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PLASTIC WELDINGwithLASER SYSTEMS

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vs.

Transparent joining part

Welding seam

Absorbing joining part

Melt zone

Lasers radiation

Laser Transmission Welding• Basics• Concepts• Examples

Material requirements:• Top part laser-transparent material• Bottom part laser-absorbent material• Compatible materials

- Melt Temp- Chemical Compatibility

Process requirements:• Good thermal contact• Pressure• Clear access for laser

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vs.

Transparent joining part

Welding seam

Absorbing joining part

Melt zone

Lasers radiation

Laser Transmission Welding• Basics• Concepts• Examples

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Joining part:• “no” absorption dopt >> d “no“ heating• volume-absorption dopt d heating across the whole thickness • surface-absorption dopt << d near surface heating

IT

Absorption Characteristics• Basics• Concepts• Examples

IL

dopt >> d

IRd

dopt << d

IL

IRd

IL

IR

IT

dopt d

d

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Laser• Basics• Concepts• Examples

CO2-Laser ND:YAG-Laser HPDL*

type of active mediums gas solid state semi conductor

wavelength [nm] 10600 1064 800 - 980

max. power cw [KW] up to 40 up to 5 0.05 up to 5 (modular)

intensity in focus [W/cm2] 106 -108 105 - 108 103 - 105

efficiency [%] 5 - 10 3 - 10 30 - 50

size (Head) [cm3/W] ~200 ~20-50 ~1

maintenance [h] ~1000 ~800 (lamps) no maintenance

properties of HPDL (diode laser) • high efficiency • compact• low-maintenance/ high life time• low beam intensity

HPDL*= high power diode laser

Lasers in material processing

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Weldable Materials

• Thermoplastics ~ Amorphous and semi-crystalline polymers (like - like) materials welded successfully:

• ABS, COC, PA, PBT, PC, PE, PMMA, PP, PS, SAN, ... • Combinations of different but compatible thermoplastics include:

• PMMA-ABS, ABS-PC, ABS-SAN, PMMA-PC…. • Thermoplastic Elastomers:

• Thermoplastic Elastomer to Thermoplastic Elastomer • Thermoplastic Elastomer to non-elastomeric thermoplastics

• Colour-combination possibilities:• Black - Black (special non-carbon colouring in one part)

• Transparent – transparent (with addition of “clearweld”)

• Other colours with special pigments

• Basics• Concepts• Examples

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Welding Seam Design• Basics• Concepts• Examples

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Globo welding Mask welding

Contour welding Simultaneous welding

Radial welding

Quasi-simultaneous welding

Welding Concepts• Basics• Concepts• Examples

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Contour welding

Contour Welding• Basics• Concepts• Examples

• Spot laser guided by X-Y Axis

• Highly Flexible

• Simple Weld Design

• Ideal for Quick Changeover

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Simultaneous Welding• Basics• Concepts• Examples

• Optic element used to form laser • One shot welding of weld seam • No relative movement • Short process times

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Quasi-simultaneous welding

Quasi-Simultaneous Welding

• Basics• Concepts• Examples

• Mirrors guide laser over weld seam • High flexibility

• Welding with displacement

• Gap bridging possible

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Mask welding

Mask Welding• Basics• Concepts• Examples

• Line Beam Laser and Mask

• Large areas and fine lines

• Complex contours and shapes • Protection of sensitive parts

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Radial welding

Radial Welding• Basics• Concepts• Examples

• Radial radiation • No rotation of part

• Short process times

• Ideal for welding axially symmetric / Cylindrical

• Push fit

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Globo welding

Globo Welding• Basics• Concepts• Examples

• Dynamic Clamping • Simple Joining Geometry

• Continuous Welding • Ideal for 3-dimensional and large parts

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Advantages of laser welding:

• high precision• high strength• minimal mechanical stress• minimal thermal stress• no damage to electronic

components• simple joining geometry• low tool wear• emission free• particulate free• no consumables

(adhesive/fasteners)• joining of elastomers

Laser Transmission Welding• Basics• Concepts• Examples

Contour welding

Globo welding

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Mask welding

Photo: Leister, by courtesy of IMM, Mainz (D)

Material:PC transparent / PC black

Specifications:• permeability • preservation of canal profile• canal width down to 100 µm• short processing time (3 seconds)

Micro pump

Requirement: welding of small structures (micro fluidics)

changeable width of welding seam

Method: line-beam-laser and structured mask

• Basics• Concepts• Examples

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Material:PC nature / PC black(both structured)

Specifications:• permeability• preservation of 3D channel profile• channel width down to 130 µm, • overall size 35 x 40 x 4 mm

Origin: FhG-ICT

Mixer-component

Mask welding

Requirement: welding of small structures (micro fluidics)

changeable width of welding seam

Method: line-beam-laser and structured mask

• Basics• Concepts• Examples

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Electronic Key

Material:PA laser transparent blackPA black

Specifications:• impermeability• no damage to electronics • no melting bulge

Photo: FHG - ILT

Contour welding

Requirement: extremely flexible with excellent welding results

Method: spot optic and axis system

• Basics• Concepts• Examples

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Electronic housing

Material:PC laser transparent blackPBT GF 30 black

Specifications:• permeability• No damage to electronic components

Photo: Leister, by courtesy of comp. Elektra, Schalkau (Germany)

Contour welding

Requirement: extremely flexible with excellent welding results

Method: spot optic and axis system

• Basics• Concepts• Examples

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Simultaneous welding

Optical Sensor

Material:PMMA transparent redPC black

Specifications:• no optical distortion• no contamination (particles)• pressure (> 12 bar)• permeability

Requirement: short-time processno relative motionmass production

Method: laser beam formed and guided byoptical elements

• Basics• Concepts• Examples

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Housing Flow-Sensor

Material:PMMA natural ABS grey

Specifications:• no contamination (particles)• preservation of electronics and

chips

Simultaneous welding

Requirement: short-time processno relative motionmass production

Method: laser beam formed and guided byoptical elements

• Basics• Concepts• Examples

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Display window

Material:PC nature PC black

Specifications:• permeability• no optical distortion

Simultaneous welding

Requirement: short-time processno relative motionmass production

Method: laser beam formed and guided byoptical elements

• Basics• Concepts• Examples

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Demo (Fair: K 2004)

Material:PC nature / PC black

Simultaneous welding

Requirement: short-time processno relative motionmass production

Method: laser beam formed and guided byoptical elements

• Basics• Concepts• Examples

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Camshaft sensor

Material:PA 66 GF 30 laser transparent blackPA 66 GF 30 black

Specifications:• permeability• no contamination (particles)• protection of electronic parts / sensors

Photo: Leister, by courtesy of comp. Delphi Automotive, Luxemburg

Radial welding

Requirement: welding of rotationally symmetrical components without relative motion

Method: two-mirror-scanner and conical mirror

• Basics• Concepts• Examples

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Globo welding

Automotive lighting

Material:PMMA transparent / ABS black

Specifications:• no thermal and mechanical stress

(Electronics)• 3D welding seam as design element• no static clamping device

Requirement: welding of 3D, large-area or endless components

flexible like contour welding

Method: spot optic combined with a dynamic clamping device

• Basics• Concepts• Examples

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Laser Welding Machines

NOVOLAS Basic NOVOLAS WS NOVOLAS micro

• Basics• Concepts• Examples• Laser

Systems

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LASERSYSTEMS

Distributed in the UK by:

For further details contact:Paul Anderson+44 1435 864239leister@horizoninstruments.co.uk

Adapted from a presentation by:Dipl. Ing. Oliver HinzProduct Manager