The Dimensional Accuracy of Thin-Walled Parts Manufactured by Laser-Powder Bed Fusion Process

Josef Tomas,Leonhard Hitzler,Ewald Werner,Markus Merkel,Marco Köller,Jonas Von Kobylinski,Michael Sedlmajer

doi:10.3390/jmmp4030091

Abstract

Laser-Powder Bed Fusion brings new possibilities for the design of parts, e.g., cutter shafts with integrated cooling channels close to the contour. However, there are new challenges to dimensional accuracy in the production of thin-walled components, e.g., heat exchangers. High degrees of dimensional accuracy are necessary for the production of functional components. The aim is to already achieve these during the process, to reduce post-processing costs and time. In this work, thin-walled ring specimens of H13 tool steel are produced and used for the analysis of dimensional accuracy and residual stresses. Two different scanning strategies were evaluated. One is a stripe scan strategy, which was automatically generated and provided by the machine manufacturer, and a (manually designed) sectional scan strategy. The ring segment strategy is designed by manually segmenting the geometry, which results in a longer preparation time. The samples were printed in different diameters and analyzed with respect to the degree of accuracy and residual stresses. The dimensional accuracy of ring specimens could be improved by up to 81% with the introduced sectional strategy compared to the standard approach.

Highlights

Laser-Powder Bed Fusion (LPBF) is a layer-based technique of 3-dimensional additive manufacturing
The dimensional accuracy of ring specimens could be improved by up to 81% with the introduced sectional strategy compared to the standard approach
For thin-walled parts, the standard stripe scan strategy led to large deviations

Summary

Introduction

Laser-Powder Bed Fusion (LPBF) is a layer-based technique of 3-dimensional additive manufacturing. One of the major advantages of the LPBF technique is the short production time for individual parts. The goal is to produce components for different industrial fields with high dimensional accuracy. The advantages of the LPBF process are the possibility of lightweight construction by lattice structures [3,4,5], the flexibility of geometry and the integration of functions [6,7]. In order to utilize these advantages, component designed for LPBF tend to have a higher level of complexity, with a significant amount of thin-walled parts. Unlike in conventional fabrication processes, the dimensional accuracy often poses a challenge in LPBF [8]

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Results

Conclusion