A new approach to the type synthesis of parallel indexing cam mechanisms is proposed.The types of the cam mechanism can be expressed by its motion program which contains many factors such as the head number of cams

roller number of followers

indexing times

initial relative position and relative motion configuration between cams and followers

and can show the kinematics characteristics of the mechanism and structure feature of the cam.The description of type of the parallel indexing cam mechanism using the motion program is very useful to establish a general design model for determining cam profiles and standard for manufacturing interchangeable cams.