An Investigation of the Influence of a Micro-Textured Ball End Cutter’s Different Parameters on the Surface Residual Stress of a Titanium Alloy Workpiece

Shucai Yang,Song Yu,Xianli Liu,Shuai Su,Yongzhi Zhou

doi:10.3390/jmmp3040094

Abstract

When machining titanium alloy parts, aside from accuracy, the other key concern when evaluating their quality is the integrity of the machined surface. Residual stress can have a significant impact upon this. A certain amount of residual stress can help to strengthen the workpiece, but excessive residual stress can lead to its deformation. In this paper, we report on an experimental study of the surface integrity of titanium alloy after milling with a microtextured ball-end cutter. Tests were conducted to assess the residual stresses on the surface of titanium alloy workpieces according to the direction of feed and milling. The impact of different micro-texture parameters was also assessed; namely, the diameter, depth, spacing and distance from the cutting edge of the individual pits. Range analysis, which is an orthogonal test, was used to analyze the results of the experiments and a prediction model of surface residual stress was established for the milling of titanium alloy with micro-textured ball-end cutters. This model can provide theoretical support for the optimization of the parameters involved in future milling processes.

Highlights

Titanium alloy components are widely used in aerospace, medical and other fields because of their high specific strength and exceptional resistance to heat and corrosion, with Ti-6Al-4V being the most commonly used kind of titanium alloy
The results show that the longitudinal torsional ultrasonic milling can effectively reduce the cutting force and cutting temperature, improve the residual stress value of machining and further increase the surface stress value by selecting appropriate process parameters and lubricating cooling conditions
The results showed residual tensile stress (d2 = 0) for dry cutting, with an increase in hydraulic pressure gradually transforming the residual stress from tensile stress to compressive stress

Summary

Introduction

Titanium alloy components are widely used in aerospace, medical and other fields because of their high specific strength and exceptional resistance to heat and corrosion, with Ti-6Al-4V being the most commonly used kind of titanium alloy. In all of their cutting tests, the maximum residual compressive stress value was reached at the same distance from the machined surface. In this paper, we present a study where we measured and observed the surface residual stress, according to feed and milling direction, for Ti-6Al-4V titanium alloy samples.

Results

Conclusion