A Study to Enhance the Accuracy of Linear Motion Ball Guide System

Abstract

A linear motion ball guide (LMBG) has infinitesimal attitude change generated by rolling element circulation, called "waving." The waving is one of the technical issues in applying LMBG system for the ultra-precision field. Especially on the ultra-precision machine tool, the waving causes a stripe-shaped cyclic processing error on the processed surface, and this error degrades the surface quality of the workpiece. Several studies have been conducted to solve the waving problem. The first report has clarified the waving generation mechanism and the waving minimize method. The second report has clarified the influence of the rigidness of the table plate on the waving. This report has also shown the design guideline of the table plate to achieve the desired magnitude of waving. The third report has analyzed the influence of misalignments due to the machining accuracy of each part to the waving. From the analyses, although horizontal alignment influences the magnitude of waving, misalignments other four directions hardly influence the waving. This paper reported experimental results to verify these analyses. As a result, experimental results as analyses were obtained; only horizontal misalignment significantly affected waving. The theory proposed in the third report has been therefore verified.