For the typical holes such as tappet holes, spark plug holes and fuel injection nozzle holes, how to improve the processing efficiency and ensure the coaxiality of each hole, More Super Hard used a multi-step machine to process composite tools, multi-stage hole centralized processing, and dilute different processing Process limits, reduce the number of tool changes, save tool change time, and reduce tool inventory. Coupled with the high precision and wear resistance of PCD, from process optimization to efficient and stable processing, it perfectly solves the processing problem of difficult-to-machine holes.