Introduction
Sheet metal parts are used in a wide variety of products that are used in our society today. From the cars we drive and the phones we hold to the girders of the buildings we inhabit and the enclosures of the appliances we use, sheet metal is the foundation of countless products.
The first and perhaps the most important step in the fabrication of these components is cutting of sheet metal. It is therefore important for engineers, designers and procurement specialists to have a good understanding of the various methods of cutting of sheet metal as this is a crucial aspect in the realization of ideas.
This paper aims at providing a detailed discussion on what sheet metal cutting entails, the tools used, the techniques applied, the parameters used, the uses of sheet metal cutting and how one can select the most appropriate method.
What is Sheet Metal Cutting?
Sheet metal is often considered to be any metal that is thinner than 6 mm (or 0.25 inches) thick. Its widespread application stems from its formability, strength-to-weight ratio, ease of recycling, and versatility. Sheet metal cutting constitutes several processes of manufacturing which involve either separating a piece of sheet metal into two or more parts or taking away some material so as to obtain a particular shape or size.
The choice of a certain sheet metal cutting method revolves around numerous considerations such as the metal cutting thickness, the edge quality and precision required, the level of cut complexity, production quantity, and other related costs.
Common Tools and Equipment for Sheet Metal Cutting
The tools and equipment used for cutting sheet metal depend on the thickness of the metal material, accuracy, quantity, and the type of edge finish needed. These can be broadly classified into hand tools, power tools and industrial instruments.
Hand tools
Hand tools are used for small and less complex operations or for finishing work on the material. These include:
Hand Shears: These are similar to scissors but are used in cutting sheet metals. They are of different types including straight cut, left cut and right cut depending on the direction of the cut and the use.
Nibblers: These tools employ a reciprocating punch to cut out small portions of the metal to enable shaping of intricate shapes and curves.
Files and Deburring Tools: These are used to eliminate sharp edges or burrs that are left behind after the cutting process to avoid any harm and to enhance the appearance of the part.
Power tools
Power tools are more efficient and are best suited for moderate to large scale production and for thicker materials.
Power Shears: These are the electric or pneumatic operated hand shears which are more powerful and faster than the hand shears.
Electric Metal Shears: These are portable power tools that are used to cut straight or curved shapes on the metal sheets.
Angle grinders with cutting discs: These are used in cutting thicker sheets of metal especially when rough cutting or when portability is a factor.
Rotary cutters: These are cutters with circular blades that are suitable for cutting straight or curved shapes in sheet metal.
Industrial equipment
Industrial equipment represents the most advanced and efficient methods for sheet metal cutting, designed for high-precision and high-volume production. These include:
Hydraulic Shears: These are large and fixed machines used to straight cut across the width of the metal sheets. They apply hydraulic force to apply a lot of pressure and this makes it easy to cut through thick materials with precision.
Punch Presses: These are machines that employ the use of punch and dies to make holes or particular shapes on the sheet metal. They are very useful for repetitive operations and are widely applied in mass production lines. Some of the punching operations include piercing, blanking, and notching.
Laser Cutting Machines: These are advanced systems that employ a laser beam to cut through the material by either melting, burning or vaporizing it along a certain path. They provide high precision, fine cutting of shapes, and little deformation of the material. Different types of lasers are used depending on the need:
- Fiber lasers: usually more appropriate for cutting thinner metals due to their higher cutting rates and lower costs of operation.
- CO2 lasers: employed on thicker materials or some non-metal materials, generally lower in the initial capital cost.
Plasma cutter: Plasma cutting is a process that involves the use of high-speed jet of plasma to melt and cut through the material. It is ideal for cutting electrically conductive metals such as steel, aluminum, and stainless steel and is most suitable for thicker materials.
Waterjet cutting machines: These are machines that cut material by focusing a high pressure water jet which may be mixed with an abrasive substance. Waterjet cutting is a versatile process that can cut any material and does not produce heat hence suitable for heat sensitive materials.
Bending machines: Though used for shaping metal sheets into the required shapes, bending machines are used in conjunction with cutting machines in the fabrication of sheet metal. These machines use different techniques to bend the cut blanks into the desired three-dimensional shapes of the parts.
Laser Tube Cutting Machines: These are machines that are specifically used in cutting tubes and pipes with a high level of accuracy and speed. These systems are useful in developing intricate designs and contours on cylindrical or other non-flat metal materials that are employed in structural or framework construction.
Key Sheet Metal Cutting Techniques Explored
It is important to choose the right cutting method in order to achieve the best results in terms of accuracy, time, and quality of the edge. There are several key approaches widely used in the industry.
| Feature | Laser Cutting | Plasma Cutting | Waterjet Cutting | Shearing | Punching/Blanking | Nibbling |
| Accuracy | ±0.02mm to ±0.1mm | ±0.2mm to ±0.5mm | ±0.05mm to ±0.1mm | ±0.2mm to ±0.5mm | ±0.1mm to ±0.3mm | ±0.3mm to ±0.8mm |
| Cutting Speed (Rel.) | Fast (Thin Material) | Fast (Thick Material) | Medium (Potentially Slower) | Very Fast (Straight Line) | Very Fast (Repetitive) | Medium |
| Suitable Materials | Wide (Various Metals) | Conductive Metals | Almost All Materials | Limited (Sheet Metal) | Limited (Thin sheet metal) | Limited (Sheet Metal) |
| Thickness Range | 0.1mm to 25mm (Fiber) | 3mm to 50mm+ | 0.1mm to 150mm+ | 0.5mm to 6mm+ | 0.5mm to 3mm | 0.5mm to 6mm+ |
| Setup/Operating Cost | $$$/$$ | $$/$$ | $$$$/$$$ | $/$ | $$$/$ | $/$ |
| Edge Quality (Rel.) | High, Smooth | Good, May Have Dross | Excellent, Clean | Relatively Clean, May Have Burrs | Good, May Have Slight Deformation | Serrated, May Require Secondary Processing |
| Heat Affected Zone | Minimal | Larger | None | None | None | None |
Laser Cutting
The process of laser cutting involves the application of a strong laser beam onto a material that needs to be cut. The energy concentrated in the laser beam either melts or burns, or converts the material to vapor, thus creating a cut with specific boundaries. The merits of laser cutting include precise measurements, the capability of dissecting intricate shapes, low kerf width (laser cutting removes lesser materials as compared to other cutting tools), and small deformation of the shape. It is commonly utilized for cutting a range of metals which include steel, stainless steel and aluminum in sectors from automotive to electronics.
Plasma Cutting
Another thermal cutting process is plasma cutting that involves the use of a high velocity stream of hot plasma to cut through electrically conductive material. The plasma is made by compressing a gas like air, nitrogen or argon and then accelerating it through a nozzle and then applying an electrical charge to it, this results in producing superheated ionized gas capable of melting metal.
Plasma cutting is used to cut through thick materials such as steel, stainless steel and aluminum at a relatively faster rate and is cheaper than laser cutting for some applications. It is not as accurate as laser cutting but is a very useful technique especially for cutting through thick conductive metals such as steel, stainless steel, and aluminum, commonly used in fabrication shops, construction, and salvage.
Waterjet Cutting
Waterjet cutting is an abrasive cutting technique that involves the use of a high-pressure water jet that may be mixed with abrasive garnet particles. This method is special in the sense that it is a cold cutting process and therefore there is no heat affected zone which makes it ideal for use in materials that are sensitive to heat.
Waterjet cutting can cut any material that is solid, and this makes it very flexible since it can cut metals, plastics, composites, stone and glass. Although it is relatively slower than laser or plasma cutting for some applications, it is a useful technique in many fields due to its flexibility and ability to produce sharp edges with minimal thermal effects.
Shearing
Shearing is a cutting operation in which two blades are used, one is stationary and the other is in motion, and the sheet metal is cut along a straight line. This method is mainly applied in making straight cuts in sheet metal and is ideal for mass production.
There are various kinds of shears such as the guillotine shears for straight cuts and rotary shears for curved cuts. Shearing is one of the most efficient and inexpensive processes of cutting sheet metal blanks for further operations.
Punching/Blanking
Punching and blanking are operations that involve the use of a punch and a die to cut through the material. In punching, the punch pushes a piece of material out of the sheet to make a hole or shape and this removed piece is scrap. In blanking, the material which is cut out is the required component while the rest of the sheet is waste. These processes are relatively very fast in producing standard shapes and holes particularly in mass production. Turret punch presses and other punching machines are versatile in that they can perform several operations at one time.
Although punching is effective for mass production of similar shapes, it entails the use of tools such as punches and dies which are expensive and time-consuming to prepare. There is also the possibility of very small edge deformation and the process is generally restricted to thin materials.
Nibbling
Nibbling is a process of cutting contours and complex shapes in sheet metal by using a series of overlapping punches. A small reciprocating punch is used to cut small portions of material along the required line of cutting in the metal object. Nibbling is ideal for small-scale production or prototyping since it does not require a die for each shape and size, making it effective for various gauge specifications. It is slower than other methods and the edge formed is scalloped and may need further refinement.
Key Parameters in Sheet Metal Cutting
To achieve the desired dimensions of the sheet metal, there is a need to consider and regulate all parameters peculiar to the selected process.
Material Thickness
The thickness of the sheet metal is one of the most important factors that define the choice of the cutting method and the choice of the process parameters. The various cutting techniques have different capacities in as much as the maximum thickness that can be cut.
Power Output (for Laser/Plasma Cutting)
The intensity of the laser beam or plasma arc determines the capability and the rate at which the material can be cut. Higher power levels can enable cutting through thicker materials or increase the speed of cutting through the material.
Kerf Width
Kerf width is the thickness of the material that is cut by the cutting tool. This parameter is crucial for the accuracy of the dimensions, especially when cutting out complex shapes or joining parts. Kerf is the width of the cut made by the laser and depends on the cutting method and parameters and must be taken into account in the design of the parts to achieve the final dimensions.
Cutting Tolerances
Tolerances are the allowable limits of the dimensions of the cut part. When it is necessary to have a very small gap between the two parts, it is necessary to use more accurate cutting tools and to control the process parameters more closely.
Cutting Force (for Shearing/Punching)
In the case of mechanical cutting processes such as shearing and punching, the force exerted by the machine is crucial in achieving the desired fracturing or piercing of the material. The cutting force is determined by the type of material, the thickness of the material and the geometry of the cut.
Nozzle Type and Condition
In plasma and laser cutting, the condition and design of the nozzle through which the plasma jet or laser beam is directed is very important in order to maintain focus and get a clean cut. Damaged or worn nozzles can also affect the quality of the cut that is made on the material.
Surface Finish
Another important factor is the required surface finish of the cut edge. Some of the cuts are smooth while others are rough, and other operations may be needed to refine the edge further.
Factors Beyond the Cut: Materials & Design
Beyond the immediate cutting process, the selection of the material being cut and the design of the part significantly impact the outcome.
Common Material Used for Sheet Metal Cutting
The choice of material is fundamental in sheet metal fabrication and significantly influences the selection of cutting techniques and process parameters. Here are some of the most common materials used:
Steel (Carbon Steel): One of the most widely used materials due to its strong, weldability, cost-effective. Easy to cut with most methods. Used in automotive body panels, structural parts, and machinery housings and general fabrication.
Stainless Steel: Corrosion-resistant, durable, aesthetic appeal, hygienic. It is applied in medical equipment, food processing and construction industries. Stainless steel is somewhat more difficult to cut than carbon steel because it is prone to work hardening and thus requires proper selection of cutting conditions.
Aluminum: Lightweight, high strength-to-weight ratio, good thermal/electrical conductivity. It is widely applied in aerospace industry, automotive industry, electronics industry, packaging industry and construction industry. It has a high thermal conductivity that can be useful in the removal of heat during cutting but has the disadvantage of being reflective to lasers. It is important to note that the machinability of aluminum depends on the type of alloy used.
Copper: Excellent electrical/thermal conductivity. Very reflective, may need to be cut with specialized lasers or water jets. It is applied in electrical parts, heat exchangers, pipes, and as an ornamental material.
Brass: Good machinability, corrosion-resistant, attractive appearance. Reflective, similar laser cutting considerations as copper. It is applied in decorative hardware and plumbing fittings.
Design for Manufacturability (DFM) Principles
It is important to design parts with manufacturing in mind in order to enhance the efficiency and cost-effectiveness of sheet metal cutting.
Kerf Compensation: Designers have to consider the width of the material that is cut off so as to arrive at the final dimensions of the product.
Corner Radii: Some techniques such as punching may not be possible to make sharp internal corners. Specifying minimum radii is crucial.
Feature Spacing: There should be enough space between the cuts and features and from the edge of the material to avoid distortion of the structure.
Nesting: It is the process of arranging the parts in such a way that they can be placed on the metal sheet in a way that will help in cutting them in the most efficient way possible so that wastage of the metal is avoided.
CAD File Best Practices: It is recommended to submit files in DXF or DWG format that are free of gaps in the contour and have the correct scale. It is also necessary to exclude such features as title blocks and dimensions from the cutting geometry.
Applications: Where Cutting Shapes Industries
Sheet metal cutting is an essential process in a wide range of industries, which is used to produce a large number of products and parts.
Automotive
In the automotive industry, sheet metal cutting is applied in the production of car body panels, chassis, clamps, and interior trims. This sector requires high accuracy and high production rates.
Aerospace
The aerospace industry uses sheet metal cutting in the fabrication of fuselage, wings, engines, and interior parts of the aircraft. This is because material requirements are high and tolerances are needed very small.
Construction & Architecture
Sheet metal cutting is a very important process in construction and architecture industries for fabrication of roofs, cladding, ventilation systems, structures and ornaments.
Electronics & Appliances
In the manufacturing of electronic devices and household appliances, sheet metal cutting is crucial in the production of computer chassis and enclosures, as well as the internal parts of appliances.
Energy (Renewable & Traditional)
The energy sector employs sheet metal cutting for manufacturing parts of solar panels, windmills, power generation, and oil and gas industries.
Medical Devices
Medical devices such as surgical tools, equipment enclosures, and implantable parts require precise cutting of sheet metal due to the high standards of accuracy and material compatibility in the healthcare industry.
Heavy Equipment & Agriculture
Construction, agricultural, and mining industries require the fabrication of heavy machines, and in the process of fabrication, sheet metal cutting is used to create structural parts, enclosures, and functional parts.
3D Printing
Although it may seem that sheet metal cutting is unrelated to 3D printing, the two can actually be used together. For example, metal sheets can be cut into the desired shapes for use as build platforms or as parts that are incorporated with 3D printed parts.
Why Choose TZR for Your Sheet Metal Cutting Needs?
Choose TZR as your premier sheet metal manufacturing partner for unparalleled precision and quality cutting services. TZR is a leading sheet metal fabrication company serving diverse industries like automotive, medical devices, 3D printing, and renewable energy. Backed by a seasoned DfM team with 30 years of experience, we offer comprehensive solutions from expert design assistance to full-scale production.
Our mastery of various cutting techniques, including laser cutting, laser tube cutting, plasma cutting, shearing, and CNC punching, ensures we can handle any metal cutting service project requirement. With extensive experience in processing steel, stainless steel, aluminum, copper, and brass, our skilled engineers optimize every cut.
Equipped with advanced machinery like our 20,000W laser cutter and adhering to ISO 9000 standards with a 98% qualification rate, we guarantee exceptional results. Partner with TZR and experience the difference that precision, expertise, and a commitment to your satisfaction can make. You can contact us today to upload your specifications for a consultation or to request a quote.
Conclusion
Sheet metal cutting is a fundamental and versatile manufacturing process with a wide range of techniques and applications. Understanding the different cutting methods, their respective tools and equipment, critical process parameters, common materials, and the influence of design is essential for achieving optimal results. And, when selecting a fabrication partner, it is crucial to consider their technical capabilities, material expertise, quality standards, and experience.
Whether utilizing hand tools for small tasks or relying on advanced industrial equipment for high-volume production, the principles of precision and efficiency are paramount. By carefully selecting the appropriate cutting technique and adhering to safety best practices, manufacturers and fabricators can effectively shape metal sheets into the components that drive innovation and progress across numerous sectors.
FAQS
Q: What safety precautions should I take when cutting metal?
A: When cutting metal, wear safety glasses, gloves, and ear protection. Ensure proper ventilation, use machines with safety guards, and follow operating instructions. Secure the metal piece and handle it carefully to avoid sharp edges. Keep the work area clean and watch for pinch points.
Q: Does sheet metal cutting affect the material’s physical properties?
A: Sheet metal cutting, especially with methods like laser cutting and plasma cutting, generates heat that can impact the material’s physical properties, such as hardness, tensile strength, and corrosion resistance. The heat-affected zone (HAZ) around the cut area may undergo changes. However, these effects can be minimized with proper cutting techniques and post-processing methods.
Q: Can I place small quantity orders for sheet metal cutting?
A: Yes, we accept small quantity orders. Whether you need prototypes, sample runs, or small batches, we can accommodate your requirements. Our cutting services are flexible, and we ensure high-quality results even for limited runs.
