www.merlin-project.eu 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
OUTLINE The demonstrator part Laser Metal Deposition The Challenge Equipment and Software Results Summary
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
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???
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.
Nozzle Choice Geometric Complexity Coaxial Multi-Jet Off-Axis Powder beam focus ~0.2-0.8mm. 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
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!
Maintaining Powder-gas beam focus on top of weld tracks
Overhanging Features LMD has no natural support mechanism for overhanging geometries 40
Overhanging Features LMD has no natural support mechanism for overhanging geometries 10 max!
Overhanging Features LMD has no natural support mechanism for overhanging geometries
Overhanging Features LMD has no natural support mechanism for overhanging geometries
A Revolution in LMD Manufacturing LMD Nozzle indexes in +z Substrate revolves and tips
Software: Slicing Actual layer thickness at tilt Required Layer thicknes s, zh 0 Slice vector, v, at z 1 Slice vector, v, at z 0 1 0 LMD tool path nx, ny, nz Ix, Iy, Iz Substrate
Software: Controlling Substrate Tilt zh 1-n LMD nozzle orientation zh 0 Z tool path >zh 0 0 0 Slice height is adapted based on tilt of table Slice height during a build is constant
Processing Conditions Laser Power 925W Powder feed rate 2.5grams/min @ 1.5 bar Argon (3.4 litres/min) Argon shielding gas @ 1.0 bar and 3.0 litres/min z increment 0.19mm per revolution ~ 0.25mm/min 8.4mm 15-45 microns IN718 powder 1200mm/min Work piece (stainless steel 304L) Powder-gas focus Laser beam focus 0.5mm 0.85mm
Automated LMD Manufacture The Future of NET Shape Manufacturing??
Surface Comparison to CAD Average tolerance 0.244mm from CAD (not including top flange). No heat treatments! 1.0mm 0.0mm -1.0mm
Wall Thickness 0.8mm 0.09 Average 0.845mm
Wall Deviation from CAD Simulation 5mm Radii - Part removed from substrate 0.8mm Radii - Part removed from substrate
Roundness 5mm Radii - Part removed from substrate 66mm height position
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)
Next Steps Fond Demonstrator is currently in final stages of manufacture (completion December 2014)
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
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)114 269 9046 E-mail: carl.hauser@twi.co.uk Web: www.twi-global.com www.merlin-project.eu