Direct Drive Friction Method
Two workpiece parts to be joined are clamped rigidly in a sturdy fixed unit usually called the tailstock fixture and a rotating chuck assembly or collet drive.
The spindle, which includes one of the workpieces to be welded, is accelerated to a predetermined speed.
Spindle drive power source continues to rotate the spindle while the non-rotating workpiece is pushed lightly against the rotating piece.
Rotation and pressure are continued for a predetermined time (or scrub/burn-off length) until the workpiece interfaces are heated.
Spindle drive power is discontinued with or without braking. At the same time, axial pressure usually increases until the completion of the welding sequence.