Abstract:Friction welding has the advantages of high strength, high welding efficiency, stable quality and good consistency, and can realize welding between different materials. Frequency conversion drive control of welding parts is the key technology of friction welding machine. Its speed control performance directly affects the welding performance and efficiency. Based on the basic working principle of friction welding and the specific technological requirements of a special welding machine for electrolytic aluminium, a new friction welding machine control system with Siemens S120 high-performance frequency converter and S7-400 programmable logic controller as the core was developed. The field operation result of the equipment shows that the scheme fully meets the technical requirements of the welding machine, and has good performance and reliable operation.