In subtractive manufacturing 3D objects are made by consecutively cutting material away from a fixed material body until a desired form is achieved. Unwanted materials are removed by cutting, drilling, or milling. Subtractive processes are inherently more wasteful than additive processes.
It is possible to create objects with tighter tolerances and better finishes using subtractive manufacturing. When it comes to precision for common functional features such as flat surfaces, drilled and tapped holes, counter sinks, and counter parts, subtractive processes generally achieve results with maximum repeatability and dimensional accuracy. Subtractive fabrication can also apply to 2D objects cut from flat stock.