Metalworking is everywhere throughout modern industry, refined over thousands of years from early wax and sand casting to automated forming, rolling, pressing and cutting to create all sorts of parts and goods. The sheer variety in metalworking processes owes to the numerous alloys used today, each best processed in particular ways. Manufacturers must choose a process based on what they’re making, the scale of operation and the economic trade-offs involved.
Casting
Casting yields a specific, desired form by pouring molten metal into a mold, then allowing it to cool and solidify. Traditional casting uses expendable molds made from wax, sand or plaster, which are broken open after cooling. To better suit large-scale production, modified methods involve reusable molds and sometimes, such as with alloy die casting, forces other than gravity to feed molten material in. Casting is ideal for precise, complex shapes such as machine components.
Forging
Earlier methods of shaping metal with mechanical force involved heated metal hammered on an anvil. The principle remains the same, but manual labor is replaced with heavy machinery. The techniques diversified in modern industry as well. Metal can be hammered into a mold, compressed under continuous pressure, or rolled into sheets, rods or wires—all with or without heat. Often, forging not only seeks to shape metal but alter its grain structure and produce new mechanical properties.
Cutting and Machining
In many cases, further work is needed after initial casting, forging or rolling. Cutting, broadly, refers to methods of removing excess material to create a specific shape. Advanced machine labor enables drilling, grinding, sawing or abrading to remove material by mechanical force. Some cutting methods instead use heat or chemicals to burn, melt, corrode or etch a product. Most notably, modern cutting frequently uses computer numerical control (CNC) to guide the process in place of manual operation. This enables cutting pieces to match specifications accurately and consistently.
