Three-coordinate numerical control milling positioning clamp capable of machining closed angle and process method

The invention discloses a three-coordinate numerical control milling positioning clamp capable of machining a closed angle and a process method. The clamp comprises a bottom plate, a positioning block, a positioning pin and a pressing plate. A machining datum hole and an alignment hole are found in the part through the three-dimensional model; when a closed angle area is machined, the machining datum hole and a fixing mechanism on one side of the clamp are positioned through a positioning pin, and the other hole and a movable mechanism alignment hole on the other side of the clamp are positioned through a positioning pin; and a numerical control machining coordinate system is established in the positioning hole area to machine the closed angle area. The whole clamp can be adjusted vertically, and the machining range is widened; and meanwhile, angle tolerance is converted into hole location tolerance through the clamp,so that the precision of machined parts is higher, and the quality is more stable compared wi