A number of techniques are used for welding plastics (polymers). Lower frequency and higher amplitude are used in ------------------- welding.

In friction welding, the two parts to be assembled are rubbed together at a lower frequency (typically 100-300 Hz) and higher amplitude than ultrasonic welding. The friction caused by the motion combined with the clamping pressure between the two parts creates the heat which begins to melt the contact areas between the two parts. At this point, the plasticized materials begin to form layers that intertwine with one another, which therefore results in a strong weld.