Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property1
Study of copper melting by laser for
additive manufacturing processes
Guillaume NORDET1-2 ; Patrice PEYRE1 ; Cyril GORNY1 ; Albin EFFERNELLI2 ; Frederic COSTE1
1- Laboratoire PIMM, groupe LASER, 151 bd de l’hoîtal, 75013, Paris
2- AddUp, 5 Rue Bleue, Z.I. de Ladoux, 63118 Cébazat
@mail : [email protected] ; [email protected]
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
AddUp
2
AddUp offers its customers complete industrial metal 3D printing solutions : (Machine design and production, Solutions
HSE, Customer assistance and advice)
AddUp is a 50/50 joint venture between Fives et Michelin
Established at Clermont-Ferrand in 2016
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Additive manufacturing : LBM process
3
Laser Beam Melting (LBM)
Selective Laser Melting (SLM)
https://www.empa.ch/web/coating-competence-center/selective-laser-melting
SLM process parameters Usual values on SLM printer
Laser emission wavelength Infrared :1030 µm
Focalisation diameter 70 – 100 µm
Laser power 400 – 1000 W
Scan Speed 1 – 10 m/s
Powder layer thickness 20 – 100 µm
Scan strategy
Powder composition Maranging steel – Titanium …
Final part density >99%
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Contents
4
LBM for
copper
Absorption of
LASER energy
Laser-mater
interaction
Green laser to
melt copper
Parameters
dependance
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Bibliographic results on the SLM of copper
5
Colopi M., & al, Procedia CIRP 74 (2018) 59–63, 2018
Ikeshoji T& al, The Minerals, Metals & Materials Society, 2017
➢ Colopi, 2018
• d = 78µm
• P = 1kW
• V =1 m/s
• Substrat : 316L Steel
• Max density: 97%
➢ Ikeshoji, 2017 :
• d = 100 µm
• P = 800 W
• V = 0.3 m/s
• Substrat : pur copper
• Max density : 97%
0
20
40
60
80
100
120
140
0 500 1000 1500 2000 2500 3000
Ther
mal
dif
fusi
vit
y (
mm
²/s
Température (K)
Copper
Inconel 718
• Low infrared absorption
• High thermal dffusivity K/(ρCp)
• Many projections of melting copper
Heider A & al, Proceedings of ICALEO, 2012
Welded copper line
SLM copper part
Mills K., “Recommended values of thermophysical properties for selected commercial alloys”, 2002
Cagran C., Diploma Thesis, 2000
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Laser energy absorption
6
LASER
Absorption
Heating
Reflection
Transmition
Material1 = 𝐴 + 𝑅 + 𝑇
For metal : T = 0
Abso
rpti
on r
ate
(A%
)
R. Fabbro et al., Icaleo, 2017
Laser energy absorption is lower for noble metal in IR mode
Usual SLM welding regime are near to the key-hole formation :
more energy is absorbed due to a laser trap
A%
E
Key-hole
formationLiquefaction
SLM area
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Measuring copper absorptivity
Laser used :
●Infrared laser (λ = 1030nm)
●Green laser (λ = 530nm)
Calculated absorptivity for a Cu bed powder
at λ = 1030nm (Gusarov, 2010) :
A= 38 %
7
Sample
Integrating
sphere
LASER
Photodiode
Sample
Photodiode
Incident
beam
Absorption rate increase for powder bed both
green and IR laser.
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Laser-mater interaction at infrared wavelength
Laser-mater interaction occurs mostly
on a liquid phase
LASER
Liquid area
Solidifiedcord
Powder bedDenudation
area
8
0,00
5,00
10,00
15,00
20,00
25,00
0 500 1000 1500 2000 2500 3000
Ab
sorp
tivit
y(%
)
Température (K)
Drude-Lorentz
Absorptivity function of temperature calculated about
a Drude-Lorentz model
200 µm
Record Rate : 6400 fps
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Copper fusion with a green laser
9
Experimental prototypeGreen laser : 500 W IPG
Laser head
Main consol
λ = 532 nm
Pmax = 500 W,
Ppick = 2500 W
Frequency : 150 MHz
Pulse duration : 1,6 ns
Duty Cycle = 24 %
Laser head
X-table
Cell for argon
Objective and
camera
Optical
focalisation
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Influence of gas shielding on copper welding
10
Weld
direction
Detrimental influence of an oxygen atmosphere :
↗ variation of the two welding modes
2 welding modes :
• Conduction → Low penetration mode
• Deep penetration → High penetration mode
With argon Without
argon
Conduction
Deep penetrationA
B
A B
Deep penetration Conduction
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Fusion weld of a copper powder bed
11
1 21 2
1
2
Without powder With powder
Conduction Deep penetrattion
More stable weld for deep penetraton mode on powder
Conference: Photonics 4 intelligent processing, 19.06.2019, Geneva Confidential Addup property
Conclusion
12
Green laser allows to create continuous
line and surface
Possible to build small parts with a green
laser in the experimental prototype
However, no industrial prototype
available with green laser
For copper, using an other wavelength to
improve absortivity is not sufficient to
optain stable penetration
Thanks
Thanks to all the people of PIMM laboratories and
AddUp for their helps and advices on the work
Work carried out as part of the Ambition FUI
project supported by BPI and Auvergne-Rhône-
Alpes and Ile-de-France region