Breaking the trade­off: multiscale optimization for lower cost, lower residual stress LPBF of SS316L

Abstract

Purpose

The purpose of this study was to use bridge curvature method (BCM) to quantify stress, while multiscale modeling with adaptive coarsening predicted distortions based on experimentally validated models. Taguchi method and response surface method were used to optimize process parameters (energy density, hatch spacing, scanning speed and beam diameter).

Design/methodology/approach

Laser powder bed fusion (LPBF) offers significant design freedom but suffers from residual stresses due to rapid melting and solidification. This study presents a novel approach combining multiscale modeling and statistical optimization to minimize residual stress in SS316L.

Findings

Optimal parameters were identified through simulations and validated with experiments, achieving an 8% deviation. This approach significantly reduced printing costs compared to traditional trial-and-error methods. The analysis revealed a non-monotonic relationship between residual stress and energy density, with an initial increase followed by a decrease with increasing hatch spacing and scanning speed (both contributing to lower energy density). Additionally, beam diameter had a minimal impact compared to other energy density parameters.

Originality/value

This work offers a unique framework for optimizing LPBF processes by combining multiscale modeling with statistical techniques. The identified optimal parameters and insights into the individual and combined effects of energy density parameters provide valuable guidance for mitigating residual stress in SS316L, leading to improved part quality and performance.

Citation

Dilawar, S., Khan, A., Ur Rehman, A., Husain, S.Z. and Jaffery, S.H.I. (2024), "Breaking the trade­off: multiscale optimization for lower cost, lower residual stress LPBF of SS316L", Rapid Prototyping Journal, Vol. 30 No. 6, pp. 1200-1215. https://doi.org/10.1108/RPJ-12-2023-0446