Study On The Structure Improvement And The Welding Procedure Of Key Weld Bead Of Loader Front Frame

The front frame is a pivotal part of loader which connects the back frame, thefront axle and the work installment. The designing level of the front frame affectscapability of the front frame and then the loader such as strength, stiffness, reliability,economy and so on.Finite element analysis and optimization are modern designmethods; the stress and strain of the front frame in each work condition are obtainedby the finite element analysis of the front frame, and the the optimization improvesthe structure and capability of the products. So the finite element analysis andoptimization play important roles in the design of the loader.Accurate results of the loads applied on the front frame in8work conditions areachieved; an appropriate finite element model of the front frame is built; and the stressand strain of the front frame in each work condition is obtained by the finite elementanalysis.Based on the results above,the initial structure optimization of the front framein the shape and layout makes the distribution of stress and strain more reasonable.Based on the results of finite element analysis of the front frame after shapeoptimization design, the design variables, constraints and the objective are selected,and then the optimization design mathematic model is built.Excellent optimizationresult of the front frame is achieved, and the maximum stress of all the work conditionis decreased to248MPa from130MPa, the weight is decreased from1537kg to1361kg,the target of the optimization is achieved overfull.Combining practical matters, the analysis discusses about the loader front frameof the robot welding engineering, combining production and teaching, we find that thetypical weld structural features of front frame is single tee fillet weld,we devise anexperiment using orthogonal test method, varying wire feed speeds, welding speedand extension rod, recording current value and voltage values, keeping the otherwelding parameters constant. We use welding robot teaching system programmingreappearance, control the parameters strictly and weld plate lab according to the testdesign scheme. Through examining appearance of weld, calculating weld heat input,watching the appearance of welding line section, measuring the size of penetrationwidth, observing metallographic microstructure, testing micro-hardness and tensiletest, we research the craft process and principle of the robot automated welding.Besides, it theoretically analyses the relationship between welding parameters and theeffect on welding quality. The analysis provides a referenced basis for production,through evaluating and analyzing the quality of weld, and giving an optimized choice for welding parameter.This article concludes that when using to weld10mm fillet sided T-shaped filletweld in front frame of loader, the parameters should be selected like follows: wirefeeding speed of13m/min, stem elongation of24mm, welding speed of0.45m/min,boat position welding.