Yves Hagedorn - Fraunhofer Institute for Laser Technology

1,817 views

Published on

Published in: Technology, Business
0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
1,817
On SlideShare
0
From Embeds
0
Number of Embeds
2
Actions
Shares
0
Downloads
55
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Yves Hagedorn - Fraunhofer Institute for Laser Technology

  1. 1. Selective Laser Melting of Net-Shaped Oxide Ceramics State of the Art in Selective Laser Melting of Alumina Zirconia Ceramics June 2012 Yves Hagedorn
  2. 2. Outline Introduction Process Development Properties of Manufactured Parts Cost Drivers Conclusion
  3. 3. Introduction SLM of Net-shaped CeramicsCompetences Rapid Manufacturing Department Process Development Qualifying Selective Laser Melting (SLM) for enlarging the scope of applicable materials Improving component’s quality Increasing productivity Developing systems and componentsApplication Development Qualifying Selective Laser Melting (SLM) for series Production Tooling Dental applications Medical implants Turbo machinery Mechanical engineering 3
  4. 4. Introduction SLM of Net-shaped CeramicsSelective Laser Melting (SLM) for Ceramics Principle 3D-CAD Model in slices Complex, net- shaped part in series material Powder material 4
  5. 5. Introduction SLM of Net-shaped CeramicsSLM Readily Applied in Industry Some Industrial Applications for Metals Tooling Spacecrafts Medical © GFE Inno-Shape Undercuts Complexity Individuality  Internal structures  Filigree structures  Tool-less production as cooling channels without joining of customized parts 6
  6. 6. Introduction SLM of Net-shaped CeramicsSLM for Ceramics Advancements in SLM Allow for Fabrication of 3D CeramicsPositive Material SLM IndustrialProperties Manufact. Process Application+ Mechanical Strength + Tool - Free Medical Applications+ Wear Resistance + Complex Geometries  Dental Restorations+ Thermal Resistance + Fast  Implants+ Bio-Compatible + High Material Yield+ Esthetics + Cost Efficient High-Tech Applications  Aerospace  Automotive 7
  7. 7. Introduction SLM of Net-shaped CeramicsSelective Laser Melting (SLM) for Ceramics Main Objective Development of SLM process for ceramicsCurrent Application Framework for dental restorations from alumina / zirconia compounds Exploitation of high material strength Improved esthetics compared to Cr/Co ® BEGO Medical 2002 8
  8. 8. Outline Introduction Process Development Properties of Manufactured Parts Cost Drivers Conclusion
  9. 9. Process Development SLM of Net-shaped CeramicsThe System Al2O3 / ZrO2 Eutectic System Utilization of eutectic powder ratio Simultaneous crystallization of alumina / zirconia crystals Fine-grained microstructure S. M. Lakiza and L. M. Lopato. J.Am.Ceram.Soc.80 (1997), 893- 902 10
  10. 10. Process Development SLM of Net-shaped CeramicsSLM for Ceramics Approach Complete melting of ceramic material High densities High strength 11
  11. 11. Process Development SLM of Net-shaped CeramicsSLM for Ceramics First results High density Micro-cracks throughout material High thermal gradients during selective melting Low strength of manufactured objects (10 MPa) 12
  12. 12. Process Development SLM of Net-shaped CeramicsSLM for Ceramics Experimental Setup I/II Homogenisation Scanner optics CO2 laser-preheating Nd:YAG-laser Focussing optics Pyrometer Decrease of thermal gradients during selective laser melting CO2 -laser beam Powder distribution (preheating) Heat Powder reservoir isolation Substrate Crack-free specimens SLM part Building plattform 13
  13. 13. Process Development SLM of Net-shaped CeramicsSLM for Ceramics Experimental Setup II/II 14
  14. 14. Process Development SLM of Net-shaped CeramicsExperimental Conduction Thermal Image High-Temperature preheating Preheating temperature ~ 1800°C Homogenous temperature distribution 15
  15. 15. Process Development SLM of Net-shaped CeramicsExperimental Challenges  High Density 1 > 99 %  Crack free specimens 2 High-temperature pre-heating  High Mechanical Strength 3 > 500 MPa (DIN Norm for dental restorations)  High Surface Quality 4 Rz < 100 µm (own specification) 16
  16. 16. Outline Introduction Process Development Properties of Manufactured Parts Cost drivers Conclusion
  17. 17. Properties of Manufactured Parts SLM of Net-shaped CeramicsDensity & Powder Spherical Powder Excellent flowing ability Full density No crack formation 1 mm 18
  18. 18. Properties of Manufactured Parts SLM of Net-shaped CeramicsMicrostructureSEM Image Al2O3 matrix (dark) Dendritic structure of ZrO2 crystals (bright) Tunable fine-grained microstructure Complete melting of ceramic material 19
  19. 19. Properties of Manufactured Parts SLM of Net-shaped CeramicsHigh-temperature Creep Creep of Alumina / Zirconia Material Sintered vs. SLM 30,00% Loading with 200 g 25,00% SLM 20,00% Eutectic material ratio Elongation 15,00% Max. elongation ~ 24% 10,00% Sintered 5,00% 0,00% 1600°C/2h 1650°C/2h 1650°C/4h 1700°C/2h 1700°C/4h Temperature/time This Analysis has been performed by Innalox bv, Netherlands SLM material shows decreased creep compared to sintered material 20
  20. 20. Properties of Manufactured Parts SLM of Net-shaped CeramicsXRD Analysis Crystallographic distribution Tetragonal ZrO2 crystals Phase shift ZrO2: tetragonal  monoclinic This Analysis has been performed by TNO Science and Industry, Netherlands Self healing abilities of ZrO2 persist despite complete melting 21
  21. 21. Properties of Manufactured Parts SLM of Net-shaped CeramicsMechanical StrengthTest Samples Eutectic material ratio Dimensions: ø 18 mm x 2.5 mm Flexural strength > 500 MPa Flexural strength of sintered material > 1000 MPa Load Specimen Support Mechanical strength sufficient for r = 5 mm dental restorations (DIN Norm) 22
  22. 22. Properties of Manufactured Parts SLM of Net-shaped CeramicsMechanical Strength Conventionally 10 mm SLM 10 mm Max. load 2299 N Max. load 1435 N Material: ZrO2 Material: Al2O3/ZrO2 Rz value: ~ 10 µm Rz value: ~ 100 µm Minimum load for application  1000 N Sufficient strength for application despite weaker material and poor surface quality 23
  23. 23. Properties of Manufactured Parts SLM of Net-shaped CeramicsSurface Quality Dimensional Accuracy Milled part ~ 50 µm SLM part ~ 150 µm 5 mm Accuracy not sufficient for fitting 24
  24. 24. Properties of Manufactured Parts SLM of Net-shaped CeramicsSurface Quality Scanning Strategy Hatch Large melt pool due to high temp. preheating Contour / hatch Contour Impact on surface quality Contour Contour parameters spacing Contour spacing Improved surface quality due to small melt pool size at contour 25
  25. 25. Properties of Manufactured Parts SLM of Net-shaped Ceramics Surface Quality Contour Parameters I/II Rz ~ 112 µm 2 mm Sa ~ 54 µmLaser output: 150 WScanning speed: 250 mm/s 26
  26. 26. Properties of Manufactured Parts SLM of Net-shaped Ceramics Surface Quality Contour Parameters II/II Rz ~ 60 µm 2 mm Sa ~ 14 µmLaser output: 40 WScanning speed: 120 mm/s Surface quality strongly depends on geometry 27
  27. 27. Properties of Manufactured Parts SLM of Net-shaped CeramicsDemonstration Object Improved Surface Quality Surface roughness Rz < 100 µm Further improvements foreseen (Rz < 50 µm) 10 mm Employment of SLM for ceramic dental restorations possible New challenging applications needed 28
  28. 28. Outline Introduction Process Development Properties of Manufactured Parts Cost Drivers Conclusion
  29. 29. SLM of Net-shaped Ceramics Cost drivers SLM Ceramics Assumptions 50 Milled part ~ 30 € Powder (200 €/kg)Cost of dental restoration in € 40 Electricity (20 kWh) 30 Depreciation (5 years) 20 Manufacturing time (20 h/50 parts) 10 SLM part 22 € Personnel costs (25 Euro/h) 0 -100 -50 0 50 100 150 200 Total investment (450 000 Euro) Relative change in % SLM is competitive compared to milled dental restorations 30
  30. 30. Outline Introduction Process Development Properties of Manufactured Parts Cost Drivers Conclusion
  31. 31. SLM of Net-shaped CeramicsConclusion  First Bridges Produced 1 Sufficient strength, fitting subject to improvements  Great Environmental Gain 2 20 crowns  50 g material  Great Economical Gain 3 Forming & densification  1 process step  Possible new Applications 4 Increased thermal stability 32
  32. 32. SLM of Net-shaped CeramicsThank you for your attention! The research was partly funded by the European 6th framework project „Custom IMD“Thanks to our project partners!Dipl.-Ing. Dipl.-Wirt.-Ing. Yves Hagedorn M.Sc.Tel.: +49-(0)241-8906-674Fax: +49-(0)241-8906-121Hagedorn@ilt.fraunhofer.dewww.ilt.fraunhofer.de 33

×