Consideration of SLM additive manufacturing supports on the stability of flexible structures in finish milling

Abstract

The supports in additive manufacturing can be used in an innovative way by being considered as supports for machining operation. This innovative use of manufacturing supports can facilitate the finishing of functional thin structures. But the flexible global workpiece-supports system can potentially cause vibrations during the machining operation. This can cause irregular surfaces with bad quality.This study highlights the importance of additively manufactured support structures on the stability of Ti-6Al-4V parts milling by using supports as a machining fixture. Nowadays, the control of the support stiffness and mechanical properties is not proposed by specific AM software. A way to develop a numerical method to optimize the post-processing of additive manufacturing parts is to use specific lattice structures as supports. Indeed, by adjusting the topology and the beam diameter of lattices, the relative stiffness and the relative density of the global structure can be controlled. The objective of this study is to show that the stiffness of the manufacturing supports is crucial for the machining operation.To validate this concept, milling tests are proceeded on thin-walled plates produced by Selective Laser Melting (SLM) using defined finish milling cutting conditions. Three types of results are obtained: cutting forces signals, displacements and surface qualities by confocal microscopy. The study reveals that milling can induces chatters. Also, surface qualities and dimensional deviations depend on the support choice.The control of mechanical properties of support structures appears to be a good way to favor machining operation of flexible and thin-walled structures. Topology and dimensional parameters of supports have to be considered in preliminary design steps of the additive manufacturing digital chain.

A Short and Technical Review on Lattice Structures Produced by Additive Manufacturing

“…Lattice structures are three-dimensional structures consisting of one or more repetitive unit cells (Cheng et al, 2018;Zhang et al, 2018;Feldshtein et al, 2019;Blakey-Milner et al, 2021;Kas and Yilmaz, 2021;Zheng et al, 2021). These structures can be named as cellular solids, cellular metals, cellular foams (Pan et al, 2020), lattice sequences (Didier et al, 2021), porous structures (Łyczkowska et al, 2014) or scaffold structures (Wauthle et al, 2015). Lattice structures have higher energy absorption, sound insulation and heat capability than solid structures.…”

Post-processing of additive manufactured parts: a numerical strategy applied in maxillary implantology

“…The supports must have a mechanical strength suitable for this machining operation so as not to deteriorate the surface quality of the manufactured part. Therefore, a previous study [21] has shown that surface qualities and dimensional deviations depend on the support structures. The choice of supports must be considered as a key step in the associated digital chain of the additive manufacturing flux.…”

Comparison of CAD Software for Designing Cellular Structures for Additive Manufacturing

“…This support method, which allows for the most stable and wa free manufacturing possible, is often used in Powder Bed Fusion (PBF) of metals (e Selective Laser Melting-SLM, Direct Laser Metal Sintering-DLMS, Electron Beam M ing-EBM, etc.) [15][16][17][18][19] and Vat Photopolymerisation (VPP, e.g., Stereolithography-S Digital Light Processing-DLP, etc.). Similar is the case of the filling of bodies with lar volumes, or the connection of two separate walls.…”