Geometric Design and Machining of Variable Pitch Lead Screws with Swinging and Translating Meshing Rollers

Abstract

The design of variable pitch lead screws with swinging and translating meshing rollers is proposed in this study. Mathematical expressions representing the surface geometry of the screw generated by an endmill cutter are derived for the purpose of calculating the meshing points on the threaded surface of the screw. This mechanism is modeled using a Silicon Graphics workstation for motion simulation. Two examples are given. Our results show that constant thickness of screw threads can be attained using the design proposed. Finally, the machining settings of a 5-axis CNC machine are provided for manufacture of the screws.