Enhancement of Machining Accuracy Based on Prediction of Tool Deflection Considering Feedrate Change of Machine Tools

Abstract

High-speed and high-accuracy machining have become indispensable requirements in modern
manufacturing, particularly with the widespread use of computer numerical control (CNC) machine
tools in precision engineering applications. However, one of the key challenges in achieving high
machining accuracy is the deviation between the programmed feedrate and the actual feedrate
during operation, caused by the acceleration and deceleration (Acc/Dec) behavior of the machine
tool's servo control system. These discrepancies lead to deviations in the toolpath, which in turn reduce the dimensional accuracy and surface quality of the machined components. Compounding
this issue, the cutting forces acting on the tool during high-speed milling operations—especially
with square-end mills—cause elastic deflection of the tool, further compromising the geometric precision of the final product. To address these challenges, this study proposes an integrated
methodology that combines modeling of actual feedrate variation with predictive estimation of
cutting force and tool deflection. The feedrate model is developed by considering the Acc/Dec
characteristics of the control axes in the machine tool, enabling accurate prediction of real tool
movements. Simultaneously, a cutting force model is constructed based on machining parameters and tool geometry to estimate the magnitude of tool deflection. By integrating both models,
the proposed approach allows for the accurate prediction of the actual toolpath and compensation for deviations arising from control limitations and mechanical deflection. The effectiveness
of this method was validated through machining experiments conducted without high-precision
contour control. The results demonstrated a strong correlation between predicted and measured
toolpaths, confirming the reliability and practicality of the proposed method. This study highlights
the importance of accounting for dynamic feedrate behavior and cutting mechanics in improving
machining accuracy, offering a valuable solution for enhancing dimensional control in high-speed
CNC milling applications.