Advances in Direct Metal Deposition

Transcription

1 Advances in Direct Metal Deposition Jyoti Mazumder* and Lijun Song University of Michigan July 15th, 21 Presented By S H Lee *Robert H Lurie Professor of Engineering A Laser Workshop on Laser Based Manufacturing

2 Outline Background History of DMD Introduction DMD System Overview Advances in DMD System Modeling Geometry Control Temperature Control Composition Prediction Microstructure Prediction Summary A Laser Workshop on Laser Based Manufacturing

3 Rapid Prototype Customer Initial CAD Model Conceptual Design Assembly Layouts Reduction in Time and Step Detailed Design SFM Prototype Production Time A Laser Workshop on Laser Based Manufacturing

4 Additive Manufacturing Additive Process Originally for Rapid Prototyping Application 3-D CAD data -> 2-D Slicing Layer by Layer Build-up Low Volume Manufacturing A Laser Workshop on Laser Based Manufacturing

5 Major RP Techniques StereoLithography (by 3D System) Laminated Object Manufacturing (by Helisys) Selective Laser Sintering (by DTM - 3D System) Fused Deposition Modeling (by StrataSys) 3D Printing (by Z-Corp.) Etc. Solid Ground Curing, Solder, Light Sculpting, Droplet Based Manufacturing, Holographic Interference Solidification,... A Laser Workshop on Laser Based Manufacturing

6 New Concept in RP Rapid Prototyping Intermediate Step Design Support or Verification Plastic Mold Part, Cast Mold Pattern or Mock-up Part Rapid Manufacturing/Production Near Net Shaped Product or Prototype (accuracy and finish) Functional Part (mold and metallic part) Better Part (multi-materials, heterogeneous) A Laser Workshop on Laser Based Manufacturing

7 Metal Deposition - Metallic Additive Manufacturing Laser sintering (LS) based Selective Laser Sintering (U of Texas, DTM, 1996) - 3D Systems Direct Metal Laser Sintering (EOS, Germany) Laser cladding (LC) based Direct Metal Deposition (UIUC, 1993) - UM/POM Laser Engineered Net Shaping (Sandia NL, 1996) - Optomec Direct Light Fabrication (Los Alamos NL, 1996) Controlled Metal Buildup (Fraunhofer, Aachen, 1996) Droplet based Droplet Based Manufacturing (UCI, 1991; MIT, 1993) A Laser Workshop on Laser Based Manufacturing

8 The Vision Imagine a global society where: scientists in Ann Arbor and Aachen, in the security of their laboratories, are analyzing, sharing and using experimental data, a global design team is collaboratively creating a new product and submitting it for fabrication to the company facility in Shanghai. Global collaboration for innovation over the Internet will cross-pollinate ideas, cut travel and reduce costs. A multi-national company designing their product in Detroit and producing in Dalian, China If the part is big, take process to the part Product on order anywhere any time A Laser Workshop on Laser Based Manufacturing

9 Part on Order Anywhere A Laser Workshop on Laser Based Manufacturing

10 Running to Moon: Mold & Mirrors.5 mm wall thickness in steel A Laser Polished Workshop to 4 on Laser Based Manufacturing Angstroms!

11 Application In Tissue engineering Titanium scaffold for implantation study in a mice spinal column * Image Provided by Prof. Scott Hollister 5 mm X-Ray of the Ti-Scaffold After Subcutenous Bone Growth Ti~ Bright White Bone ~ Blue Grey A Laser Workshop on Laser Based Manufacturing

12 MR-DMD System Control Room Robotic Work Area Paradigm change Mobility Process goes for the Part to be serviced. Container: DMD Package, Robot, Laser, HVAC, Utilities, etc. Adaptable Integration Different robot size Different laser power (1.-5. kw fiber-coupled Diode Laser, etc.) Cost-effectiveness Robot vs. CNC based platform A Laser Workshop on Laser Based Manufacturing Work Stations

13 MR-DMD System Robot Fiber optic Conduit Rotary Table Work Table Base Plate A Laser Workshop on Laser Based Manufacturing

14 Challenges to achieve the vision Remote Manufacturing with hot editing Precision for Near Net shape 3-D components in order of microns Approach: Closed loop Process control to keep outcome to the desired level A Laser Workshop on Laser Based Manufacturing

15 DMD Process Overview Copyright 1999 POM Company Inc. All rights reserved A Laser Workshop on Laser Based Manufacturing

16 Overview DMD Process Overview 1. Direct Metal Deposition High power laser builds parts layer-by-layer out of gas atomized metal powder 2. DMD Characteristics.5 dimensional accuracy Fully dense metal Controllable microstructure Heterogeneous material fabrication capability Control over internal geometry A Laser Workshop on Laser Based Manufacturing

17 Overview DMD Process Overview Water Cooling Laser Beam Channel Power Delivery Channel Blending of 5 common methodologies: Laser CAD CAM Sensors Power Metallurgy Omni directional concentric laser-powder-gas nozzle Shaping Gas Changeable Tip A Laser Workshop on Laser Based Manufacturing

18 Closed-Loop Process DMD Process Overview CO 2 Laser Closed-loop process Improves dimensional accuracy CAD/CAM Work Table Control Panel NC Chiller Feed-back Controller Power Supply Unit No need for intermediary machining of parts when deposit builds irregularly Near net shape within fraction of millimeter is possible Resulting in significantly reduced post DMD finishing and reduced cost Better thermal control and thus better microstructure control Better microstructure leading to better mechanical properties Significantly reduced distortion and thus post process complication and cost Left: DMD with feedback control Right: DMD without feedback control Example of direct metal fabrication with POM s closed loop height controller. Left: A Laser Workshop on Laser Based Manufacturing w/height controller; Right: no height controller.

19 Moving Optics DMD Process Overview Why moving optics? Part mass does not affect the usable work envelop (Velocity, acceleration etc) Part handling concerns reduced Angular deposition without moving part 1 Tons Note Complex angles of deposition A Laser Workshop on Laser Based Manufacturing

20 Energy, Environment, Economy DMD Process Overview Will save energy Will provide designed functionality Will reduce lead time & Economy friendly Environmentally Benign A Laser Workshop on Laser Based Manufacturing

21 How does DMD Machine Looks Like? DMD Process Overview Why moving optics? Part mass does not the usable work envelop (Velocity, acceleration etc) Part handling concerns reduced Angular deposition without moving part 1 Tons Note Complex angles of deposition A Laser Workshop on Laser Based Manufacturing

22 DMD System CO 2 Laser Work Table Control Panel NC Chiller Power Supply Unit CAD/CAM Feed-back Controller A Laser Workshop on Laser Based Manufacturing

23 Comparison of Material Properties: DMD vs. Wrought/Casting Material Fe and steel Material condition Tensile Strength Yield Strength Elongation Elastic Modulus Charpy Impact Hardness (Mpa) (ksi) (Mpa) (ksi) (%) (Gpa) (Mpsi) (J) (ft-lb) (HRC) H 13 H 13, DMD Wrought H 13 H 13 Wrought (Matweb) L SS 316SS, DMD L SS wrought Ni-Alloys Wasp Alloy Wrought Wasp alloy Co-Alloys Stellite 21 Cast Stellite SS, wrought Wasp Alloy, DMD Wasp alloy, wrought aged Stellite 21, DMD Stellite 21, cast Ti-Alloys Ti6Al4V (Grade V) Wrought Ti6Al4V (V) Al-alloys 447 Al 413 Al (cast) Cu-Alloys Ti6Al4V DMD, Inert atm Ti-6Al4V (V), wrought annealed parallel to deposition HV Cu-3 Ni HV Cu-3 Ni HV A Laser Workshop on Laser Based Manufacturing

24 Z (mm) DMD System Overview Conceptualization CAM tool path CAD Data Z Y X Product Y (mm) COMP: m/s X (mm) DMD with Advanced Modeling, Sensing and Control

25 Direct Metal Deposition DMD with closed loop control DMD Machine

26 Mathematical Modeling Process modeling of DMD to develop quantitative relationships between parameters for improved process control

27 Modeling: Governing Equation Continuity equation: Momentum equation: t u t u uu u l K u l p x Energy equation: C pt t ( c) t Convection term Diffusion term Darcy term u C T k T pl Convection term Conduction term f L f C pt Solute equation: uc D c D c c f c c t l s s t Phase change term at S/L interface s l s u Phase diffusion term Phase motion term

28 Multiple Track Deposition Model Beam size Transition Finish Overlap Scanning width Start Z The computation domain is not symmetric along laser moving direction Y

29 Evolution of Temperature Field Laser power: 19 W, beam diameter: 1.8 mm, scanning speed: 6 mm/min, and powder flow rate: 8 g/min.

30 Z (mm) Z (mm) Composition and Liquid Velocity Distribution Computed chromium concentration profile: Y X COMP: y-z surface -.1 COMP: Y (mm).5 1 m/s 1 2 X (mm) x-z surface and x-y surface 1 m/s Y (mm).5 1 X (mm)

31 Thermal Cycle

32 Geometry Control Camera Image acquisition cards DMD Processing Center (Logic OR) Over limit Laser beam gating signal Height Controller Figure 8 Cladding

33 Laser power (Kw) Melt pool temperature ( C) Temperature Control: Dynamics Experimental Setup Input and Output GPC Temperature Controller Laser powder Pyrometer Collecting lens Substrate bead Time (s) H13 powder flow rate: 1g/min; Scanning speed: 65mm/min; Standoff: 2mm (beam size 2mm)

34 Molten pool temperature ( C) (mean of temperature has been removed) Amplitude Temperature (1a) Control: Dynamics State Space Model Step Response: k 1 k k e k X AX Bu K k k k e k y CX Du Dynamic Model Output Step Response From: u1 To: y1 System: Goe I/O: u1 to y1 System: Goe Settling Time (sec):.323 I/O: u1 to y1 Rise Time (sec): Time (sec) Rise time : 165ms Time (s)

35 GPC Controller with constraints Simulink Model 1. GPC Controller 2. A/D D/A interface to DMD process 3. State Estimation

36 Laser driven voltage (V) Temperature ( Molten pool temperature ( C) Noise and disturbance ( Laser power (W) Simulation: Weight on control: 1 Prediction horizon: 3 Control horizon: 5 Tfilter = [1 -.8] Melt Pool Temperature Control Experimental: Weight on control: Prediction horizon: 16 Control horizon: 5 Tfilter = [1 -.8] 4 C) C) Time (s) time (s) Red: reference temperature Black: experimental

37 Cladding height (mm) One Inch Cube Cladding with Temperature Control Molten Pool Temperature Control Cladding (a) (b) a 3mm step Substrate b A z y x (c) (d) With control, a With control, b No control, a No control, b 4 2 Pictures of the deposition at (a) 1 th layer, (b) 2 th layer, (c) 3 th layer and (d) 4 th layer Cladding layer number Cladding height at different layers

38 Composition Prediction Alloys without Phase Transformation Cr-Fe Ni-Fe Alloys With Phase Transformation Ti-Fe Ni-Al Ni-Ti Hopper1 Hopper2 bead Laser beam Substrate Signal processing unit spectrometer Collecting lens Experimental Setup

39 Cr-I nm/Fe-I nm Cr-I nm/Fe-I nm plasam temperature (K) Cr-I nm/Fe-I nm Cr-I nm/Fe-I nm Composition Prediction: Cr-Fe Alloy Calibration Curve Cr weight percentage Cr weight percentage Cr weight percentage Line Intensity Plasma Temperature

40 composition variation (%) Prediction of Cr% in the Alloy Composition Variation < 5% from single line ratio from temperature from electron density from four averaged line ratio from seven averaged line ratio from seven averaged line ratio and electron density Cr weight ratio percentage

41 Cr composition (%) Cr composition (%) Composition Sensor for Time Domain Prediction Cr % for 19.8% Cr % for 22.36% Measurement point Measurement point Resolution = 2 δ = 4.1%

42 Ni 349nm / Fe 363nm Ni 349nm / Fe 364nm Ni 346nm / Fe 363nm Ni 346nm / Fe 364nm Calibration Curve for Fe-Ni Alloy Ni/Fe weight ratio Ni/Fe weight ratio Ni/Fe weight ratio Ni/Fe weight ratio

43 Fe-I 44.6nm/Ti-II 417.4nm Fe-I 47.2nm/Ti-II 417.4nm Fe-I 44.6nm/Ti-II 416.4nm Fe-I 47.2nm/Ti-II 416.4nm Microstructure Sensor: Ti-Fe Alloy (Patent Pending) Calibration Curve um Weight percent Ti Weight percent Ti Hypereutectic Ti 56 Fe Weight percent Ti Weight percent Ti Hypoeutectic Ti 7 Fe 3 Hypereutectic Ti 62 Fe 38 Eutectic Ti 67.5 Fe 25.5 Hypoeutectic Ti 73 Fe 27

44 plasma temperature (K) plasma electron density (/cm 3 ) Ti-Fe Alloy Calibration Curve for Ti-Fe Alloy Plasma Temperature Electron Density 62 3 x Weight percent Ti Cr/Fe weight ratio

45 Al-I nm/Ni-I nm Al-I nm/Ni-I nm Al-I 394.4nm/Ni-I nm Al-I 394.4nm/Ni-I nm Ni-Al Alloy Phase Transformation and Line Intensity Ratio um Atomic percent Ni Atomic percent Ni B2 Ni 65 Al Gamma Prime Ni 8 Al Atomic percent Ni Atomic percent Ni B2 Ni 65 Al 35 Gamma Prime Ni 65 Al 35? Ti 67.5 Fe 25.5

46 Intensity(Counts) XRD Pattern of Ni8Al2 Sample as Deposited [Z2639.raw] NI8AL2 (111) > AlNi 3 - Aluminum Nickel 75 5 (2) 25 (1) (11) (21) (211) (3) (22) (311) (222) (4) (32) (321) Two-Theta (deg)

47 Tl-I nm/Ni-I nm Tl-I nm/Ni-I nm Tl-I nm/Ni-I nm Tl-I nm/Ni-I nm Ni-Ti Alloy Phase Transformation and Line Intensity Ratio Ni-Ti Alloy Ni 79 TI Atomic percent Ni Atomic percent Ni Ni 87 Tl Atomic percent Ni Atomic percent Ni Ni 84 TI 16 1 um Ni 9 Tl 1

48 Process Model Summary and Conclusion Simulate melt pool temperature, velocity, fluid interface thermal cycle, and composition evolution and distribution Process Sensor and Control Design, Optimization and Implementation Geometry Control Melt pool temperature dynamics and control Composition sensor Microstructure sensor First time in the world one will have the capability to predict the microstructure during the process from plasma, leading to considerable cost and lead time saving

49 Thank you for your attention! Any questions or comments?