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Metal AM + HIP
Combining Metal AM and Hot Isostatic Pressing (HIP): Application and process innovations A technical session at the Euro PM2017 conference, held in Milan, Italy, October 1-5, 2017, investigated three different concepts in processes that combine metal Additive Manufacturing with Hot Isostatic Pressing (HIP). In the following report, Dr David Whittaker reviews three papers that consider the use of SLM for the manufacture of HIP capsules, HIP as a final densification process in AM, and finally HIP as a process to join EBM processed components into larger structures.
Selective Laser Melting for thin-walled HIP capsule manufacture A paper from Sebastian Riehm, Anke Kaletsch and Christoph Broeckmann (RWTH Aachen, Germany) and Sandra Wieland and Frank Petzoldt (Fraunhofer IFAM, Bremen, Germany) investigated the use of Selective Laser Melting (SLM) for HIP capsule manufacture, as an alternative to the expensive and time-consuming approach of fabrication from sheet metal. The investigated approach was to build open capsules by SLM and fill them conventionally with powder for HIPing. In the reported study, the production of monolithic components through this combination of SLM and HIP was presented. As a further variant of this route, the outer capsule could be made from a wear- or corrosion-resistant material, with the inner bulk material offering high toughness and strength. For this approach, the capsule was manufactured as an open hollow
Vol. 3 No. 4 Š 2017 Inovar Communications Ltd
body. Building components by SLM is a time-consuming process and, therefore, the thickness of the capsules was kept to an absolute minimum. After SLM-building, a filling pipe was conventionally welded onto the capsule, allowing filling and closing of the capsule. This combined process allows the production of complex net-shape composite components.
Table 1 shows four combinations of materials: two monolithics, where capsule and bulk were from the same material, and two composites, where a capsule of stainless or wear resistant steel was to be filled with powder of tool steel. The chemical compositions of the investigated powders can be seen in Table 2. While the goal of this project was to build complex composite components
Fig. 1 316L cylinders produced by SLM [1]
Metal Additive Manufacturing | Winter 2017
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