The Research Of Push-pullwire Feed Welding Equipmentand Process

With the development and the progress of modern science andtechnology,Welding technology has become one of the most important modernmanufacturing technology.Energy saving, reduction of material and reducingconsumption has become the inevitable trend of industrial development and progress,so the demand for sheet metal welding will continue to increase.The problems ofsheet metal welding to be solved are improving weld quality and reducing heatinput.Designing a push-pull welding wire of low energy which is different with thetraditional method of short circuit transition,it uses the external mechanical force tocomplete drop short circuit transition.This method can reduce the input of energy, andcan reduce welding splash,and control the energy of the whole welding process bysetting the parameter.Eventually it make stable welding process and weld is good.In order to meet the requirements of the above methods,designed a push-pullwire feed welding system,it includes the main power supply, control systems, wiresystem. Main power section features a full-bridge inverter form,power control sectionuses the dual-loop current-mode PWM,it uses current-controlled chip UC3846as thecore.Control system uses DSP computing power of16-bit microcontrollerdsPIC30F6011as the master chip and designs specific control scheme to coordinatewith the main power wire system’s work.Wire system uses a permanent magnetsynchronous motor with laboratory original motor drive system to meet therequirements of the wire feed control.According to the design of the control scheme,we has carried on the selectionand optimization of welding parameters and realized the stable weldingprocess,molten droplet smooth transition,weld uniform appearance, energy adjustablerange of push-pull wire feed welding system.Wire speed and wire feed speed isstudied on the influence of weld forming and welding energy.With the increase ofwire feed speed, the weld is widen and the parent metal heat input is larger.Thenarrower the welding speed, the greater the weld and the higher.When the wire feed control strategies conditions remain unchanged,differentoutput power parameters has been studied the influence law of the matching of thewelding process.The results show that when the the early stage of the arc currentvalue Iapand time Tapboth increase, the energy input in the process of welding andwelding wire deposition rate are increased.We Have studied the different Iapand Tap on the influence law of weld matching relations.More energy can be used to melt thewelding wire and reduce heat input for the base metal when increasing Tapanddecreasing Iap.In wire control strategies under the same conditions, different outputpower parameters has been studied the influence law of the matching of the weldingprocess.When the power output conditions remain unchanged,wire feed controlstrategies has been studied the influence law of the matching of the weldingprocess.The results show that when the other parameters constant, with the increase ofwithdrawing delay time, frequency of short circuit transition welding process andwelding energy as is reduced, but the drop size bigger.When fixed Withdrawing delaytime,with Withdrawing speed increasing, the welding energy becomes larger.Byincreasing the speed of wire feed system and improve current control scheme toimprove the system performance,to further improve the welding quality and expandthe application range.