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1
Design Guidelines Laser Plastic Welding
© 2011
2
Josh Brown Marketing Development
Representative
Watch the video recording here
Follow us @LPKF_USA
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Topics
• Application examples
• How it works
• Design considerations
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Applications and Advantages
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Applications and Advantages
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Factors Affect Weld
Material
Melting Temperatures
Energy Interaction
Fillers, colorings, additives
Part
Joint design • Thickness • Ribs and other
features
Other considerations
Clamping
Tooling and nest
Gaps and tolerances
Force
Laser
Process
Laser power
Wavelength
Time – speed/weld length
Machine/Process
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How It Works
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Temperatures Melting/Softening Range Decomposition Range
212 302 392 482 572 662 752 842 932 Temp F° Temp C°
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Material Compatibility
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Energy Interaction w/ Material
808 or 980nm Diode
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Energy Interaction w/ Material
5%
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Fills, Additives and Colors
• Glass fiber • Carbon fiber Fills
• Flame retardants • UV stabilizers • Heat stabilizers
Additives
• Pigmentations • Dyes Colors
Scattering
Absorption
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Color Combinations
Degree of Weld Difficulty
Transparent Transparent
White White
Color 1 Color 1
Color 1 Color 2
Color 1 Black
Black Black
Transparent Black
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Factors Affect Weld
Material
Transmit, reflect, absorb or scatter
Fillers, colorings, additives
Melting Temperature
Part
Joint design • Thickness • Ribs and other
features
Other considerations
Clamping
Tooling and nest
Gaps and tolerances
Force
Laser
Process
Laser power
Wavelength
Time – speed/weld length
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Basic Joints
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Lap Joint(s) w/ Collapse Rib
Clamping
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Lap Joint
Post-collapse Pre-collapse
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Material Thickness and Transmission
Material BKV 30 H2.0 - PA6, Nylon, 30% glass fill
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Tube Radial Weld
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Radial Welding
Fixed laser / moving part Fixed part / moving laser
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Overall Part Sizes
47” x 47” 18”x18” 8”x8”
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Beam Access
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Beam Access
90° +/- 15 °
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Beam Access - Molding Gates
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Beam Access - Molding Gates
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Factors Affect Weld
Material
Transmit, reflect, absorb or scatter
Fillers, colorings, additives
Melting Temperature
Part
Joint design • Thickness • Ribs and other
features
Other considerations
Clamping
Tooling and nest
Gaps and tolerances
Force
Laser
Process
Laser power
Wavelength
Time – speed/weld length
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Process Types
Contour •Laser makes single pass, robot assisted •Pros: flexible, large and 3D parts •Cons: slower
Quasi-simultaneous •Laser makes multiple passes •Pros: fast cycle times, flexible •Cons: for mainly 2D parts
Simultaneous •Many lasers heat entire joint simultaneously •Pros: very fast •Cons: very expensive tooling, little flexibility
Hybrid •Halogen assisted laser source •Improves cycle time •Improves joint quality •Softens and anneals plastic
Processes
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Laser Staking
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Wavelength
• 800 – 1,000nm
• Diode at 808nm or 980nm
Laser speed or time of laser on weld
• More time = more heat
Laser power
• 14watts – 300watts
Spot size
• 0.6mm – 3mm (smaller with fiber laser)
• Fiber lasers – 0.07mm
Laser Effects on Weld
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Factors Affect Weld
Material
Transmit, reflect, absorb or scatter
Fillers, colorings, additives
Melting Temperature
Part
Joint design • Thickness • Ribs and other
features
Other considerations
Clamping
Tooling and nest
Gaps and tolerances
Force
Laser
Process
Laser power
Wavelength
Time – speed/weld length
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Clamping Tooling
Transparent, acrylic Hybrid: metal/acrylic All metal, dual clamping
Joint Example
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Acrylic Clamp Tooling
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Nest
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Clamping Tooling - Tolerances
Part tolerances + positional tolerances = total tolerance X/Y position • accomplished through accurate nesting • No hard and fast tolerances Z tolerances • gaps > .05 mm significantly affect weld quality
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Results of Gapping G
apN
o G
ap
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Cycle Time
Factors affecting cycle time:
• Transmission rate (fillers, colors, thickness)
• Absorption rate
• Laser power
• Weld seam length/width
• Melting temp
• Conductivity (thermal transfer)
• Thermal load to cooling time
• Process method (contour, quasi-simultaneous, etc.)
30 sec
2-5 sec
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Thank you for attending!
Design_Guidelines.pdf
Would you like more information?
Download or request a copy of our Design Guidelines Document
• jbrown@lpkfusa.com
• 503-454-4231
• Link
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