Sheet Metal Forming

Laser cutting uses a laser to cut the sheet metal part. A high-power laser is directed onto the sheet and intensified with a lens or mirror to a concentrated spot. In the specific application of sheet metal forming, the focal length of the laser varies between 1.5 to 3 inches (38 to 76 millimeters), and the laser spot size measures around 0.001 inches (0.025 mm) in diameter. Laser cutting is more precise and energy-efficient than some other cutting processes, but cannot cut through all kinds of sheet metal nor the very highest gauges. (a.) Part accuracies of better than 0.002 inches (0.05 mm). (b.) Kerf widths of 0.006 inches (0.15 mm) to 0.015 inches (0.38 mm). (c.) Material versatility.

Air-assisted cutting is a laser cutting technique that uses compressed air as the assist gas instead of more expensive gases like nitrogen or oxygen. It is widely used for cutting thin sheet metals such as carbon steel, stainless steel, and aluminum. This method reduces operating costs while maintaining good edge quality and cutting speed for suitable applications.

When the sheet metal needs to be punctured with holes, a designated punching machine is generally more efficient than the above cutting methods. Punching involves sandwiching the sheet between a punch and a die; when the punch moves into the die, it forces a hole in the sheet. The process can also be used to form irregular shapes, by making several small punches in series. Most sheet metals can be punched, but the diameter of a round hole should generally be larger than the thickness of the chosen metal.

Sheet metal bending is used to create V-shape, U-shape and channel shape bends using a machine called a brake. Most brakes can bend sheet metal to an angle of up to 120 degrees, but the maximum bending force is dependent on factors such as metal thickness and tensile strength. In general, sheet metal must initially be over-bent, because it will partially spring back towards its original position.

Stamping is another deformation process used to form sheet metal into a desired shape. The process uses a stamping die — either mechanic or hydraulic — to press the sheet metal into its new form. Stamping is used on cold sheet metal, but the friction caused by the die causes the metal to heat up to high temperatures. Individual stamping processes include, but are not limited to. (a.) Coining, in which a pattern is pressed onto the sheet metal part. (b.) Curling, in which the sheet metal is deformed into a tubular shape. (c.) Hemming, in which sheet metal is folded on itself for extra thickness. (d.) Ironing, in which the sheet metal part is reduced in thickness.

Sheet metal spinning is a deformation process — conceptually similar to pottery spinning — that is used to create hollow parts with rounded features. The spinning process involves manually or mechanically rotating a sheet metal blank on a lathe and pressing it against a tool, which creates the interior shape of the part. Spinning can be used to create shapes like hemispheres, cones and cylinders.

A product may be designed so that several sheet metal parts can be fitted together with joints, screws or other common methods. This usually comes after the parts have undergone any required finishing processes.

Sheet metal parts sometimes need to be joined together using the process of welding, which fuses components together with heat. Sheet metal materials like aluminium and stainless steel have high weldability.