Investigation on dynamic tool deflection and runout-dependent analysis of the micro-milling process. (1st October 2022)

• Record Type: Journal Article
• Authors: Wang, Dongqian; Penter, Lars; Hänel, Albrecht; Yang, Yang; Ihlenfeldt, Steffen
• Is Part Of: Mechanical systems and signal processing. Volume 178(2022)
• Publication Date: 2022-10-01
• Subjects: Micro-milling -- Receptance coupling -- Dynamic tool deflection -- Runout-dependent effect -- Stability; Structural dynamics -- Periodicals; Vibration -- Periodicals; Constructions -- Dynamique -- Périodiques; Vibration -- Périodiques; Structural dynamics; Vibration; Periodicals; 621
• DOI: 10.1016/j.ymssp.2022.109282
• Languages: English
• ISSNs: 0888-3270

Abstract

Highlights: Two measurement schemes are designed: dynamics of tool dummy and runout. The runout-dependent effect is studied and the real entry/exit angles are obtained. A method considering trochoidal path with runout and tool deflection is proposed. A 3D-Stability lobe diagram is built for different feed per tooth with runout. Both runout and increase of feed per tooth can improve the stability limit. Abstract: Micro-milling is essential for manufacturing miniature precision components. The process involves free/restricted tool overhang length, runout, deflection, force and stability. In comparison to a macro-milling process, it is very difficult to determine the micro-milling force and stability in such a small machining scale due to higher spindle speeds, runout and deflection of the tool point. In this paper, we have proposed a complete and practical model for micro-milling process, which includes dynamic tool deflection and establishment of a stability lobe diagram (SLD) with runout-dependent effect. First, a multi-sections discretization method combined with dynamic tests was employed to the tool holder and tool dummy so that the frequency response function (FRF) at tool point was identified. Two runout models were introduced with the corresponding parameters, and the instantaneous uncut chip thickness (IUCT) was obtained by numerical solution. Then the dynamic tool deflection was developed by the product of force decomposition and FRF at tool point. Finally, the interaction between feed per tooth, runout and dynamic tool deflection was studied, which led to the proposed SLD. The experiments demonstrated that tool deflection as well as runout affected the IUCT, and runout enabled the cutter pitch angle acting on the workpiece to change, which enhanced stability limits despite reducing machining accuracy. In addition, the increase of feed per tooth also contributed to the improvement of stability boundary.