Milling force prediction in titanium alloy thin-walled components side milling based on Tri-Dexel model with comprehensive consideration of tool runout and workpiece deflection

Abstract

Titanium alloy thin-walled structures are extensively used in aerospace, automotive manufacturing and other industries due to their exceptional performance. However, the low rigidity of thin-walled components makes them highly susceptible to deflection and vibration during the side milling process, adversely impacting machining accuracy and surface quality.

This paper presents an accurate and reliable prediction model for cutting forces during the side milling of titanium alloy thin-walled components using flat-end mills. This method comprehensively accounts for the effects of tool runout and workpiece deflection on the undeformed cutting thickness (UCT), examines the chip geometry due to cutting force-induced workpiece deflection and develops a milling force prediction model. Based on the proposed model, a virtual machining simulation environment is constructed using computer graphics technology and Tri-dexel geometric modeling technology, and the development of a milling simulation software prototype based on the Tri-dexel model is completed. The software utilizes the established Tri-Dexel model to calculate the chip geometries and material removal volume of the cutter-workpiece engagement (CWE) area, enabling the estimation of milling forces during the machining of thin-walled components. The cutting force coefficients, tool runout values, as well as the workpiece's natural frequency and damping ratio are calibrated by cutting experiment, dial gauge experiment and modal hammer experiment, respectively. Moreover, to investigate the variation patterns of milling forces and validate the effectiveness of the milling force prediction model, a comparative study is performed to analyze milling force variations with different machining parameters and methods. The experimental results demonstrate that the proposed model provides more accurate milling force predictions in the X-, Y- and Z- directions compared to classical milling force prediction method. Some conclusions obtained and the methods utilized can be used in side milling, virtual manufacturing and computer numerical control (CNC) simulation software development etc., and can be further applied in the machining of various metallic materials.