Direct Drive Friction Welding

Direct Drive Friction Welding is a variation of friction welding in which the energy required to make the weld is supplied by the welding machine through a direct motor connection for a preset period of the welding cycle.

In Direct Drive Friction Welding, one of the work piece is attached to a motor-driven unit while the other is restrained from rotation. The motor-driven work piece is rotated at a predetermined constant speed. The work pieces to be welded are forced together and then a friction welding force is applied. Heat is generated as the faying surfaces (weld interfaces) rub together. This continues for a predetermined time, or until a preset amount of axial shortening (upset) takes place. The rotational driving force is discontinued and the rotating work piece is stopped by the application of a braking force or a weld itself (Inertia Welding). The friction welding force (forge force) is maintained, or increased, for a predetermined time after rotation ceases. The relationship between the Direct Drive Friction Welding parameter characteristics is shown in the diagram.

MTI's Hybrid Direct Drive Friction Welders use AC or DC variable speed drives that eliminate clutches and brakes. Proportional hydraulic controls guarantee smooth up and down force control. Through manipulation of deceleration times and forge force ramp up time, welds can be made ranging from near Inertia Friction welds to classic Direct Drive Friction Welds.