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using the technology have high hardness, density, Young’s modulus, etc. Görgl looked at the technology’s applications and capabilities in laser cladding, repairing and reshaping and Additive Manufacturing, comparing the strengths and limitations of the technology against those of L-PBF for component production. Fused Filament Fabrication (FFF) was addressed by Dr Christian Kukla, from Montanuniversität Leoben’s Industrial Liaison Department, in his presentation ‘Material extrusion with filaments for the production of metal parts and feedstock.’ FFF can be used to shape parts with feedstocks similar to those used in Powder Injection Moulding (PIM), resulting in the production of green parts which must be debound and sintered. The use of filaments imposes a strict set of requirements on the feedstock, such as the flexibility to be spooled, stiffness to avoid buckling and a constant diameter to ensure a consistent mass flow. However, it also enables the use of a wide range of metal powders, which are already available in the market, and employs the already established and standardised process of sintering, resulting in a homogeneous microstructure. During his presentation, Kukla offered his insight into the available powders, feedstocks, equipment and respective processing parameters for FFF, along with a number of examples of part shrinkage rates, densities, surface quality and other mechanical properties. Developing new processes Looking at the development of new processes, Dr Michael Kitzmantel of RHP-Technology GmbH, Seibersdorf, Austria, introduced ‘XL multi-material AM using an economic blown powder process,’ in which a plasma transferred arc system is used as a heat source in combination with powder feeding for the production of parts. Kitzmantel offered examples of how the technology can be used to manufacture parts from different materials, such as titanium alloys, iron-based alloys and nickel-based alloys, and the capability of the
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Fig. 3 Metallic green parts manufactured by LMM (Courtesy Lithoz)
technology to produce multi-material components and gradient structures when two powder feeders are used simultaneously. Gerald Mitteramskogler, Lithoz GmbH, Vienna, Austria, presented the first results achieved with a new process known as Lithography-based Metal Manufacturing (LMM), in which a photopolymer filled with metallic particles is selectively cured with a light engine based on digital light processing (Figs. 3-4). In his paper, ‘Lithography-based Additive Manufacturing of functional metal components,’ Mitteramskogler compared LMM to Metal Injection Moulding (MIM), in that both technologies require debinding and sintering in the green state and achieve similar relative densities (up to 98.5%). Mitteramskogler stated that LMM enables the production of highly complex parts in 316L, to good geometrical accuracy and with a very low surface roughness, resulting in mechanical properties comparable to conventionally manufactured 316L.
Fig. 4 Internal detail of the design shown in Fig. 3 (Courtesy Lithoz)
Post-processing of AM parts Methods for post-processing and quality assurance were also discussed in detail during the conference. In a paper titled ‘Surface engineering for parts made by Additive Manufacturing’, Markus Hatzenbichler, Fotec, Vienna, offered insight into the surface engineering
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