The welding of thermoplastics principally includes the fusion of plastified join partners into a substance-to-substance bond under pressure.

Welding depends on the following three essential factors:

• welding temperature,
• welding load,
• welding periods

All three factors are typical of every weldable thermoplastic and have to be within certain tolerance ranges. If only one of the three factors mentioned lies outside these tolerances, the quality of the welding seam is fundamentally called into question.