Metal fabrication is the building of metal structures by cutting, bending, and assembling processes.
--- from wikipedia
Proper design and use of tools with machinery creates a repeatable form which can be used to create products for many industries, including jewelry, aerospace, automotive, construction, civil and architectural.
Main article: Machining
Machining is the process of removing unwanted material from the block of metal to get the desired shape. Machining is a trade in and of itself, although fab shops generally entail a limited machining capability including metal lathes, mills, and drills, along with other portable metal working tools.
Most components such as gears, bolts, screws, and nuts are manufactured by a machining process.
Main article: Welding
Welding is the main focus of steel fabrication. The formed and machined parts will be assembled and tack welded into place then re-checked for accuracy. A fixturemay be used to locate parts for welding if multiple weldments have been ordered.
The welder then completes welding as per the engineering drawings if welding is detailed, or as per his/her own judgement if no welding details are provided.
Special precautions may be needed to prevent warping of the weldment due to heat. These may include re-designing the weldment to use less weld, welding in a staggered fashion, using a stout fixture, covering the weldment in sand during cooling, and straightening operations after welding.
Straightening of warped steel weldments is done with an oxy-acetylene torch and is somewhat of an art. Heat is selectively applied to the steel in a slow, linear sweep. The steel will have a net contraction, upon cooling, in the direction of the sweep. A highly skilled welder can remove significant warpage using this technique.
Steel weldments are occasionally annealed in a low-temperature oven to relieve residual stresses. Such weldments, particularly those employed for engine blocks, may be line-bored after heat treatment.
After the weldment has cooled it is generally sand blasted, primed and painted. Any additional manufacturing specified by the customer is then completed. The finished product is then inspected and shipped.