The first stage in most machining operations is cutting, regardless of the shape of the workpiece, rod, bar, or sheet. Cutting refers to splitting the workpiece or converting it into the required geometry. There are two common types of cutting processes, shear, and non-shear cutting.
In our previous article “Fundamentals of Sheet Metal Cutting Processes”, we delved into shear-cutting techniques such as sawing, punching, broaching, blanking, and slitting, which involve applying shear force beyond the material’s maximum shear strength to cut a designated position.
In this article, however, our focus will be on non-shear-cutting approaches. Specifically, we will be discussing the capabilities of three major non-shear cutting techniques: laser, water jet, and plasma cutting. Non-shear cutting is becoming increasingly important in the manufacturing industry due to its ability to cut complex shapes, work with a wide range of materials, and produce high-quality results. With that said, let’s explore the benefits and applications of laser, water jet, and plasma cutting.
CNC Laser Cutting Capabilities
CNC laser cutting
The CNC laser cutting technique uses an intense laser beam to cut the workpiece into the desired shape. It is one of the precise manufacturing processes which applies to a wide range of materials. It is best suitable for brittle materials with low conductivity, such as carbon steel & mild steel.
The laser emits the photon in the form of a concentrated beam that hits the cutting position, melts the workpiece, and creates a strong joint.
- Thickness capability
Machining projects require cutting sheets and other workpieces having different thicknesses. The laser cutting approach can cut the workpiece from 0.5 to 12 mm. The thickness range depends on the capability of the laser machine and the type of material.
Increasing the power of laser cutters improves the capability of cutting the thickest workpiece. However, a thickness above 12 mm is not recommended. It lowers the quality of the result.
|Laser Capacity ( W)
|Maximum Thickness (mm)
- Manufacturing flexibility
Laser cutting offers more freedom for designers because of the capability of complex cutting with a range of material options.
- Cutting speed
Laser cutting is quicker than other traditional and blade-based cutting approaches, which can be up to 2 meters (70″) per minute, depending upon complexity, desire tolerance, and type of material.
- Precision capability
Laser cutting provides high accuracy even with the intricate & smallest possible cuts because of contactless cutting. Fiber laser can maintain a tolerance of ± 0.001″, while CO2 laser maintains ±0.002″.It can be your best option if your project demands sharp and clear edges.
- Material option
Laser cutting is compatible with several materials, such as stainless steel, copper, titanium, aluminum, brass, carbon steel, wood, acrylic, and more. However, it is unsuitable for some common manufacturing materials, such as PVC, ABS, and fiberglass.
- Wet Cutting Capability
While cutting the tubes, the laser can reach the internal wall and cause thermal damage. However, it can be eliminated using a water flow (low, dia. < 0.1″) inside the tubing.
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Water-jet Cutting Capabilities
Waterjet uses a high-pressure water jet to cut the material. For the harder materials, the water jet might contain abrasive particles, such as silicon carbide, aluminum oxide, sand, and granite. When the Water jet strikes the cutting position with high pressure (210–620 MPa), it speeds up erosion all the way to the cutting edge.
There are two types of water jet cutting; pure water & Abrasive water jet cutting. Pure water jet applies to softer materials such as fabrics, plastics, and metal foils. At the same time, abrasive is useful in cutting stainless steel, carbon steel, copper, and other metallic workpieces.
Using a water jet to shape the workpiece is a very effective approach for various applications, especially where damage in thermal properties impairs the functionality of parts.
- Thickness capability
Using highly abrasive materials like Silicon Carbide, you can cut up to 30 cm thick (Hard materials) & up to 100 cm (Soft materials like foam). Therefore, water jet cutting is the best method for cutting thick sheets.
The capacity to cut thicker workpieces is enhanced when the hard material particle mix in water. Additionally, water jet pressure also impacts this.
|Up to 18 cm, the ideal scenario is 10 mm
|0.5 to 17cm
The general tolerance offered by water jet cutting is ± 0.05 mm. The precision of cutting depends upon the Thickness of the workpiece, and accuracy slightly drops with the increase of Thickness. However, it does not exceed 2.5 mm in any case.
- Material option
Water jet cutting is applicable for almost every material (Except Diamond). It can cut all types of metals, alloys, composites, plastics, and many more. Soft materials can be cut with a pure water jet, and a water jet with an abrasive particle is suitable for hard materials.
- The capability of property retention
Cutting the metal with heat affects the surrounding of the cutting position (Heat affected zone). Thermally damaged sections lose strength and other mechanical properties. Since water-jet cutting uses intense pressure instead of intense heat, there won’t be any heat-affecting zone & will retain all the properties of the workpiece.
- Cutting Speed
Water jet cutting has a low-cutting speed than laser cutting. However quicker than other traditional and blade-based cutting approaches, which can be up to 50 cm ( 30″) per minute, depending upon complexity, hardness of abrasive particles, desired tolerance, and hardness of workpiece.
Plasma Cutting Capabilities
Normally plasma refers to the highest thermal state of matter; it comes after solid, liquid, and gas. You get the plasma after intense heating of the gas. Plasma cutting use argon, nitrogen, compressed air, and other gases to convert it into plasma by heating an electric arc. The temperature of plasma can reach up to 25000o C.
The concentrated beam of plasma creates an effective and precise cutting mechanism. At the time, plasma strikes the material surface and melts down the cutting position, where high pressure of gas removes the molten material as the plasma beam travel along the thickness end.
CNC plasma cutting has various capabilities in aspect precision to repeatability. It produces the best result while working with electrically conductive materials. The capability of working in the water is one of the biggest advantages.
- Thickness capability
Generally, plasma can cut the workpiece up to 50mm thick, but the sophisticated, automated plasma cutter offers more than 100 mm. However, it also depends on the material type. For example, aluminum is not recommended to go above 40mm. Other factors that affect the capability of cutting thick sheets include the temperature of plasma, the concentration of the beam, rated output, etc.
The general tolerance for Plasma arc cutting is ± 0.3 to 2.54mm. The cutting-edge equipment (such as Hypertherm cutting technology) can maintain as low as ±0.015. In addition, the material, Thickness, and cutting machine technology also impact the tolerances.
- Cutting Speed
The cutting speed ranges from 350 to 800 mm/min. However, the speed can be affected by the operator’s skill, the rated output of the machine, Thickness, and hardness of the workpiece.
- Material Option
Plasma cutting is ideal for cutting electrical conductive materials like copper, steel, and brass. However, other materials like stainless steel & aluminum are also fairly compatible because of the low melting points that cause the reflection of the torch. It is recommended to avoid plasma cutting with poorly conductive materials such as manganese, lead, tungsten, and tin.
- Underwater cutting capabilities
Plasma-cutting technology is ideal for underwater operation. The limit of cutting Thickness depends on the type of material and rated power. For example, Aluminum, Stainless steel, and carbon steel can be cut underwater up to 2 inches thick.
Non-shear cutting techniques allow for the creation of more intricate shapes. There are several capabilities of non-shear cutting techniques. A laser beam can cut with high speed & accuracy, plasma offers underwater cutting abilities, and the water jet can cut very hard &thick materials. Each non-shear cutting technique also shows some unique capabilities. Laser cutting offers design flexibility, there will be zero damage to thermal properties with a water jet, and plasma can produce the best result for material with high melting points.
Different non-shear cutting technique capabilities allow the freedom to cut any material with precision. Although, machine automation, operator skill, and engineering experience affect the quality of the end result.
Prolean is dedicated to providing customers with better one-stop machining services. Our sheet metal fabrication services cover three mainstream non-shear cutting techniques – laser cutting, plasma cutting, and water jet cutting – to manufacture parts with more complex shapes. This allows us to meet the requirements for different thicknesses, part complexities, and other complex machining processes. Our experienced engineers are always available to answer your questions and provide a typical quotation time of within one hour. You can trust our quality and on-time delivery capabilities, as we have years of experience in the industry and a solid reputation. Submit a quote request through our website form or directly via email to learn more about how Prolean can meet your precision manufacturing needs.
What does it mean by the non-shear cutting principle?
Cutting or converting raw workpieces into shapes without applying shear force (or using a blade mechanism) is known as the non-shear cutting principle. It uses intense heat, pressure, or abrasive media.
Which non-shear technique is capable of producing tight tolerances?
The laser cutting techniques produce tight tolerances than other non-shear techniques. It easily maintains a tolerance of ± 0.002″ with all compatible material sheets. In addition, it also offers high cutting speed.
What are the advantages of using non-shear cutting techniques?
It can be used with practically any material, cut workpieces of a high thickness, and provide precision, and tight tolerances, among many other unique advantages. A laser beam offers high cutting high speed & accuracy, laser cutting has underwater cutting abilities, and a water jet can cut very tough & thick materials.
What are the applications of the non-shear-cutting approach?
Non-shear cutting approaches are suitable for automotive, construction, hardware, electronics, piping, aerospace, thermal, and other applications.