Research On Welding Equipment And Control Technology Of Friction Plug-riveting Hybrid Welding

In recent years,with the rapid growth in the use of automobiles,the energy crisis and environmental pollution issues are imminent.Lightweight bodywork is an important way to achieve energy saving and emission reduction.Aluminum alloys are widely used due to their light weight and high strength.However,there are some problems with the connection of aluminum alloy and steel.Traditional welding methods will produce brittle and hard intermetallic compounds at the joints and affect the joint performance.Friction plug-rivet composite welding is a welding technology that uses high-speed rotating rivets to penetrate aluminum alloy and perform friction welding with steel.This welding technology can directly connect aluminum alloy and highstrength steel without pre-drilling and pre-treatment.It is favored by the high-end automotive industry.This subject develops a friction plug-riveting hybrid welding starting from the welding process.Welding tests on aluminum alloy and high-strength steel are performed to verify the practicability and stability of the welding equipment.This paper analyzes the technology of friction plug-rivet composite welding,determines the functions required for welding equipment,and formulates the equipment design requirements and performance indicators.Welding equipment is divided into three major systems: mechanical,electrical and software control.According to the required functions and motion characteristics of the equipment,the mechanical system is divided into a driving part,a transmission part,an execution part and an auxiliary support part,and the schemes of each part are compared and determined.At the same time,the control scheme of the electrical control system was also determined.According to the design scheme of the mechanical system,the axial motion device,the rotary motion device and the frame are designed.Calculate and select the ball screw,timing belt,reducer and servo motor used for axial movement,and select a suitable encoder according to the positioning accuracy.The servo motor and film coupling used for the rotary motion are used for calculation and selection.Finally,a three-dimensional model of the mechanical structure was designed in Inventor software to complete the overall assembly of the mechanical structure of the equipment.According to the design scheme of the electrical system control,AB PLC was selected as the controller,and Kunlun touch screen as the man-machine interface.Due to the high positioning accuracy of the welding axial movement,the semi-closed loop feedback of the servo motor encoder alone cannot meet the accuracy requirements,so the full closed-loop motion control is used.The hardware design of the equipment is completed,and the control cabinet is laid out for each component to realize the motion control of welding.Design human-machine interface for setting process parameters and monitoring operation status.Functional tests were performed on the friction plug-rivet composite welding equipment.First,configure the controller,human-machine interface and servo driver,and then test the manual operation,automatic operation and parameter setting modules,which all meet the design requirements.The accuracy of the axial motion positioning was tested to meet the performance indicators.Finally,6061 aluminum alloy and 980ultra-high-strength steel were used for several welding tests,and good welding results were obtained.The test results prove the practicability and stability of the friction plugrivet composite welding equipment studied in this subject.