Research On Welding Seam Tracking Arc Sensor Under Non Uniform Longitudinal Magnetic Field

With the large-scale construction of various domestic projects,the track forming and processing of complex parts are widely used in various fields,so there is a very urgent demand for the automatic welding of complex tracks.Welding is an irreplaceable material forming and processing technology in the field of advanced manufacturing.TIG welding(tungsten inert gas welding)has the advantages of high stability and good weld bead quality,which is widely used in complex trajectory forming welding process.But TIG also has its own shortcomings: low welding efficiency,slow welding speed,etc.with the scale construction of domestic construction,automobile,electronics,aviation and other fields of manufacturing projects,the TIG arc welding process at this stage has been unable to meet the growing production demand,so optimizing its process and improving its degree of automation has become an urgent problem to be solved.Because TIG arc is full of various charged particles,the external magnetic field can be introduced to control the arc to achieve the purpose of improving the welding intelligence,and the magnetic control sensor can not only obtain the weld space position information for weld recognition,but also improve the energy distribution of the arc by changing the shape of the arc,so as to improve the welding efficiency and optimize the weld forming effect.Therefore,the new subject of MAG arc is to improve welding efficiency and weld formation.In order to solve the problem of noise interference in the process of mechanical welding seam identification,a TIG welding seam identification technology based on non-uniform longitudinal magnetic field is proposed.Magnetic controlled arc has the advantages of strong real-time performance and not easy to be affected by arc light.It is widely used in various material processing processes.With the help of COMSOL software,magnetohydrodynamic(MHD)equation is established as the simulation model of plasma arc.The heat,voltage,current and flow field of TIG arc column change with the change of external magnetic field under the action of longitudinal magnetic field(LMF),and the mechanism is analyzed.Finally,the numerical analysis and experiment are compared,The evolution law of arc particle rotation radius,arc swing frequency and arc temperature distribution controlled by non-uniform longitudinal magnetic field is revealed.The introduction of longitudinal magnetic field can change the arc trajectory,so as to improve the arc voltage and temperature distribution.The arc spirals downward,and the distance of charged particles' trajectory increases.Macroscopically,the length of arc column becomes longer,which leads to the increase of arc voltage.At the same time,the flow of molten pool intensifies,which changes the crystal crystallization conditions.By introducing the magnetic field condition of simulation results,the experimental platform of longitudinal magnetic field traction TIG arc trajectory is built.The arc trajectory under the influence of different longitudinal magnetic field distribution intensity is stored by using high-speed camera,and the effect of multiple groups of longitudinal magnetic field distribution intensity on arc trajectory is analyzed;At the same time,the current voltage sensor is used to collect the arc signal under the action of LMF.The results show that the non-uniform longitudinal magnetic field can pull the direct current TIG plasma to shrink or expand and deflect periodically,which further proves the possibility of non-uniform longitudinal magnetic field to pull the TIG plasma arc column for weld identification.Therefore,the research on weld identification of DC Positive TIG arc controlled by non-uniform longitudinal magnetic field can greatly improve the quality of welding products and welding production efficiency,and achieve a breakthrough in welding technology.