Experiment Study of Rapid Laser Polishing of Freeform Steel Surface by Dual-Beam

Yongquan Zhou,Haibing Xiao,Zhenyu Zhao,Wei Zhang,Xiaomei Xu

doi:10.3390/coatings9050324

Abstract

One of the challenges regarding widespread use of parts made from alloy steel is their time-consuming polishing process. A rough freeform surface of part has been often expected to be polished rapidly up to a smooth surface finish. The focus of this study is to develop a fast polishing method of freeform surface by using dual-beam lasers. The dual-beam laser system consists of continuous laser (CW) and pulsed laser based on a five-axis CNC device. In this study, a series of experiments of CW laser polishing present the effects of different spot irradiation on surface topography, then the combination trajectory of zigzag and square waveform of pulsed laser is explored to realize a “melting peak for filling into valley” (MPFV) method. The polishing experiment on a semisphere of S136H steel polished by dual-beam shows that a rough semisphere surface was rapidly polished from initial state value of Sa (=877 nm) to post-polished value of Sa (=142 nm), and the polishing efficiency is as high as 2890 cm2/H.

Highlights

Freeform surface plays significant role of enhancing functional and aesthetical properties of products
Due to the low polishing efficiency (typically maximum 30 cm2 /H from initial state value of Sa (=877 nm) to post-polished value of Sa (=142 nm) by a skilled worker, it is often expected that the time consuming polishing process should be replaced by an innovative rapid one
Typical roughness after laser polishing are in the range of Sa (150–512 nm), which meets the medium demand on surface quality of a large number of parts in many industrial fields

Summary

Introduction

Freeform surface plays significant role of enhancing functional and aesthetical properties of products. Current automated polishing techniques often cannot be used on parts with freeform surfaces and functional relevant edges, the finishing for these parts is often done manually [1,2]. One new approach to automate this work is rapidly polishing by means of laser radiation. This is why, in recent years, laser polishing has become more widely used due to the ability to quickly and efficiently polish surfaces [3]. Typical roughness after laser polishing are in the range of Sa (150–512 nm), which meets the medium demand on surface quality of a large number of parts in many industrial fields

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Conclusion