| Stud welding is widely used in automobile,ship,bridge,pavement and other fields.It has the advantages of simple welding and fast forming.At present,the demand for studs at home and abroad is increasing every year,and the demand for welding quality is getting higher and higher.The number of welding workers can not meet the needs of the market,so they begin trying to use robots for welding.But when the designed welding robot is working,there are arc offset,Welding is not uniformity,etc.In this paper,the problem of welding robot is studied.A magnetic installation which is suitable for robot is designed to control the welding arc,avoid arc offset,and control the melting amount of welding metal.Making the welded studs uniform.The main research contents are as following:1.Choosing the magnetic type which is suitable for stud welding: Analyzing whether transverse magnetic field,longitudinal magnetic field,sharp angle magnetic field and rotating magnetic field are suitable for stud welding,and finally choosing rotating magnetic field to control welding arc;The feasibility and principle of magnetic field controlled welding arc are analyzed.2.Design open-close magnetic installation: Referring to the principle of three-phase asynchronous motor,six magnetic poles are used to produce the magnetic field.The designed magnetic installation mainly includes the excitation iron core,the excitation coil,the magnetic guide rod,the opening and closing mechanism,Excitation power PLC control program and insulation treatment.The magnetic field inatallation uses open-close type,which dosen't interfere with the robot;The magnetic installation can be automatically controlled by PLC.3.Analyzing the magnetic installation: Using ANSYS to analyze the harmonic magnetic field of the magnetic installation,changing the relative factors affecting the magnetic field intensity,observing the distribution of the magnetic inductance line and the change of the magnetic field intensity.Finding when the number of coil turns and the angle of the magnetic guide rod and the iron core change,the magnetic field is distorted,but the degree of distortion is very small,which has little effect on the magnetic field.According to the analysis results,choose parameters of the designed magnetic installation in order to making full use of the magnetic installation's space and maximizing the magnetic field's intensity.4.Experiment of magnetic controlled stud welding: When the welding robot appears arc offset,the magnetic field is applied to the welding area of the stud.By adjusting the excitation power supply voltage,the magnetic field's intensity of the device is changed.Several welding experiments were carried out.In contrast with the welding stud quality,with different magnetic field intensity and the application of magnetic field,we can know that applying magnetic field can control the welding arc and avoid the phenomenon of arcoffset.It can also control the amount of welded metal melting,making the welded stud more uniformity,explaining the design is feasible. |
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