Tube inversion including free deformation under conical die is an advanced forming process for manufacturing complicated thin-walled parts with high strength/weight ratio, high efficiency, and good flexibility for siz...Tube inversion including free deformation under conical die is an advanced forming process for manufacturing complicated thin-walled parts with high strength/weight ratio, high efficiency, and good flexibility for size changing.However, the successful reality of forming process, the change of deforming mode and shape and size of part formedare mainly on the die angle. Based on the analysis of the forming process, the model of rigid-plastic FEM (finiteelement method) is established and a numerical simulation system is developed. The effect of die angle on the tubeinversion forming process is investigated with the code developed. The results of the effect of half die angle on shapeof free deformation zone and on deforming load are obtained. There is an optimal die angle (about 75 deg), whichmakes the forming load minimum.展开更多
Polishing is an important finishing process in die and mold manufacturing. Hand polishing takes long time and much labor. Efforts are made to automate the polishing process while keeping accuracy. Recently grinding ce...Polishing is an important finishing process in die and mold manufacturing. Hand polishing takes long time and much labor. Efforts are made to automate the polishing process while keeping accuracy. Recently grinding centers have been developed, which are used for free surface polishing in the present work. The new polishing technique applies the same cutting locus as used in the cutting process to remove only cusp height effectively, keeping the form accuracy generated in the cutting process.展开更多
The bending section of tube between the bending die and the guider is in a less constrained state during the free bending process.The free bending dies have the important impact on the plastic deformation behavior and...The bending section of tube between the bending die and the guider is in a less constrained state during the free bending process.The free bending dies have the important impact on the plastic deformation behavior and the forming quality of tube.To study the evolution law of the deformation behavior of tube with the die structure parameters and optimize the free bending die parameters,the free bending experiments and the corresponding numerical simulations were carried out.The design principle of free bending die was illustrated.The free bending experiment was conducted to verify the reliability of the numerical simulation method.Based on the numerical simulation results,the influence of the distance between the center point of bending die and the front end of guider on the forming quality of bent tube is more obvious than that of the fillet of guider.However,the fillet of bending die hardly affects the stress and strain distribution and the evolution of the wall thickness.Finally,the free bending experiments with the newly determined free bending dies were conducted.The ultimate bending radius of bent tube is reduced and the forming quality is improved.展开更多
基金The authors would like to thank the National Natural Science Foundation of China for Distinguished Young Scholar (No.50225518), NSFC (59775055) and Doctorate Foundation of Northwestern Polytechnical University for support to enable the perform ing of this research.
文摘Tube inversion including free deformation under conical die is an advanced forming process for manufacturing complicated thin-walled parts with high strength/weight ratio, high efficiency, and good flexibility for size changing.However, the successful reality of forming process, the change of deforming mode and shape and size of part formedare mainly on the die angle. Based on the analysis of the forming process, the model of rigid-plastic FEM (finiteelement method) is established and a numerical simulation system is developed. The effect of die angle on the tubeinversion forming process is investigated with the code developed. The results of the effect of half die angle on shapeof free deformation zone and on deforming load are obtained. There is an optimal die angle (about 75 deg), whichmakes the forming load minimum.
基金Project supported by the Natural Science Foundation of Shaanxi Province(Grant No.2006E112)
文摘Polishing is an important finishing process in die and mold manufacturing. Hand polishing takes long time and much labor. Efforts are made to automate the polishing process while keeping accuracy. Recently grinding centers have been developed, which are used for free surface polishing in the present work. The new polishing technique applies the same cutting locus as used in the cutting process to remove only cusp height effectively, keeping the form accuracy generated in the cutting process.
基金The investigation was supported from the Opening Project of State Key Lab of Digital Manufacturing Equipment&Technology(No.DMETKF2021004)the National Natural Science Foundation of China(Nos.52105360,U1937206,and 52175328)+1 种基金2021 Jiangsu Shuangchuang Talent Program(JSSCBS20210157)Fundamental Research Funds for the Central Universities(No.NS2022061).
文摘The bending section of tube between the bending die and the guider is in a less constrained state during the free bending process.The free bending dies have the important impact on the plastic deformation behavior and the forming quality of tube.To study the evolution law of the deformation behavior of tube with the die structure parameters and optimize the free bending die parameters,the free bending experiments and the corresponding numerical simulations were carried out.The design principle of free bending die was illustrated.The free bending experiment was conducted to verify the reliability of the numerical simulation method.Based on the numerical simulation results,the influence of the distance between the center point of bending die and the front end of guider on the forming quality of bent tube is more obvious than that of the fillet of guider.However,the fillet of bending die hardly affects the stress and strain distribution and the evolution of the wall thickness.Finally,the free bending experiments with the newly determined free bending dies were conducted.The ultimate bending radius of bent tube is reduced and the forming quality is improved.
