Study on the effect of ice-cold constraint on the machining accuracy and quality of AZ31B magnesium alloy thin-walled parts

Abstract

A high-precision milling method of magnesium alloy thin-walled parts with the consideration of ice-cold effect was proposed to address the problems of large milling deformation of magnesium alloy thin-walled parts, burning of magnesium chips at high temperature, poor machining accuracy of parts, and low yield. A comparison test of the machining quality of thin-walled parts under the two working conditions of dry cutting and ice-cold cutting was conducted to verify the validity of the method. The influences of milling parameters, tool paths, and freezing temperatures on the machining deformation and machining quality of magnesium alloy thin-walled parts under the ice-cold effect were comprehensively analyzed. Results show that: Compared with the traditional milling method, the ice-cold cutting reduces cutting temperatures in the machining area as well as suppresses cutting forces on thin-walled magnesium alloys. The flatness value and parallelism value are reduced by 11.02%–58.89% and 4.76%–43.71%, respectively. The surface roughness value is decreased by 2.9%–27.95%. Ice-coled cutting also increases the residual compressive stress on the surface of the workpiece. The study can provide a new common solution for the efficient and high-precision machining of aerospace thin-walled structural parts.