Research On Thermo-plastic Forming Simulation And Forming Technology Of 2A12 Aluminum Alloy Tail Seat

In this paper,the major research object is the 2A12 Aluminum alloy the tail seat.The wall thickness of the part of Axisymmetric structure is thinner and it has many small groove,and its ends of the Max Outside Diameter were greater than the middle section.This subject decided to produce the parts in thermoplastic extrusion plus a small amount of block machining way.This subject also design elaborately processing technology,and improve the process in the method of finite element simulation.The last,we verify the feasibility of the process scheme through practical tests.The shape and size of forming parts is design,after the shape structure and forming difficulty of the parts are analyzed in detail.And accordingly we preliminary design of the shape and size of the blank,Determine the thermal forming process and the design of the die.According to the characteristics of materials and past related experience,the range of process parameters,such as extrusion speed and extrusion temperature,was determined.The geometric model is established,and introduced into the DEFORM-3D finite element software to simulate the extrusion process.After the Simulation results are analyzed,we find out the existing problems and optimize the preliminary design process plan,and improve the new process plan again and again until the good results of the simulation are obtained.Through the simulation analysis,it is found that there are some problems about the initial design process plan,traditional way,of unidirectional extrusion.When the bottom branches of the trail seat is deformed,the problem of folding is fund.Therefore,the second process plan is designed,and a set of compound die with double convex die is designed.Though the method of double step forming by single set die,the folding problem in the first process plan was solved perfectly,and the required load is smaller in forming.In the second process plan,firstly fixed lower punch,let the die and the lower material plate move down,the upper part of the trail seat is completed by this step;then punch through loading,and finish forming part of the trail seat base branches.In addition to the above problem of folding,when the extrusion deformation is simulated on the second plane,after the first load is completed,the central tail of the part appears at the top of the part.And when the second step is deformed,there is a problem of folding here.Later,the problem was successfully solved by increasing the thickness of the spare parts at the bottom of the part.The minimum pressure residual thickness to avoid the increase of central tails is determined by simulation,about 5mm.In addition,the simulation analysis of different process parameters,the optimum deformation temperature is 450 ?,the optimum deformation rate:deforming the 25mm with 10mm/s firstly,At the speed of 5mm/s until the first step is finished;when the second upper punch is loaded,it takes 10 mm/s to 13mm,and then 5mm/s to the end of the extrusion.After the final process was determined,the stress analysis of the die is carried out by DEFORM-3D in this subject,and the specific dimensions of the mold and auxiliary components are designed and manufactured.Finally,the second process plan is tested,the results show that the design process and the die structure can be applied effectively;the metal flow is uniform;the filling effect is good;the precision of the product is high and the finish is good;and the desired effect is achieved,which lay the foundation for the actual production of parts.It is also proved that the numerical simulation has a certain guiding significance for the actual production.