Abstract: A processing mechanism is provided, including: a welding head, where the welding head has a welding mark end surface at an end in a second direction, and a middle portion of the welding mark end surface in a first direction protrudes, so that the welding mark end surface is curved in an arch shape; and welding teeth distributed on the welding mark end surface. Since a front portion or rear portion of the welding mark end surface in a reciprocating vibration direction is bent away from a to-be-welded workpiece, when the welding mark end surface is inclined due to friction, a pressing force of the front portion or rear portion of the welding mark end surface on the to-be-welded workpiece can be reduced, avoiding or reducing the risk of cracks occurring in the front portion or rear portion of a welding mark region.