Simulation and experimental study of the hole-making process of Ti-6Al-4V titanium alloy for selective laser melting

Abstract

Towards improving the hole-making accuracy and surface quality of titanium alloy workpieces after selective laser melting (SLM), this paper carried out simulation and experimental research on hole processing. Specifically, it is divided into three process methods: directly milling without preformed holes, milling SLM-formed preformed holes, and drilling SLM-formed preformed holes, compared and studied the dimensional hole accuracy, surface morphology, cutting force, and tool wear, analyzing chip and burr formation mechanism. Firstly, the geometric model of SLM titanium alloy workpiece containing features such as collapse, sticky powder, and lack of fusion hole was established by ABAQUS finite element software, and cutting simulation analysis was conducted based on Johnson-Cook failure criterion to investigate the stress distribution and cutting force variation law under different hole diameter and cutting speed; Then hole-making experiments with hole diameters ∅1 mm-∅3 mm were conducted, and the experiment results showed that: The surface quality of milling SLM-formed preformed holes is better, as shown by smaller burr size, stable chip pattern, less tool wear, better hole size, and best overall forming quality; the average error rate of drilling SLM-formed preformed holes was the smallest 1.458 %, and dimensional accuracy improved by 67.3 %, but they had larger burr sizes and slightly poorer surface quality. The axial force obtained by a higher cutting speed and lower material removal rate at the same bore diameter is small. The experiment results verify the accuracy and validity of the simulation analysis, and the average error of the simulation results is 8.4 %.