Chemical or phase changes relating to precision machining

Precision machining is a process in which the dimensions or properties of a workpiece are changed with a processing machine. According to the temperature state of the workpiece to be processed, it is divided into cold processing and hot processing. Generally processed at room temperature, and does not cause chemical or phase changes in the workpiece, called cold processing. Generally, processing at a state higher than or lower than normal temperature will cause chemical or phase changes in the workpiece, called hot processing.

Cold processing can be divided into cutting processing and pressure processing according to the difference in processing methods. Common hot work is heat treatment, forging, casting and welding. It generally refers to the processing of more than IT5 precision requirements, and it is difficult to meet the requirements with ordinary processes and equipment. It is generally necessary to use precision machine tools, well-designed processes, special tools and measuring instruments to complete the processing in a suitable environment.

Fine machining, broadly speaking, refers to the processing of small sizes or small operating sizes. The general outline size is less than 3 mm, and the processing technology with little or no cutting is a fine processing. It is widely used in aerospace, precision instruments, biomedicine and so on. In addition to mechanical processing, fine processing mostly uses electrical processing, chemical processing, wave processing, plasma, laser, particle, lithography and other technological means.

Rapid prototyping technology was developed in the 20th century to quickly produce samples or parts according to CAD models. It is a material accumulation processing manufacturing method, that is, through the orderly accumulation of materials to complete three-dimensional forming. Rapid prototyping technology integrates CNC technology, material technology, laser technology and CAD technology and other modern scientific and technological achievements, is an important part of modern advanced machining technology.