Precision and special processing is an interdisciplinary advanced technology, requiring not only consideration of the processing method itself but also factors such as the material of the workpiece being processed, processing equipment and tools, inspection methods, working environment, and the skill level of the personnel. The integration of precision and special processing technology with systems theory, methodology, computer technology, information technology, sensor technology, and digital control technology has led to the formation of precision and special processing systems engineering.

Precision processing includes micro-processing, finishing processing, and precision finishing, etc., which is closely related to special processing.

Special processing refers to non-traditional machining methods (NTM, Non-Traditional Machining) that utilize energy sources such as machines, light, electricity, sound, heat, chemistry, magnetism, and atomic energy for processing. Their distinguishing features from traditional cutting processes include:

① Primarily not reliant on mechanical energy, but rather utilizing other forms of energy (such as electrical, thermal, light, sound, and chemical energy) to remove material from workpieces.

② The hardness of the cutting tool can be lower than the hardness of the workpiece material, and in some cases, such as during laser, electron beam, and ion beam processing, no tools are needed at all.

③ During the processing, there is no significant mechanical cutting force between the tools and workpieces. The workpieces are not subjected to mechanical forces, making them particularly suitable for precision processing of low stiffness components.

Due to these characteristics, special processing technology can handle metals, non-metals, or composite materials of any hardness, strength, toughness, or brittleness. It is particularly suitable for processing complex, fine-surface, and low-stiffness parts. Moreover, some methods are also applicable to ultra-precision, mirror, and polishing processing, as well as nanoscale (atomic-level) processing.

Special processing techniques can not only employ individual processing methods but also utilize composite processing techniques.

Precision and special processing technologies have brought about many changes in the field of mechanical manufacturing:

⑴ Enhanced the workability of materials. The workability of the workpiece material is no longer directly related to its hardness, strength, toughness, brittleness, etc. Materials like diamond, hard alloy, quenched steel, quartz, glass, ceramics, etc., are difficult to process. Now, various methods such as electrical discharge, electrolysis, and laser are used for processing and manufacturing tools, dies, wire drawing dies, etc.; processing quenched steel with electrical discharge or wire cutting is easier than unquenched steel.

⑵ Altered the typical process route for parts. In traditional processing, all other machining processes, such as shaping, except for grinding, must be scheduled before the quenching heat treatment process, which is an unbreakable process principle. With the emergence of precision and special processing technologies, to avoid deformation after processing and subsequent quenching heat treatment, it is generally done by quenching first and then processing. For example, processes like electrical discharge wire cutting and electrochemical machining must be quenched first before further processing.

The emergence of precision and special processing has also affected the "dispersion" and "concentration" of previous processes. Due to the lack of significant mechanical forces in the precision and special processing, even for larger and complex processing surfaces, they are often produced with a complex tool and a simple motion path, through a single installation and a single process, resulting in a more concentrated process.

③ Significantly reduces the new product prototyping cycle. By utilizing precision and special processing techniques during the prototyping phase, it is possible to directly machine various special and complex secondary surface body parts. This eliminates the need for designing and manufacturing corresponding tools, fixtures, gauges, molds, and secondary tools, thereby greatly shortening the new product prototyping cycle.

The structural design of product components is greatly influenced. For instance, in the case of Yama-type silicon steel sheet punches, which used to commonly employ mosaic structures, now with the adoption of electrospark and wire-cutting machining technologies, even molds or cutting tools made of hard alloy can be produced in a monolithic structure.

The assessment criteria for the traditional structural workmanship have been significantly impacted. Previously, it was commonly believed that square holes, small holes, bent holes, and narrow slots were indicative of poor workmanship, and were something designers and engineers greatly "avoided," with some even being considered "forbidden zones" in mechanical structures. For electrical discharge drilling and wire electrical discharge cutting, the difficulty in processing square holes is the same as that of round holes. With the advent of electrical discharge and wire cutting, now, to avoid defects such as cracking and deformation due to quenching treatment, it is specifically arranged to drill holes and cut slots after the quenching process.