Investigation on the Cause-Effect Relationships between the Process Parameters and the Resulting Geometric Properties for Wire-Based Coaxial Laser Metal Deposition

Avelino Zapata,Christian Stadter,Michael F Zaeh,Cara G Kolb,Christian Bernauer

doi:10.3390/met12030455

Abstract

Coaxial Laser Metal Deposition with wire (LMD-w) is a valuable complement to the already established Additive Manufacturing processes in production because it allows a direction-independent process with high deposition rates and high deposition accuracy. However, there is a lack of knowledge regarding the adjustment of the process parameters during process development to build defect-free parts. Therefore, in this work, a process development for coaxial LMD-w was conducted using an aluminum wire AlMg4,5MnZr and a stainless steel wire AISI 316L. At first, the boundaries for parameter combinations that led to a defect-free process were identified. The proportion between the process parameters energy per unit length and speed ratio proved crucial for a defect-free process. Then, the influence of the process parameters on the height and width of single beads for both materials was analyzed using a regression analysis. It was shown that linear models are suitable for describing the correlation between the process parameters and the dimensions of the beads. Lastly, a material-independent formula is presented to calculate the height increment per layer needed for an additive process. For future studies, the results of this work will be an aid for process development with different materials.

Highlights

IntroductionIn recent years, Directed Energy Deposition (DED) processes have contributed to expand the application fields of metal Additive Manufacturing (AM) [1]
This contribution aims (i) to investigate correlations between the process boundaries for a coaxial Laser Metal Deposition with wire (LMD-w) process with aluminum and stainless steel, (ii) to develop models through linear regression that allow assessing the influence of the process parameters on the height and width of the beads, and (iii) to investigate the influence of the height increment for each consecutive layer for multi-layer processes
The results are summarized in process maps shown in stainless steel were identified

Summary

Introduction

In recent years, Directed Energy Deposition (DED) processes have contributed to expand the application fields of metal Additive Manufacturing (AM) [1]. Exemplary applications are coating surfaces by depositing thin material layers, repairing damaged parts by reapplying missing material, and producing freeform parts by gradually depositing multiple layers [2]. Among the distinct advantages of DED processes is the ability to produce large parts at high material deposition rates [3]. The process involves the controlled melting of material fed to the process zone as wire or powder. Using a wire as feedstock offers various advantages over powder use like a facilitated handling, an easy access to standardized feedstock, a higher material usage, higher deposition rates, and an increased operational safety [4,5]. Different systems can be utilized to melt the wire.

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