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© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Dynamic beam shaping for high power laser applicationsDr. Andreas Wetzig, Dr. Jens Standfuß et al.
Fraunhofer-Institut für Werkstoff- und Strahltechnik Dresden
Source: Goppold, et al., (2016) Transient beam oscillation with a highly dynamic scanner for laser beam fusion cutting, Advanced Optical Technology, January, 13, DOI 10.1515/aot-2015-0059
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Introduction
Fast Galvo Scanners for Beam Shaping
Laser Welding
Laser Cutting
Novel Approaches through MEMS-Scanners
Summary
Dynamic beam shaping for high power laser applications
Outline
2
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Introduction
Dynamic beam shaping for high power laser applications
http://www.holoor.co.il/Diffractive_optics_Applications/Application_Notes_BeamShapers.htm
Static beam shaping through Diffractive Optical Elements
Sophisticated light distribution possible
http://spie.org/newsroom/5850-diffractive-optics-technologies-further-advance-photonic-systems
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Introduction
Fast Galvo Scanners for Beam Shaping
Laser Welding
Laser Cutting
Novel Approaches through MEMS-Scanners
Summary
Dynamic beam shaping for high power laser applications
Outline
3
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Fast Galvo Scanners for Beam Shaping
Dynamic beam shaping for high power laser applications
Laser heat treatment of turbine blades by means of direct diode lasers1D Galvo Scanner with f = 200 Hz
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Fast Galvo Scanners for Beam Shaping
Dynamic beam shaping for high power laser applications
Design
Special beam path
Limited beam aperture
Working field size depends on dynamic
Specification
4 kHz beam oscillation in x and y direction
up to 4 kW laser power (solid state laser)
Typical oscillation amplitudes 0.1 – 0.5 mm
Working field: low dynamic 10 mm x 10 mmhigh dynamic 1.5 mm x 1.5 mm
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© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Fast Galvo Scanners for Beam Shaping
Dynamic beam shaping for high power laser applications
Software
Fully control of scanner movement and laser power
Processing of feedback signals + adapting of position values = constant oscillation conditions at various frequencies
Independent programming of x and y oscillation
Scanner position related laser power modulation
Lis
sajo
us
-Fig
ure
s
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Introduction
Fast Galvo Scanners for Beam Shaping
Laser Welding
Laser Cutting
Novel Approaches through MEMS-Scanners
Summary
Dynamic beam shaping for high power laser applications
Outline
5
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Laser Welding
Dynamic beam shaping for high power laser applications
fScan = 200 Hz fScan = 700 Hz
Vweld / VWIRE = 1
Spot = 210 μm
fscan = 350 Hz
505
ca. 27 m
m
596
ca. 25 m
m
up to 1,5 mm up to 3,5 mm
Vweld / VWIRE = 3
Spot = 600 μm
fscan = 100 Hz
Laser-Multi-Pass-Narrow-Gap welding (LMPNG)
Example: hot crack sensitive Al-6082
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Laser Welding
Dynamic beam shaping for high power laser applications
Laser-Multi-Pass-Narrow-Gap welding (LMPNG)
50 m
m
6
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Laser Welding
Dynamic beam shaping for high power laser applications
Joining of aluminum wrought alloy and die cast
rotation of the beam on an elliptic track
extension of the keyhole
- less pores- less spattering
Extension of melt pool life time
Increasing of degassing time for bubbles
Homogeneous, slow solidification
Die Cast
Al Tube
Die Cast
Al Tube
without Beam Oscillation
with Beam Oscillation
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Laser Welding
Dynamic beam shaping for high power laser applications
Joining of aluminum wrought alloy and die cast
Machine
Optical Set-up
7
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Introduction
Fast Galvo Scanners for Beam Shaping
Laser Welding
Laser Cutting
Novel Approaches through MEMS-Scanners
Summary
Dynamic beam shaping for high power laser applications
Outline
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Laser Cutting
Dynamic beam shaping for high power laser applications
Thick plate fusion cutting of stainless steel 1.4301
Al Tube
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© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Laser Cutting
Dynamic beam shaping for high power laser applications
Thick plate fusion cutting of stainless steel 1.4301
feeddirection
Source: Goppold, et al., Beam oscillation –periodic modification of the geometrical beam properties, LIM Conference 2015
Source: Goppold, et al., Beam oscillation –periodic modification of the geometrical beam properties, LIM Conference 2015
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Laser Cutting
Dynamic beam shaping for high power laser applications
Ro
ug
hn
ess
Rz
Material 1.4301Thickness 12 mmMulti mode fiber laser
Laser power 3 kW; Cutting speed 0.4 m/min Laser power 3 kW; Cutting speed 0.5 m/min
Source: Goppold, et al., Beam oscillation –periodic modification of the geometrical beam properties, LIM Conference 2015
Static laser beam High frequency beam oscillation
9
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Laser Cutting
Dynamic beam shaping for high power laser applications
CO2 Laser Fiber Laser
Beam Shaping without Beam Shaping without
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Introduction
Fast Galvo Scanners for Beam Shaping
Laser Welding
Laser Cutting
Novel Approaches through MEMS-Scanners
Summary
Dynamic beam shaping for high power laser applications
Outline
10
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
MEMS-Scanner
Dynamic beam shaping for high power laser applications
Initial idea – MEMS Scanner for display applications
Requirements for high power laser application
Large Apertures 7 mm ... 20 mm High Scan frequencies 1 kHz ... 20 kHz High average laser power 50 W ... 4 kW Scan angles of 0.03 ° up to 5 °
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
MEMS-Scanner
Dynamic beam shaping for high power laser applications
Current Status
Usage of open MEMS-Scanner instead of capsuled Tests with IR laser power up to 4 kW Experiments on micro applications (5 kHz, 16 W) Proof of principle for laser fusion cutting
11
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
MEMS-Scanner
Dynamic beam shaping for high power laser applications
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
MEMS-Scanner
Dynamic beam shaping for high power laser applications
T43,4 kHz
L = 16 WSG = 1500 mm/sRR = 100 kHzA= 50 mV
T53,4 kHz
L = 16 WSG = 750 mm/sRR = 100 kHzA= 50 mV
T63,4 kHz
L = 16 WSG = 300 mm/sRR = 100 kHzA= 50 mV
T75 kHz
L = 16 WSG = 500 mm/sRR = 160 kHzA= 50 mV
12
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
High dynamic beam shaping opens up new possibilities of laser material processing.
New material combination can be joined by laser welding as well as Laser-Multi-Pass-Narrow-Gap welding can be realized.
Cutting edge quality and speed can be improved at same laser power compared to conventional processing.
Galvanometer based scanners for frequencies up to 4 kHz are available.
Biaxial MEMS scanners have the potential to reach frequencies beyond 4 kHz and to become a valuable complementation of conventional scanning technology.
Summary and Outlook
Dynamic beam shaping for high power laser applications
© Fraunhofer IWS
WET: 01.06.2016 Dynamic Beam Shaping
Thank you for your attention!
Parts of these works were supported by:
The joint research initiative MabriLAS of the Federal Ministry of Education and Research (BMBF) within the research program "Optical Technology - Made in Germany” (13N10197)
FhG Internal Programs under Grant No. WISA 824 747
Many thanks go to Jan Hauptmann, Patrick Herwig, Cindy Goppold, Thomas Pinder, Achim Mahrle, Dirk Dittrich, Axel Jahn, Berndt Brenner, Ulrich Hofmann, Frank Senger
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