SLS Total Quality Management (TQM) for Rapid Manufacturing

Transkript

1 SLS Total Quality Management (TQM) for Rapid Manufacturing Gideon N. Levy 1, Ralf Schindel, Peter Schleiss, Adriaan Spierings FHS University of Applied Sciences St. Gallen, Switzerland Institute for Rapid Product Development ( 1 Head of Institute) Frankfurt, November 2006 Mitglied der Fachhochschule Ostschweiz FHO 1

2 FHS St. Gallen Welcome! Institute RPD Mitglied der Fachhochschule Ostschweiz FHO by FHS St. Gallen FHS St.Gallen Mitglied der Fachhochschule Ostschweiz FHO 2

3 Institute RPD at the EMPA SG Institute RPD Institute RPD Architect: Theo Hotz, Zurich Inauguration: 15th August 1996 Award-winning: European Prize for industrial buildings Constructer-Prize 1996 Mitglied der Fachhochschule Ostschweiz FHO 3

4 Institute RPD Mitglied der Fachhochschule Ostschweiz FHO 4

5 Institute RPD Mitglied der Fachhochschule Ostschweiz FHO 5

6 Institute RPD Mitglied der Fachhochschule Ostschweiz FHO 6

7 SLM Institute RPD Mitglied der Fachhochschule Ostschweiz FHO 7

8 Agenda Introduction What is Rapid Manufacturing (RM)? The Rapid Manufacturing Process TQM Matrix Overview Some Specific Requirements SLS in line quality Examples Q1 Materials Q2 Layering Q3 Components Q4 Post processing Conclusions Mitglied der Fachhochschule Ostschweiz FHO 8

9 What is Rapid Manufacturing (RM)? Rudgley M. defines RM as the manufacture of enduse products using additive manufacturing techniques (solid imaging) RM must guarantee long-term consistent component use for the entire product life cycle or for a defined minimal period for wearing parts. This calls for a most significant role of materials in the LM technologies as argued later. RM must guarantee TOTAL QUALITY components Definition and Classification Mitglied der Fachhochschule Ostschweiz FHO 9

10 RM of: Wash Blocks Rapid Manufacturing Mitglied der Fachhochschule Ostschweiz FHO 10

11 RM of: Transport elements Rapid Manufacturing Mitglied der Fachhochschule Ostschweiz FHO 11

12 RM of: Transport elements Logistics [Stück] Bestell - Eingang Geometrie 4 40 Geometrie 3 35 Geometrie 2 30 Geometrie [Zeit] Rapid Manufacturing Mitglied der Fachhochschule Ostschweiz FHO 12

13 The Rapid Manufacturing Process Q1 DATA Plastics Metals Ceramics Composites Q3 Solid Liquid Gases Powder Foil Wire post processing Material Q2 traditional processing Thermal Layering Part Chemical Layering coating finish Q3 Q4 Q5 Q6 TQM Model Mitglied der Fachhochschule Ostschweiz FHO 13

14 Rapid Manufacturing TQM Matrix Overview Description Pre-requirements Process dependency existing Means new Q1 Q2 Q3 Component Layering Materials Input quality of process specific material grades Behavior over time Shelf time Process equipment state Energy source Material ageing Recycling Dimensional quality mechanical physical chemical, electrical properties Database Characterization Virgin material standards Calibration Preventive maintains Repeatability Geometry and allowances Product spec strongly process and material grade dependent Strongly materials, parameters and system stability Destructive add-on parts Existing standards RE techniques Existing standards Materials norms Durability over time, Porosity measure TQM Model Q4 Post treatment Removal residual loose materials Infiltration, Post curing Heat treatments Mitglied der Fachhochschule Ostschweiz FHO 14

15 Some Specific Requirements Use simple quick straight forward verification methods Based on scientific and experimental specific data As generic as possible Based on known standards and procedures Avoid component specific intensive investment needs in labor and equipment Minimal preparation work in programming and procedures Usable for as many as possible Layering process Propose new Rapid Manufacturing Standards if necessary TQM Model Mitglied der Fachhochschule Ostschweiz FHO 15

16 Q1 Material Mitglied der Fachhochschule Ostschweiz FHO 16

17 Virgin Material Specifications deviations consistency Average 6 Batches Mean STABW Variant Ø σ 6σ Particle size <100 µ % % < 63 µ % % < 10 µ 0-5 % % D µ % influence? Fluidizing factor (SAMES) > % 90 better! Melting point of polyamide DSC C % 0.14 Crystallization point DSC C % 0.11 Mold Flow Index (@235c) MFI virgin > 235 C???? missing Delivered virgin material in specifications Virgin material in close allowances Good repeatability Spec. not always available to end user MFI a significant value missing Fluidization? Are other values needed? Q1 Material Mitglied der Fachhochschule Ostschweiz FHO 17

18 Fluidization humidity control others? Q1 Material Influence range? Mitglied der Fachhochschule Ostschweiz FHO 18

19 Virgin powder MFI 235 c Virgin PA powder has different thermal and viscosity properties then recycled powder Virgin PA powder has shorter polymer chains and lower viscosity Virgin low viscosity PA powder is more economic in the recycling MFI measurement standards? C 235 C Linear (235 C) Linear (190 C) Q1 Material Mitglied der Fachhochschule Ostschweiz FHO 19

20 Material aging (shelf time?) DSC measurement Q1 Material Mitglied der Fachhochschule Ostschweiz FHO 20

21 Q2 Layering Mitglied der Fachhochschule Ostschweiz FHO 21

22 ATC Advanced Temperature Control Q2 Layering - System Mitglied der Fachhochschule Ostschweiz FHO 22

23 TEMPERATURE STABILIZATION UPGRADE STABLETEMP TEMPERATURE STABILIZATION UPGRADE Integra Services now offers the StableTemp Temperature Stabilization Upgrade for your 2000, 2500 CI, 2500 Plus, and Vanguard Laser Sintering Platforms. StableTemp will eliminate the need to ramp your part bed temperatures during a build no matter the build height. Just set your temperatures, run the build and StableTemp will take care of the rest, build after build. Q2 Layering - System Mitglied der Fachhochschule Ostschweiz FHO 23

24 Q2 Layering - System Mitglied der Fachhochschule Ostschweiz FHO 24

25 Q2 Layering - System Mitglied der Fachhochschule Ostschweiz FHO 25

26 Sytem controls: The Pro Sinterstation Scanning galvo motors working in closed position loop CO2 laser beam energy measured and kept constant The themo IR sensor is on line calibrated closed loop control Mitglied der Fachhochschule Ostschweiz FHO 26

27 Boeing Patent EP A1 (Pri ) Q2 Layering - System Mitglied der Fachhochschule Ostschweiz FHO 27

28 Powder Management The powder is changing propertied over use The melting point is raising The viscosity is growing For good results and constant quality we have to take care and worked under constant conditions in a well define allowence field For PA 12 the sieving, mixing virgin, humidity control and other (?) parameters are essential. The most significant parameters have to be measurable and adjustable or controllable. A strict documented powder management is required No standards or agreed methods available No reporting Mitglied der Fachhochschule Ostschweiz FHO 28

29 Regeneration mixing principle and system X? Q2 Layering - Recycling Mitglied der Fachhochschule Ostschweiz FHO 29

30 Powder Materials (MFI) Measurement Q2 Layering - Recycling Mitglied der Fachhochschule Ostschweiz FHO 30

31 Examples: Q2 Layering (MFI) material prior Virgin Recycled Inferior quality MFI QA MFI Linear (MFI) Build (run) Q2 Layering - Recycling Mitglied der Fachhochschule Ostschweiz FHO 31

32 Poor MFI of PA powder (orange peel) Use: virgin PA powder or recycled only Use: constant MFI material for each batch Gain: constant viscosity and melting point Obtain: better builds, better accuracy better repeatability Q2 Layering - Recycling Mitglied der Fachhochschule Ostschweiz FHO 32

33 Q3 Components Mitglied der Fachhochschule Ostschweiz FHO 33

34 Examples: Q3 Components (dimensions) Measurements conventionally or with RE methods, especially for freeform parts with larger allowances. Q3 Parts Dimensions Mitglied der Fachhochschule Ostschweiz FHO 34

35 Examples: Q3 Surface Topology : how standards? Q3 Parts Dimensions Mitglied der Fachhochschule Ostschweiz FHO 35

36 Q3 Components - Properties Product connector set Inbuilt destructive ring specimen Testing machine Inbuilt special designed mechanical testing procedure specimen and testing equipment, (SLS Duraform ) Source: Griesbach, VG. Kunststofftechnik Component placeholder, build especially in a measurable geometry and is undergoing a destructive test Q3 Parts Properties Mitglied der Fachhochschule Ostschweiz FHO 36

37 RPD Periodik Consistency test T bone Groups (5 connected) 5 pillars points X position 5 plane orientations 4 sidewall Total: [5x5x5] + [4x5] = 145 T bones to measure! (x parameter set)!!! Q3 Parts Properties Mitglied der Fachhochschule Ostschweiz FHO 37

38 Density ( Archimedes) stainless steel ρ s = m a m a m w ρ w () t Q3 SLM Density Mitglied der Fachhochschule Ostschweiz FHO 38

39 Density ( Archimedes) stainless steel Density material DIN Temperature 23.5 c (23,5) water Concept laser M1 Laser scann speed [mm/sec] Dencity [g/cm3] Weight in air [g] Weight in distilled water [g] Density [g /mm3] Density deviation to mean % % % % % % mean Density DIN [g /mm3] V [mm/sec] standard deviation ρ s = m a m a m w ρ () t Mitglied der Fachhochschule Ostschweiz FHO 39 w Q3 SLM Density

40 Comparison standard material CL20 - RPD material development for stainless steel Mechanical properties of Tensile strength > MPa - Yield point R P0.2 > 530 MPa Rp0.2 [MPa] Yield point stainless steel - SLM Slice Thickness 30 um 0 degree 45 degree 90 degree Significant higher values compared to Concept CL20 Representative calibration and qualification of system, material in * After SLM process accordance with usual standards actually confirm periodically supplier or own material data CL M Rm [MPa] Tensile Strength stainless steel - SLM Slice Thickness 30 um 0 degree 45 degree 90 degree CL M Q3 SLM Density Mitglied der Fachhochschule Ostschweiz FHO 40

41 Comparison standard material CL20 - RPD material development for stainless steel Very high density - > 99% for standard processing parameters -Typical 99.5% Q3 SLM Density (RPD) (Concept CL20) * After SLM process Mitglied der Fachhochschule Ostschweiz FHO 41

42 Q4 Post processing Mitglied der Fachhochschule Ostschweiz FHO 42

43 Q4 Post processing Infiltration I Temperatur [ C], Debinding 0:00 1:16 2:33 3:49 5:06 6:22 7:39 8:56 Thermal Sintering Mechanical supporting Tdi < C 10:12 11:29 Time [h, min] 12:45 14:02 15:18 16:35 17:51 19:08 20:24 Set Bottom Top Q4 Post processing Mitglied der Fachhochschule Ostschweiz FHO 43

44 Q4 Post processing Infiltration II INFILTRATION PROTOCOL Parts Build 719_LF_XITZ Date Sinterstation DTM Oven cycle 213_LF 100 oven heat ramp ( /h) 120 temperature ( C) 1080 hold time (h) 3 N2 flow (l/h) 40 Part Part 1 Part 2 Part 3 Part 5 green part weight (g) green part + tabs weight (g) bronze % factor calculated bronze weight (g) actual bronze weight (g) % difference (.< 1%) 0.93% 0.93% #DIV/0! #DIV/0! length bronze bar (mm) Actual infiltrated parts weight (g) infiltrated part weight (g) infiltrated part + tabs weight (g) infiltrated part weight (%) #DIV/0! #DIV/0! #DIV/0! #DIV/0! infiltrated part + tabs (> 99%) 99.50% 99.50% #DIV/0! #DIV/0! Q4 Post processing Mitglied der Fachhochschule Ostschweiz FHO 44

45 Conclusions The introduction of a TQM methodology and model in the Rapid Manufacturing branch is vital. The amount of dedicated scientific and applied work is still very limited. The problem is complex multidimensional and often material and RP process dependent. Nevertheless the conventional methods standards and instrumentation deliver a good applicable base. The appeal and confidence in Rapid Manufacturing can and must be increased dramatically by applying TQM. The topic has to be on the RM community agenda. An extensive agreed TQM methodology supported by international standards is a must. Otherwise the RM will remain a higher volume Rapid Prototyping affair Conclusions Mitglied der Fachhochschule Ostschweiz FHO 45

46 Keep an eye on quality: Mitglied der Fachhochschule Ostschweiz FHO 46