It’s understandable to be confused about the approach to use when cutting sheet metal for the first time. You have a range of machine options, and cutting sheet metal permanently alters its size or geometry. Correcting a mistake after a wrong cut can be lengthy and costly.
Stay calm! With the right strategy in terms of steps, machinery, and expertise, it is possible to get clean-cut sheet metal in the right size, promptly. Professionals who have worked with all types of materials and sizes know exactly what it takes to cut sheet metal.
Read on for an overview of how this exercise is done successfully.
What Is Sheet Metal Cutting?
First, what is sheet metal cutting all about? Sheet metal cutting is the precise removal or separation of a specific part from the stock. It entails the application of high forces or sharp cutting edges to the stock along the intended separation line.
Note that thickness is the main difference between sheet metal and plate metal. The surface area to volume ratio for sheet metal is higher, with thickness being up to 6 mm. Plates are larger than this. So, the focus is on removing specific parts from this kind of material.
Main Methods Of Cutting Sheet Metal
The art of cutting sheet metal entails different approaches, each designed for a particular situation or requirements. Considering the time these options emerged, the cutting methods can be categorized as conventional and modern.
Conventional Sheet Metal Cutting Techniques
The use of mechanical force and manual effort has been used in sheet metal cutting for centuries. Some of the approaches used by artisans and metalworkers in the pre-industrial era evolved and can be seen in some relatively conventional options like chiselling, nibbling, and bandsaw cutting.
What is shearing in sheet metal?
Metal shearing entails placing the material between two opposing blades, which slice it to make a clean cut devoid of any material wastage. Sheet metal shearing is versatile, cost-effective, and retains the material’s structure.
Hacksaw Cutting
A hacksaw can cut through sheet metal and produce a clean cut, and it does so on any metal you can think of. It is also inexpensive, with blade replacement being the only recurrent cost to worry about. The biggest challenge with this method is the amount of manual effort required to get the job done.
Chiseling
This is another inexpensive way to cut sheet metal. The user only needs a hammer and a chisel to cut metal sheets for small projects. A lot of patience is required for this one, because it is also labor-intensive.
Bandsaw Cutting
This power tool features a continuous blade that rotates between two wheels. It can make curved or straight cuts on sheet metal and is available in different sizes. Although it is relatively slow, the bandsaw can make clean cuts in different sheet metal sizes.
Nibbler
You can also cut sheet metal with a nibbler, a tool based on the punch-and-die mechanism. The tool makes short punches or strokes as it moves across the sheet metal, with each stroke making a notch.
A nibbler can be manual or CNC, making it one of the more versatile means to cut sheet metal.
Modern Sheet Metal Cutting Techniques
Most modern manufacturing processes require a blend of speed, precision, and repeatability, and that’s where the following CNC sheet metal cutting technologies come in. Options such as CNC punching, EDM, and plasma cutting are compliant with the demanding nature of today’s industries.
CNC Punching
CNC punching entails using a machine controlled by a computer program to produce shapes in sheet metal. This method does more than just cut; it can also generate accurate louvres, countersinks, and other profiles on sheet metal.
Electrical Discharge Machining (EDM)
The EDM uses an electric spark to erode (cut) a metal sheet. The wire EDM version, which uses a wire strand, is perfect for this process. This technology is regarded for its reliability in cutting complex geometries.
CNC Laser Cutting
CNC laser cutting is one of the most reliable sheet metal fabrication techniques in the industrial setup because it is fast, accurate, and powerful. It comprises a CNC-controlled laser beam that melts or vaporizes sheet metal. This technique creates perfect cuts in different metals, including brass, aluminum, and steel.
Oxy-fuel Cutting (Oxy-acetylene)
For oxy-fuel cutting, an oxyacetylene flame comes out of a cutting torch, which harbors a chemical combustion reaction between oxygen and iron elements.
Oxy-fuel cutting uses a flame from an oxyacetylene torch to oxidize and melt the metal, typically steel, through a combustion reaction with oxygen. The flame oxidizes and blows away the sheet metal surface, creating a cut.
CNC Plasma Cutting
Plasma cutting works by accelerating a hot plasma jet in a computer-controlled manner through a nozzle to cut sheet metal. It is a highly versatile, fast-processing, and precise method popular in the aerospace and automotive industries.
Waterjet Cutting
Waterjet cutting applies a combination of abrasives and water, plus high speed and pressure, to cut sheet metal. It is versatile and cuts relatively thicker sheets.
Guide On How To Cut Sheet Metal
Many variables apply when choosing an effective strategy to cut sheet metal. Some techniques are ideal for fast-cutting or budget-friendly applications, while others suit accuracy over speed and cost.
This brings several variables to consider, including the cutting machine type, material properties, the production volume, and the thickness of the material. So, what should you do?
- Consider The Sheet Metal Properties
Sheet metal properties such as ductility, thickness, reflectivity, hardness, and thermal conductivity can influence the choice of cutting method. Some metals, for instance, have high thermal conductivity and can easily get distorted with the wrong cutting approach.
- Determine The Cut Precision And Quality
The precision requirements of the sheet metal part are also significant when choosing a cutting technology. In aerospace, medical, and other high-stakes industries, tolerances must be very tight, ranging from ±0.025 to ±0.127 mm, and repeatability must be high.
EDM and laser cutting are the leading technologies in these areas.
- Define The Volume And Timeline
The volume required and the project timeline are other important angles to check when choosing a suitable sheet metal cutting technique. If you are looking for high speed and repeatability, consider options like laser cutting and CNC punching.
The conventional methods are mostly for low-volume work where customization is more preferable to high throughput.
Traditional sheet cutting methods often support low-to-medium volume work, especially for customized or simpler shapes. For higher throughput, laser cutting, CNC punching, and other modern solutions are more preferable.
- Check The Tool’s Availability And Affordability?
Finally, there will be the question of the investment cost and whether the technology is readily available. Techniques like plasma cutting and laser cutting are excellent, but they need relatively significant investments.
The budget may be available, but the local service provider or workshop lacks the technology. Eventually, the choice comes down to what sheet metal service is affordable and available, and meets the cut quality requirements.
Conclusion
The sheet metal cutting trade has come a long way, from the era of manual cutting to now, when evolutionary solutions such as CNC cutting have taken over. Whether you are fabricating a large machine or assembling a home artifact, carefully determining how to cut sheet metal can make the difference.
