Quasi dry machining is a new machining method, which uses micro lubrication to replace the traditional lubrication cooling method. At present, it has been applied in some enterprises. Under the condition of quasi dry cutting, the cutting process is different from the traditional wet cutting, for example, the feed speed, cutting depth and cutting speed are different from the traditional cutting, which is mainly shown in that the cutting tool edge is generally protected by negative chamfer; The cutting principle involves a wider range of factors. At present, the theoretical basis of quasi dry cutting is far less mature than traditional metal cutting theory, and it is difficult to analyze the machining mechanism of quasi dry cutting with a theory.

Gear hobbing has some particularity to its cutting movement, but the theory of quasi dry cutting and cutting mechanism have something in common. Its cutting theory includes green cutting theory, metal softening theory during cutting, low temperature brittleness and improvement of cutting cooling. The specific contents are as follows: (1) Theoretical analysis of cutting force when the cutting tool edge is worn and not worn; (2) The cause of serrated chip; (3) Metal softening effect; (4) Roughness quality of machined surface; (5) MQL cooling lubrication effect. Centering on these theories and specific contents, we can guide us to better apply quasi dry machining to gear hobbing, so as to achieve good machining effect, longer service life of cutting tools, and a clean machining environment.

In order to achieve good machining effect, the general idea of quasi dry cutting for gear hobbing is to improve the cutting speed, shorten the contact time between the cutting tool and the workpiece to be machined, and let the chips take away a lot of cutting heat; It is supplemented by cold air at low temperature and micro lubrication technology. This idea is mainly based on the fact that most of the cutting energy will be converted into heat energy. It is expected that the heat will be quickly taken away by the chip, and the heat transferred to the cutting tool and workpiece will be minimized. In this way, the service life of the cutting tool is extended and the thermal expansion of the workpiece is reduced. During high-speed gear hobbing, even under ideal conditions, a small amount of cutting heat is absorbed by the cutting tool. For current applications, the cutting heat of the cutting tool is significantly dissipated after being cooled by compressed air. If it is coupled with low-temperature cold air, better processing results will be achieved.