Cutting is usually the first phase in the sheet metal fabrication process. You can cut different shapes or structures from rectangular metal sheets to meet design requirements. The main cutting techniques involved two categories: cutting without shear and with shear.
There are several processes that enable adequate cutting through sheet metal material without shear force. These techniques involve extreme heat, high pressure, vaporization, and abrasive blasting to shape the sheet metal fabrication parts. They include the following:
Sheet metal laser cutting involves using focused laser beams to melt metals in localized areas. Laser cutters are compatible with a long list of metals, ranging from non-ferrous metals to mild steel and stainless steel.
This technique consists of two concurrently running sub-processes. The first one involves concentrating a high-powered laser beam on the sheet metal. The material absorbs the laser beam’s thermal energy, making it vaporize.
At the same time, the second process involves a cutting nozzle providing blowing gas for laser cutting. This gas is usually oxygen or nitrogen. It helps to prevent the processing head from splashes and vapors during sheet metal fabricating engineering.
Plasma cutting is a thermal cutting process involving metal with ionized gas called plasma. The method uses substantial heat to cut the metal, which creates large burrs and an oxidized zone close to the cut area. In addition, it allows faster cutting, high precision, and repeatability in sheet metal manufacturing.
The plasma cutting tool works effectively only on electrically conductive sheet metals. Consequently, it is one of the most suitable methods for cutting conductive materials with medium aluminum thickness.
This cutting process involves using a high-pressure stream of water to cut metal sheets. Waterjet cutting is versatile and can cut various hard and soft materials using pressurized water and abrasive. It is ideal for cutting soft materials, metal foils, fabrics, or rubber. At the same time, it is suitable for cutting hard materials like copper, carbon steel, aluminum, and carbon steel.
The pressure involved is usually about 60,000 psi, with a 610m/s supply of velocity to cut through different types of metal sheets. However, waterjet cutting is a better substitute for the laser cutting technique.
The processes under this category cut metal materials using shearing force to overcome the metal’s ultimate shear strength. They usually involve using dies, punches, and shear presses to enable adequate cutting of the metal. The techniques here include the following:
Shearing is suitable for high-scale applications and cutting soft materials that don’t need clean finishes, like brass, aluminum, and mild steel. It cuts straight lines on sheet metals with a flat surface. The shearing method involves applying a shear force on the surface, causing the flat metal material to split at the cutting point.
This is often the ideal process for making straight edges on a metal sheet with rough edges. It is cost-effective for high-volume operations when manufacturing thousands of sheet metal fabrication parts within a short lead time. However, shearing may not be perfect for applications that need quality finishes due to the burrs and material deformations it causes.
Punching uses shear force to make holes in the sheet metal. In this sheet metal fabrication process, the scrap material is the material removed from the hole, while the final component is the remaining material on the die.
Punching is suitable for making cutouts and holes of different shapes and sizes. However, using the punching process can take much time. You have to match the dies and punching knives correctly.
Blanking is an ideal process for economic sheet metal fabrication. It involves removing a portion of sheet metal from a larger piece of the stock material using a blanking punch and die. The punch makes a “blanking force” through the sheet metal while the die holds it during the process.
The extracted material is the preferred component, while the remaining material on the die is the leftover black stock. This process is suitable for making economic custom parts due to its high repeatability, dimension control, and excellent accuracy.
Sawing cuts metal materials using a sawtooth tool to create a series of tiny cuts in the metal. A sawtooth uses shear force and friction to tear apart a small part of the metal material. Band saws have various fine and marginally bent teeth suitable for cutting brass, aluminum, and other non-ferrous sheet metal.
Horizontal band saws help to cut longer bar stocks to desired sizes. On the other hand, vertical band saws help to achieve complex cuttings that need accurate contours in the metal parts.
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