While additive manufacturing boasts of its ability to construct freeform structures with internal surfaces, these features can be particularly difficult to reach with traditional surface finishing processes. Therefore, we developed the magnetically driven internal finishing (MDIF) system, which features a magnetic polishing tool with coated abrasives to provide an intermittent sliding wear mechanism to polish internal surfaces with localized freeform surface generation and corrective polishing [1]. The material removal mechanisms of this novel process was derived from our established framework that determines the micro-contact pressure distribution over the conformal contact between rough surfaces [2]. Additionally, we have built an advanced algorithm to precisely control the material removal volume considering the time-variant removal characteristics of the tool [3], which can determine the evolution of the surface quality. The MDIF can successfully improve the surface quality of additively manufactured metal tubes [4].

Publications

[1] J. Zhang, et al., A novel magnetically driven polishing technique for internal surface finishing, Precision Engineering, 54 (2018) 222–232.

[2] J. Zhang, et al., Experimental and theoretical study of internal finishing by a novel magnetically driven polishing tool, International Journal of Machine Tools & Manufacture, 153 (2020) 103552.

[3] J. Zhang and H. Wang, Generic model of time-variant tool influence function and dwell-time algorithm for deterministic polishing, International Journal of Mechanical Sciences, 211 (2021) 106795.

[4] J. Zhang and H. Wang, Magnetically driven internal finishing of AISI 316L stainless steel tubes generated by laser powder bed fusion, Journal of Manufacturing Processes, 76 (2022) 155–166.

Acknowledgements

This research is proudly supported by the Singapore MOE Academic Research Fund Tier 2 Grant (MOE2018-T2-1-140).