Laser Welding Design Guidelines
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Common Joint Designs
Laser welding uses a precise IR laser beam that is directed through a transmissive material and penetrated into an absorptive material. As with all plastic joining technologies, a properly designed weld joint is critical to achieving the desired weld strength and appearance.

General Guidelines
- The transmissive part must be transparent/translucent to IR, but does not have to look transparent to the human eye.
- The transmissive part should be approximately 3 mm thick or less for semi-crystalline materials and can be much thicker for amorphous materials as long as they are transparent.
- If the transmissive part has glass filler, as the percentage increases, the maximum thickness decreases due to scattering of the laser energy.
- Typically weld ribs are 2 mm wide, but narrower or wider is feasible and depends on customer requirements.
- Typically plan for 0.2 – 1.0 mm interference (displacement) in the weld joint unless it is a simple lap joint or an inline lap joint that doesn’t allow for displacement.
- Make gaps twice as tall as displacement depth to account for flash.
Lap Joint Designs
T Joint Designs
Radial Welding Joint Design
Material Compatibility Chart
This compatibility chart shows which materials are known to be compatible with each other.
Please note: Weld compatibility depends on the absorption and transmissivity of the materials.
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