Study on processing characteristics and mechanisms of thermally assisted laser materials processing

Abstract

Nanosecond pulsed lasers have been widely applied to interact with and characterize many different materials, and industrial users are exploring more avenues for various application processes. For the purpose of achieving broader application, the current challenge is to achieve a high processing efficiency for laser materials processing. In this study, thermally assisted laser materials processing (TALMP), which introduces heat from an external source to increase the workpiece material's temperature and make it easier to carry out ablation or modification, was developed and investigated. Moreover, to investigate the materials processing characteristics and mechanisms of TALMP, practical applications using TALMP, including surface ablation on WC-Co, and surface polishing on additive manufactured Ti-6Al-4V, were carried out. The results showed that TALMP can be successfully applied to various materials by different laser materials processing applications. Due to the workpiece material's high temperature and heat content, the coupling between laser and target materials can be enhanced; thus, physical ablation and modification for laser surface ablation can be achieved effectively. However, with a high offset temperature, a little decrease of ablation accuracy and quality could occur, and a two-step approach is proposed to eliminate this unwanted effect. Moreover, this strategy is proven to be able to achieve the desired surface ablation with high efficiency and high-quality surfaces. For thermally assisted surface polishing, due to higher temperature field with long duration, a smoother and flatter polished surface can be obtained more easily. The experimental results proved the superiority and versatility of TALMP.