High Power Fusion CuttingStefan Wittwer and Oliver Bühler

Bystronic Laser AG

© Bystronic |

Bystronic Laser AG

12.2015 1

field of activity: systemsfor sheet metal processing

founded

1986

headquartersNiederönz

Switzerland

1

© Bystronic |

principle of fusion cutting

02.2016 2

cuttingdirection

molten metal

sheet metalN2

laser

beam

no

zzle

Compared to O2-assisted laser cutting:

➢ more laser power meltsmore metal per time

➢ faster cutting speed

➢ no oxide layer toremove

2

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fiber revolution

02.2016 3

CO2 fiber

year

0

1

2

3

4

5

6

7

8

9

10

1985 1990 1995 2000 2005 2010 2015 2020

laser

po

wer (

kW

)

fiber cutting samples

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high power fusion cutting: feasibility

02.2016 4

✓ power limited rather by components than by processing physics

✓ commercially profitable costs per part considering invest and running costs

✓ available and suitable test equipment mainly limited to 10kW

decision for cutting @ 10kW

� is there a physical limit?

� what power level makes sense?

� can we test it?

ByStar Fiberwith 10 kW

(Euroblech 2016)

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high power fusion cutting: optical setup

02.2016 5

➢ adjustable focal diameter and focal position

➢ optimized imaging

➢ suitable to monitor the process

➢ design to high power:

➢ minimum focal shift to achieve a stable process

➢ minimum number of transmissive optics

➢ active cooling

specification of the optical setup

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additional beam shaping optics

optical setup: reflective/transmissive, no collimation unit

02.2016 6

end cap

protective glass

fix or adaptive mirror

lens

end cap

plano mirror

protective glass

process monitoring

process monitoring

6

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optical setup: mode of operation

02.2016 7

• no collimation unit

• only three transmissiveoptics (end cap, lens & protective glass)

• rel. focal shift <2%/kW

• short thermalisation time

large focus

end cap

lens

protective glass

nozzle

sheet metal

small focus

optic body

7

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cutting speed: stainless steel, 6kW vs. 10kW

02.2016 8

increased power = increased cutting speed

250%

200%

150%

50%

0%

100%

10mm 15mm 20mm 25mm

cu

ttin

gsp

eed

thickness

80%

15%

10kW production

10kW max. lab results

30%

230%

stainless steel

6kW production

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cutting quality: stainless steel 10 mm

02.2016 9

increased power = increased cutting quality

9

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cutting speed: mild steel fusion cutting

thickness [mm]

0%

25%

50%

75%

100%

4 6 8 10 12 15

cu

ttin

gsp

eedmild steel

02.2016 10

fusio

ncutt

ing

6kW

fib

er

fusion cutting 10kW fiber

flame cutting 6kW fiber

10

© Bystronic |

high power fusion cutting: mild steel 6 mm

02.2016 11

comparison mild steel 6mm

fiber 10kW fiber 6 kW CO2 6kW

11

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summary

02.2016 12

➢ increased fiber laser power

✓ increases the speed and the quality of fusion cutting

✓ expands the fusion cutting range to thick sheets and continues to substitute the CO2 laser

➢ a transmissive optical setup without collimation unit works fineat 10kW