Schumacher, Ralf
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Schumacher, Ralf
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Publikation Reduction of particles on SLM surfaces(2018) Zimmermann, Simon; Schumacher, Ralf; Bill, Oliver; Dalcanale, Federico; de Wild, Michael04B - Beitrag KonferenzschriftPublikation Pre-process calculation to optimize laser parameter in selective laser melting(2018) Matter, Nathalie; Schuler, Felix; Schumacher, Ralf; de Wild, Michael04B - Beitrag KonferenzschriftPublikation Mechanical anisotropy of titanium scaffolds(De Gruyter, 2017) Weber, Franz E.; de Wild, Michael; Rüegg, Jasmine; Schumacher, RalfThe clinical performance of an implant, e.g. for the treatment of large bone defects, depends on the implant material, anchorage, surface topography and chemistry, but also on the mechanical properties, like the stiffness. The latter can be adapted by the porosity. Whereas foams show isotropic mechanical properties, digitally modelled scaffolds can be designed with anisotropic behaviour. In this study, we designed and produced 3D scaffolds based on an orthogonal architecture and studied its angle-dependent stiffness. The aim was to produce scaffolds with different orientations of the microarchitecture by selective laser melting and compare the angle-specific mechanical behaviour with an in-silico simulation. The anisotropic characteristics of open-porous implants and technical limitations of the production process were studied.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Patient-specific hip prostheses designed by surgeons(De Gruyter, 30.09.2016) Coigny, Florian; Todor, Adrian; Rotaru, Horatiu; Schumacher, Ralf; Schkommodau, ErikPatient-specific bone and joint replacement implants lead to better functional and aesthetic results than conventional methods [1], [2], [3]. But extracting 3D shape information from CT Data and designing individual implants is demanding and requires multiple surgeon-to-engineer interactions. For manufacturing purposes, Additive Manufacturing offers various advantages, especially for low volume manufacturing parts, such as patient specific implants. To ease these new approaches and to avoid surgeon-to-engineer interactions a new design software approach is needed which offers highly automated and user friendly planning steps.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation 3D Printing in Medicine: Yesterday – Today - Tomorrow(06/2016) Schumacher, Ralf06 - PräsentationPublikation Degradable Mg scaffolds produced by selective laser melting (P1035)(05/2016) Rüegg, Jasmine; Böhringer, Stephan; Kessler, Anja; Schumacher, Ralf; Schkommodau, Erik; de Wild, Michael06 - PräsentationPublikation So profitiert die Medizintechnik vom 3D Druck(Springer, 27.01.2016) Moser, Silvio; Schumacher, Ralf01A - Beitrag in wissenschaftlicher ZeitschriftPublikation 3D Printing in Medicine: Revolution or Illusion?(2016) Schumacher, Ralf06 - PräsentationPublikation Preliminary microstructural investigation of Mg produced by SLM(European Cells and Materials, 2016) Saxer, Sina; Rüegg, Jasmine; Dietschy, Alain; Schumacher, Ralf; de Wild, Michael; Wiese, Björn; Wohlfender, Fabian01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Influence of microarchitecture on osteoconduction and mechanics of porous titanium scaffolds generated by selective laser melting(Mary Ann Liebert, 2016) de Wild, Michael; Zimmermann, Simon; Rüegg, Jasmine; Schumacher, Ralf; Fleischmann, Thea; Ghayor, Chafik; Weber, Franz E.Bone regeneration is naturally based on bone forming cells, osteoinduction by diverse growth factors, and osteoconduction. The latter one used as term in this study is the ingrowth of bone in 3D structures, which leads to an optimal case in creeping substitution of the scaffold by newly formed bone. Autologous bone is still the gold standard for bone substitutes. In most cases, newly developed bone substitutes consist of calcium phosphate, since hydroxyapatite is the main component of bone and mimics cancellous bone in microstructure. In this study, we wanted to elucidate the optimal microarchitecture for osteoconduction and determine compression strength and Young’s Modulus of the selected architectures. Selective laser melting of titanium was used as tool to generate diverse architectures in a repetitive and precise way. To link 3D scaffold architecture to biological readouts, bone ingrowth, bone to implant contact, and defect bridging of noncritical-sized defects in the calvarial bone of rabbits were determined. In this series, 5 different microarchitectures were tested with pore sizes ranging from 700 to 1300 lm and constrictions between 290 and 700 lm. To our surprise, all microstructures showed the same biological response of excellent osteoconduction. However, the mechanical yield strength of these structures differed by the factor of three and reached up to three times the strength of cancellous bone at a porosity of 72.3–88.4%. These results suggest that the microarchitecture of bone substitutes can be optimized toward mechanical strength in a wide range of constrictions and pore sizes without having a negative influence on osteoconduction.01A - Beitrag in wissenschaftlicher Zeitschrift