Precision die forging refers to the die forging process with complex shape and high precision on die forging equipment. Such as precision die forging bevel gear. The tooth shaped part can be forged directly without cutting. The dimensional accuracy of die forging can reach IT12~ITL5, and the surface roughness Ra is 3.2~1.6 μ m。   Precision die forging has high requirements for blanks, requiring small quality tolerance of blanks, small section collapse angle, flat end face, and being perpendicular to the axis of blanks. The blank surface shall be free of pits, cracks, pits, large scratches or bruises; In addition, before forging, the surface must be cleaned (polishing, polishing, pickling, etc.), and the oil stain, slag inclusion, bruise, depression, etc. on the surface must be removed. Sawing and turning blanking are mainly used for aluminum alloy precision die forging, and sawing blanking is more commonly used. During precision die forging, crankshaft forging press, precision forging machine or other different equipment can be used for combined die forging. Repeated die forging for many times. Generally, the precision forging is 2-3 times after the ordinary die forging, up to ± 0.2~± 0.3mm, and the surface roughness is lower than Ra6.3. In order to achieve higher dimensions, the cold fine pressing on the fine press can reach ± 0.1mm, and the surface roughness is lower than Ra0.80. Inspection and cleaning must be carried out between several processes of forging production. The next precision die forging process can only be carried out after polishing or polishing blank surface defects. Precision die forging is a new non cutting process developed on the basis of common dies. It directly forges or leaves only a few grinding scenes to meet the accuracy requirements of some parts that need to be cut and machined in the past. Therefore, adopting the precision die forging process requires more strict technical requirements for the relevant links of die forging, such as controlling blank blanking quality and surface quality; Reasonably design the prefabricated blank; Less blank, no oxidation heating; Heating specification and cooling specification control; Mold manufacturing and use accuracy control; Select proper lubrication and cooling conditions. Precision die forging has the obvious advantages of saving metal and reducing cutting time, but due to strengthening the relevant links of die forging, part of the cost will increase. Therefore, according to the comprehensive economic indicators of finished parts and the special requirements of parts structure and performance, it is comprehensively considered whether the precision die forging process is selected for specific products.