Experimental Study On Multi - Point Compound Progressive Forming Of Metal Sheet

Sheet metal incremental forming is a new rapid prototyping technology that has no need to use a die. It has been gradually used in aerospace components, car parts, medical devices and some plate and shell parts which is one-piece, small batch, and varied due to forming without special die. For single point incremental forming process, due to the uneven force leads to the instability of plank, the uneven wall thickness and the problem of stress concentration and low forming efficiency, combining high efficiency advantages of multi-point forming (MPF), this paper proposed a new method of sheet metal parts forming the sheet metal, which is called incremental multi-point forming.This method not only reduces the defects in the single point incremental forming process, but also avoids the difficulty in the accuracy of MPF controling on a large number of substrates. Finite element simulation analysis and the forming experiments were used to carry on the experimental research on the quality of incremental multi-point forming.Main research results of this paper:(1) Combining sheet metal single point incremental forming and MPF mechanism, this paper has proposed a new method of sheet metal parts forming called metal sheet incremental multi-point forming technology.The forming experiment machine is developed based on the forming principle and experimental requirements.(2) By establishing the MPF incremental forming finite element model and analyzing the impact of different forming paths on the quality of incremental multi-point forming on the circumstance of the same process parameters, this article has found the best forming path of incremental multi-point forming for metal sheet.(3) Based on the defects of sheet incremental multi-point forming, the quality evaluation criteria has been established. By the orthogonal experiment, the author analysed the problems such as the uneven wall thickness and so on, used the range method to get the most optimal process parameters combination of the evaluation indicators, got the influences of process parameters on the forming quality trend by the regression analysis, and set up the regression forecasting model of process parameters and evaluation indicators. By using the main target method to optimize the comprehensive evaluation model of incremental multi-point forming, the optimal process parameters were obtained.(4) The author used the testing machine of metal sheet incremental multi-point forming which is independently developed to experience the worst set of optimal process parameters and the best, which had been tested by the simulation experiments, and verified the correctness of the finite element model through the experimental results. At the same time, the vibrational and incremental multi-point forming experiment was carried out. The results show that vibration applying based on the incremental multi-point forming has some advantages that are a lower plate deformation resistance, processing and energy consumption, and improvement of the forming quality of parts, etc.The author studied the influence of different process parameters on forming quality in incremental multi-point forming, which provided a reliable basis for the theory analysis of sheet incremental multi-point forming, filled with a wealth of research value.