sls total quality management (tqm) for rapid manufacturing
TRANSCRIPT
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SLS Total Quality Management (TQM) for Rapid Manufacturing
Gideon N. Levy1, Ralf Schindel, Peter Schleiss, Adriaan SpieringsFHS University of Applied Sciences St. Gallen, SwitzerlandInstitute for Rapid Product Development (1Head of Institute)
Frankfurt, November 2006
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FHS
St. G
alle
n
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FHO
© 2001 by FHS St. Gallen
Welcome!
Inst
itute
RPD
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Institute RPD at the EMPA SG
InstituteRPD
Architect: Theo Hotz, ZurichInauguration: 15th August 1996
Award-winning: European Prize for industrial buildings
Constructer-Prize 1996
Inst
itute
RPD
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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
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What is Rapid Manufacturing (RM)?
• Rudgley M. defines RM as “the manufacture of end-use 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
Def
initi
on a
nd C
lass
ifica
tion
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RM – of: Wash Blocks
Rap
id M
anuf
actu
ring
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RM – of: Transport elements
Rap
id M
anuf
actu
ring
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RM – of: Transport elements Logistics
05
10
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[Stück]
07.10.05 21.10.05 04.11.05 18.11.05 02.12.05 16.12.05
[Zeit]
Bestell - EingangGeometrie 4Geometrie 3Geometrie 2Geometrie 1
Rap
id M
anuf
actu
ring
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The Rapid Manufacturing Process
TQM
Mod
el
Plastics
Metals
Ceramics
Composites
Solid Liquid Gases
Powder
Foil
Wire
Material
Thermal Layering
Chemical Layering
postprocessing
traditionalprocessing
coatingfinish
Q1
Q2 Q3
Q4 Q5 Q6Q3
Part
DATA
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Rapid Manufacturing TQM Matrix Overview
Means Description Pre-requirements Process
dependency existing new
Q1
Mat
eria
ls • Input quality of process
specific material grades • Behavior over time • Shelf time
• Database • Characterization • Virgin material • standards
strongly process and material grade dependent
Q2
Laye
ring
• Process equipment state Energy source
• Material ageing • Recycling
• Calibration • Preventive
maintains • Repeatability
Strongly materials , parameters and system stability
Existing standards
• Materials norms
• Durability over time,
• Porosity measure
Dimensional quality Geometry and allowances
RE techniques
Q3
Com
pone
nt
• mechanical • physical • chemical, • electrical properties
Product spec Destructive add-on parts
Existing standards
Q4
Post
trea
tmen
t
• Removal residual loose materials
• Infiltration, • Post curing • Heat treatments
TQM
Mod
el
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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
Mod
el
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Virgin Material Specifications deviations consistencyAverage 6 Batches Mean STABW Variant
Ø σ 6σ
Particle size <100 µ 95 - 100 % 99.22 0.35584266 2.15% 0.15828< 63 µ 60 - 85 % 71.79 2.61514359 21.86% 8.54872< 10 µ 0 - 5 % 3.35 0.56856310 101.71% 0.40408
D50 40 - 60 µ 52.79 1.46059714 16.60% 2.66668 influence?
Fluidizing factor (SAMES) > 100 132 8.19679816 37.33% 90 better!
Melting point of polyamide DSC 183 - 189 °C 185.5 0.32015621 1.04% 0.14
Crystallization point DSC 145 - 155 °C 147.4 0.29154759 1.19% 0.11
Mold Flow Index (@235c) MFI virgin > 100 @ 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
Mat
eria
l
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Fluidization humidity control others?
Influence range?
Q1
Mat
eria
l
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Virgin powder MFI measure @ 235 °c
0.00
20.00
40.00
60.00
80.00
100.00
120.00
30.07
.2004
30.10
.2004
30.01
.2005
30.04
.2005
30.07
.2005
30.10
.2005
30.01
.2006
30.04
.2006
190 C 235 C Linear (235 C) Linear (190 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?
Q1
Mat
eria
l
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Material aging (shelf time?) DSC measurement
Q1
Mat
eria
l
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ATC Advanced Temperature Control
Q2
Laye
ring
-Sys
tem
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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
Laye
ring
-Sys
tem
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Sytem controls: The Pro Sinterstation
Scanning galvomotors working in closed position loop
CO2 laser beam energy measured and kept constant
The themo IR sensor is on line calibrated closed loop control
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Boeing Patent EP 1 486 317 A1 (Pri. 10.6.2003)
Q2
Laye
ring
-Sys
tem
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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
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Regeneration mixing principle and system
X ?
Q2
Laye
ring
-Rec
yclin
g
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Powder Materials (MFI) Measurement
Q2
Laye
ring
-Rec
yclin
g
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Examples: Q2 Layering (MFI) material prior
-10.0
0.0
10.0
20.0
30.040.0
50.0
60.0
70.0
80.0
90.0
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65
Build (run)
MFI
QAMFILinear (MFI)
Virgin
Recycled
Inferior quality
Q2
Laye
ring
-Rec
yclin
g
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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
Laye
ring
-Rec
yclin
g
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Examples: Q3 Components (dimensions)
Measurements conventionally or with RE methods, especially for freeform parts with larger allowances. Q3
Part
s –
Dim
ensi
ons
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Examples: Q3 Surface Topology : how standards?
Q3
Part
s –
Dim
ensi
ons
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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 Q
3 Pa
rts
–Pr
oper
ties
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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
Part
s –
Prop
ertie
s
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Density ( Archimedes) stainless steel 1.4404
( )tmm
mw
wa
as ρρ ⋅
−= Q
3 SL
M D
ensi
ty
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Density ( Archimedes) stainless steel 1.4404
( )tmm
mw
wa
as ρρ ⋅
−=
Density material DIN 1.4404 13.11.2006
Temperature 23.5 c
(23,5) water 0.9974 Concept laser M1
Laser scann speed [mm/sec] Weight in air [g] Weight in distilled water [g]
Density [g /mm3]
Density deviation to
mean250 16.412 14.344 7.913671037 2.394%300 16.304 14.238 7.872820324 1.865%350 16.128 14.069 7.813701462 1.100%400 15.790 13.743 7.695175413 -0.433%450 15.684 13.624 7.591634155 -1.773%500 15.200 13.175 7.485005658 -3.153%
mean 7.728668008
standard deviation 0.142181007
Density DIN 1.4404 [g /mm3]
7.47.57.67.77.87.9
8
0 100 200 300 400 500 600
V [mm/sec]
Den
city
[g/c
m3]
Q3
SLM
Den
sity
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Comparison standard material CL20 -RPD material – development for stainless steel
* After SLM process
Mechanical properties of 1.4404- Tensile strength > 650 – 700 MPa- Yield point RP0.2 > 530 MPa
⇒ Significant higher values compared to Concept CL20
Yield point stainless steel - SLMSlice Thickness 30 um
0
100
200
300
400
500
600
700
0 degree 45 degree 90 degree
R p0.
2 [M
Pa]
CL20
1.4404M
Tensile Strength stainless steel - SLMSlice Thickness 30 um
0100200300400500600700800900
0 degree 45 degree 90 degreeR m
[MPa
]
CL20
1.4404M
Representative calibration and qualification of system, material in accordance with usual standards actually confirm periodically supplier or own material data
Q3
SLM
Den
sity
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Comparison standard material CL20 -RPD material – development for stainless steel
* After SLM process
Very high density- > 99% for standard processing parameters- Typical ≈ 99.5%
1.4404 (RPD) 1.4404 (Concept CL20)
Q3
SLM
Den
sity
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Q4 Post processing – Infiltration I
0
200
400
600
800
1000
1200
0:00
1:16
2:33
3:49
5:06
6:22
7:39
8:56
10:12
11:29
12:45
14:02
15:18
16:35
17:51
19:08
20:24
Time [h, min]
Tem
pera
tur
[ ° C ] ,
Tdi < 450 0CDe-binding
Mechanicalsupporting
Thermal Sintering
SetBottomTop
Q4
Post
pro
cess
ing
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Q4 Post processing – Infiltration IIINFILTRATION PROTOCOL Parts Build 719_LF_XITZ
Date 20.06.2006Sinterstation DTM 2500 ++
Oven cycle 213_LF 100oven heat ramp (°/h) 120
temperature (°C) 1080hold time (h) 3N2 flow (l/h) 40
Part Part 1 Part 2 Part 3 Part 5green part weight (g)
green part + tabs weight (g) 75 75bronze % 0.72 0.72factor 1.72 1.72calculated bronze weight (g) 54 54actual bronze weight (g) 54.5 54.5% difference (.< 1%) 0.93% 0.93% #DIV/0! #DIV/0!length bronze bar (mm) 9.1 9.1 0.0 0.0
Actual infiltrated parts weight (g)infiltrated part weight (g)
infiltrated part + tabs weight (g) 128.35 128.35infiltrated part weight (%) #DIV/0! #DIV/0! #DIV/0! #DIV/0!
infiltrated part + tabs (> 99%) 99.50% 99.50% #DIV/0! #DIV/0!
Q4
Post
pro
cess
ing
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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
Con
clus
ions