Study On Welding Technology And Equipment Of Magnetic Separator Dielectric Box

The dielectric box is the core part of the magnetic separator,which determines the purity and efficiency of iron ore screening.Moreover,the dielectric box is easy to damage.At present,the dielectric box adopts non-melting argon arc welding,which is completed by manual welding.Manual welding not only has low production efficiency,high labor intensity and low product qualification rate,but also is very harmful to workers' eyes and skin.Therefore,it is of great significance to design a dielectric box welding equipment with high welding efficiency,good welding quality and high qualification rate to reduce the labor intensity of workers,reduce the cost of enterprises and improve the competitiveness of enterprises.The dielectric box is composed of three nickel-iron alloy plates and a large number of soft magnetic alloy bars.At present,manual welding process is selected according to experience,not only the welding quality is poor,but also the product qualification rate is low.Therefore,this paper studies the influence of welding current,welding speed,argon flow,nozzle diameter,arc voltage and other welding processes on the welding quality.Then,three important process parameters(welding current,welding speed and arc pressure)are optimized by orthogonal test to determine the optimal welding process parameters.Finally,the process optimization results are verified by experiments.The welding sequence has great influence on the welding deformation of the dielectric box.Therefore,this paper uses ANSYS to analyze the temperature field,stress field and deformation field of the single-pass welding seam of the dielectric box,and obtains the influence of TIG welding on the stress and deformation of the dielectric box.Then,ANSYS is used to simulate the different welding sequences of the dielectric box.The effects of different welding sequences on the transverse and longitudinal deformation of the dielectric box were compared.Find the welding sequence that produces the minimum shape variable.Finally,the simulation results are verified by experiments.After analyzing the structure,welding technology and quality requirement of the dielectric box,this paper designs the special rectangular coordinate welding equipment for dielectric box.The device uses a symmetrical mechanical structure with a moving gantry double-arm double welding torch.Simultaneous welding of the double-sided symmetrical position of the dielectric box is achieved.Not only the welding deformation of the dielectric box is reduced,but also the welding efficiency is improved.The welding equipment adopts mechanical structures such as ball screws,rack and pinion,linear slide rail and servo motors to realize linear motion in three directions of X-axis,Y-axis and Z-axis.Not only is the development cost low,but the motion accuracy is high.In order to reduce development cost and shorten development cycle,this paper adopts modular design to design the control system of welding equipment,and complete the design of main control module,arc voltage acquisition module,arc voltage distance-regulating module and human-computer interaction module.Because the thermal deformation of the dielectric box leads to the nonlinear change of arc voltage and affects the welding quality,the design of arc voltage distance-regulating system is carried out in this paper.The arc voltage distance-regulating system can adjust the distance between the tungsten electrode and the welding spot by detecting the arc voltage,so that it can be stabilized in a reasonable range.The system adopts LMS filtering algorithm and expert PID control algorithm to realize the accurate measurement and adjustment of welding arc voltage.Matlab was used to establish the functional model of the arc voltage distance-regulating system and carry out simulation analysis.Finally,the experimental results show that the arc voltage control accuracy reaches ±1V.