Design Of Resistance Butt-welding Machine Based On PLC

Pc strand is characterized by its high-strength,low-relaxation,which can help to improve sharply the life of building,therefore,it is widely used in various fields.The key factor to limit the production efficiency and the product quality of Pc strand is the welding of fracture of wire.As the welding character of the raw material is not so good,which is liable to form a martensite microstructure inside the welding field,leading to produce the seam in the drawing and skipping process,thus causing the fracture of wire.This thesis is focused on the positive current experiment on the current resistance butt-welding machine,therefore,it not only discovers the internal law of the welding parameters,but also finds out the defection of the current resistance butt-welding machine.The upsetting force and upsetting quantity is so small,which cause the loosen microstructure and the welding waste in the welding field.Therefore,the mechanics character of the welding field is far more lower than its parent materials,which can not meet the production requirements.On basis of the shortcoming of the butt welding machine,this thesis designs a totally new mechanic structure,adds the upsetting force and upsetting quantity,and adds the forcing pressure accordingly,which can ensure the non-moving of the cable materials between electric poles during the course of welding.In order to realize the efficient functioning of the mechanic structure,this thesis adopts Siemens,S7-200 series PLC,and TD400C screen,which form the electric control system.By means of adding the welding thermos and adding the dual annealing thermos PID adjusting,it can improve the welding and annealing function effectively.Through a good combination of software and hardware,it can realize perfectly the welding and annealing operation of the butt-welding machine,and also it successfully develops a resistance butt-welding machine based on the PLC.Through the positive current experiment,the best welding and annealing parameters of the double-upsetting resistance butt-welding machine is confirmed.Under such technique parameters,the welding experiment anti-pulling tension can reach 1010MPa,and the extension rate is around 26 per cent,also the welding line diameter is around 95 per cent of its parent materials,also,the grain inside the welding field is refined.During the production practice,by using the machine,the rate of fracture of wire is dropping down to 1 time per 100 tons from 4 times per 100 tons..Thus,the company can add RMB 2 million per year as profit.