Optimization Analysis Of Multi-point Forming Scheme For Aluminum Alloy Profiles

With the continuous development of industrial technology,the personalized demand for aluminum alloy curved parts is increasing.The application of multi-point forming technology is more and more extensive,one machine multi-purpose characteristics not only reduce the production cost,but also easier to achieve automatic production and improve production efficiency.Multi-point forming(MPF)method,although compared with other forming method has great advantages,but in profile parts forming processing applications are still less.so when profiles are formed using the multi-point forming technology,how to choose the appropriate multi-point forming method,and which process parameters need to be adjusted in the early production of the new process.These are the research emphases of this paperIn this paper,the forming method of aluminum alloy profile is studied combining with the finite element numerical simulation technology.According to the simulation results,the forming method and parameters are adjusted.Finally the profile parts with higher quality and shape accuracy meeting the requirements are formed,which will guide the actual production in turn.The main research contents of this paper are as follows:(1)The process characteristics and forming difficulties of aluminum alloy profiles are analyzed.The finite element mathematical models and springback models of three multi-point forming process,namely multi-point press forming,multi-point stretch forming and multi-point stretch-press forming,are established.(2)Analyze and compare the above three multi-point forming methods from forming precision and quality of parts.The results show that: There exist a slight crease and a large rebound in multi-point press forming parts;The shape error of multi-point stretch forming parts is relatively large,and there is the problem of poor film lamination;Multi-point stretch-press forming parts have better forming quality and higher shape precision.Therefore,this kind of aluminum alloy profile is more suitable to be formed by multi-point stretch-press forming method.(3)The influence of the process parameters such as friction coefficient,pretension and transition zone on the forming quality of parts is studied.The larger the pretension,the smaller the maximum springback of parts.Considering that the greater the pretension,the greater the thinning of parts,the pretension of 141 k N is chosen;The smaller the friction coefficient,the more uniform the stress and strain distribution of the formed parts,so the friction coefficient should be reduced as much as possible in actual production;The larger the transition zone is,the better forming quality will be,but it will lead to a large utilization rate of materials.Therefore,the length of transition zone should be reduced as far as possible while ensuring the forming quality of parts.The length of the transition zone is about 70 mm.(4)The springback compensation coefficient k = 1.128 was adjusted according to the finite element simulation results.After the springback compensation,the maximum error between the profile parts and the target shape is effectively reduced,and the shape accuracy of the parts is greatly improved.(5)Carry out actual test according to existing equipment.The results show that the contour curves of the test parts are basically consistent with those of the finite element simulation parts.The experimental results verify the correctness of the finite element model and provide a basis for the reliability of the work in this paper.