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Diode laser systems for materialsDiode laser systems for materialsprocessing applicationsprocessing applications

Introduction to diode lasers

State-of-the-art high power diode lasers

Gary Broadhead Gary Broadhead –– Laser Lines LtdLaser Lines Ltd

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Applications

Conclusion

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Diode Laser Diode Laser -- Single Emitters and BarsSingle Emitters and Bars

A high power diode laser system comprises a number of individual semiconductor laser devices (usually based on GaAs wafers) whose beams are optically combined to achieve the required total power. These individual elements are either “Single Emitter” or “Bar” devices. A bar is a monolithic linear array of devices fabricated on the wafer. The wavelength of laser diode systems is usually 9xx nm (915/940/980)

Single Emitter Bar

Power 10 W 150 W

Efficiency 50 % 30 – 40 %

Cooling Passive Passive or active

MTBF > 500,000 hours Up to 80,000hours

Passively cooled bar (above)

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Single Emitter

Actively cooled bars

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Diode Laser Diode Laser -- Single Emitters and BarsSingle Emitters and Bars

Typical fibre-coupled single emitter based sub-module containing 10 to 16 devices inside. Output power up to 120 Watts at 940/980nm. Air cooled.

Size approx 12cm x 5cm x 2.5cm

Multiple SE modules can be readily combined to provide laser powers of around 1kW.

Typical bar based sub-module (“Stack”) in this case comprising 6 bars. A 10 bar stack could deliver 1.5kW of laser power.

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Size approx 5cm x 5cm x 2cm

Multiple stacks can be combined to provide laser powers in excess of 12kW.

Modular Product

Coupling methods: wavelength and polarisation

Basics: Laser Beam SourceBasics: Laser Beam Source

Polarisation couplingEasy upgrade in output power

Beam geometry & intensity distribution readily adapted

Diode laser stack(or SE module)

Polarisation coupling

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Laser diodes

µ-OpticsWavelength coupling

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Beam Quality TrendsBeam Quality Trends

Fiber DiameterFiber Diameter150 mm mrad

100 mm mrad

60 mm mrad

40 mm mrad

30 mm mradLas

er p

ow

er [

W]

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Diode Applications since 1999

1000

mra

d]

Market Movement Market Movement forfor Diode LasersDiode Lasers

Diode Applications since 2002

Diode Applications since 2004

10

100

10 100 1000 10000

Diode Applications since 2007

Cutting

Bea

m q

ua

lity

[m

m m

6Laser Lines Ltd

Diode Applications2009

Laser power [W]

Future ApplicationsDiode laser systems 2007

Diode laser systems 2009

Limits in Power and Beam quality

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4,000 W diode laser with a beam quality of 30 mm mrad (comparable with lamp pumped YAG)

Current top end specificationsCurrent top end specifications

)

Diode laser with 10,000 W laser power at the end of a 1mm fiber (100mm mrad)

2,300 W diode laser the size of an industrial PC

Compact packaging: 10,000 W in less than a

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square meter footprint

5 year warranty on diode laser elements

Excellent Beam Quality and PowerExcellent Beam Quality and Power

specification

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p

max. output power 2,000 W 3,000 W 4,000 W 5,000 W

beam quality 20 mm∙mrad 30 mm∙mrad 40 mm∙mrad

laser light cable 400 µm, NA 0.1 300 µm, NA 0.2 or 600 µm, NA 0.1 400 µm, NA 0.2

min. spot at f = 100 mm 0.2 mm 0.3 mm 0.4 mm

power consumption, max. 7.5 kW 10 kW 13 kW 17 kW

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Control system upgrade

Profibus, Interbus, Device Net, Profi Net, Ethernet connection

Typical system options

Visible pilot laser

Up to 6 fibre outputs and time-share

Typical System OptionsTypical System Options

PC control: LL Control Software

Separate control panel

Teleservice via safe VPN connection

Wavelength stabilization for pump applications

Extended programming and

p pbeam switch

Cover slide cassette

Fiber length up to 100 m

Application specific optics

Closed loop pyrometer control

Dust and humidity protection

9Laser Lines Ltd

Extended programming and interaction functionalityGalvanometer scan heads

Easy integration in systems for production. Ease of use and service.

Modular optics for flexible adaptation to any process

R b t d i f hi h

OpticsOptics

Robust design for high power processes

Straightforward solutions for complex tasks

Customer specific focus geometries for almost every requirement

Optics for welding, brazing and cladding

Compatible with industrial standards

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Specialty SpotsSpecialty Spots

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System integrationSystem integration

The fibre coupled diode laser is simple to integrate and is particularly suited to robotic applications.

12Laser Lines Ltd

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ApplicationsApplications: Spot : Spot RequirementsRequirements

Rectangular spot: 3 x 3 – 10 x 60 mm

1000

mra

d]

Spot: 1.5 – 3.5 mm

Spot: 0.3 – 0.8 mm

Spot: 0.6 - 3 mm

Spot: 0 2 – 0 6 mm

Spot: 1 - 6 mm

10

100

10 100 1000 10000

Be

am

qu

alit

y [m

m m

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Spot: 0.6 - 2 mm Spot: 0.5 - 5 mm

Spot: 0.2 – 0.6 mmLaser power [W]

Diode Laser can meet most of the spot requirements

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Heat Conduction Welding: steelHeat Conduction Welding: steel

Diode lasers are used in various application areas of mass production

Heat conduction welding of stainless steel sinks

Welding of bellows

Welding of battery housings

Tube welding

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Absorption of laser radiation: AlAbsorption of laser radiation: Al

High absorption peak of aluminum t 800 900at 800 – 900 nm

Degree of absorption A [%]:Nd:YAG => 5%Diode => 14%

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Source: Audi, C.Ebert EALA 2009

Brazing Brazing

Related process of welding with filler wire

For requirements of high strengths and small heat affected zone

Photo: Irepa

High demands on appearance of the weld, visible weld

Main products at car body: roof seams, trunk lids, doors, C-pillars, water channels

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Laser Price & Beam Quality (joining)Laser Price & Beam Quality (joining)

Laser Price

Aluminium& Steel

Remotewelding

welding

Brazing

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Beam quality [mm mrad]

8-12 25-40 60-150

Beam quality should only be as good as required

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Laser Price & Beam Quality (joining)Laser Price & Beam Quality (joining)

Laser Price

Aluminium& Steel

Disc /Fiber Laser

∆ = 15 - 20 %

Remotewelding

welding

BrazingDiode Laser 30 mm mrad

∆ = 25 - 35 %

Diode Laser 100 mm mrad

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Beam quality [mm mrad]

8-12 25-40 60-150

Beam quality should only be as good as required

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Cladding and Coating : PrincipleCladding and Coating : Principle

Laser Beam

Powder and assist gas is fed into the laser beam

coaxially or off-axis

Powdernozzle

and gas

Laser Beam melts powder and eventually base

material

Alloying or depositing of powder onto base

material in one or more layers

Repair or coating in a single process

Spot geometry adapted to parts and process

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Cladding zone

Spot geometry adapted to parts and process

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Cladding Installation with Diode Laser Cladding Installation with Diode Laser

Cladding/Coating with Diode laser

High precision thick deposits (0.5 – 4 mm)

Cladding rates of 9kg/hour have beenachieved with a 6kW laser

Fully automated, industrial process

Repair of valuable parts

Wear protection

Successful replacement of CO2 laser

Applications

Oil drilling – down hole tools

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Photo: Technogenia/Laser Cladding Technology Ltd

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Aerospace and maritime industries

Foundries – pan scrapers

Steel industry – conveyor rollers in steel mills

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Hardening: Typical DataHardening: Typical Data

Fiber-coupled or direct diode laser 1-6 kW

Rectangular spot, may vary by applications

First industrial installations in 1999First industrial installations in 1999

Pyrometer typically used for closed-loop process

control

Homogenized focus24 x 8 mm

21Photo: Erlas

Laser Lines Ltd

20 mm

Polymer Welding Polymer Welding

Transmission welding of thermoplastics

Contour welding on robot for even huge 3d-parts

Quasi-simultaneous weldingQuasi-simultaneous welding

Welding with base material strength

Main products: sensor housing, tubes, flat parts, leak/gas-proof containers, head/tail lights of cars

Special wavelengths possible. Eg. 14xx nm for welding of clear/clear acrylic

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High electrical/optical efficiency of more than 40 percent

Low investment and maintenance costs

ConclusionConclusion

Low investment and maintenance costs

Outstanding reliability and robustness (up time > 99 %)

Mobility and compactness

Easy integration in systems for production. Ease of use and service

Excellent beam quality

L i t d i (0 5 d )

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Low maintenance design (0.5 day per year)

Excellent process stability and reproducibility

Thank you for your attention

Gary BroadheadLaser Lines Ltd

garyb@laserlines.co.uk

24Laser Lines Ltd