Joining of plastics
Plastic welding is primarily applicable to thermoplastics , which soften or melt when heated and solidify again on cooling. Thermosets, thermoset-matrix composites and highly cross-linked materials are not normally fusion welded; they are joined by adhesive bonding, mechanical fastening or special processes.
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Plastic welding is primarily applicable to thermoplastics , which soften or melt when heated and solidify again on cooling. Thermosets, thermoset-matrix composites and highly cross-linked materials are not normally fusion welded; they are joined by adhesive bonding, mechanical fastening or special processes.
Joint quality depends on material compatibility, cleanliness, moisture, surface oxidation, pressure during joining, heating time, tool temperature, stable cooling and prevention of polymer degradation.
PE, PP, PVC-U/PVC-C, PVDF, ABS, PA, PC, PMMA and other thermoplastics can be fusion joined when they are compatible and the surface is uncontaminated.
Amorphous plastics soften around the glass-transition temperature; semi-crystalline plastics have a more distinct melting temperature. Their process windows, cooling behaviour and shrinkage differ.
What the module covers
- Plastics are not joined like metals: polymer softening, chain diffusion and controlled cooling determine the result.
- Material logic: what the welding engineer must know before selecting a process
- Weldable materials
- Amorphous versus semi-crystalline
- Overheating is not preheating
- Drying and cleanliness
- Overview of plastic-joining methods
- Typical heated-tool butt-welding cycle for PE
Continue with the practical module.
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