Laser Beam Welding in Vacuum - NRW.INVEST

Laser Beam Welding in VacuumIncrease in Quality and Productivity Dr. Christian [email protected]

Seite 2Confidentiel17.03.21

- Solution provider for laser beam welding in vacuum- Founded 04/2018 - Spin-Off of FH Aachen University of Applied Science - Location TPH 1 in Herzogenrath- Customer relations worldwide- Different certification

LaVa-X GmbH

ISO 3834


LaVa-X GmbH – Business Model

YOUR SOLUTION PROVIDER FOR WELDING CHALLENGES!

EquipmentJob-ShopConsulting


“LaVa-Effect”

Ø Change of Melting Point < 1 K Ø Change of Evaporation Point approx. 1000 K

0

500

1000

1500

2000

2500

3000

0,001 0,01 0,1 1 10 100 1000

Tem

pera

ture

[°C]

Pressure [mbar]

Boiling Temperature over Pressure

Cu [°C] Al [°C] Fe [°C]

Evaporation PointMelting Point

- Lower temperature leads to thinner melt pool around keyhole- Increased Keyhole stability (at lower welding speed)

ΔT =𝑇! ∗ Δ𝑉 ∗ ∆𝑝

𝐻!Clausius Clapeyron

(simplified)

𝑇! = Melting Point𝐻! = 𝑀𝑒𝑙𝑡𝑖𝑛𝑔 𝐸𝑛𝑡ℎ𝑎𝑙𝑝𝑦Δ𝑉 = 𝑉𝑜𝑙𝑢𝑚𝑒 𝑐ℎ𝑎𝑛𝑔𝑒 𝑑𝑢𝑟𝑖𝑛𝑔 𝑚𝑒𝑙𝑡𝑖𝑛𝑔

Minimal volume change (~ 3-5%)∆𝑝 < 1000 𝑚𝑏𝑎𝑟


LaVa-Welding

Increase of qualityNo pores or cracks in weld seams evenin alloys difficult to weld.

Increase of ProductivityIncrease of penetration depth or reduction of laser power. No distortion.

Avoidance of spattersNo adherend spatters, avoidance ofvapour deposition and oxidation

Economic and ecologicUse of low power laser sources. No compressed air and less shielding gas.


Exemplary Fields of Application LaVa-Welding

Sensor Industry- No pores & component contamination

- Heat input reduced by up to 60 % / 500 W ≙ 3 mm depth- Less welding distortion & spatter

Medical Industry- Highest weld quality & a 100 % protection against oxidation

- Titanium, nitinol, gold, tantalum and chrome-nickel steel - Good automation capability and high reproducibility

Automotive- Additive manufactured components

- Difficult weldable alloys- Material combinations


System Technology - LaVaCELL 450Laser & Optics- Fiber & Disc Laser- 40 µm Spot (500 W)- 55 µm Spot (2000 W)- 150 µm Spot (2000 W)- 450 µm Spot (8000 W)- 375 µm Spot (12000 W)

LaVaCELL450

Y-Axis Turntable

DN250

DN250

Vacuum Chamber

Rotation Axis

X-Shift Cover Plate

Counterholder

X-Shift

Welding Head Typ R Welding Head Typ T

Modular System

- 20 µm – 40 mm

40 mm


- LaVa-Welding of Bipolar Plates- 1.4301 & 1.4760 (Crofer®)- 55 µm Spot (PL=45 W; v=200 mm/s)

Stainless Steel (Example Bipolar Plates)

Overlap Weld

t=75 µm


- 85 µm Spot (PL=120 W; v=900 mm/s)

Stainless Steel (Example Bipolar Plates)

- Transfer line with- pressure stage system- à NO secondary

time for evacuation


Challenges laser welding of AlPhysics

[1] G. Schulze, Die Metallurgie des Schweißens, Berlin: Springer Verlag, 2007

Temperatur [K]

Cracks

Temperature [K]933 2743

100

0,01

Pores

0 100 200 300 400 500

Cu [°C]

Al [°C]

Fe [°C]

Thermal Conductivity [W/mK]

Thermal Conductivity


Challenges laser welding of Al

Atmosphere

LaVa

Weld pool + 33%

Lower difference stabilized weld pool.Less Oxygen leads to a better outgas of pores.

896,8

1809,8

0

500

1000

1500

2000

Al [°C]

Tem

pera

ture

[°C]

Difference between Boiling- and Melting Temperature

LaVa Atmosphere


- LaVa-Welding of Flat Cable- EN AW 1050 (99,5%)- 150 µm Spot (PL=1800 W; v=25 mm/s)

Aluminum (Flat Cable) Butt Joint

Topside

Bottom

4 m

m


Challenges laser welding of CuPhysics

Temperature [K]

Absorption Melting Interval

1400

1300

1200

1100

1000

900

800 0 0,002 0,004 0,006 0,008 0,012

α+Cu2O

α

Gew.-%

K

100

80

60

40

20

0

Abso

rptio

n in

%

Wavelength λ in nm100 1030 -1080 10000

15

10

5 Abso

rptio

n in

%

Surface temperature T in K0 1000 2000500 1500

0

20

0 100 200 300 400 500

Cu [°C]

Al [°C]

Fe [°C]




Challenges laser welding Cu

Atmosphere

LaVa

Reduced melt pool stabilized Keyhole and increased efficiency

Weld pool + 52% 532,38

1510,38

0200400600800

1000120014001600

Cu [°C]

Tem

pera

ture

[°C]

Difference between Boiling- and Melting Temperature

LaVa Atmosphere


Copper with IR LASER

Influence beam oscillation with 2000 W

Penetration 250 µm with 350 W

Penetration 6 mm with 6000 W


- LaVa-Welding of Hairpins- Cu-ETP & Cu-OF -55 µm Spot (PL=2000 W; t=0,12 s)

Copper (Hairpins)

Cu-OF


- LaVa-Welding of Hairpins- Cu-ETP & Cu-OF -55 µm Spot (PL=2000 W; t=0,12 s)

Copper (Hairpins)

Cu-OFCu-ETP


Challenges Welding of Mixed MaterialsPhysics Crystal System Intermetallics

FCC

BCC

0

1000

2000

3000

4000

Cu [°C] Al [°C] Fe [°C]

Tem

pera

ture

[°C]

Melting- and Boilingpoint

Boilingpoint Melting Point

0 100 200 300 400 500

Cu [°C]

Al [°C]

Fe [°C]



Al-Cu

[2] MSI Eureka

Al2Cu

[2]


- LaVa-Welding Current Contacts- ETP-Copper with Al 99,5 (EN AW 1050)- 150 µm Spot (PL=600-2000 W; v=25-60 mm/s)

Mixed Materials (Al-Cu)

Overlap Weld

t = 0,2 - 4,0mm

0

20

40

60

80

100

120

Al 1,5 mm Al 3,0 mm

Tens

ile S

tren

gth

[N/m

m²]


Mixed Materials (Al-Cu)

α(Al)

EAl2Cu

Cu

[3] Otten, Welding in the World, DOI 10.1007/s40194-015-0280-x, 2016

Kernel Average Misorientation

Stress peaks at the grain boundaries lead to failure.


LaVa-Welding Solves Problems

Hugh Potential for large Structures!

New Materials

1mm

500 µm

Reduced Laser Power500 W vs. 2 kW

Stationary Machines

conventional

20m

m

Thick Plate Applications

LaVa

50m

m

[4] Jakobs, Dissertation, 2016


Comparison of ambient Pressure and Vacuum

PL = 12 kW; vs = 10 mm/s; A = 0,5 mm; F = 200 Hz

Atmosphere Vacuum


Laser Welding with mobile vacuum

All stationary machines resluts are transferable to mobile vacuum applications!

5 mm

Pene

trat

ion

dept

h20

mm

P L=

6 kW


Edge Misalignment and Gap Bridgin AbilityWith Filler-Wire

Gap Width 1 mmWithout Filler-WireGap Width 1 mm

Edge Misalignment0 mm

Edge Misalignment2 mm


- LaVa-X is a Solution Provider for Welding Challenges

- LaVa-Welding is a Suitable Technique for varies applications

- Steel: LaVa-welds can be conducted up to 900 mm/s

- Aluminum: Pores, cracks and heat-input can be reduced with LaVa

- Copper: Spatters can be reduced and penetration depth can be increased

- Al-Cu Mixed Joints: Stable Keyhole leads to reproducible temperature-time-gradient

- Thick Plate Applications: Significant Increase of Penetration Depth and Quality

Conclusion

Please Contact me for further questions!ContactDr. Christian Otten02407 95389 [email protected]

Laser Beam Welding in Vacuum - NRW.INVEST

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