Printing Metals and Light Absorbing Ceramics, using the DLP method J. Opschoor (ECN) March 2016 ECN-L--16-015
Printing Metals and Light Absorbing Ceramics, using the DLP method Additive World 'Industrial 3D Printing Conference' Jan Opschoor Eindhoven 22 March, 2016 www.ecn.nl
Why DLP AM for metals and light absorbing ceramics Using the strengths of the Powder Metallurgy (PM) basic process blending shaping sintering Particle size, distribution, shape Impurities Homogeneity Stability Strength green product Sintering dopes Sintering ambient, Temp Density / porosity 2
Advantages of PM based DLP technology Isotropic properties and microstructure Stress free material Segregation free Ultra high purity materials Flexibility by unique alloying/doping 3
High Resolution TEM of pure W Triple junctions (TJs) and grain boundaries (GBs) analysedby contrast in HRTEM and by X- EDS. representative observed atomic structure of a GB in the material. No impurity atoms or amorphous phase are seen on these GBs. 4
Controlled Microstructure by doping alloying (MIM W by ECN) 5
DLP (of Metals) basic proces Indirect, slurry based process 6 Admatec.nl
Proven Technology for oxidic ceramics Ceramic Materials Al 2 O 3 & ZrO 2 High Quality, small features, accurate details low roughness Blood analysis device 80 x 80 x 15mm 7 Admatec.nl
Limitating material properties Absorbtion& Light Scattering Light Scattering Polymerisation Photon Scattering Mie Theory Polymerisation Final Shape Light Absorbed by resin Changing of PI distribution Absorbed by UV Absorber or particle Absorbed by PI Polymerisation
Mismatch in refractive Index More dificult to cure The higher refractive index difference between particle and resin, the stronger the light scattering. (Less cure depth) * Additive Manufacturing of Ceramics: A Review J. Deckers Im. Refractive Refractive Index Material Index n n @ 437 nm Resin 1,46 0 SiO 2 1,47 0 Al 2 O 3 1,7 0 ZrO 2 2,25 0 SiC 2,69 0,7 Steel 2,48 2,6 W 3,41 2,6 Influence of the refractive index and solid loading of ceramic filler on the polymerisation conversion of a acrylate filled resin 9
MIE scattering 1/tot att coeff (µm) 6,00 5,00 4,00 3,00 2,00 1,00 Alumina 40% Vol 0,00 250 350 450 550 λ(nm) 120% 100% 80% 60% 40% 20% 0% D=0,1 µm D=0,5 µm D=1 µm D=3 µm 1/tot att coeff (µm) 6,00 5,00 4,00 3,00 2,00 1,00 penetration depth W35% vol 0 20 40 60 80 Penetration depth (µm) Tungsten 35% Vol 0,00 250 350 450 550 D=0,1 µm D=0,5 µm D=1 µm D=3 µm D=5 µm λ(nm) D=0,1 µm D=0,5 µm D=1 µm D=3 µm D=5 µm 10
To be succesfull Preparing a dedicated slurry to match your process is key. Photo Initiator Refractive Index Wave length Viscosity Solid content Powder Size Resin Material Curing Energy Polymer composition Absorbtion Distribution Additives Scattering 11
316L gyroid Sintered 316L part Size: 5x5x10 mm ECN 2015 ECN 2015 Detail of 3D printed geometry - sintered 3D printed geometry - sintered 12
316L gyroid Sintered 316L part Micro Structure Detail of 3D printed geometry - sintered 3D printed geometry - sintered 13
Printed details 14
Sintering process 316L Higher sintering temperature 15
Comparison with other AM techniques Without post processing Perpendicular to build direction. Binder Jet ExOne (Indirect Process) Photo Polymerisation 316L Sintered - ECN (Indirect Process) Powder Bed Fusion (Direct Process) 16
Metal Printing ECN: indirect and also direct Indirect method Direct method Pro - Isotropic high quality structure - Complex features possible - Low cost printing equipment Contra - Separate densification process - Shrinkage - Build speed lower than ceramics Pro - Direct - Low stress compared to SLM - Finer Features / channels possible Contra - Expensive equipment, comparable to Vat Photo Polymerisation equipment - Anisotropic microstructure Patents - Pending 3x - Assigned 1x Patents - Pending 1x 17
SiCand (Si 3 N 4 ) Photo Polymerisation SiC- ECN SiC after de-binding- ECN 18
Conclusion AM processes for Metals by Liquid solidification (melted droplets) (spot) welding (selective laser melting) Thermal spraying (preheated powder deposition / impact) Sintering Best AM metals by sintering! A production process comparable to PM Steel production and /or Metal Injection Moulding possible by VAT polymerization / DLP even for Metals AM of non oxidicceramics (SiCand Si 3 N 4 ) feasible by DLP Production speeds of cm / hour (full area) are realistic 19
Thank you for your attention Jaco Saurwalt Jan Opschoor saurwalt@ecn.nl opschoor@ecn.nl +31 885154696 +31 610313175 ECN North West Westerduinweg 3 1755 LE Petten The Netherlands ECN South East High Tech Campus 21 5656 AE Eindhoven The Netherlands T +31 885154949 F +31 885154480 info@ecn.nl www.ecn.nl 20 Solliance Building HTC21
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