Metal Forming Processes: sheet-metal forming, information and definitions

Compared to casting and forging, sheet-metal parts offer the advantages of light weight and versatile shape.

Sheet metal forming is a grouping of many complemetary processes that are used to form sheet metal parts. One or more of these processes is used to take a flat sheet of ductile metal, and mechanically apply deformation forces that alter the shape of the material. Before deciding on the process(es), one should determine whether a particular sheet metal can be formed into the desired shape without failure.

DETAILS:

Process	Characteristics
Roll forming	long parts with constant complex cross-sections; good surface finish; high production rates; high tooling costs.
Stretch forming	large parts with shallow contours; suitable for low-quantity production; high labor costs; tooling and equipment costs.
Drawing	shallow or deep parts with relatively simple shapes; high production rates; high tooling and equipment costs.
Stamping	includes a variety of operations, such as punching, embossing, bending, flanging, and coining; simple or complex shapes formed at high production rates; tooling and equipment costs can be high, but labor cost is low.
Rubber forming	drawing and embossing of simple or complex shapes; sheet surface protected by rubber membranes; flexibility of operation; low tooling costs.
Spinning	small or large axisymmetric parts; good surface finish; low tooling costs, but labor costs can be high unless operations are automated.
Superplastic forming	complex shapes, fine detail and close tolerances; forming times are long, hence production rates are low; parts not suitable for high-temperature use.
Peen forming	shallow contours on large sheets; flexibility of operation; equipment costs can be high; process is also used for straightening parts.
Explosive forming	very large sheets with relatively complex shapes, although usually axisymmetric; low tooling costs, but high labor cost; suitable for low-quantity production; long cycle times.
Magnetic-pulse forming	shallow forming, bulging, and embossing operations on relatively low-strength sheets; most suitable for tubular shapes; high production rates; requires special tooling.