Grinding is the key process of precision mould processing. In finishing grinding, grinding deformation and grinding cracks should be strictly controlled, and even micro-cracks on the workpiece surface should be controlled. The following aspects should be considered when formulating precision grinding technology. 

(1) Selective grinding wheel for precision die: According to the characteristics of high tungsten, high vanadium, high molybdenum, high alloy and high hardness of die material, PA chrome steel-jade grinding wheel and GC green silicon carbide grinding wheel can be selected; when processing hard alloy and high hardness material, diamond grinding wheel with organic binder and organic binder grinding wheel can self-grind. It has good advantage, the precision of the workpiece is above IT5, and the roughness can reach Ra=0.16 micron. CBN cubic boron nitride grinding wheel is used in CNC forming grinder, coordinate grinder, CNC internal and external grinder for finishing, the effect is better than other kinds of grinding wheel. In grinding process, the grinding wheel should be dressed in time to keep its sharpness. When the grinding wheel is passivated, it will scratch, scratch and extrude the workpiece surface, resulting in burns, micro-cracks or grooves on the workpiece surface, which will affect the processing accuracy. 

(2) Selection of feed quantity of precision die: the feed quantity of precision grinding should be small, the cooling should be sufficient in grinding, the coolant medium should be selected as far as possible for precision die, and the parts with processing allowance within 0.01 mm should be grinded at constant temperature. 

(3) Workpiece clamping: Shaft parts are characterized by a number of revolving surfaces. Precision machining methods are generally used in internal and external grinding machine grinding. In the process of processing, the grinder chuck and tailstock are used to clamp and locate the workpiece or the workpiece is located by the two top points of the head and tailstock. At this time, the connection between the chuck and the center of the top is the center line of the workpiece after grinding. If the center line jumps, the coaxiality of the workpiece after processing can not meet the requirements, so the chuck and the top should be well coordinated before processing. Cardiac examination and head-tail apex alignment examination. When grinding thin-walled inner holes, the clamping process table should be considered, that is, the bending strength under the action of the vehicle is the design criterion, the stability under the axial pressure Fb of the telescopic arm is checked, and the computer program is used to search the different number of segments, the length of each segment (not greater than the length of the longest arm) and the height of the side plate of the box section in a cyclic way. The initial total weight of the telescopic arm can be obtained according to the material density.