

Manufactured by British company Ferranti showcased the first CMMs in 1959 at the International Machine Tool Exhibition in Paris. They were large mechanical devices that relied on mechanical probes and analogue scales for measurement. These early CMMs used basic X, Y, and Z axes to move the measuring probe and recorded measurements manually.

During the 1960s, CMMs continued to advance as they automated the measuring process by incorporating computers and software. These advancements allowed for their application in various industries, including automotive, medical, and electronics manufacturing, during the 1970s and 1980s. Several major companies from developed countries started producing commercial CMMs, leading to widespread adoption across businesses of all sizes.

The third generation of CMMs emerged in the 1990s, featuring improved accuracy, speed, and flexibility. These machines utilised advanced probing systems, such as touch-trigger and non-contact laser probes, allowing more precise and efficient measurement. CMM software became more sophisticated, offering advanced geometric dimensioning and tolerancing (GD&T) capabilities and graphical user interfaces (GUIs) for easier operation

Portable CMMs were later developed in the 1990s, enabling measurements and inspections to be done on-site. This development proved particularly useful in construction and shipbuilding, where engineers could accurately measure large, complex parts in place.

Technological Advancements

CMMs are constantly evolving alongside technological advancements, including incorporating laser scanning and 3D imaging. Engineers utilise these machines for various purposes, such as quality control, reverse engineering, and dimensional analysis.

In the modern era, CMMs have embraced advanced technologies to enhance their capabilities. They now employ high-precision linear motors, air bearings, and advanced materials to achieve higher levels of accuracy and speed. Furthermore, the integration of optical and 3D scanning technologies has expanded the scope of CMMs, enabling them to swiftly and comprehensively measure intricate shapes and surfaces with irregular contours.

The emergence of Industry 4.0 and the Internet of Things (IoT) has significantly influenced CMMs as well. By seamlessly integrating with digital manufacturing systems, these machines facilitate the exchange of data and real-time monitoring, allowing them to actively contribute to automated production processes and quality control measures.

The future of CMMs will likely revolve around further advancements in automation, artificial intelligence (AI), and data analytics. CMMs can make intelligent decisions and enable predictive maintenance by incorporating AI algorithms. Moreover, advanced data analytics will provide valuable insights for process optimisation and quality enhancement.

What is CMM Inspection?

CMM inspection is crucial to manufacturing quality control, ensuring that products meet quality standards. The process involves inspecting products for quality and measurement, ensuring that the product meets size, weight, colour, and other characteristics. Inspecting with CMMs ensures the correctness of product production and identifies and corrects deviations from standards.

CMM inspection is a highly beneficial tool for ensuring that products meet high standards and perform as expected. It offers versatility through multiple probes and techniques and can measure difficult-to-measure items. 

The precision of CMMs is a significant advantage, allowing manufacturers to detect defects early in the production process and reduce the number of defective parts. This can lead to improved efficiency and cost savings by preventing costly mistakes. Additionally, CMMs are faster than manual methods, allowing manufacturers to increase production rates while maintaining high levels of quality. 

Using CMM inspection can also improve consumer confidence and demonstrate a commitment to quality, which can increase competitiveness. However, CMM inspection also has some limitations, such as the requirement for the probe to touch the surface, soft parts leading to defects, and the need to select the suitable probe for the measurement task. 

Despite these limitations, CMMs have transformed how manufacturers ensure their products’ quality, providing several benefits such as cost reduction, improved efficiency, and enhanced product safety and consumer confidence.

CMM Machine Components

Understanding the functions of the components of a CMM machine is crucial to gaining a comprehensive knowledge of its operation. Here are the essential parts of a CMM machine.

Probe 

The probe is an essential component of a CMM machine as it is the part responsible for taking the measurements. It is usually made from a hard, rigid material like ruby or zirconia. The tip can also come in many shapes, including spherical, needle-shaped, and flat. This allows the tip to remain stable even if the temperature changes.

Granite Table

CMMs use a granite table as it provides a high level of stability and is not prone to the effects of temperature. Moreover, granite is less likely to undergo wear and tear compared to other materials. This makes it an ideal material for achieving highly accurate measurements as its shape remains consistent over time.

Fixtures

Fixtures are essential in many manufacturing operations, providing stability and support. As a component of the CMM machine, fixtures serve the crucial role of holding parts in place during measurement. Without proper fixation, a moving part could introduce errors in the measurement process. Other common fixing tools used with fixtures include fixture plates, clamps, and magnets.

Air Compressors and Dryers

Air compressors and dryers are typically standard components in CMM machines, including bridge and gantry-type machines.

Software

Although not a physical component, the software is a crucial component of the CMM machine. It plays a significant role in analysing the probes or other sensitivity components used during measurement.

CMM Capabilities

CMMs can measure various parts with a broad range of capabilities, including:

• Profile measurement: CMMs can capture the profile information and form of 2D and 3D objects.
• Depth mapping: With the help of two stereo images, CMMs can precisely map the depth of any object.
• Dimensional measurement: CMMs can measure multiple axes of an object to obtain comprehensive dimensional information.
• Angle measurement: CMMs can measure the angles and orientation of two different points of an object.

These versatile instruments provide accurate and comprehensive measurements for various applications, making them advantageous for multiple industries.

CMMs are used in the automotive industry to measure engine blocks, transmissions, and chassis. This helps reduce defects, improve product quality, and increase customer satisfaction.

The aerospace industry extensively uses CMMs to inspect complex and high-precision components such as turbine blades, engine components, and structural parts. By measuring these parts using CMMs, manufacturers can ensure they meet the required specifications and tolerances, which is critical for the safety and reliability of aerospace components.

In the medical field, CMMs inspect surgical instruments, implants, and medical devices to ensure they meet safety standards, improving overall quality and minimising defects.

Manufacturers in the electronics industry use CMMs to inspect printed circuit boards (PCBs) and other electronic components, ensuring they meet the required specifications and tolerances. This reduces the risk of defects and improves the overall quality of electronic products.

How CMMs Work

CMMs work on the principle of measuring the coordinates of points on an object’s surface using a combination of mechanical probes, optical sensors, or laser scanners. 

The measurement process involves several steps:

1. Preparation: The object to be measured is securely placed on the CMM’s measuring platform. The CMM is then calibrated to establish a reference point for all subsequent measurements.

2. Probing: The CMM’s probe is brought into contact with the object’s surface, or a non-contact measurement method, such as laser scanning, is used. The probe collects data points from the object’s surface, capturing its dimensions and geometrical features.

3. Data collection: The collected data points are processed by the CMM’s software, which analyses the measurements based on the specified measurement parameters and generates a detailed report.

4. Analysis and reporting: The measurement data is analysed to evaluate the part’s conformity to the desired specifications. The CMM’s software generates comprehensive reports highlighting deviations or defects, providing valuable insights for quality control.

What Are Some Benefits Of Using CMM Inspection?

• There are several benefits to using CMM Inspection:
• Ensures that the product meets the highest standards.
• It allows the company to ensure that the product will perform as expected.
• Versatile with Multiple Probes and Techniques
• Measures items that are difficult to measure with other measuring tools
• Gives the customer confidence in the product.
• Saves money by preventing costly mistakes.
• It makes the company more competitive because it shows customers that it cares about quality.

What Are Some Limitations Of Using CMM Inspection?

While Coordinate Measuring Machines (CMMs) are powerful inspection tools, they do have some limitations, such as:

• The probe’s accessibility limits CMMs to inspect only the reachable surfaces. Consequently, areas that are obstructed or difficult to reach might not be accurately inspected.
• Limitations in measuring resolution, limiting their ability to detect smaller defects or features.
• Can be expensive and may require skilled operators to operate and maintain them.
• Measurement errors can occur due to various factors, including probe deflection, thermal expansion, and mechanical wear. These errors can impact the accuracy and reliability of inspection results.

Types of Coordinate Measuring Machines

There are four main types of coordinate measuring machines (CMMs): bridge, cantilever, gantry, and horizontal arm. The choice of CMM type will depend on its intended use. 

Each CMM has three orthogonal axes – X, Y, and Z – operating within a 3D coordinate system. Some CMMs use contact probes, while others use non-contact probes. 

Regardless of the type of probe used, all CMMs collect and analyse data to verify the accuracy of the measured component. 

Let’s explore the various types of coordinate measuring machines and their applications.

Bridge CMM

A typical 3D Bridge CMM permits movement of the probe along three orthogonal axes in a three-dimensional cartesian coordinate system. Each axis has sensors that monitor the probe’s position with micrometre precision. The contact point of the position sensors measures the object’s surface and repeats to create a ‘point cloud’ that describes the surface areas of interest.

Bridge CMMs are commonly used in quality control and inspection processes in aerospace, automotive, and medical devices. They are versatile and can measure various part sizes and shapes. They can measure features such as holes, slots, and angles and check a part’s overall form and position.

Guaranteed Accuracy

Bridge CMMs commonly have tactile probes that make contact with the part being measured. These probes come in different shapes and sizes and can be selected based on the feature being measured and the required level of accuracy. In addition, non-contact probes such as laser scanners can be used to capture a part’s surface information quickly and accurately.

Bridge CMMs often use temperature compensation systems to enhance measurement accuracy. These systems incorporate sensors to monitor the temperature of the CMM and the part being measured, and then adjust the measurements to compensate for any thermal expansion or contraction that may affect the results.

Manufacturers often consider bridge machines the workhorses of CMMs due to their basic structure and low cost to build and maintain. However, there are pros and cons to their function. For instance, the uprights holding the X-axis beam may obstruct access to the measured part, making reaching it challenging. Additionally, placing heavy components on the machine may require the use of a lift truck or crane, which increases the risk of accidentally bumping the device.

The Bridge CMM remains unmatched in accuracy, versatility, and cost-effectiveness when measuring machined parts with high tolerances, despite these challenges.

The pros of bridge CMMs

• Excellent accuracy and precision, making them ideal for measuring machined parts with high tolerances
• Suitable for measuring machined parts with tight tolerances
• Ideal for small to medium-sized components
• Can perform multi-sensor measurements, including probing and scanning
• Fairly basic structure that is simple to build, resulting in lower costs to build and maintain.

The cons of bridge CMMs

• Limited measurement volume
• The machine is not portable and requires either bringing parts or utilising specialised equipment to move it.
• Sensitivity to vibrations, requiring use in a stable metrology lab environment
• Each part requires a rigid setup for inspection
• Complex operations and programming require skilled workers.

Cantilever CMM

Cantilever CMMs are another common coordinate measuring machine used in manufacturing and quality control processes. These machines provide open access to the operator on three sides, making them ideal for measuring relatively small parts. They attach the head to only one side of the rigid base, unlike bridge-style CMMs.

One of the main advantages of a cantilever CMM is its speed. The column’s large support base combined with the low weight means that cantilever CMMs can move quickly, making them an ideal choice for applications where time is critical. Additionally, these machines are highly accurate, with a low measurement uncertainty level. Therefore, inspectors predominantly use cantilever CMMs for measuring gauges and master parts.

Versatility

Another advantage of a cantilever CMM is its versatility. The open design of the machine allows for easy loading and unloading of parts, making it ideal for shop floor applications. The ability to automate the loading and unloading process further increases the machine’s efficiency, making it a popular choice for high-volume manufacturing operations.

Despite their many advantages, cantilever CMMs do have some limitations. One of the main drawbacks of these machines is their limited measurement volume. Cantilever CMMs are best suited for measuring small parts and may not be suitable for larger components. Additionally, cantilever CMMs are sensitive to vibrations and must be used in a controlled environment, such as a metrology lab. Finally, these machines can be complex, requiring skilled workers to program the device.

In summary, cantilever CMMs are popular for measuring small parts quickly and accurately. These machines offer an open design, making them ideal for shop floor applications, and their speed and accuracy make them an excellent choice for gauges and master parts. While they have limitations, cantilever CMMs remain important for manufacturing and quality control processes.

The pros of cantilever CMMs

• High accuracy and low measurement uncertainty level
• Provide open access to the operator on three sides, making them ideal for measuring relatively small parts
• The large support base and low weight of the column enable quick movement
• Popular for use in automatic loading and unloading processes on shop floors
• Suitable for measuring gauges and master parts

The cons of cantilever CMMs

• Limited measuring volume compared to other types of CMMs
• Not ideal for measuring large or heavy parts due to their limited weight capacity
• The cantilever design is less stable than other types of CMMs, making them more sensitive to vibrations
• The one-sided attachment of the head may cause measurement errors due to deflection or vibration
• Higher cost compared to some other types of CMMs

Gantry CMM

Gantry CMMs are designed for measuring large parts and are characterised by a crossbeam that moves along two uprights or columns. The automotive, aerospace, and construction industry commonly use gantry CMMs for accurately measuring large parts.

The measuring range of a gantry CMM varies from 1x2x1m XYZ to 4x10x3m XYZ, and it is possible to have even larger, custom-made units built.

The gantry-style design allows for high precision and accuracy, even when measuring large components. The operator can move the crossbeam to any position along the columns’ length, providing maximum flexibility in measuring different parts.

Gantry CMMs have a reputation for delivering high speed and throughput, making them an excellent choice for production lines that require quick and accurate part measurements. The large measuring volume and the ability to measure complex shapes make them suitable for various applications.

However, gantry CMMs are more complex and expensive to build and maintain than other CMMs. They require a large amount of floor space and are not easily portable, which can be a disadvantage in some applications. The large size of gantry CMMs also means they are more sensitive to vibrations, which can affect measurement accuracy.

Overall, gantry CMMs are an excellent choice for measuring large, complex parts that require high precision and accuracy. Still, they may not be the best option for smaller parts or applications where portability is essential.

The pros of gantry CMMs

• Larger measuring volumes make them ideal for measuring large components.
• High accuracy, similar to that of bridge CMMs.
• You can load heavy parts directly onto the floor for safe handling.
• Access to programming is easier, making programming simpler.
• Easy to insert surface plates for smaller components, making measurements less time-consuming for the operator.
• Commonly used in the aerospace industry, where high accuracy is necessary for large components.

The cons of gantry CMMs

• Requires a substantial foundation and must be mounted directly to the floor, which can be expensive.
• Not portable and takes up a lot of space.
• It may not be suitable for measuring small parts due to their larger measuring volume.
• Limited accessibility to the part being measured due to the machine’s structure.
• Higher cost compared to other CMM machines due to their larger size and the need for a foundation.

Horizontal Arm CMM

Horizontal Arm CMMs are coordinate measuring machines that use a horizontal arm to hold the measurement probe. The probe moves along the arm to collect data points from the workpiece, usually stationary on a flat measuring table. Horizontal Arm CMMs are a popular choice for measuring large parts, such as car bodies or aircraft components, because they have a long reach and can easily access the top and sides of the workpiece.

One of the benefits of using a Horizontal Arm CMM is the ability to measure parts with complex geometries, such as curved surfaces, without the need for complex fixturing or part orientation. The measuring range of Horizontal Arm CMMs varies from a few meters to over 20 meters, making them a versatile solution for measuring parts of all sizes.

High Accuracy

Horizontal Arm CMMs offer high accuracy in measuring parts to meet the required tolerances. Operators can equip them with a range of probes and sensors to measure features such as edges, holes, and surfaces. Additionally, these machines can perform non-contact measurements using laser scanners or optical sensors.

However, Horizontal Arm CMMs also have some drawbacks. They require a large amount of floor space, making them unsuitable for small workshops. They also demand a high level of skill to operate, as the operator needs to move the arm to the correct position and orientation for each measurement. Moreover, frequent recalibration of the probe is necessary to maintain accuracy, which can be time-consuming and can impact productivity.

Overall, Horizontal Arm CMMs are a powerful tool for measuring large, complex parts with high accuracy. While they have some limitations, their ability to access all sides of the workpiece and measure complex geometries makes them an essential part of the measurement toolkit for many industries.

The pros of horizontal arm CMMs

• Ideal for measuring large and heavy parts due to their long reach and high load capacity.
• It can reach inside complex parts, making it easier to measure features that would be difficult to access with other CMM types.
• Horizontal arm CMMs are often equipped with tactile probes, laser scanners, or vision systems, which can capture various measurements and data.
• These machines can provide high accuracy and repeatability, making them suitable for critical measurements and quality control.
• Horizontal arm CMMs are relatively fast and efficient at measuring large parts, making them suitable for high-volume applications.

The cons of horizontal arm CMMs

• Horizontal arm CMMs require a large amount of floor space and a sturdy foundation, making them less portable than some other CMM types.
• They require a skilled operator to program and operate the machine effectively.
• Due to the size and complexity of the machine, maintenance and repair can be time-consuming and costly.
• The accuracy of the machine can be affected by vibration and temperature changes in the surrounding environment.
• Horizontal arm CMMs are typically more expensive than other CMM types, which can be a significant investment for smaller businesses.

CMM Probes

CMM probes are an essential component of Coordinate Measuring Machines. They are used to measure the geometry of an object by touching its surface at specific points or scanning it with a non-contact method. CMM probes come in different shapes and sizes to suit various measuring tasks.

The most common type of CMM probe is the touch-trigger probe. Touch-trigger probes transfer pressure through a stylus to a sensor inside the probe body, which triggers a measurement. Typically, manufacturers use hard-wearing materials like ruby to make the stylus tip, and they can vary in size from a few microns to several millimetres.

Scanning probes, another type of CMM probe, drag across the surface to be measured, collecting measurement points at pre-programmed intervals. This probe type is typically used for measuring freeform surfaces or scanning parts that are difficult to touch-trigger. Scanning probes are faster than touch-trigger probes and can collect a large number of points in a short amount of time, allowing for a more detailed analysis of the object’s surface.

Optical Scanning

In some cases, contact probes can be replaced with optical scanning probes. These scanning probes use reflections of light to triangulate measurement points on the object’s surface. Recently, technological advances have allowed optical scanners to increase in accuracy and range. As a result, stand-alone optical scanners are replacing CMMs for some applications.

CMM probes play a crucial role in achieving the desired accuracy of a CMM. The probe selection depends on the measuring task’s complexity, the object’s material and shape, and the required measurement accuracy. A well-calibrated probe is essential to ensure the CMM can provide precise and accurate measurements.

What Are The Different Types Of Measurement Probes?

The type of probe used largely determines the ability of a Coordinate Measuring Machine. There are various types of probes available, including contact and non-contact probes. Contact probes measure workpieces by making physical contact with them, while non-contact probes utilise lasers or machine vision for scanning with optical sensors.

Generally, people consider contact probes to be a more accurate method of measurement. In contrast, laser or machine vision probes are typically faster to use while maintaining high accuracy.

In addition to these basic types of probes, there are also multi-sensor probes that combine both touch and optical scanning capabilities. These probes offer the advantages of both contact and non-contact probes in a single tool.

Contact Probes

Touch Trigger Probes and Analog Scanning Probes are the two most common contact probes.

Touch-trigger probes

Renishaw invented the first touch-trigger probe, developed to solve a specific inspection requirement for the Olympus engines used in Concorde aircraft. A touch-trigger probe comprises a stylus attached to a bearing plate, connected to pressure sensors inside the probe’s housing. Each time the probe contacts the workpiece, it generates an electrical signal sent back to the CMM for accurate measurements.

The touch-trigger probe is mounted at the end of one of the CMM’s moving axes and can be rotated manually or automatically. It can accommodate a variety of attachments and stylus tips for increased versatility and flexibility.

One advantage of touch-trigger probes is their versatility and flexibility. The use of piezo-based sensors eliminates the effect of stylus bending, while advancements in strain gauge technology ensure that the probes trigger with constant force regardless of the angle of contact with the workpiece. These advancements eliminate directional sensitivity, resulting in a sub-micron level of accuracy for touch-trigger probes.

Analog Scanning Probes

Analogue scanning probes are a type of stylus-based probe used for measuring contoured surfaces like sheet metal assemblies. The analogue probe maintains continuous contact with the workpiece and takes measurements as the user moves it across. This provides a more accurate reading compared to digital probes, which only touch individual points.

Continuous analogue scanning (CAS) probes offer superior data acquisition capabilities compared to digital probes because they provide continuous contact measurements.

These analogue scanning probes are useful for measuring complex shapes like turbine engine blades, automobile bodies, cams, prosthetics, and crankshafts.

Closed Or Open?

Continuous analogue scanning, or CAS, systems come in two types:

1. Closed-Loop Systems: The probes can detect even the smallest surface direction and contour changes. Not only that, they can also automatically adjust their position to ensure continuous contact with the surface. This remarkable feature proves to be extremely beneficial when measuring intricate and unfamiliar shapes with the utmost precision and accuracy.
2. Open-Loop Systems:  These probes follow a pre-determined path driven by dimensional information from a data file while using data sourced from a file to determine a given object’s dimensions accurately. This open-loop methodology is particularly beneficial when it is necessary to rapidly collect data pertaining to parts that possess clearly defined geometries, whether through surface points and vectors or CAD data.

Analogue probes can collect up to 50 times more data than touch-trigger probes within the same period. This extensive data collection enhances confidence in the accuracy of the measurements. However, large gaps between data points can compromise the accuracy of the data.

Analogue scanning probes offer another advantage over digital probes – they can also function as touch-trigger probes, offering greater flexibility to the operator. When using analogue scanning probes, operators can determine which features necessitate a brief touch and which demand a longer, continuous contact for more precise measurement. For critical features particularly complex, continual contact is necessary to capture all the necessary data points.

Non-Contact Probes

Non-contact probes measure workpieces that cannot tolerate the pressure of a contact probe or require high-precision measurements. These probes use either laser or vision-based technology.

Laser Probes

Laser probes can be used with Coordinate Measuring Machines (CMMs) to measure workpieces as one type of non-contact probe. They offer particular usefulness in measuring workpieces that traditional contact probes may easily deform or damage.

Laser probes use a concentrated beam of light to take readings of the workpiece. The probe receptor reads the position of the part by triangulation through a lens inside, after projecting an optical switch beam of light onto it. This method resembles the approach utilised by surveyors to determine a position or location by calculating bearings based on the known distance between two stationary points.

Laser probes have several advantages over contact probes when measuring simple and complex geometric shapes. They can accurately measure without physical contact, which reduces the risk of damage or distortion to the object being measured. For example, they can take measurements quicker, leading to faster inspection times. Additionally, they can measure parts with high accuracy and precision, including parts with very tight tolerances.

Can Lasers Do It All?

One disadvantage of laser probes is that they can be more expensive than contact probes, and they may not be suitable for all types of workpieces. Additionally, they may not be able to measure parts with certain surface properties, such as those that are shiny or reflective.

Many different laser probes are available for CMM machines, including single-point probes and scanning probes. Single-point probes measure specific points on the workpiece, while scanning probes take continuous measurements across the part’s surface. Laser probes are capable of measuring the X, Y, and Z dimensions of the surface being measured, as well as the angle.

Overall, Laser probes are a powerful tool for CMM machines, enabling high accuracy and precision measurements of various workpieces.

Vision-Based Probes

Vision-based probes are a type of non-contact probe that use cameras to capture high-resolution images of workpieces. You can accurately measure the workpiece’s features and geometry using these images.

One of the main advantages of vision-based probes is their ability to capture measurements from workpieces with complex geometries, including small or fragile parts that contact-based probes could damage. Vision-based probes can also be used to capture 3D images of the workpiece, providing a complete view of the part’s geometry.

The Renishaw REVO probe is a popular example of a vision-based probe for CMM machines. This probe uses a high-definition camera to capture multiple measurement points in one frame, allowing more efficient data collection. You can measure and compare the features captured by the camera by counting the pixels, which allows for highly accurate measurements.

One of the key advantages of vision-based probes is their ease of use. Less experienced users can operate vision-based probes more easily compared to contact-based probes, which require a skilled operator to position the stylus and take measurements. The calibration process is also simpler, as the lens only requires calibration once.

However, there are some limitations to vision-based probes. While they can capture a large amount of data in a short time, the measurements’ accuracy may not be as high as contact-based probes. 

Additionally, vision-based probes are typically more expensive than contact-based probes, making them less suitable for smaller manufacturing operations with limited budgets.

White Light Probes

White light probes are another type of non-contact probe that is commonly used in CMM machines. These probes work by projecting a structured light pattern onto the surface of the part being measured, which is then captured by a camera to generate a 3D representation of the part’s surface. This technology is sometimes referred to as “optical scanning” or “3D scanning”.

White light probes are especially useful for measuring complex free-form shapes, such as those in aerospace and automotive components. You can use them to measure delicate or easily deformable materials, such as soft plastic or rubber.

One advantage of white light probes is their speed – they can quickly generate large amounts of data, which can be useful in high-volume production environments. They are also non-destructive, meaning they do not damage the surface of the measured part.

However, there are some limitations to the accuracy of white light probes. The accuracy can be affected by factors such as the distance between the probe and the part, the surface finish, and the presence of shiny or reflective surfaces. As with other non-contact probes, the accuracy may not be as high as with contact probes, so they may not be suitable for all applications.

Overall, white light probes are useful for capturing detailed 3D data quickly and non-destructively and can be a valuable addition to a CMM machine’s measurement capabilities.

Probe Features

CMM probes utilise various sensor technologies to obtain measurements, each with unique strengths suitable for different applications.

Here are some of the commonly used sensor technologies:

• Kinematic or switch technologies are the smallest CMM probe types and offer low over-travel force, simple interfacing, and robust and universal filament.
• Strain-sensing CMM probes offer fewer lobing errors, long operating life, a wide operating speed range, and are ideal for peck or stitch scanning.
• Piezoelectric, LVDT, and optoelectronic CMM probes are available as well. Piezoelectric devices have few lobing errors, large stylus-carrying capability, multi-mode sensor operating, extended versatility, and a restricted operating speed range. LVDT sensor types provide high accuracy and large stylus carrying capacity. Optoelectronic devices offer higher accuracy than kinematic sensor types and high data rates.

In addition to these, there are also laser triangulation, capacitive, and video imaging sensor types. Laser triangulation sensors provide single-axis profile measurements, while capacitive CMM probes use a fixed stylus to provide non-contact technology.

Video imaging sensor types provide suitability for 2-D, flexible parts, and automatic edge detection. However, they can be affected by surface reflectivity and ambient light.

Overall, the choice of sensor technology depends on the specific requirements of the measurement task. It is important to consider the probe’s accuracy, speed, and range, as well as the workpiece’s material type and surface finish.

Best Practices For Operating Coordinate-measuring Machines

To ensure optimal performance and accurate measurements, following best practices when operating CMMs is essential. 

Here are some key guidelines:

• Calibration: Regularly calibrate the CMM to maintain measurement accuracy. Qualified technicians should perform calibration to ensure reliable and consistent results.
• Cleaning and maintenance: Keep the CMM and its probes clean and debris-free. Regularly inspect and maintain the machine to prevent mechanical issues affecting measurement accuracy.
• Operator training: Provide comprehensive training on effectively operating the CMM and its software. Familiarise them with measurement techniques, data analysis, and reporting capabilities to maximise the benefits of using CMMs for quality control.
• Quality assurance procedures: Implement robust quality assurance procedures, including regular checks and audits, to verify the accuracy and reliability of the CMM’s measurements. This helps maintain confidence in the measurement results and ensures consistent quality control.

Common Challenges In Quality Control With CMMs

While CMMs offer numerous advantages, there are some challenges that manufacturers may encounter when using them for quality control. 

These challenges include:

• Programming complexity: CMMs require specialised programming to define the measurement routine and parameters. Programming can be complex, requiring skilled personnel or training to ensure accurate and efficient measurements.
• Surface accessibility: Some parts may have complex geometries or hard-to-reach surfaces, making it challenging to obtain accurate measurements using CMMs. In such cases, alternative measurement methods or specialised probes may be required.
• Data interpretation: Analysing and interpreting the measurement data can be complex. It requires expertise in statistical analysis and understanding the tolerances and specifications of the measured parts.
• Integration with existing systems: Integrating CMMs into the existing quality control process and software systems can be a challenge. It requires careful planning and coordination to ensure seamless data transfer and compatibility with other manufacturing systems.

Integrating CMMs Into Your Quality Control Process

To effectively incorporate Coordinate Measurement Machines (CMMs) into your quality control process, consider the following guidelines:

First, assess your specific measurement needs by evaluating the requirements of your parts or processes. Determine the desired accuracy, measurement volume, and inspection capabilities necessary for your quality control objectives.

Next, select the appropriate type of CMM that aligns with your measurement needs. Take into account factors such as the size and complexity of the parts, as well as any portability requirements. Seeking advice from CMM manufacturers or experts can help you choose the most suitable machine for your application.

Develop comprehensive measurement routines and programs for your CMM. Define the measurement parameters, tolerances, and reporting formats to ensure consistent and standardised measurements.

Provide thorough training to operators on operating the CMM, performing measurements, and analysing the resulting data. Emphasise the importance of adhering to standard operating procedures and quality assurance guidelines.

Establish seamless integration between the CMM and other existing quality control systems, such as statistical process control software or manufacturing execution systems. This integration enables efficient data exchange and real-time monitoring of quality control metrics.

Continuously evaluate and improve your quality control process by analysing the measurement data generated by the CMM. Identify areas for enhancement, implement necessary corrective actions, and monitor the impact of these improvements on product quality.

By following these steps, you can effectively integrate CMMs into your quality control process and enhance the accuracy and efficiency of your measurements, leading to improved product quality and customer satisfaction.

CMMs Role In CNC Machining

Coordinate Measurement Machines can be an integral part of CNC (Computer Numerical Control) machining processes. While CNC machining refers to the automated control of machine tools using pre-programmed computer software, CMMs are specialised machines used for precise measurement and inspection of manufactured parts.

CNC machines are primarily used for cutting, shaping, and machining raw materials into finished parts based on computer-generated instructions. These instructions, known as G-code, guide the CNC machine in executing specific tool paths and operations to create the desired component.

Once the CNC machining process is complete, CMMs come into play for quality control and inspection. CMMs accurately measure the machined parts, ensuring they meet specifications, tolerances, and geometric features. CMMs utilise probes, sensors, and advanced measurement techniques to precisely capture dimensional data, compare it against the design specifications, and identify any deviations or defects.

The integration of CMMs with CNC machining allows for efficient quality assurance and verification throughout the manufacturing process. By using CMMs to verify the dimensional accuracy and quality of machined parts, manufacturers can ensure that the produced components meet the required standards and specifications. This integration helps in minimising errors, reducing rework or scrap, and maintaining consistent quality in CNC machining operations.

Conclusion And Key Takeaways

Coordinate-Measuring Machines (CMMs) have revolutionised quality control in the manufacturing industry, enabling precise and accurate measurements of complex parts. 

By harnessing the power of CMMs, manufacturers can optimise their quality control processes, improve product quality, and enhance customer satisfaction. 

Understanding the various types of CMMs, their advantages, and best practices for their operation is essential for mastering quality control in today’s competitive manufacturing landscape. 

By embracing CMM technology and integrating it into your quality control process, you can unlock a new level of precision and efficiency in your manufacturing operations.

CMM Inspection at Varlowe

At Varlowe Industrial Services, our CMM inspection service offers top-notch solutions, including dimensional analysis, CAD comparisons, tool certifications, and reverse engineering.

Give us a call on 01902 861042, or email info@varlowe.co.uk for more information.

What Is Pipe?

Pipes are essential components in many industries, transporting various liquids and gases over long distances through complex networks. 

They come in different sizes, shapes, and materials like metal, plastic, ceramic, or composite. Pipes can fail, and engineers must replace parts while still in use, making pipe welding a crucial aspect of maintenance and repair.

Pipe welding is a crucial process that ensures the longevity and safety of piping systems. It is crucial to understand the significance of proper pipe welding to ensure the safety and longevity of your piping. In this post, we will explore the basics of pipe welding.

What Does A Pipe Welder Do?

A pipe welder joins sections of pipes to create a continuous pipeline. They are responsible for welding various types of pipes, including steel, copper, and plastic, using different welding techniques, such as arc welding, gas tungsten arc welding (GTAW), and gas metal arc welding (GMAW).

Pipe welders work in various industries, including construction, manufacturing, and oil and gas. They may be responsible for fabricating and installing pipes for heating and cooling systems, gas and oil pipelines, and water supply systems.

Essential duties include installing metal pipes fittings, securing pipes to structures, and working with metal cutting, forming, and joining. Other essential responsibilities include interpreting blueprints and schematics, troubleshooting and diagnosing pipe problems.

As a pipe welder, it is crucial to focus on two key aspects to maintain the safety of pipe systems. Firstly, ensuring the quality of fittings, and secondly, ensuring their proper positioning. These factors are essential when dealing with substances like oil, gas, steam, chemicals, and water.

There are various welding procedures and types, each with advantages and disadvantages.

Which Type Of Welding Is Used For Pipes? 

While there are many different methods of welding nowadays, Pipe welders usually use one of the following arc welding processes:

Shielded metal arc welding (SMAW)

Pipe welding often uses the Shielded Metal Arc Welding (SMAW) technique, commonly called stick welding. 

This method uses a stick-shaped electrode to generate an electric arc that melts the metal during welding. The welder uses a flux-coated electrode to protect the weld metal and prevent atmospheric contamination.

When welding pipes, individuals often utilise SMAW to join hard-to-reach areas and thicker materials. SMAW is a versatile process that a pipe welder can apply to various metals, including carbon steel, stainless steel, and cast iron.

To begin the process, thoroughly clean the pipe area to be welded to remove rust, oil, or other contaminants. Then, position the electrode and establish an arc between the workpiece and the electrode. As the electrode melts, the flux coating vaporises, producing a shielding gas to protect the weld pool from atmospheric contamination.

By adjusting the angle of the electrode and moving it along the joint at a certain speed, the welder controls the size and shape of the weld.

Gas Metal Arc Welding (GMAW)

Gas metal arc welding (GMAW) is a process that uses a continuous wire electrode to weld metal. The arc between the electrode and the workpiece heats the metal, causing it to melt and join.

GMAW is a versatile process that can weld various metals, including carbon steel, stainless steel, aluminium, and magnesium. It is popular for welding pipes because it is easy to use and produces a high-quality weld.

To weld pipe with GMAW, you will need a welding machine, a welding gun, a wire electrode, and shielding gas. 

The process of GMAW is relatively simple:

1. To begin welding, connect the welding machine to the power source to provide the necessary electrical power to the arc.
2. Connect the welding gun to the machine. This tool holds the electrode and delivers the necessary shielding gas to the weld area.
3. Select the proper wire electrode and shielding gas for the type of metal you are welding. The wire electrode is responsible for melting and creating the weld. The shielding gas is tasked with protecting the molten weld pool by preventing exposure to the surrounding atmosphere.
4. Position the welding gun at the joint and strike an arc between the electrode and the workpiece.
5. Feed the wire electrode into the weld pool and move the welding gun in a circular motion once you establish the arc. As you do this, the wire electrode will melt and join the metal, forming a weld.

GMAW is a safe and effective welding process when used correctly. However, following all safety precautions when using GMAW equipment is essential. These precautions include wearing safety glasses, gloves, and a welding helmet while ensuring you ventilate the area where you will be welding.

Flux-Cored Arc Welding (FCAW)

Flux-Cored Arc Welding (FCAW) is an exceptional welding technique that employs a tubular electrode filled with flux instead of a solid wire. The flux safeguards the weld area against atmospheric contamination while also imparting additional elements to the weld to enhance its quality. 

FCAW is versatile enough to weld various materials, including carbon steel, low alloy, and stainless steel. To perform the task, you only require a steady voltage power supply and a wire feeder to move the electrode to the welding point. Once the electrode and the base metal form an arc, the electrode melts, creating a weld pool. The flux layer around it safeguards the weld from impurities, shapes it, and enhances its quality.

FCAW is a highly efficient and productive welding process that can generate high-quality welds rapidly and efficiently. It benefits welding pipes with thicker walls or those requiring higher deposition rates. One of the significant advantages of FCAW is its ability to provide a stable and consistent weld, thereby ensuring a robust and reliable final product.

Submerged Arc Welding

Submerged arc welding (SAW) is commonly used for welding low and high-alloy steel and carbon steel pipes. It involves creating a welding arc submerged beneath a flux layer, protecting the weld pool from atmospheric contamination. 

SAW is an efficient and productive welding process that can produce high-quality welds with minimal operator intervention. Pipe welding applications commonly use it because it creates a robust and high-quality weld at a relatively fast speed.

The SAW process requires a constant voltage power source and a wire feeder that delivers the welding wire to the weld joint. The weld is created when the arc is struck between the wire and the base metal, melting the wire and creating a weld pool. The flux layer surrounding the weld pool protects the weld from atmospheric contamination and helps control the weld’s shape and quality. 

Submerged arc welding effectively welds pipes of different diameters, thicknesses, and lengths. The pipe welding industry frequently requires long and straight seams, which make this technique particularly suitable for the job.

Tungsten Inert Gas (TIG)

Tungsten Inert Gas (TIG) welding, also known as Gas Tungsten Arc Welding (GTAW), is commonly used in pipe welding to weld stainless steel, aluminium, and other non-ferrous materials. 

TIG utilises a non-consumable tungsten electrode which creates an arc with the workpiece, melting the electrode and the base metal to create a weld pool. A filler metal is added to the weld pool to create a durable weld.

TIG welding requires a constant current power source and an inert gas, such as argon or helium, to shield the weld area from atmospheric contamination. TIG welding is an exact and controlled welding process that can produce high-quality welds with excellent mechanical properties.

One of the main advantages of TIG welding is its ability to produce a clean, precise weld with minimal heat distortion. It can also weld fragile materials, making it well-suited for thin-walled pipes.

Pipe Welding Steps

As with all welding work, a project manager has several questions to answer for the project to be successful, such as –

• Pipe material
• Pipe diameter and wall thickness
• Welding location
• Weldment properties
• Welding direction (Uphill or downhill)
• Required welding quality
• Economic considerations
• Health and Safety

Once everything is agreed upon, it’s over to the engineer to begin the fabrication and welding of the pipework.

They have their own set of steps, such as –

Pipe End Cleaning

To ensure a good quality weld, the surfaces to be joined must first be cleaned. 

Before welding can start, the pipe must be free from moisture, coating, rust, oxides, and other contaminants to prevent defects and costly repairs in the future. You can clean using any suitable means, such as a file, wire brush, grinding, buffing wheel, etc.  

After cleaning the surfaces, you can prepare them for welding.

Aligning The Joint

Aligning the joint is critical for a successful welding application. A line-up clamp is ideal for this process as it securely holds both ends of the pipes in place to maintain correct alignment. 

If a line-up clamp is unavailable, another option would be to develop a jig; with an angle suitable for smaller diameters or a channel or I-beam for larger pieces.

It is also essential to ensure the necessary root spacings. Root spacing should equal the filler rod used for arc and oxy-acetylene welding. 

 Root spacing should exceed the filler rods when using a backing ring at the root. 

While this method allows for full penetration joints, it may not always be permissible because of other design limitations.

Backing Rings

The backing ring is a device that helps prevent the weld from penetrating too deeply into the pipe wall. It prevents any metal from entering the ID of the pipe through a burn-through or spatter sprayed around during the welding. This allows the weld to penetrate only the outer surface of the pipe, leaving the inner surface unwelded.

Positioning backing rings between two pipe pieces before connecting them helps align the pipes and ensures that their centrelines are in sync. However, the use of a backing ring is sometimes restricted by design factors such as when the design requires a smooth, undisturbed fluid flow inside the pipe.

To prepare for welding, fit one pipe with a backing ring and place the other pipe over it. Secure the backing ring and tack weld the pipes at four to six points around their circumference.

Backing Gas

When you are welding, you are heating up two pieces of metal to join them together. However, as the metal heats up, it can react with the air around it, causing oxidation and other chemical reactions that can weaken the weld. This is where backing gas comes in.

Backing gas is a type of gas that is used to protect the back side of the weld from atmospheric gases during the welding process. It is commonly used in welding processes such as gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW). 

The purpose of backing gas is to prevent oxidation and other atmospheric contaminants from entering the weld area, which can negatively impact the quality and strength of the weld.

In GTAW, welders often use argon gas as a backing gas. The argon gas flows around the back side of the weld and creates a shield that prevents oxygen and other atmospheric gases from entering the weld area. This helps to ensure that the weld is strong and free from defects.

The type and composition of backing gas used depend on the welding type and the welded materials.

Backing gas is an important consideration in welding, as it can greatly impact the quality and strength of the final weld.

Tack Welding

Tack welding is a form of spot welding where two metal pieces are joined using small, temporary beads of molten metal. 

Just like a tailor uses pins to hold two pieces of fabric in place before sewing, people use it to keep the parts ready for the final weld.

Tack welds offer the advantage of easy removal and reapplication if necessary, allowing for precise alignment due to their size and fragility.

The number of tacks required depends on the pipe diameter, with larger pipes potentially requiring up to eight tack welds. 

This technique holds the pipes securely without affecting their alignment due to shrinkage caused by root passes.

Welding

Pipe welding is a specialised practice that requires careful preparation and consideration of materials, electrodes and welding parameters. 

When welding starts, you must perform the initial passes, known as the “root pass,” followed by a “hot pass,” before proceeding to the filling and final cap passes.

Let us dive into passes in more detail.

Pipe Welding Passes

Pipe welding involves several sequential passes to create a perfect, strong weld.

The welding passes refer to the order of execution required when carrying out the pipe welding process.

The four passes typically used in pipe welding include the root pass, hot pass, fill-up pass and capping.

Root Passes

A root pass is the first step in any welding process and involves joining two pieces to form one structure. 

In this step, we heat the filler metal to an exceptionally high temperature and pass it through the gap between the pipes.

Utilising the root pass requires more expertise than the following passes, so it is essential to exercise caution.

To ensure complete fusion, the welder should use quality control measures like backing gas.

In order to complete the weld pass, you must keep the root face smooth and uniform. If there are any imperfections on the weld face, you can correct them by grinding it out, so it does not have to be smooth or uniform initially.

Hot Passes

When completing a butt weld, the hot pass is the second phase which involves using higher amperage to produce a hotter weld. This helps to eliminate any impurities left behind by the root pass, resulting in a flatter and more uniform weld. 

The hot pass is also known as the “welding pass” and is used to connect the root weld to both faces of a pipe. 

By heating and joining the area around the root weld with the pipe’s face, this process can quickly remove any trapped slag that traditional chipping and wire brush methods cannot. 

Additionally, welders can use a high current setting and faster-than-normal speeds during this process to reshape or modify the root weld.

Fill Passes

The filler passes are the intermediary steps in welding pipe joints. 

This involves making a series of weld passes and filling the groove with molten metal. 

The welder can make the filler passes using a series of stringer beads or a weave bead, depending on experiance.

Stringer beads require less metal to be molten at one time and are, therefore, simpler for beginner welders to perform. 

After completing the filler passes, the welder has properly welded the joint.

Cap Passes

The cap pass is the final stage of welding a pipe joint. 

It requires a thin weld with minimal build-up beyond the surface. To achieve optimal strength, the engineer must perform good beading and remove any contamination before completing the cap pass. You should also clean up the weld edges and use a file to remove any spatter.

Electrodes Used

For pipe welding, you can use either E6010 or E6013 electrodes for the full weld or to perform the root pass. Use E7018 electrodes to finish the joint.

Welding Positions For Pipe

Welding positions for pipe describes the technique used to join metal object in their existing positions or with specific components. 

All welding processes have different capabilities and can fall into one or more of the following weld positions: horizontal, flat, vertical, overhead, or even on the floor. 

Sometimes, you cannot achieve all welds successfully in a horizontal/flat position, and you may need to use other positional welding techniques. This is necessary to design and manufacture assemblies and adapters in the desired orientation, regardless of the shape and size of the workpiece.

Pipe Welding Positions

When welding pipes, it is important to consider the position of the pipe. The position can be determined based on whether the pipe needs to be stationary or rotating. It is also based on whether it is placed horizontally, vertically, or at an angle. These factors combine to determine the welding position of the pipe.

There are four pipe welding positions; PA Position, PC Position, PF and H-L045 (uphill)/J-L045 (downhill). 

Welders will learn each type of position, with PA being the easiest to master and H-L045/J-L045 the most difficult. 

To ensure safety while performing pipe welds, welders must be certified in each position before taking on different poses. Consequently, someone with a qualification in PA cannot weld PC, PF or H-L045/J-L045. Only those with H-L045/J-L045 certification are eligible to attempt any other pose.

These standards preserve the safety of the work environment when performing pipe welds.

Let’s take a look at each welding position.

PA Welding (1G)

PA Welding is a position where the workpiece remains stationary, and the welder rotates around it to create a weld. In this position, the welder performs a 360-degree rotation around the workpiece, evenly distributing the welding material and forming a strong and secure weld.

Welders often use this position to weld pipes, ensuring a complete and even weld by welding all around the circumference of the pipe. The PA welding position requires good technique and dexterity to control the electrode and maintain proper weld penetration and fusion.

PC Welding (2G)

When performing PC Welding, also known as 2G welding, the welder holds the components stationary while placing the pipe in an upright vertical position and allowing it to rotate along its Y-axis. The welder performs the welding horizontally on the side of the pipe, using heat and pressure to join two pieces of metal.

Welders commonly use this technique to join pipes by vertically placing the pipe and rotating around it while welding. In PC welding, the welder must maintain a consistent electrode angle and control the welding process to ensure proper heat input and penetration. Good agility, control and physical endurance are required from the welder to work in an overhead position for extended periods, are necessary for this welding position.

PF Welding (5G)

PF Welding is where the pipe is placed horizontally, and the welder moves around it vertically to create the weld. This method eliminates the need to rotate the pipe, which can be difficult or impossible in specific welding scenarios, and allows for more accurate welds with less effort.

Welding in the PF position requires good control and dexterity from the welder to maintain proper electrode angle and weld bead shape, as well as to prevent weld spatter and ensure proper weld penetration. The vertical movement of the welder in the PF position also requires physical endurance, as the welder must be able to work in a confined space for extended periods.

H-L045 Welding (6G)

H-L045 is a method used to weld pipes at a 45° angle. This welding position requires more expertise from the welder than 5G welding, as the welder must move around the pipe while maintaining a fixed position. Highly experienced welders usually perform the H-L045 welding position, which is considered the most complex of the four welding positions. The H-L045 position is uphill, whereas J-L045 is downhill.

Welding in the H-L045 position requires good control and dexterity from the welder and a high level of welding skill to maintain proper electrode angle and weld bead shape, prevent weld spatter, and ensure proper weld penetration. Additionally, due to the angle of the weld, the welder must prevent gravity from affecting the weld pool and maintain proper welding techniques to ensure a strong and secure weld.

Categories Of Piping

Low-pressure or light structural piping

Low-pressure piping is an economical option for the reliable distribution of non-critical materials in industrial settings. People typically use it for transporting water, non-combustible chemicals, and other non-hazardous materials. Because its contents are not hazardous or flammable, low-pressure pipes provide a safe and cost-effective solution for many applications.

Example – PVC or Thin-walled stainless

Medium-pressure piping

Many industrial and commercial applications utilise medium-pressure piping as an important component. Low-pressure steam heating systems transport corrosive or flammable chemicals and waste. Additionally, medium-pressure piping constructs highway signs, railings, light posts, trailer axles, equipment frames, and stands.

Example – Schedules 10 to 40 or EN10255(BS 1387) medium/heavy pipe

High-pressure piping

Various industries use high-pressure pipes to transport steam, radioactive materials, and other fluids in pipelines, fired or unfired boilers, and refinery reactor lines. Engineers design these systems to withstand extreme pressure and temperature levels to meet safety protocols.

Example – Schedule 80 to 160

How To Test Your Welds

Testing pipe welds are essential to any welding project to ensure quality and strength. 

Non-destructive testing (NDT) is the most commonly used method for weld evaluation. It evaluates weld integrity and size without damaging it.

Here is an overview of the NDT testing methods.

Visual Inspection of the Weld

Visual inspection is a non-destructive testing weld quality check process. The examiner visually checks the weld during the test to determine surface discontinuities.

An experienced welding inspector must conduct the process. Visual inspection of welded connections is the most common weld quality testing method. 

This type of inspection is the most underrated and often misused method of welding inspection because of its simplicity.

X-Ray Testing

NDT professionals frequently use radiographic and ultrasonic inspection to inspect welds by passing X-rays generated by an X-ray tube or gamma rays from a radioactive isotope through the weld.

As the radiation penetrates the solid object, it creates an image of its interior structure on a destructive testing film. 

The same basic principles apply in both medical radiography and X-ray weld inspection.

The Liquid Dye Penetration Test

The Liquid Dye Penetration Test is a non-destructive testing technique used to inspect finished products and components for surface-breaking defects such as cracks, porosity or lack of fusion. 

This method uses capillary forces to draw a liquid penetrant into surface discontinuities, making the flaws visible to the naked eye. 

This process can be used on welds and parent materials but not highly porous materials. 

The dye penetrant method helps determine flaws in manufactured parts, which are vital to ensuring their quality and performance.

Ultrasonic Testing

Ultrasonic Testing (UT) is a non-destructive testing technique that uses high-frequency sound waves to detect internal defects, measure thickness, and evaluate the material properties of various objects.

The ultrasonic transducer produces high-frequency sound waves that travel through the object being tested during testing. Any changes in the material, such as defects or interfaces between different materials, reflect back to the transducer when the sound waves encounter them. The transducer then converts the reflected waves into an electrical signal, which analysts use to determine the characteristics of the material being tested.

Various industries use UT for quality control and inspection of materials such as metals, plastics, composites, and ceramics, including aerospace, automotive, construction, and manufacturing. Some typical applications of UT include detecting cracks or flaws in welds, measuring the thickness of pipes or plates, and evaluating the bonding between layers of materials.

Magnetic Particle Testing

Magnetic Particle Testing (MPT) detects surface and subsurface defects in ferromagnetic materials like iron, steel, and nickel using a non-destructive testing technique.

To test the material, we magnetize it by applying a magnetic field. Next, we apply a liquid suspension of magnetic particles to the surface, and these particles are attracted to any areas of magnetic flux leakage caused by defects in the material, forming a visible indication on the surface. We can examine the indications to determine the size, shape, and location of the defects.

MPT is commonly used in the aerospace, automotive, and construction industries for quality control and inspection. It is handy for detecting surface-breaking cracks in welds, castings, and forgings, as well as fatigue cracks in gears and other components subject to cyclic loading.

The below two are examples of destructive testing.

Macro Etch Testing

Macro Etch Testing is a destructive method of material testing used to evaluate welded joints. 

This process requires a small sample from the weld joint, then polished and etched with a mild acid. 

The acid etching of this sample reveals the depth of penetration and any lack of fusion, root penetration issues, internal porosity, or cracking shown at the base material fusion line. 

Macro etch testing can also be used to identify welding problems such as crack initiation in failure analysis. 

Sampling inspection using this method provides an overview of the overall quality of production welds.

Fillet Weld Break Test

The Fillet Weld Break Test is a type of welding test used to determine if there are any discontinuities within a sampled weld. 

To perform this test, a sample fillet weld that has been welded on one side only is loaded with a press, and the force gradually increases until a break occurs. 

After the sample fails, it undergoes an inspection to identify and measure any present welding defects like lack of fusion, internal porosities and slag inclusions.

The Fillet Weld Break Test provides a more comprehensive understanding of the entire length of the specimen, unlike the macro etch test, which only speculates at cross-sections. Combining the two tests can yield more detailed results.

Common Welding Issues

Welding issues can be frustrating and costly. Poor welding techniques can cause many problems, including inconsistent welds, weak joins, contamination, and dissolved base materials. 

It is essential to ensure that the welding process is properly controlled to avoid these issues. 

Typical steps to help minimise weld defects include:

• Using the right tools.
• Pre-weld preparation.
• Maintaining consistency when welding and proper post-weld treatment. 

Here are some of the most common problems with welding and how to fix them.

Porosity

Porosity is a weld defect which occurs when nitrogen, oxygen and hydrogen are absorbed into the molten weld pool. The weld solidifies and releases this gas, which creates tiny cavities within the weld metal. 

Various factors can cause porosity, such as:

• Moisture or debris on the plate edges,
• Insufficient shielding gases or
• Welding on small gaps with air pockets. 

To prevent porosity in a weld joint, the welder should:

• Use fresh welding consumables,
• Check for gas nozzle leaks in the welding torch
• Ensure that the plate edges are clean and dry

Furthermore, it is important to double-check the shielding gas types and flow rates and keep an appropriate torch angle to the plate.

Lack Of Fusion

Lack of fusion in welding can result from either incomplete root penetration or incomplete root fusion. 

Incomplete root penetration occurs when the weld metal fails to reach both sides of the joint, while incomplete root fusion happens when the weld doesn’t join on one side. 

To fix these issues, employ a wider root gap and larger electrodes relative to the size of the gap width of the material being welded. 

In addition, use a slower travel speed and weaving technique between two plates, which should assist in getting the outcome you want.

Misalignment

HiLo, also known as misalignment, is the difference between two piping systems’ inner and/or outer heights. 

This mismatch can significantly negatively impact the integrity of a welded joint – it weakens it and makes it less able to withstand fatigue over time. 

Poor fit-up is usually the cause of HiLo; when the fittings being welded onto the pipe have different dimensional tolerances, HiLo occurs. 

Such an issue will create a flawed pipeline system that can cause corrosion and contamination due to bacterial colonies and blocked drainage. Misalignment usually happens more with larger pipes (6 inches or more in diameter) which can become warped during storage or transport, making them harder to fit correctly. 

Improving pipe fit-up is essential to reduce HiLo before welding.

Common Pipe Issues

Several common issues can affect pipes, which can cause disruptions in the flow of liquids or gases through them. Some of the most common pipe issues are:

Cracks

Cracks are a common issue with pipe welding. There are many reasons for cracks, including improper weld preparation, poor quality materials, and improper welding techniques. You should fix any cracks in your pipes as soon as possible to prevent them from worsening and causing leaks.

Leaks

Leaks occur when water escapes from the pipe due to damage or corrosion. Cracks, holes, or pinholes can cause leaks in the pipe. When repairing leaks, make sure to use high-quality materials and proper techniques.

Corrosion

Corrosion occurs when metals react with oxygen and moisture in the air. This causes rust to appear on metal surfaces. You can remove rust using a wire brush, sandpaper, or steel wool. It is advisable to apply a layer of paint to safeguard the surface after removing the rust.

Fretting

Fretting is a condition where the ends of two pieces of metal rub together, causing them to wear down. It can be prevented by keeping the pipes clean and dry.

Stress Fractures

Stress fractures are small breaks in the pipe wall that occur when the pipe is under extreme pressure. Either overloading or incorrect installation can cause cracks to occur in the pipe. Keep the pipe at a constant temperature to prevent stress fractures and avoid bending or twisting.

Pitting

Pitting is a type of corrosion that occurs when the inside of the pipe becomes pitted. It can occur due to excessive exposure to sunlight or chemicals in water. To prevent pitting, keep the pipe out of direct sunlight and ensure the water does not contain chlorine or other chemicals.

Dents

Dents are small indentations that occur on the outside of the pipe. Heavy objects or vehicles can cause dents through impact or collision. To prevent dents, drive slowly and avoid hitting the pipe.

Pipe Welding At Varlowe

Our highly experienced pipework fabricators have years of expertise in fabricating and prefabricating. They possess the necessary skills and credentials to provide top-quality services that meet the demands of today’s market. 

As a result of our excellent service, our customer base has grown, and we have established a stellar reputation over our 17 years of trading. Our accurate, reliable, efficient, and high-quality pipe services have made us the preferred choice for many in the industry.

We offer a wide range of pipe-related services, including welding and installation.

Call us on 01902 861042 or email info@varlowe.co.uk.

The steel industry is one of the world’s most important industries, producing about half of all manufactured goods worldwide.

The global steel demand is growing faster than any other material due to the increasing need for infrastructure development, especially in developing countries.

From cars to trains, bridges to buildings, and ships to machinery, it is a primary manufacturing method.

But what is Steel fabrication? Let us dive into this crucial manufacturing method.

Steel Fabrication, What Is It?

Steel fabrication makes products using various techniques for many industries, such as construction, automotive, aerospace, and manufacturing.

Fabrication differs from other manufacturing processes as it can create end products or develop parts for making end products. 

It involves taking raw materials, like steel, and assembling them to their required form using a variety of processes, such as:

• Cutting
• Grinding
• Punching
• Forming
• Shearing
• Stamping
• Welding
• Machining
• Jigging

Instead of simply assembling it, fabrication uses semi-finished or raw materials to create something from start to finish. 

However, The manufacturing approaches change depending on the material and the end product. 

The most common materials joined are: 

• Stainless Steel 
• Carbon Steel 
• Aluminium 
• Copper
• Brass

Assembling metal components includes many processes of metal manipulation, which depend on the required result, type of metal and shape.

The Advantages of Steel Fabrication  

Fabrication is a process that creates three-dimensional objects from two-dimensional plans. 

Fabrication has many advantages over other manufacturing processes, such as:

• It is cheaper and quicker than most other manufacturing processes. 
• The product quality is very high
• We can tailor it to the customer’s needs and quickly implement design changes.
• Manual, mechanical, or fully automated methods using CNC technologies can complete the task

Primary & Secondary Fabrication

It is important to distinguish between primary and secondary metal manufacturing methods. 

The term “primary” refers to the first stage of production, where the raw material turns into semi-finished metal products such as plates, sheets, tubes, and bars. 

This process involves melting the raw materials and pouring them into moulds. Large furnaces typically produce it using casting, forging, rolling, extrusion, wire drawing, and sintering methods.

Secondary manufacturing refers to the stage of production where semi-finished metal products are reshaped and assembled to make a final product. 

This process often occurs in a machine shop or fab shop.

Steel Fabrication Process

The fabrication journey will use one or more of the following processes:

Cutting

Cutting is a very common process in which the fabricator can manipulate the metal by cutting it into smaller sections. 

It can be the first or only step required to finish the fabrication.

There are multiple ways to cut metal, such as: 

• Oxy-Fuel Cutting – Oxy-fuel cutting involves heating the material to around 1000 degrees, which causes the metal to melt and turn into a liquid state. Then, oxygen is blown on top of the melted metal, which burns away the surface layer of the metal due to an exothermic reaction, leaving behind a clean cut. Oxy-fuel cutting uses various fuels such as acetylene, propane, propylene, or hydrogen.
• Laser Cutting – A laser cutter uses a powerful laser focused through a lens in the cutting head. It is narrowed down to an extremely thin, concentrated beam which can precisely cut thin or medium metals and even etch designs by heating the surface of the workpiece.
• Waterjet Cutting – Water jet cutting uses water channelled through a very narrow jewelled nozzle at a very high pressure to cut through the metal. Since they don’t generate heat, Water jet cutters are handy for cutting sheet metals with a low melting point.
• Plasma Arc Cutting – The plasma arc cutting process uses electricity to heat a small amount of oxygen and hydrogen gases to create a superheated plasma stream. This stream of ions is directed onto the surface of the material being cut, melting the metal and creating a clean edge.

Grinding

Metal grinding is an essential step in the manufacturing process of many products.

It is used to remove excess material from the surface of a metal part, smooth out any burrs or rough edges, and create the desired shape.

Manual metal grinding can be achieved simply by using a file. Most of the time, it is often performed with a grinding machine.

Handheld grinders typically are used for small jobs where access is limited.

Stationary grinders are usually mounted on a bench and are used for larger projects.

Industrial grinders are similar to stationary grinders except that they are much bigger. They can handle larger pieces and grind complex materials with the help of special tools.

There are several types of grinders available today, such as –

• Belt Grinder
• Bench Grinder
• Cylinder Grinder
• Surface Grinder
• Bit Grinder
• Jig Grinder

These grinders perform various functions depending on the type of product being manufactured.

Some grinders are designed for only one specific function, whereas Others can perform multiple functions.

In addition to removing excess material, grinding is used to create the desired look on a metal part.

Grinding is often labour-intensive, therefore, an expensive part of the fabrication process.

Steel Forming

The term ‘forming’ comes from the French word “forme”, which means ‘shape’. It is used to describe any operation that changes the shape of a material.

It can be done manually, mechanically, hydraulically, pneumatically, electrically, or chemically.

Forming itself includes various manufacturing technologies, such as:

Rolling

Rolling is the most widely used and most economical deformation process. It consists of passing metal between two spinning rollers, which compressive forces reduce the metal thickness. Rolled products include plate, sheet, strip, coils, billets, bars and rods. Many of these shapes will be the starting blocks for wire drawing, forging and machining.

Hot Rolling 

Hot rolling involves heating the metal above its recrystallisation temperatures and passing it between two rollers to flatten it. It is done to improve strength, ductility, formability and weldability.

Cold Rolling

The cold rolling process involves passing the metal between two rollers, causing the metal to become thinner and more rigid. It is usually done after the hot rolling stage when the metal is already very thin.

Forging

Forging is the steel-making process that involves heating scrap metal until it becomes liquid. While in a liquid state, carbon and other elements are added to make the metal more robust. To harden it, quenching (rapidly cooled) is applied to the molten metal. This process is repeated several times before the final product is ready.

Extrusion

 A compressive force moves metal from an enclosed cavity through a die. This process creates a product with a specific shape and size. It’s often used to make parts out of materials that aren’t strong enough to withstand the forces involved in traditional manufacturing methods. Some examples of metals that can be extruded include aluminium, brass, lead, tin, copper and steel. 

Extrusion can be performed hot or cold:

• Hot extrusion is done above the material’s recrystallisation temperature to keep the material from hardening and make pushing the material through the die easier.
• Cold extrusion – is performed at temperatures significantly below the melting temperature of the deformed alloy and generally at room temperature.

Drawing

Drawing is a manufacturing process that involves pulling a metal piece through a die using a tensile force applied to the exit side. This process is similar to metal extrusion, with the difference being in the application of pressure.

Stamping

Stamping is a manufacturing process used to make large quantities of identical items. It involves pressing a sheet of material between two dies. The first die is stationary, while the second is moved down onto the sheet. This causes the material to flow under pressure into the impression left by the second die.

Pressing

The pressing process involves heating the material until it becomes malleable enough to be formed. Then, the part is placed on a flat surface, and a die is pressed against it. This causes the metal to flow around the shape of the die, creating the desired part.

Punching

Metal punching is a cutting process in which material is removed from a metal sheet.

The first use of punches and dies dates back to ancient times when people used stone tools to create simple shapes out of metal.  

However, technology did not advance much until the Industrial Revolution.  

During the 19th century, punch presses were developed to make mass production possible.  

These early machines were powered by steam engines and could only operate on flat metal sheets.  

By the 20th century, punch presses had become automated and could be operated by electricity.  

Today, these machines are controlled by computers and can be programmed to produce intricate patterns and shapes.

The machine consists of a press head which holds a punch and dies. The punch is driven down on top of the die, which leaves uniquely designed holes in the metal. 

Shearing

Shearing is used for many purposes, including cutting sheet metal, trimming parts, and removing excess material.

It is achieved by combining two tools, one at the top and the other at the bottom, which causes the metal to separate when applying pressure.

Several tools and machines are available, one of the most common being a bench shear (Also known as a lever shear).

Bench shears are the most commonly used type of shear because they’re simple to operate and require little maintenance. They’re also portable and easy to store. However, they do need a solid surface to mount on.

Other types of shears include guillotine machines and hydraulic shears, typically used for heavy-duty applications where the weight of the equipment isn’t an issue.

These are larger and heavier than bench shears, making them harder to move around.

Hydraulic shears are typically used for heavy-duty applications where the weight of the equipment isn’t an issue.

Welding

Welding is a process where two or more metals are joined using heat and applying pressure using a torch.

There are several types of welding, each with its advantages and disadvantages.

The most commonly used method is stick welding, which uses a rod of filler material to fill the joint between the two pieces being welded.

Another type of welding is arc welding, where electricity passes through a wire to create a stream of molten metal.

The third type of welding is gas tungsten arc welding, which uses a mixture of gases to produce a plasma stream.

Other versatile applications used in industrial metal fabrication shops are spot and stud welding.

You can read more about welding in our articles “What Is Welding“, “Welding Types“, and “Welding Positions“.

Machining

The term “Machining” comes from the French word “Mache”, meaning “to cut”.

It refers to any process where a tool removes material from a surface.

Machining generally involves cutting, drilling, grinding, milling, polishing, sawing, shaping, threading, tapping, turning, and welding.

It is often done on a machine tool, a device that uses mechanical power to cut, grind, polish, or otherwise modify materials.

The most common machines include lathes, milling machines, drill presses, and saws.

Machining can be done manually, but Much of today’s machining is carried out by computers that control movement and operation. This is known as computer numerical control (CNC).

You can read more about CNC Machining in our article “CNC Machining Explained.”

Jigs And Fixtures

Jigs and fixtures allow manufacturers to fabricate identical parts quickly and efficiently accurately. 

They are often used in manufacturing industries where there is a need for high-volume production of similar items. 

Using jigs and fixtures provides a range of additional benefits to the manufacturing process, including:

• Increased production levels
• Provides interchangeability
• Requires less skilled labour
• Assures high accuracy
• Reduce production costs

Jigs

A Jig is a device that holds, supports and locates the workpiece, which guides the cutting tool for precise operation. 

In the early days of machining, a jig was simply a wooden block on which a part could be mounted. This allowed the operator to quickly locate and position the part for cutting. 

Later, metal jigs were developed to hold parts in place while being cut. These metal jigs were made of cast iron or wrought iron and were shaped like a T, U, V, or X.

A jig’s primary goal is to provide repeatability, accuracy, and interchangeability.

Fixture

A fixture is a workpiece holding device used to support and position a workpiece during manufacturing.   

They are usually made of metal or plastic and may include holes or slots to allow attachment points on the workpiece. A fixture is unique because each is built to hold a particular shape.

Some fixtures are designed to hold a single workpiece, while others can hold multiple pieces simultaneously.   

Fixtures often include a clamping mechanism to secure the workpiece, allowing the operator to perform operations without removing it from the fixture. For example, Fixtures are often used to hold parts while being cut, drilled or welded.

Common Materials Used in Steel Fabrication

In steel fabrication, the term “material” refers to the metal used.

The three main categories of metal fabrication materials include 1) structural metals, 2) speciality metals, and 3) composite materials.

Structural Metals: These are the primary metals used in manufacturing. They are strong, durable, and resistant to corrosion. Examples include steel, stainless steel, aluminium, copper, titanium, and brass.

Speciality Metals: These metals are not typically used in manufacturing because they don’t meet the strength requirements for specific applications. Examples include nickel, cobalt, chromium, molybdenum, tungsten, and tantalum.

Composite Materials: These are made of two or more materials bonded together. Examples include carbon fibre composites, glass fibre composites, and ceramic matrix composites.

Each metal has its benefits and drawbacks. Some metals are easier to cut than others. Others are harder to bend or weld. And some are better at resisting corrosion.

But the quality of any metal is entirely relative. There are factors to consider, such as the material’s cost, quality, and availability. How do you want your finished product to function, and what finish do you want to achieve

Choosing the Right Material for Your Project

To get started, here are some questions to ask yourself when selecting a metal fabrication material:

• Which metal will give me the best strength or weight ratio? 
• Will I need to use a lot of it? 
• Is it expensive?
• Is it easy to work with? 
• Does my fabrication shop offer it?   

Once you’ve answered those questions, you’ll have a clearer idea of what kind of metal you should choose.   

Here are some examples of common metals used in metal fabrication: 

Steel

Steel is an alloy that combines iron ore, limestone, coal, and other elements. It is the most utilised metal in fabrication and has many applications in manufacturing, transportation, construction, and defence. Steel is strong and durable, but it’s not very flexible. 

Stainless Steel

Stainless steel is an iron alloy that contains nickel, molybdenum, manganese, copper, chromium and carbon. It is highly durable, but it can be more expensive and challenging to manipulate than other materials. Stainless steel is resistant to rust and corrosion, which makes it an ideal material for use in various applications such as kitchen utensils, cutlery, medical equipment, food processing, and construction.

Carbon Steel

Carbon steel is the most used material for metal fabrication as it is easy to weld and cut. This type of steel has a higher carbon content, which gives it a lower melting point, yet it is harder than mild steel.

Copper

Copper is a soft, ductile, malleable, and hardenable metal, but it’s prone to oxidation. It is an excellent electrical conductor and is heat-resistant. It is used in many industries, especially electronics, because of its low cost and high conductivity.

Titanium 

Titanium is a chemical element named after the planet Titan. It’s the third most abundant metal on Earth, behind iron and oxygen. It’s also very rare, so it’s not found naturally on Earth. However, scientists have managed to create it artificially. They do this by bombarding titanium atoms with neutrons, which causes them to split apart. The resulting atoms are mixed and heated until they fuse again. This process creates a new titanium form, much stronger than the original.

Nickel

Nickel is a lustrous, silvery-white metal that exhibits high levels of corrosion resistance due to its ability to form a protective oxide layer on its surface. Despite its durability, nickel is a relatively soft metal and can be challenging to cut or shape.

Zinc

Zinc, a bluish-white metal, is widely known for being an inexpensive and easily weldable material. However, it is also characterized by its low strength and high susceptibility to corrosion, which makes it less durable and reliable than other metals.

Tungsten

Tungsten, also known as wolfram, is a steel-gray metal that boasts exceptional strength and resilience. It is highly resistant to corrosion, has the highest melting point of all metals, and is often used in applications that require extreme durability, such as in the production of filaments for incandescent light bulbs, electrical contacts, and rocket engine nozzles.

Iron

Iron is a versatile and essential metal that occurs naturally in the earth. It is a vital component of the planet’s crust, making up approximately 8% of its composition. In fact, iron is the fourth most abundant element in the earth’s crust, following oxygen, silicon, and aluminum. Its unique properties make it a crucial material in many industries, including construction, transportation, and manufacturing. Without this remarkable metal, our world would be a very different place.

Aluminium

Aluminium is a lightweight element that is versatile and durable but doesn’t hold up well to heat or chemicals. It also has excellent thermal conductivity, which is whyThe most common use of aluminium today is in beverage cans. About 90% of all aluminium produced goes into making cans. Other services include building materials, appliances, cars, and even aeroplanes.

Bronze

This remarkable copper alloy possesses exceptional strength, surpassing that of steel, despite its relatively lower melting point. Due to its remarkable properties, it is extensively used in the manufacturing of coins, armor, cookware, and weapons, providing superior durability and sturdiness.

Magnesium

Magnesium is a lightweight, soft, malleable, and ductile metallic element. Despite its brittle nature, it is widely used in various industries. Being abundant in nature, it is the third most abundant element on Earth after oxygen and silicon. Due to its high melting point, magnesium is a popular choice in the aerospace industry. It is also commonly used in various machinery like automobiles, trains, and boats.

Brass

Brass is an alloy of about 75% zinc and 25% copper. It is rugged and durable, but it tends to warp when heated. The two metals combine to make a hard, shiny metal that resists corrosion. Brass is used to cast musical instruments like trumpets, trombones, tubas, horns, and bells. It also makes pipes, valves, door knobs, and other mechanical parts.

As you can see, selecting a material can be a complex task. It involves choosing a suitable material for the job, knowing how to use it properly, and understanding how it will perform under real-world conditions.

Experienced engineers can help you select the best materials for your project as they know which materials are available, how to choose between them, and how to apply them correctly.

What Are The Basic Raw Materials In Steel Fabrication?

Here are a few basic raw materials that are necessary for many metal fabrication projects:

Flat Metal Raw Materials

Flat metal is a type of raw material used in manufacturing. It comes in many forms, including sheets, plates, coils, and strips. Sheet metal is often used for making architectural components. In contrast, flat plate metal makes car, truck, and plane parts.

This type of metal is pressed into flat pieces, and the thickness can vary. 

Depending on the thickness, they are divided into:

• Foil or leaf metal: the thinnest type of flat metal
• Sheet metal: thickness is less than 6mm
• Plate metal: thickness greater than 0.25in

Sectional Metals

Sectional metals are steel and are used in engineering and construction projects. 

Some of the types include:

• I-beam: It is a cross-sectional beam that looks like the shape of the letter “I.” 
• Z-shape: A metal beam in the form of the letter “Z.”
• Hollow structural section (HSS): Hollow piping that is available in square, circular, rectangular and elliptical shapes
• Rod: Rod is metal that is circular or square
• Bar: A flat piece of rectangular cross-sectioned metal

Welding-Wire

The term’ welding wire’ refers to any type o used in welding. 

These include tungsten inert gas (TIG) welding wire, used when welding steel; MIG welding wire, commonly used for aluminium; and flux core welding wire, typically used for stainless steel. 

It may refer to a single, or multiple strands of wire twisted together. 

The welding wire generally comprises copper, aluminium, steel, stainless steel, brass, nickel, titanium, tungsten, molybdenum, graphite, silver, gold, platinum, and palladium. 

Hand Tools Used In Steel Fabrication

Metalworking requires several types of tools and equipment. Let’s go over the most commonly used:

Bandsaw

A bandsaw is a powered saw that consists of a motorised spindle which drives a circular saw blade. The blade is mounted on a wheeled carriage which slides along a track. The blade is usually hardened steel and may be straight or curved.

Hacksaw

The hacksaw is a handheld cutting tool with a sharp-toothed blade to cut through metals. The hack saw features a C-shaped frame attached to a pistol-grip handle. In the early 1900s, wood was the primary material of choice. Today, hacksaws use high-quality materials like stainless steel, carbon steel, aluminium, titanium, and brass.

Hammer

The most common types of hammers are the claw hammer, the ball-peen hammer, the sledgehammer, and the mallet. Claw hammers are generally steel and have a curved claw on the end of the handle. Ball-peen hammers have a flat face and a rounded head. They are usually made of cast iron or steel. Sledgehammers are typically wood-made and have a long handle and a large head. Mallets are often made of wood and have tapered ends.

Bench Shears

Bench shears are hand tools with two blades attached to a handle. They are used to cut sheet metal, wood, plastic, leather, cardboard, and more. Bench shears are often used when cutting out parts from larger pieces of material. The main drawback is that they cannot achieve delicate cuts.

Power Shears

Power shears are used to cut sheet metal. The blades are made of hardened steel and are attached to a motor which rotates them. This rotation causes the blades to move back and forth across the sheet metal. The cutting action is achieved when the blade’s edge contacts the metal.

Tin Snips

Tin snips are versatile and handy tools that are specifically designed for cutting sheet metal with precision. They are compact, handheld devices that feature two parallel blades hinged together and held in place by a sturdy handle. The blades are composed of high-quality carbon steel, which ensures that they are durable and long-lasting. With their sharp and precise cutting action, tin snips are the perfect tool for any job that requires cutting sheet metal.

Chisels

A chisel is a versatile tool that can be used for a variety of tasks such as trimming, shaping, or carving metal. It consists of a blade with a sharpened edge that is typically made of high-carbon steel or tungsten carbide. The blade is attached to a handle that can be made of wood, plastic, or metal. To use a chisel, it is often struck with a hammer or mallet to create precise cuts and shapes. The force of the hammer can be adjusted to control the depth and intensity of the cut. Chisels are commonly used by metalworkers, woodworkers, sculptors, and other craftsmen who require precise and intricate cuts.

Grinders

Grinders are power tools that utilize circular-shaped discs to effectively reduce the size of various materials, including metal, wood, and concrete. However, they are not limited to just grinding and can also be utilized for polishing and smoothing metal surfaces to a smooth, shiny finish. This makes them an essential tool for metalworkers and DIY enthusiasts alike.

Wire Cutters

Wire cutters are tools used to cut wire. They consist of two parts: a pair of handles connected by a pivot point and a jaw which holds the wire when closed. The jaw opens up to allow the wire to pass through.

FAQ’s

What is meant by steel fabrication

Steel fabrication is the process of cutting, shaping, and assembling steel materials to create various products and structures. It involves cutting, shaping, welding, machining, assembly, and surface treatment to produce custom steel components for different industries and applications.

What is steel fabrication used for?

Steel fabrication is used for various applications, including construction, manufacturing, infrastructure, transportation, etc. It is employed to create structural components, machinery, architectural elements, industrial equipment, and consumer products, among other things. Steel’s strength and versatility make it an essential material for various industries and projects.

What type of steel is used in the fabrication

The type of steel used in fabrication can vary depending on the specific application and requirements of the project. Some common types of steel used in fabrication include:

• Carbon
• Stainless
• Alloy Steel
• Tool Steel
• Mild Steel
• High-Strength Low-Alloy Steel (HSLA)

What are the three three types of metal fabrication?

Metal fabrication encompasses various processes for shaping and assembling metal materials. While there are numerous specific techniques and methods, the three primary types of metal fabrication are:

• Cutting
• Forming
• Joining

Steel Fabrication At Varlowe Industrial Services

Varlowe Industrial Services Limited specialises in bespoke stainless steel fabrication.

We can provide a complete fabrication service working to coded specifications. We have the expertise to work with all grades of steel, ferrous and non-ferrous.

Varlowe has the resources to manage your project at every process stage. Please visit our Steel Fabrication page for more information.

You can also call us on 01902 861042 to discuss your project with a staff member.