Additive manufacturing of CERAMICS technology overview. 3D Printing Materials Conference

Transcription

1 Additive manufacturing of CERAMICS technology overview 3D Printing Materials Conference Maastricht, January 27, 2015

2 Increase the competitiveness of companies through technological innovations

3 Sirris 25 years of Additive Manufacturing AM centre Leading position in EU since engineers and technicians 10+ high-tech additive technologies in house Most complete installed base in EU Driving technology companies in applications 3

4 (IN)DIRECT PROCESS Stereolithography 4

5 Stereolithography Vat filled with photopolymer (resin) Photopolymer= expoxy or acrylate Local cured by an UV-source (laser/dlp/ ) Materials: transparent/non-transparent/filled 5

6 Stereolithography Resin loaded with % ceramic nano-particles Improved thermal resistance (< 250 ⁰C) Improved rigidity Improved wear resistance Increased brittleness Examples: Nanoform, Ceramax Images 3DSystem 6

7 Stereolithography - Optoform Principle identical to stereolithography Resin loaded with % ceramic microparticles Build material paste Thixotropic material Machine adaptations Only a building plate, no box New recoater-concept 7

8 Stereolithography - Optoform Shaping Debinding - Sintering Accuracy: +/- 0,3% Wall: min. 600µm Pore: min. 700µm Available materials HA/TCP Al 2 O 3 SiC SiO 2 ZrO 2 8

9 Stereolithography - Optoform Benefits Drawbacks Flexibility for new material developments Good relative density Satisfying mechanical properties Possibility to have very fine details Low cost for short runs, small parts or complex design Long development for new materials Indirect process Process is not suitable for massive parts (1cm³, debinding) Require supports Cleaning limitation *** No geometrical limitation *** 9

10 INDIRECT PROCESS Binder Jetting 10

11 Binder jetting thre3d.com Layer of powder is spread Local binder depositioning on demand Post curing & infiltration needed with metals Polymers / metals / ceramics / sand 11

12 Binder jetting Indirect Printing Powder layer Binder Thermal process Debinding Infiltration Presintering Fullsintering Postprocessing 12

13 Binder jetting 13

14 Binder jetting Benefits Flexibility for new material developments Good relative density (infiltration or sintering) Possibility to build big parts/small series Indirect process Drawbacks Lots of manual labour Composite material often brittle with poor corrosion resistance * No geometrical limitation No supports needed Good mechanical properties * 14

15 DIRECT PROCESS Powder Bed Fusion - Laser Beam Melting 15

16 Laser Beam Melting Laser beam Main tank Melted zones Argon Recoater Spread powder Previous layers Initial plate 16

17 Laser Beam Melting Imperial Renishaw 3T / Within ConceptLaser

18 Laser Beam Melting Problems with ceramics: High density (> 99%) but cracks Thermal gradient Low strength Adaptation of SLM machine Preheating (1800 C for Al 2 O 3 -ZrO 2 ) homogenous temperature high mechanical strength (> 500MPa) high surface quality (R z < 100µm) but need to be improved!!! Source: 18

19 Laser Beam Melting Benefits Drawbacks Flexibility for new material developments Possibility to work with fine powders 10µm (d50) for very fine details Good density and mechanical properties No geometrical limitation Process is wall thickness dependent. (not suitable for massive parts) Process involving internal stresses in the parts need additional annealing/preheating Process requiring strong supports (anchoring and heat transfer) Need to use build plates of the same material than the powder used in the machine (e.g.: ceramic) 19

20 DIRECT PROCESS Direct Energy Deposition 20

21 Direct Energy Deposition Laser + central gaz (coaxial) Shape Gas Carrier gas + powder Track Meltpool Motion direction Substrate Heat Affected Zone The idea is to replace the drill on a 5 or more axes machine by a material deposition nozzle, a bit like the welding robots on a car production chain. Powder reaches the nozzle thanks to carrier gas and is blown through the laser beam. A part of the laser power melt the powder, the other part heat the substrate. 21

22 Direct Energy Deposition Coating : Easy way to coat any piece from its CAD file in order to improve properties such as : Wear resistance Corrosion resistance hardness Laser cladding service Laserline Alspi 22

23 Direct Energy Deposition Repair : IREPA ICE Pototyping (LENS) Fraunhofer center for surface and laser processing IWS fraunhofer 23

24 Direct Energy Deposition Benefits Drawbacks Vast material deposition possibilities Suitable for metals, ceramics, composites, Works on non-flat surfaces Can deal with two (or more) materials at the same time High cooling rate giving fine microstructure Works at room temperature in normal atmosphere Suitable for coatings of complex surfaces Slow process Poor accuracy Thick layers Fix tool unable to process bigger parts, unless placed on a robot Unknown metallurgical properties Recyclability of material gradients? Low geometry complexity for 3D manufacturing The nozzle has to be very close to the meltpool (~3-10 mm) access limitations in narrow area Thermal conditions change during a high part manufacturing Hard to keep the deposition conditions constant 24

25 CONCLUSIONS What you should remember 25

26 Conclusions Several techniques are available to print ceramics Stereolithography Stereolithography Optoform Binder jetting Laser beam melting Laser cladding Mechanical properties quite similar to traditional techniques, except for fatigue Lot of design freedom, although some limitations to take into account (size, powder and support removal, accuracy, surface quality) 26

27 Stijn Lambrechts, Additive Manufacturing sirris