The oil outlet valve coupling is one of the precision parts in the fuel injection pump. During the injection process, the oil outlet valve coupling can control the residual pressure in the high-pressure oil pipe, and the residual pressure directly affects the injection timing, injection law and speed characteristics of the high-pressure system. At present, the key processes of each part of Weifu’s oil outlet valve are processed by imported equipment, such as Japan Seiko medium hole face grinder, German Pittwater double-end grinding machine, Swiss STUDER CNC cylindrical grinding machine, etc.