Case Study: Laser Powder Metal Deposition Manufacturing of Complex Real Parts

Transcription

1 Case Study: Laser Powder Metal Deposition Manufacturing of Complex Real Parts Aerospace applications for 5 axis 3D Printing using Laser Metal Deposition Carl Hauser, Principal Project Leader

2 OUTLINE The demonstrator part Laser Metal Deposition The Challenge Equipment and Software Results Summary

3 The Demonstrator Part Component: Helicopter engine combustion chamber Virole (Turbomeca) Application: Test bed validation during R&D phase. Lead Time: 2 months for conventional manufacture Size: 300mm diameter x 90mm tall. Material: Inconel 718 Surface roughness: <20 m RA Image supplied courtesy of Turbomeca

4 The Challenge Consistent thin wall (0.8mm ±0.12) Long straight wall sections (max 42mm) Fillet Radii (R10, R5 and R0.8) 90 degree flange (overhangs!) Net shape, defect free and <20 microns RA Heat distortion? Laser Metal Deposition or Selective Laser Melting???

5 Laser Metal Deposition Powder filler material CO2 Laser melts filler and substrate Strong metallurgical bond Low dilution (mixing) with substrate Full density weld track Large build envelope High % powder usage Nozzle and/or chamber gas shielding Multiple layering techniques for 3D Printing Applications: Coatings, repair and rebuild and 3D part manufacture.

6 Nozzle Choice Geometric Complexity Coaxial Multi-Jet Off-Axis Powder beam focus ~ mm. Laser Power <2KW. High precision. Deposition Rate Powder beam focus >1mm. Laser Power <6KW. 3D Contours. Powder beam focus >>1.5mm. Laser Power <10KW. Surface Cladding. LMD Nozzle images from Fraunhofer ILT

7 Circular Path Powder Focus Fluctuations Ideal Poor Surface finish Good Surface finish Reality Difficult to fine tune deposition parameters Rotating substrate would be better than moving a nozzle in a circular path!

8 Maintaining Powder-gas beam focus on top of weld tracks

9 Overhanging Features LMD has no natural support mechanism for overhanging geometries 40

10 Overhanging Features LMD has no natural support mechanism for overhanging geometries 10 max!

11 Overhanging Features LMD has no natural support mechanism for overhanging geometries

12 Overhanging Features LMD has no natural support mechanism for overhanging geometries

13 A Revolution in LMD Manufacturing LMD Nozzle indexes in +z Substrate revolves and tips

14 Software: Slicing Actual layer thickness at tilt Required Layer thicknes s, zh 0 Slice vector, v, at z 1 Slice vector, v, at z LMD tool path nx, ny, nz Ix, Iy, Iz Substrate

15 Software: Controlling Substrate Tilt zh 1-n LMD nozzle orientation zh 0 Z tool path >zh Slice height is adapted based on tilt of table Slice height during a build is constant

16 Processing Conditions Laser Power 925W Powder feed rate 1.5 bar Argon (3.4 litres/min) Argon shielding 1.0 bar and 3.0 litres/min z increment 0.19mm per revolution ~ 0.25mm/min 8.4mm microns IN718 powder 1200mm/min Work piece (stainless steel 304L) Powder-gas focus Laser beam focus 0.5mm 0.85mm

17 Automated LMD Manufacture The Future of NET Shape Manufacturing??

18 Surface Comparison to CAD Average tolerance 0.244mm from CAD (not including top flange). No heat treatments! 1.0mm 0.0mm -1.0mm

19 Wall Thickness 0.8mm 0.09 Average 0.845mm

20 Wall Deviation from CAD Simulation 5mm Radii - Part removed from substrate 0.8mm Radii - Part removed from substrate

21 Roundness 5mm Radii - Part removed from substrate 66mm height position

22 Summary 0.8 ±0.9mm thin wall structure successfully built with 5 Axis LMD. Key to success is letting substrate do most of the work. Tool path can be modified to correct for geometric distortion >99.5% wall density throughout (Mechanical properties being tested > focus is with corrosion resistance) 70% powder efficiency: 700 grams of powder fused in the part and 1.2kg passed through nozzle. Deposition rate ~0.9kg/h (build time reduced from months to 7.5 hours)

23 Next Steps Fond Demonstrator is currently in final stages of manufacture (completion December 2014)

24 Rubin Vase 400mm x 380mm 26 hour build time Continuous spiral path 2400 rotations 1.8Km weld track 0.9mm wall thickness 4kg of powder (3kg fused in vase) Inconel 718

25 Acknowledgements and Contact Dr Carl Hauser Joining Technologies Group TWI Technology Centre Yorkshire Advanced Manufacturing Park, Wallis Way, Catcliffe Rotherham. S60 5TZ, UK Tel: +44 (0) Web: