Title: Directivity process modelling for the figure error correction of dual-rotation magnetorheological finishing

Authors: Yuyue Wang; Yun Zhang; Zhijing Feng

Addresses: Department of Mechanical Engineering, Tsinghua University, Haidian District, Beijing, China ' Beijing Key Lab of Precision/Ultra-precision, Manufacturing Equipment and Control, Tsinghua University, Haidian District, Beijing, China; Department of Mechanical Engineering, Tsinghua University, Haidian District, Beijing, China ' Beijing Key Lab of Precision/Ultra-precision, Manufacturing Equipment and Control, Tsinghua University, Haidian District, Beijing, China; Department of Mechanical Engineering, Tsinghua University, Haidian District, Beijing, China

Abstract: To study dual-rotation magnetorheological finishing (DRMRF) technology and obtain a smoother surface, the model for the polishing process of the figure error correction (directivity process model) in DRMRF was established in this paper. Existing researches ignored the influence of feed rate and revolution upon removal function. In this paper, a method of modifying the removal function is presented, which takes the relative velocity of the magnetorheological fluid (MR fluid) and the part into consideration. The directivity of removal amount during modelling adds a new dimension for analysis. The numerical simulation results of removal amount and its directivity show that the removal amount distributed more evenly along every direction because of the revolution of the wheel in DRMRF. The removal amount distribution is one of the fundamental differences between common MRF and DRMRF. Finally, a Fused Silica planar blank was polished by DRMRF, and the initial figure error was 10 nm RMS and 67 nm PV. The surface figure error is corrected to 2.4 nm RMS and 20 nm PV (full aperture = 95% diameter), and the stripe-like scratches are suppressed. The numerical simulation results and the experimental result indicates the effectiveness of DRMRF and the correctness of directivity process model.

Keywords: magnetorheological finishing; dual-rotation magnetorheological finishing; figure error correction; directivity modelling; optical fabrication; nanomanufacturing.

DOI: 10.1504/IJNM.2019.100458

International Journal of Nanomanufacturing, 2019 Vol.15 No.3, pp.239 - 258

Received: 22 Sep 2017
Accepted: 22 Sep 2017

Published online: 29 Mar 2019 *

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