Machining without material retention
Machining processes without material retention are those that remove parts of the material and create swarf (metal chips) as waste. Swarf looks like the curls that appear when scraping a knife over butter.
Drilling simply entails creating a round hole in the metal using a drill.
Turning means turning a piece of metal against a cutting tool, scraping off a layer of the material.
Milling is the process of machining using rotary cutters to remove material by advancing a cutter into a work piece.
Grinding is done to post-process a near-finished product, for example to smooth out the surface, using a grinding wheel.
A part of the material is cut through using a teethed sawing blade.
Cutting (spark, wire, laser)
Another alternative to remove pieces of metal is cutting. Metal can be cut through several different means, such as a high-powered laser.