Who we are and what we do - FHNW. Untersuchungen und Oberflächenmodifikationen. von SLM Strukturen. M. de Wild. Location: area of Basel

Transcription

1 Untersuchungen und Oberflächenmodifikationen von SLM Strukturen M. de Wild University of Applied Sciences Northwestern Switzerland, Institute for Medical Technologies IMA, CH 4132 Muttenz, Switzerland Who we are and what we do FHNW University of Applied Sciences Northwestern Switzerland FHNW Location: area of Basel students employees (head counts) School of Life Sciences School of Art and Design School of students 120 employees (head counts), 100 FTE IMA IEC ICB IPT 60 students 19 employees (head counts)

2 Overview Medical titanium scaffolds Mechanical and metallographic characterization, heat treatment Surface modification Outlook Individualized implants for temporary or permanent bone replacement virtual representation physical representation R. Schumacher, M. de Wild, S. Fabbri, A. Yildiz, E. Schkommodau, Rapid Manufacturing of Individualized Ti6Al4V Bone Implants, European Cells and Materials Vol. 17/22, 1 (2009).

3 Bone tissue Engineering GF Muschler et al., JBJS 86A (2004) 1541 Filigree Ti6Al4V structure with 200 µm struts Starting Material: Ti6Al4V Particle size distribution, chemical composition

4 Selective Laser Melting SLM SLM Realizer 100 from MTTTechnologies Measurement of outer proportions and deformation ATOS III 3DScanner (Guillenteguy, Schumacher et al 2008).

5 characterization of the bulk SLM microstructure Power 2000 Power 3600 Influence of the laser energy on the Ti6Al4V microstructure M de Wild, R Schumacher, S Fabbri, A Yildiz, E Schkommodau, Analysis and Surface Modification of Rapid Prototyped Titanium Structures, European Cells and Materials 17/6, 1 (2009). Ti6Al4V: fine grained lamellarα/β microstructure

6 Microstructure after different heat treatments BOYER Rodney. Materials properties handbook : Titanium alloys, ASM international, ISBN : E Modulus [GPa] Rp0.2 [MPa] Rm [MPa] A% No annealing 780 Heat treated in an inert atmosphere Heat treated ASTM F 136 Mechanical properties: Tensile tests on TAV SLM samples DIN ISO Ti6Al4V SLM structure, sample diameter d0=4mm and a gauge length L0=15 mm according to DIN M. de Wild, R. Schumacher, S. Fabbri, A. Yildiz, E. Schkommodau, Structural Analysis and Surface Modification of Rapid Prototyped Materials, 22nd European Conference on Biomaterials, 0812th September, 2009, Lausanne (Switzerland).

7 2500x 1200x no annealing annealing annealing under protective atmosphere Scanning electron analysis shows the microstructure of generatively fabricated Ti6Al4V sample a) asreceived b) after recrystallization anneal treatment c) after the same heat treatment in inert gas atmosphere. M. de Wild, R. Schumacher, S. Fabbri, A. Yildiz, E. Schkommodau, Structural Analysis and Surface Modification of Rapid Prototyped Materials, 22nd European Conference on Biomaterials, 0812th September, 2009, Lausanne (Switzerland). Fracture analysis Fracture of Ti6Al4V SLM structure Fatigue fracture of conventional structure traumatic rupture structure fatigue fracture fatigue striations

8 Servohydraulic testing machine: fatigue, material failure, fracture Native SLM surface Sintered spherical titanium particles that were not fully fused into the solid body. No visible scan trajectories.

9 sandblasted surface A) for abrasion and cleaning, B) for compaction. A A+B electropolished SLM surface confocal laser scanning microscope surface roughness 32um cutoff, 20x SLM TAV native SLM TAV A SLM TAV AB SLM TAV EP SLM TAV 140V SRa [µm] SRq [µm] Geometrical Product Specifications (GPS) Surface texture: Profile method spark anodized surface

10 Hydrophilicity native A&B A mod. native S.J. Ferguson, N. Broggini, M. Wieland, M. de Wild, F. Rupp, J. GeisGerstorfer, D. Buser. J. Biomed Mat Res. A. 78(2):2917, F. Rupp, L. Scheideler, N. Olshanska, M. de Wild, M. Wieland, J. GeisGerstorfer. Enhancing surface free energy and hydrophilicity through chemical modification of microstructured titanium implant surfaces. J. Biomed. Mater. Res. 76A, (2006). Conclusion The Additive Manufacturing method is suitable for direct forming of customized implants out of CAD or anatomical data (CT, MRI). Complex designs are possible: defined pores, inner structures, porous metallic scaffolds. There is a significant difference in mechanical properties between generatively and conventionally processed Ti6Al4V. The performance can be enhanced with carefully selected thermal postprocessing. The SLMsurfaces can be chemically or topographically modified to enhance the bonetissue integration.

11 Acknowledgements Ralf Schumacher Matthias Näf Sandro Fabbri Matthias Jeker Theo Bühler Helmut Falli Uwe Pieles Erik Schkommodau Michael Szymanski, Andreas Walter, Michel Wüthrich Boris Agbuga, Theo Walser Förderverein Fachhochschule Nordwestschweiz Solothurn Thank you for your attention!