Wide roller guide machining by four-axis machine tools for cylindrical cams

Abstract

A new regenerating method for cutter location paths using smaller tools to produce cylindrical cams is presented. Based on the expected motions, cams are used in various applications in the mechanism. For a cylindrical cam, the roller follower operates in a groove cut on the periphery of an end mill with the diameter the same as that of the roller. Using the conventional method, a 2D expanding diagram, restricts flexibility in choosing cutting tools for a wide roller guide. The manufacture of cylindrical cams is complicated and precise work that depends on the generating method and types of machine tools employed. Since the guiding curve cannot be offset exactly along the cylindrical surface, approximating problems occur. Though toolpath generation using the same size tools as the rollers is applied in practice, research into NC programs using unequal tools to meet high precision requirements is lacking. This paper presents a system for the design and manufacturing of cylindrical cams to cut the roller groove. In the proposed system, a new interference-free toolpath 3D regenerating method was applied to four-axis machining of a wide roller guide. Eleven types of follower motion for a translating and oscillating follower are considered. This proposed 3D offset-based generating method can regenerate toolpaths for standard cutting tools instead of larger ones and is implemented on a CAM system. Examples with wider grooves are given to demonstrate its effectiveness.