Layer-to-Layer Melt Pool Control in Laser Powder Bed Fusion

TL;DR

This paper presents a novel layer-to-layer control method for laser powder bed fusion that optimizes laser power to regulate melt pool depth, improving process reliability and providing new insights into LPBF physics.

Contribution

It introduces a trajectory optimization-based control strategy for LPBF melt pool management, validated through high-fidelity simulations, advancing additive manufacturing process control.

Findings

Successful regulation of melt pool depth on complex geometries

First demonstration of layer-to-layer input optimization effectiveness

Insights into physics of controlled LPBF process

Abstract

Additive manufacturing processes are flexible and efficient technologies for producing complex geometries. However, ensuring reliability and repeatability is challenging due to the complex physics and various sources of uncertainty in the process. In this work, we investigate closed-loop control of the melt pool dimensions in a laser powder bed fusion (LPBF) process. We propose a trajectory optimization-based layer-to-layer controller that adjusts the laser power input to the next layer to track a desired melt pool depth and validate our controller by placing it in closed-loop high-fidelity multi-layer smoothed particle hydrodynamics simulator of a 2D LPBF process. Detailed numerical case studies demonstrate successful regulation of the melt pool depth on brick and overhang geometries and provide first of its kind results on the effectiveness of layer-to-layer input optimization for the LPBF process as well as detailed insight into the physics of the controlled process. Computational complexity and process performance results illustrate the method's effectiveness and provide an outlook for its implementation onto real systems.