A Novel Digital Design Approach for Metal Additive Manufacturing to Address Local Thermal Effects

Vignesh I Perumal,Ahmad R Najafi,Antonios Kontsos

doi:10.3390/designs4040041

Abstract

The reliability and performance qualification of additively manufactured metal parts is critical for their successful and safe use in engineering applications. In current powder-bed fusion type metal additive manufacturing processes, local thermal accumulations affect material microstructure features, overall part quality and integrity, as well as bulk mechanical behavior. To address such challenges, the investigation presented in this manuscript describes a novel digital design approach combining topology optimization, process simulations, and lattice size optimization to address local thermal effects caused during manufacturing. Specifically, lattices are introduced in regions of topology optimized geometries where local thermal accumulations are predicted using the process simulations with the overall goal to mitigate high thermal gradients. The results presented demonstrate that the proposed digital design approach reduces local thermal accumulations while achieving target mechanical performance metrics. A discussion on how post-manufacturing heat treatment effects could be also considered, as well as comments on the computational implementation of the proposed approach are provided.

Highlights

Metal additive manufacturing (AM) holds a great promise for engineering applications, e.g., in the aerospace and biomedical industries
If there are any additional regions of high local thermal accumulation after the introduction of the lattices, the procedure is repeated until no thermal accumulations above a user-specified limit are observed in the process simulations
The cantilever dimensions of 0.3 × 0.15 × 0.015 m (Figure 2) were determined based on the maximum length that can be accommodated in the build volume of the powder bed fusion (PBF) printer considered in this investigation

Summary

Introduction

Metal additive manufacturing (AM) holds a great promise for engineering applications, e.g., in the aerospace and biomedical industries. AM further allows for patient specific design of implants, incorporation of porosity to mitigate stress shielding [6]. In the context of AM, 3D-architected cellular materials such as lattices have become viable options for manufacturing. This new class of manufactured materials enable control of material properties at several length scales, while achieving target macroscale properties such as specific strength and stiffness that are not achievable with existing metals, alloys, or composites. Lattices have been found to have superior thermal and impact dissipation properties compared to corresponding solid geometries, making them a great choice for multifunctional applications [10,11]

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Discussion

Conclusion