©2018 inspire AG
Polymer Powders for Laser Sintering
Manfred Schmid, inspire icams
©2018 inspire AG
Agenda
- Additive Manufacturing and Laser Sintering (LS)
- Market for Polymer Powders
- Essential Powder Properties
- Polyamide 12 (PA12) for LS
- Processing of PA12 (commercial materials)
- Properties influencing process and parts
©2018 inspire AG
Introduction – inspire AG
Competence centre for the Swiss Industry regarding production technique and tooling. Founded on an initiative of ETH-Zürich and machine building industry. Approved as ETH-research annex institute (non-profit foundation).
ETH
inspire Industry
SME
Universities of applied science
Basic R&D Application driven
R&D Technology
Development Product development
Inspire, icams is working with Additive Manufacturing since 20 years
©2018 inspire AG
Introduction – Additive Manufacturing
©2018 inspire AG
Additive Manufacturing – state of the art
Source: Gartner
©2018 inspire AG
Introduction – Laser Sintering (LS)
Invented from Carl Deckard (1986 Univ. Austin (TX))
©2018 inspire AG
Introduction LS powders
©2018 inspire AG
PA12 unfilled
85%
PA12 filled 10%
PA11
others
Introduction LS powders
©2018 inspire AG
Introduction LS powders
Polymer Powders for Laser Sintering
Duraform® PA / Orgasol® invent smooth
©2018 inspire AG
An: Energy per unit area (or volume considering layer thickness)
)( ThicknessLayerSpeedScanSpaceScan
PowerLaserAN
PA 12 Used range:
100 ~ 200 J/cm3
Introduction LS process
©2018 inspire AG
work on DTM 2500plus for best processing, part details and good productivity
part bed temp: 175 C
laser power: 38 W
hatch distance: 0.25 mm
Laser speed: 10 m/s
An = 15 x 10-3 J/mm2
part bed temp: 164 C
laser power: 48 W
hatch distance: 0.15 mm
Laser speed: 10 m/s
An = 32 x 10-3 J/mm2
> < > =
LS process – building parts
©2018 inspire AG
Polymer powders for Laser Sintering
Duraform® PA / Orgasol® invent smooth
©2018 inspire AG
LS process – mechanical properties
Tensile tests with parts in X-, Z-direction
Charpy tests with parts in X-, Z-direction
Duraform® PA
175 C / 38 W / 0.25 mm
An = 15 x 10-3 J/mm2
Orgasol® invent smooth
164 C / 48 W / 0.15 mm
An = 32 x 10-3 J/mm2
©2018 inspire AG
LS process – mechanical properties
Duraform® PA Orgasol® invent smooth
values from MDS – 3DS inspire values MDS - Arkema inspire values
build direction X Z X Z X Z X Z
Young‘s
modulus
ISO
-52
7
MPa 1586 --- 1677 ± 41
1800 --- 1500 ± 25
max. Tensile
Strength MPa 43 --- 47.6
± 1.5 45 --- 51.7
± 0.7
Elongation
at Break % 14 --- 6.6
± 0.7 20 --- 12.0
± 0.4
Charpy
unnotched
ISO
19
7
1e
U
kJ/m2 --- --- 32.3 ± 2.6
34 --- 34.6 ± 2.0
Charpy
notched
ISO
19
7
1e
A kJ/m2
--- --- 2.0
± 0.5 --- --- 2.6
± 0.5
pronounced loss of mechanical properties in Z-direction for Orgasol® invent
Duraform® PA Orgasol® invent smooth
values from MDS – 3DS inspire values MDS - Arkema inspire values
build direction X Z X Z X Z X Z
Young‘s
modulus
ISO
-52
7
MPa 1586 --- 1677 ± 41
1611 ± 61
1800 --- 1500 ± 25
1580 ± 21
max. Tensile
Strength MPa 43 --- 47.6
± 1.5
40.6 ± 3.4
45 --- 51.7 ± 0.7
29.3 ± 3.6
Elongation
at Break % 14 --- 6.6
± 0.7
3.7 ± 0.6
20 --- 12.0 ± 0.4
1.9 ± 0.3
Charpy
unnotched
ISO
19
7
1e
U
kJ/m2 --- --- 32.3 ± 2.6
10.2 ± 2.0
34 --- 34.6 ± 2.0
2.8 ± 0.7
Charpy
notched
ISO
19
7
1e
A kJ/m2
--- --- 2.0
± 0.5
2.1 ± 0.1
--- --- 2.6 ± 0.5
1.3 ± 0.2
©2018 inspire AG
LS process – surface characterisation
GelSight® for fast and reliable surface characterisation in mm- and µm-range
Duraform® PA
Orgasol® invent smooth
©2018 inspire AG
LS process – surface characterisation
top surface bottom surface upright surface
Dura
form
® P
A
Org
asol®
inv s
mooth
MountainsMap® Imaging Topography 7.3.7690
Orgasol Flat Bottomface
Surface Investigation Gelsight Magnification 3xPrimary surface; S1-nesting index (ni) = 0.008 mm
SF surface; F-operator = poly. degree 6; S1 = 0.008 mm
0 1 2 3 4 5 6 7 mm
mm
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
µm
0
10
20
30
40
50
60
70
80
90
I SO 25178
Height Parameters
Sq 7.67 µm
Ssk 0.410
Sku 5.34
Sz 97.1 µm
Sa 5.96 µm
Spatial Parameters
Sal 0.163 mm
Str 0.923
Std 50.7 °
Hybrid Parameters
Sdq 0.403
Sdr 6.47 %
Feature Parameters
Spd 32.7 1/mm²
S10z 64.3 µm
Other 3D Parameters
Miscellaneous
Sdar 40.2 mm²
Spar 37.8 mm²
I SO 12781
Flatness Parameters
FLTt 28.5 µm
FLTp 18.3 µm
FLTv 10.2 µm
FLTq 3.37 µm
1
10
100
1000
10000
100000
0.01 0.1 1 mm
I nformation
Method Enclosing boxes
Parameters Value
Fractal dimension 2.39
Scale of analysis
Num
ber
of
encl
osi
ng b
oxes
0°
10°
20°
30°
40°
50°
60°70°
80°90°100°110°
120°
130°
140°
150°
160°
170°
180°
Parameters Value Unit
Isotropy 92.3 %
First Direction 33.8 °
Second Direction 90.0 °
Third Direction 0.202 °
µm
0.000
97.146
24.286
48.573
72.859
0 20 40 60 80 100 %
0 5 10 15 20 25 %
MountainsMap® Imaging Topography 7.3.7690
Orgasol Lying Topface
Surface Investigation Gelsight Magnification 3xPrimary surface; S1-nesting index (ni) = 0.008 mm
SF surface; F-operator = poly. degree 6; S1 = 0.008 mm
0 1 2 3 4 5 6 7 mm
mm
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
µm
0
50
100
I SO 25178
Height Parameters
Sq 16.7 µm
Ssk 0.399
Sku 3.64
Sz 148 µm
Sa 13.0 µm
Spatial Parameters
Sal 0.142 mm
Str 0.871
Std 84.7 °
Hybrid Parameters
Sdq 0.532
Sdr 10.6 %
Feature Parameters
Spd 13.8 1/mm²
S10z 113 µm
Other 3D Parameters
Miscellaneous
Sdar 41.8 mm²
Spar 37.8 mm²
I SO 12781
Flatness Parameters
FLTt 37.7 µm
FLTp 21.3 µm
FLTv 16.4 µm
FLTq 6.04 µm
10
100
1000
10000
100000
0.01 0.1 1 mm
I nformation
Method Enclosing boxes
Parameters Value
Fractal dimension 2.29
Scale of analysis
Num
ber
of
encl
osi
ng b
oxes
0°
10°
20°
30°
40°
50°
60°70°
80°90°100°110°
120°
130°
140°
150°
160°
170°
180°
Parameters Value Unit
Isotropy 87.1 %
First Direction 33.8 °
Second Direction 90.0 °
Third Direction 116 °
µm
0.000
147.644
36.911
73.822
110.733
0 20 40 60 80 100 %
0 5 10 15 %
MountainsMap® Imaging Topography 7.3.7690
Orgasol Standing
Surface Investigation Gelsight Magnification 3xPrimary surface; S1-nesting index (ni) = 0.008 mm
SF surface; F-operator = poly. degree 6; S1 = 0.008 mm
0 1 2 3 4 5 6 7 mm
mm
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
µm
0
50
100
150
I SO 25178
Height Parameters
Sq 20.1 µm
Ssk -0.105
Sku 2.76
Sz 150 µm
Sa 16.3 µm
Spatial Parameters
Sal 0.113 mm
Str 0.0448
Std 90.0 °
Hybrid Parameters
Sdq 0.546
Sdr 10.9 %
Feature Parameters
Spd 11.5 1/mm²
S10z 96.8 µm
Other 3D Parameters
Miscellaneous
Sdar 41.9 mm²
Spar 37.8 mm²
I SO 12781
Flatness Parameters
FLTt 44.4 µm
FLTp 19.7 µm
FLTv 24.7 µm
FLTq 9.14 µm
10
100
1000
10000
100000
0.01 0.1 1 mm
I nformation
Method Enclosing boxes
Parameters Value
Fractal dimension 2.28
Scale of analysis
Num
ber
of
encl
osi
ng b
oxes
0°
10°
20°
30°
40°
50°
60°70°
80°90°100°110°
120°
130°
140°
150°
160°
170°
180°
Parameters Value Unit
Isotropy 4.48 %
First Direction 90.0 °
Second Direction 83.6 °
Third Direction 94.9 °
µm
0.000
150.182
37.546
75.091
112.637
0 20 40 60 80 100 %
0 2 4 6 8 10 12 %MountainsMap® Imaging Topography 7.3.7690
PA12 Lying Bottomface
Surface Investigation Gelsight Magnification 3xPrimary surface; S1-nesting index (ni) = 0.008 mm
SF surface; F-operator = poly. degree 6; S1 = 0.008 mm
0 1 2 3 4 5 6 7 mm
mm
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
µm
0
50
100
I SO 25178
Height Parameters
Sq 17.8 µm
Ssk -0.295
Sku 3.04
Sz 143 µm
Sa 14.2 µm
Spatial Parameters
Sal 0.142 mm
Str 0.866
Std 86.2 °
Hybrid Parameters
Sdq 0.568
Sdr 11.7 %
Feature Parameters
Spd 15.2 1/mm²
S10z 117 µm
Other 3D Parameters
Miscellaneous
Sdar 42.2 mm²
Spar 37.8 mm²
I SO 12781
Flatness Parameters
FLTt 41.1 µm
FLTp 20.3 µm
FLTv 20.8 µm
FLTq 6.60 µm
10
100
1000
10000
100000
0.01 0.1 1 mm
I nformation
Method Enclosing boxes
Parameters Value
Fractal dimension 2.28
Scale of analysis
Num
ber
of
encl
osi
ng b
oxes
0°
10°
20°
30°
40°
50°
60°70°
80°90°100°110°
120°
130°
140°
150°
160°
170°
180°
Parameters Value Unit
Isotropy 86.6 %
First Direction 90.0 °
Second Direction 146 °
Third Direction 0.130 °
µm
0.000
142.804
35.701
71.402
107.103
0 20 40 60 80 100 %
0 5 10 15 %
MountainsMap® Imaging Topography 7.3.7690
PA12 Lying Topface
Surface Investigation Gelsight Magnification 3xPrimary surface; S1-nesting index (ni) = 0.008 mm
SF surface; F-operator = poly. degree 6; S1 = 0.008 mm
0 1 2 3 4 5 6 7 mm
mm
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
µm
0
50
100
150
I SO 25178
Height Parameters
Sq 19.6 µm
Ssk -0.026
Sku 3.12
Sz 172 µm
Sa 15.6 µm
Spatial Parameters
Sal 0.175 mm
Str 0.887
Std 55.3 °
Hybrid Parameters
Sdq 0.552
Sdr 11.0 %
Feature Parameters
Spd 10.6 1/mm²
S10z 147 µm
Other 3D Parameters
Miscellaneous
Sdar 41.9 mm²
Spar 37.8 mm²
I SO 12781
Flatness Parameters
FLTt 48.0 µm
FLTp 24.2 µm
FLTv 23.9 µm
FLTq 8.48 µm
10
100
1000
10000
100000
0.01 0.1 1 mm
I nformation
Method Enclosing boxes
Parameters Value
Fractal dimension 2.26
Scale of analysis
Num
ber
of
encl
osi
ng b
oxes
0°
10°
20°
30°
40°
50°
60°70°
80°90°100°110°
120°
130°
140°
150°
160°
170°
180°
Parameters Value Unit
Isotropy 88.7 %
First Direction 63.5 °
Second Direction 0.177 °
Third Direction 33.8 °
µm
0.000
172.000
43.000
86.000
129.000
0 20 40 60 80 100 %
0 5 10 15 %
MountainsMap® Imaging Topography 7.3.7690
PA12 standing part (90deg)
Surface Investigation Gelsight Magnification 3xPrimary surface; S1-nesting index (ni) = 0.008 mm
SF surface; F-operator = poly. degree 6; S1 = 0.008 mm
0 1 2 3 4 5 6 7 mm
mm
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
µm
0
50
100
150
I SO 25178
Height Parameters
Sq 24.3 µm
Ssk -0.0963
Sku 2.98
Sz 197 µm
Sa 19.4 µm
Spatial Parameters
Sal 0.155 mm
Str 0.0413
Std 3.00 °
Hybrid Parameters
Sdq 0.604
Sdr 13.1 %
Feature Parameters
Spd 8.36 1/mm²
S10z 150 µm
Other 3D Parameters
Miscellaneous
Sdar 42.7 mm²
Spar 37.8 mm²
I SO 12781
Flatness Parameters
FLTt 70.3 µm
FLTp 37.0 µm
FLTv 33.2 µm
FLTq 11.1 µm
10
100
1000
10000
100000
0.01 0.1 1 mm
I nformation
Method Enclosing boxes
Parameters Value
Fractal dimension 2.25
Scale of analysis
Num
ber
of
encl
osi
ng b
oxes
0°
10°
20°
30°
40°
50°
60°70°
80°90°100°110°
120°
130°
140°
150°
160°
170°
180°
Parameters Value Unit
Isotropy 4.13 %
First Direction 0.0885 °
Second Direction 90.0 °
Third Direction 63.5 °
µm
0.000
196.787
49.197
98.394
147.591
0 20 40 60 80 100 %
0 5 10 15 %
Sq = 19.0 μm
Sa = 15.6 μm
Sq = 16.7 μm
Sa = 13.0 μm
Sq = 17.8 μm
Sa = 14.2 μm
Sq = 24.3 μm
Sa = 19.4 μm
Sq = 7.7 μm
Sa = 6.0 μm
Sq = 20.1 μm
Sa = 16.3 μm
Sa and Sq are the Average Roughness and Root Mean Square
Roughness are evaluated over the complete 3D surface respectively.
©2018 inspire AG
Polymer powders for Laser Sintering
Duraform® PA / Orgasol® invent smooth
Summary 1
©2018 inspire AG
Polymer powders for Laser Sintering
Duraform® PA / Orgasol® invent smooth
©2018 inspire AG
Arkema
Orgasol® invent smooth
3D Systems
Duraform® PA
Evonik (Vestosint®) Arkema (Orgasol®)
Production: Precipitation Production: Polymerisation
LS Materials – powder production
Orgasol® invent smooth
µm
DuraForm® PA
µm
©2018 inspire AG
Eρ = LP / HS*v (J/mm2)
∑Porosität (SLS) = 4% - 6%
Orgasol® i.s.
Duraform® PA
LS parts – microstructure and porosity
©2018 inspire AG
LS Materials – thermal behavior
melting
crystallisation
pro
cess
win
dow
Dtmax =4ºC 97% area Dtmax =10ºC
©2018 inspire AG
LS Materials – thermal behavior
temperature sensitivity of Orgasol® invent smooth
partial curling
©2018 inspire AG
C
H O
N
(CH2)11
Lauryllactam
+ H2O
n
PA 12 (open chain ends)
H2N COOH
n
PA 12 (blocked chain ends)
X X
LS Materials – molecular properties
polymerisation of polyamide 12 (PA12)
Orgasol® invent smooth
Duraform® PA
post condensation during SLS processing
increasing chain length
increasing melt viscosity
= reactive end groups -NH2 and -COOH MVR values (235 C / 2.16 kg):
Orgasol® IS:
remain at about 15 cm3/10 min
Duraform® PA:
reduction 60 20 cm3/10 min
©2018 inspire AG
Chemical equilibrium depends on Δp and T
SLS provides best conditions for ‘successful’ post condensation
T > 100°C; dry N2 atmosphere drying chamber!
H2O
(CH2)11
n
OH C
O
H
H
N (CH2)11
m
OH C
O
H
H
N
(CH2)11
n+m
OH C
O
H
H
N +
+
T, t, ΔpH2O Kp,T = [chain(m+n)] H2O
[chain(m)] [chain(n)]
LS Materials – molecular properties
©2018 inspire AG
mirror Laser
SLS building chamber
powder
new part
top layer
3rd layer
2nd layer NH2
COOH
NH2
CONH
COOH CONH
NH2
COOH
Inter-layer bonding intra-layer bonding
low melt viscosity
at process start
post condensation
of powder (aging)
LS Materials – molecular properties
unwanted
©2018 inspire AG
Duraform® PA Orgasol® invent smooth
production precipitation direct polymerisation
Particle shape „potato“
compromise regarding
flowability
spherical
more detailed parts
better part surfaces
Thermal situation larger Sintering window
easier processing
crystal size and structure!
needs more stable temp.
situation during processing
thermal problems
Powder distribution broad (bimodal) narrow
high powder flowability
better powder density
PA12 chain ends
(termination)
open
easy flowing melt
enhanced properties due
to „post condensation“
blocked
less powder „aging“
(economy)
mechanical
properties
more homogenous in all
directions
pronounced drop in z-
direction
Summary 2
©2018 inspire AG
lesson learned
©2018 inspire AG
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