Abstract: A wave cam is rotatably and integrally mounted on a drive shaft of a compressor. Pistons are connected to cam surfaces of the wave cam via shoes. The shoes move relatively to the cam surface along a predetermined orbital path. The predetermined orbital path defined on the cam surfaces is ground by bringing a grinding surface of a grinding stone, attached to a rotary shaft, into contact with the cam surfaces. During grinding, the grinding surface is perpendicular in respect with the cam surface. The axis of the grinding stone coincides with the axis of the rotary shaft.

Abstract: A cam having a front surface and a rear surface to reciprocate a double-headed piston of a compressor twice for every rotation of a drive shaft. A positioner is provided on the front and rear surface of the cam to position the cam on a fixture used for grinding of cam surfaces. The cam surfaces are formed by grinding the front and rear surface of the cam into a convex shape with the cam positioned to the fixture by the positioner. The front cam surface and the rear cam surface have identical shapes and their phases are offset by a predetermined angle with respect to one another. The positioner is arranged at the same position on the front and rear surfaces of the cam with respect to the cam shape.