Analysis and compensation for the dominant tool error in ultra-precision diamond ball-end milling

• Published in: Journal of materials processing technology 2023-09, Vol.318, p.118034, Article 118034
• Main Authors: Wu, Liqiang, Liu, Hanzhong, Zong, Wenjun
• Format: Article
• Language: English
• Subjects: Compensation method; Diamond ball-end milling; Machining accuracy; Rotation profile; Tool error; Tool off-center
• ISSN: 0924-0136
• DOI: 10.1016/j.jmatprotec.2023.118034

Diamond ball-end milling is an enabling technology to fabricate complex curved surfaces with a nanometer level roughness. However, limited by the errors of tool manufacturing and installation, the cutting edge profile of a single-bladed diamond milling tool cannot form an ideal sphere crown in rotation, which will significantly worsen the machining accuracy. Although a titled milling method and a tool error reduction method based on milling-test have been proposed to improve the machining accuracy, a complete analysis of the effects of multiple tool errors on the machining accuracy have not been performed. Therefore, the present work contributes an analytical model to accurately calculate the tool rotation profile under various position and orientation errors. The results reveal that the horizontal off-center error of tool cutting edge is the dominant error among all the tool errors. According to the results, a novel high precision identification process is developed to evaluate the horizontal off-center error in view of the cutting-mark, and subsequently a tool center shift method is proposed to compensate for such error. Finally, experiments on millimeter scale spherical surface, micro sphere array and micro sinusoidal surface confirm that the proposed tool error compensation method can significantly improve the form accuracy. The average form errors (PV) of three test surfaces are reduced from 2.29 μm, 0.90 μm and 0.88 μm, down to 0.61 μm, 0.28 μm and 0.18 μm, respectively. [Display omitted] •An analytical model is established to determine the dominant tool error.•An identification method is developed to calibrate tool off-center error.•A tool center shift method is proposed to compensate tool off-center error.•Surface profile accuracy is significantly improved after tool error compensation.