Title: Approaches to minimize overhang angles of SLM parts
Authors : Cloots, Michael
Zumofen, Livia
Spierings, Adriaan Bernardus
Kirchheim, Andreas
Wegener, Konrad
Published in : Rapid Prototyping Journal
Volume(Issue) : 23
Issue : 2
Pages : 362
Pages to: 369
Issue Date: 2017
License (according to publishing contract) : Licence according to publishing contract
Type of review: Not specified
Language : English
Subjects : SLM; Overhanging surfaces; Scan strategies; Supportless
Subject (DDC) : 670: Manufacturing
Abstract: Purpose For geometries exhibiting overhanging surfaces, support structures are needed to dissipate process heat and to minimize geometrical distortions attributed to internal stresses. The use of support structures is often time- and cost-consuming. For this reason, this study aims to propose an approach which minimizes the use of such structures. Design/methodology/approach For minimizing the use of support structures, process parameters in combination with a contour-like exposure strategy are developed to realize support-less overhanging structures of less than 35°. These parameters are implemented in a shell-core strategy, which follows the idea of applying different processing strategies to the critical (overhanging) shell and the uncritical core of the part. Thereby, the core is processed with standard parameters, aiming a dense material. On the critical shell, optimized processing parameters are applied, reaching good results in terms of surface quality, especially at extreme overhang situations. Findings The results show that the selective laser melting (SLM) technology is able to realize support-less overhanging surfaces by choosing suitable scan strategies and process parameters. Particularly good results are always obtained when the exposure direction of the shell is parallel to the contour of the sample. Originality/value The validity of the results is demonstrated through the successful reproduction of the build strategy on two commercial SLM machines, reaching support-free builds of surfaces with an angle to the horizontal of less than or equal to 30°.
Departement: School of Engineering
Organisational Unit: Centre for Product and Process Development (ZPP)
Publication type: Article in scientific Journal
DOI : 10.1108/RPJ-05-2015-0061
ISSN: 1355-2546
URI: https://digitalcollection.zhaw.ch/handle/11475/4987
Appears in Collections:Publikationen School of Engineering

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