Precision machining is a process that alters the shape, size, or properties of workpieces using machining equipment. Depending on the temperature state of the workpiece being processed, it is divided into cold processing and hot processing. Generally, cold processing is done at room temperature and does not cause chemical or phase changes in the workpiece. Hot processing, usually conducted at temperatures above or below room temperature, can cause chemical or phase changes in the workpiece. Cold processing can be further categorized into cutting processing and pressure processing. Hot processing commonly includes heat treatment, forging, casting, and welding.