Development Of Robot Hollow Stud Rotating Arc Welding Gun And Study On Its Welding Process

Aiming at the requirement of automatic welding of hollow studs,based on the research of robot automatic welding system,this paper presents the hollow stud arc welding scheme,and designs an automatic rotating arc welding gun.The welding gun includes stepping motor unit,electromagnetic arc stud welding gun body,gripper unit,radial symmetrical magnetic field unit and linkage mechanism According to the characteristic of the welding gun,the corresponding robot work station is designed.The workstation includes hollow stud welding gun,six-axis industrial robot,flexible welding platform,stud welding power supply and rotating arc magnetic field power supply,and the corresponding control module.The workstation can automatically weld hollow studs and improve positioning accuracy,welding efficiency and degree of automation.Welding torch design mainly includes the application of magnetic field to rotate the arc,the use of stepper motor automatically control the height of stud welding arc,the new gripper chuck,and redesigned the framework of the gun.The welding gun is stable and reliable.It can grasp any stud from 12mm to 60mm height and diameter from Φ12mm to Φ32mm.The height of the arc can be adjusted from 0mm to 5mm,radial symmetric magnetic field unit can produce a radial symmetry magnetic field through the end face of the stud,Let the welding arc rotate,and perform welding procedure tests。After the magnetic field was applied to the welding arc,the shape of the arc was changed.Using COMSOL Multiphysics to construct the 1:1 scale model,the magnetic field was defined to simulate the distribution of the magnetic field between the stud and the base metal.Welding current and magnetic field current,the result shows that we can get a best welding joint when the radius of rotation arc is 2mm larger than the radius of the stud.And design an APP to adapt to facilitate the process simulation of other types of studs.Through the analysis of the control requirements of each module,the control scheme of maniplating the welding gun and welding process with robot control cabinet is designed.Which uses Siemens PLC,and EM253 module control stepper motor,NX100 control cabinet outputs signals to the PLC in the form of 4-bit binary number,control screw nut movement distance in 0.5mm units,and ultimately control the arc height,while NX100 output The terminal block directly controls the opening and closing of the solenoid valve,the welding power supply and the rotating arc power supply,and finally completes the whole welding process directly through the preparation of the robot programExperimental study on the hollow stud process with 16mm outer diameter and 8mm inner diameter,the optimum welding parameters are arc height of 3mm,pre-pressing depth of 4mm,welding current of 800A,welding time of 800ms and arc magnetic field current of 0.7A,and the shear strength of the joint can be achieved 362Mpa,The comparison of the process shows that the application of arc-magnetic field basically solves the problem of partial arc,and the increase of magnetic field current helps to spread the arc outward.The main results and innovations of the study are as follows:On the basis of the original welding gun design,a new automatic hollow stud rotary arc welding gun and automatic control scheme are designed by using the principle of rotating arc,which provides complete welding equipment for hollow stud automatic welding,the equipment is stable and easy to operate,and the equipment is used to carry out a kind of stud process test to obtain a welded joint with good appearance and high shear strength,the mechanism of spiral arc process is analyzed by software simulation,and the mechanism of welding current and arc current is analyzed,which can lay the foundation for stud process test of other models.