Essentially, metal extrusion is the process through which a piece, a long brass slab or rod, for instance, is forced into a shaping die with a similar albeit smaller cross-section, thus forming a new product or a larger piece out of the work. This is useful when creating various cross-sectional pieces for different applications like plumbing, roofing, or construction.
The great thing about metal extrusion is that it is capable of reshaping or reforming a solid metal object more than any other industrial forming processes. It is also commonly referred to as a semi-continuous manufacturing operation because it continues manufacturing the exact same dimension of cross-section as long as the work billet (the original metal) is fed to it.
Hot versus Cold
Extrusion processes can be classified into two. Hot extrusion uses extremely hot temperatures (typically 50 to 70 percent of the metal’s boiling point) and can produce materials for automotive parts, construction supplies, and aircraft parts. Cold extrusion, on the other hand uses, room temperature and can be used for applications like aluminum cans, gear blanks, and the like.
Direct versus Indirect
Direct extrusion is the process whereby a ram uses force to push the work billet into a forming die until it comes out the other end reshaped. The indirect process, meanwhile, uses a chamber that is completely closed off on one side, and instead of the ram pushing it, the billet moves to the opposite direction.