This method also belongs to the friction-welding processes. The top tool - and with it the weld part's upper half - is put into a rotating vibration, whereby the specified movement characteristics can range from a flat ellipse to a circle. After applying appropriate vertical pressure this frictional movement causes plasticising in the weld zone. Once the subsequent cool-down phase is completed the weld part halves are homogenous and firmly joined.
The advantage of the constant frictional velocity is besides the relatively very brief welding time the extremely short deflections and low shear forces. They allow for greater freedom in the construction design of the weld parts compared to the linear process and permit thinner wall strengths.
