Abstract

Metal additive manufacturing offers great potential to translate optimized product designs into usable parts with superior performance. Among the existing process categories, powder bed fusion with laser beam (PBF-LB/M) has gained the largest acceptance in industrial applications. Parts are created layer-by-layer with repetitive melting of newly added metal powder layers with a laser beam. Rapid solidification causes shrinkage, which leads to the development of residual stresses and distortions. To avoid geometric part failures, finite element (FE) models are used to predict and compensate for the expected part distortions. However, especially thin-walled parts, for whose production PBF-LB/M is particularly well suited, are difficult to print first time right within tight geometric tolerances. In this study, we show two approaches to improve the prediction and compensation capability of a part-scale FE model for PBF-LB/M simulation. A refined super layer approach was used to capture local shrinkage effects at abrupt part cross-section changes and an iterative, non-uniform compensation approach helped to minimize the distortions. Thin-walled artifacts were printed from AlSi10Mg powder and 3D scanned in as-built condition to measure the distortions. The experimental validation showed good agreement with the simulation results. The overall shape deviation of the thin walls was reduced by 50% and the maximum wall distortions were reduced from 0.36 mm to 0.13 mm. Despite some remaining local distortions, the used approaches contribute to the desirable first-time-right manufacturing with the PBF-LB/M process and make simulation based pre-deformation more effective for thin-walled parts.

URL

https://link.springer.com/chapter/10.1007/978-3-031-49043-9_12