Research on cylindrical indexing cam’s unilateral machining

Junhua Chen,Chuhua Jiang,Xiaowei Mu,Xuze Zhang

doi:10.1177/1687814015595202

Abstract

The cylindrical cam ridge of the indexer is a spatial curved surface, which is difficult to design and machine. The cylindrical cam has some defects after machining because conventional machining methods have inaccuracies. This article aims at proposing a precise way to machine an indexing cam, using basic motion analysis and analytic geometry approach. Analytical methodology is first applied in the cam’s motion analysis, to obtain an error-free cam follower’s trajectory formula, and then separate the continuous trajectory curve by thousandth resolution, to create a three-dimensional discrete trajectory curve. Planar formulae and spherical formulae can be built on the loci. Based on the machine principle, the cutting cutter’s position and orientation will be taken into account. This article calculates the formula set as presented previously and obtains the ultimate cutter path coordinate value. The new error-free cutter path trajectory is called the unilateral machining trajectory. The earned results will compile into numerical control processing schedule. This processing methodology gives a convenient and precision way to manufacture a cylindrical indexing cam. Experimental results are also well supported.

Highlights

The cam-actuated indexing mechanism is very important in automated machinery.[1]. It is widely used in packing machinery, punching machinery, and pharmaceutical machinery, which has advantages of small size, compact structure, high stiffness, large transmission torque, and high transmission accuracy.[2,3]
The cylindrical indexing cam ridge is a spatial curved surface which is very hard in design and to machine
This article first analyzed the drawbacks of the existing machine methodologies, which is low in efficiency and in precision and built the error-free follower’s trajectory equation

Summary

Introduction

The cam-actuated indexing mechanism is very important in automated machinery.[1] It is widely used in packing machinery, punching machinery, and pharmaceutical machinery, which has advantages of small size, compact structure, high stiffness, large transmission torque, and high transmission accuracy.[2,3] The cylindrical indexing cam ridge is a spatial curved surface which is very hard in design and to machine. Bovisov[4] put forward an algorithm that considered the indexing cam contour surface as a linear surface development; GonzalezPalacios et al built uniform equations for the spatial indexing cam contour surface using the spiral motion theory. Tsay and Lin[7] put forward a new theory: the geometry of cam contour surface was formed by the cutter’s sweep.

Objectives

Conclusion