Research On The Method Of Double Side Incremental Forming And The Strategy Of Tools' Cooperative Motion

Compared with the traditional stamping technology,incremental sheet forming(ISF)is a new-type dieless and flexible manufacturing technology,which is used for producing low batches of sheet metal parts rapidly.Double side incremental forming(DSIF)is an emerging technology in ISF in recent years.Comparing to the conventional single point incremental forming(SPIF)process,the DSIF process employs two forming tools on both sides of the sheet,which can provide additional process flexibility and produce complex geometries without the need of using a backing plate or supporting die.However,in addition to the two tools' movement strategy,combining the DSIF process and the existing forming processes together should be further explored and analyzed.Therefore,the deformation mechanism and mechanics analysis of the material in ISF have been summarized,and the technological measures to improve the formability and accuracy have been sum up.Based on these work,a kind of toolpath generation methodology and some new types of DSIF strategy are developed in this paper.The main research results are as follows:1)Based on the triangular mesh stratifying method in STL files and geometric analysis method,the ISF toolpath generation methodology was constructed.By employing this methodology,the DSIF contour or helix toolpath can be generated with a constant step size or constant scallop height.It can improve the computational efficiency and provide the feasibility for the subsequent research on DSIF process and tools' movement strategy.2)By employing the advantages of the multi-pass ISF and DSIF,a multi-pass DSIF strategy was proposed,which could effectively form the complex sheet metal parts.Comparing with the SPIF process,this strategy has a higher geometric accuracy and more uniform thickness distribution with the thinning rate decreasing by 19%.Additionally,a design algorithm of intermediate profile in multi-pass DSIF process was developed,which could generate the geometric profile effectively.3)A DSIF reverse bending strategy and a DSIF squeezing strategy were presented,and the working principle of the two DSIF processes was qualitatively analyzed.The experiment results indicate that the DSIF reverse bending strategy has a characteristic of springback compensation and straightening function by bending and reverse bending the sheet to reduce the residual stress,which can reduce the degree of springback by 60%.And the results also reveal that the DSIF squeezing strategy has a characteristic of suppressing springback with a squeezing effect,which can reduce the degree of springback by 30%.In addition,the rule of different parameters influencing on the springback was summarized.In current work,the studies about the multi-pass DSIF process,DSIF reverse bending strategy and DSIF squeezing strategy,benefit to obtain better understanding of ISF process.It can effectively deal with the problems of thickness thinning and springback in ISF.The achievements of this research vigorously promote the application of DSIF process to the industrial field.