Metal fabrication involves design, cutting, bending, and assembling of sheet metals for use in various industries including HVAC (heating, ventilation, air conditioning), appliances, and medical.
The design phase will involve prototyping. Before going into production with a large run, a sample prototype of the finished product is produced for evaluation first.
In many cases, the finished product may need to be produced to very high tolerances. That means that if the specification calls for dimension to be 40 +/- 0.1 millimeter, then the finished dimension must not deviate from true by more than 0.1 millimeter in either direction. For obvious reasons, higher or tighter tolerances are more difficult and hence more costly.
Sheet metal fabrication shops take raw material that may be aluminum, steel, copper, or brass and cut them to specification. The most common cutting method is shearing, also known as die cutting. Specialized saws such as band saws and chop saws are also used. In modern shops, you will find computer numerical control (CNC) torch cutting tables known as burn tables. These torches are traditionally powered by natural gas. But now plasma, lasers, and even water jet cutters are being used. These advanced cutters are actually robots with cutting heads that can move in three dimensions around the sheet metal. The robots movements are pre-programmed into the computer using computer-aided design (CAD) and computer-aided manufacturing (CAM) software.
After cutting, the design may call for punching, rolling, and bending. The sheet metal is bent into exact angles using hydraulic press brakes which can also be robotic. Sometimes machining may be needed. This involves using smaller metal lathes, mills, and drills for more intricate pieces.
A large part of metal fabrication involves welding and assembly. Welding methods include manual metal arc welding, to traditional tungsten inert gas (TIG) welding, to advanced technologies such as 3-D laser welding. Laser welding has the benefit of being able to produce consistent welds at faster speeds and with a more attractive finished appearance.
Depending on the specification of the customer, the assembled product may be sandblasted, primed, and/or painted. The fabricated product is then inspected and shipped.