No-go's - design errors
To address the most common design faults, the most important ones are listed below:
The upper part should have a flat surface above the weld seam and no special geometries. If possible, the laser beam should be more or less perpendicular to the component. Small angles are not a problem, but if the tilting becomes too strong, the transmitted laser power is reduced and the beam deflection must be compensated.
When welding with a scanner, one needs to consider that the laser beam is no longer incident vertically in the outer areas of the working field. Protrusions near the weld seam in the upper part or the clamping tool can lead to partial or complete shading of the laser beam.
Design injection molding tool
When designing the injection molding tool, no injection points should be located in or near the weld seam. They are susceptible to surface irregularities and inhomogeneities in the plastic.
Ejectors of the parts from the mold cavity should also not be located in the weld seam area itself.
Deformation of plastic parts
Bending and warping of the parts from the manufacturing process need to be avoided or prevented during the design phase. If the parts deform too much, they no longer fit together or larger gaps appear.
In some cases, the clamping unit can push the components back into their original shape for welding. However, a large internal stress is built up in the parts, which can lead to the weld seam bursting open again. This is particularly delicate with three-dimensional parts with reinforcing ribs.