Optimization of Process Parameters and Remelting Techniques for Residual Stress Reduction in Ti6Al4V Fabricated via SLM

Abstract

This study investigates the reduction of residual stresses in Ti6Al4V parts fabri- cated via Selective Laser Melting (SLM) by optimizing process parameters and incorporating remelting techniques. The effects of laser power, scanning speed, hatch distance, and remelt- ing cycles were analyzed using bridge-shaped samples and deformation angle measurements. The Taguchi method optimized parameter combinations, reducing experimental workload. Results show that higher laser power and multiple remelting cycles reduce residual stress significantly but increase variability, while scanning speed and hatch distance had minimal impact on residual stress. A modified Volumetric Energy Density (VED) formula, account- ing for remelting cycles, offered deeper insights into energy distribution and stress formation. The best parameter set for lowest average residual stress level in terms of laser power, scan- ning speed, hatch distance, and remelting cycles is (200 W , 1000 mm/s, 0.05 mm, 5), while (250 W , 500 mm/s, 0.2 mm, 3) provided greater stability. However, the set (200 W , 1000 mm/s, 0.05 mm, 5) or (200 W , 1000 mm/s, 0.05 mm, 5) is more practical. These findings highlight the trade-offs between stress reduction and stability, providing practical guidance for optimizing SLM processes for Ti6Al4V applications.