Research And Optimization On Numerical Control Incremental Sheet Forming Process Through Multi-Step Toolpaths Of Taillight Supporter Of Car

Automobile panel plays an important role in the development of new automobileproducts. However, at the present most product development of concept vehicles mainlyrelies on traditional technologies of die-testing, which takes much time and funds.Therefore, it’s urged that new techniques be provided to the automobile panelproduction. It is Numerical Control Incremental Sheet Forming (NCISF) that fits in withnew products development. Hot concerns are focused in this new field. NCISF is a newsheet metal forming technology, which meets the demands of market and has wideapplication because it can accelerate the new products development and improve theforming quality. This paper breaks through the past research limitations onaxis-symmetric parts in sheet incremental forming and focuses on the forming ofTaillight Supporter of Car with the characters of high geometrical complexity andtypical deep-drawing. An in-depth study of the NCISF in taillight supporter will becarried out through theoretical analyses, process planning, finite element simulationsand experimental studies, which makes an important significance to the development ofautomobile manufacture, especially the new vehicles.First of all, the process scheme of ISF through multi-step tool-paths of taillightsupporter is designed detailed. the technology model of taillight supporter ISF isdesigned after the feasibility analysis of parts ISF. A multi-step ISF strategy isspecifically designed for taillight supporter ISF because of vertical wall and concave pitcannot be formed in single-step strategy. transition surface is designed by the methodof surface construction and the multi-step tool-paths is designed of taillight supporterISF，a blank-holder device is also designed.Secondly, based on elastic-plastic finite element theory and by means of dealingwith some key problems, such as element types, material models, strategies of dynamicload of tool-paths, contact conditions and friction models, etc, a finite element model ofISF of taillight supporter with consideration of both precision and efficiency isestablished, which can objectively reflect the ISF process through multi-step tool-paths.The technologic surface is optimized and reconstructed according to the numericalsimulation results of the parts’ wall-thickness and stress-strain parameter, which solvesthe problems arising during the parts’ incremental forming processes. Thanks to theminimum wall-thickness of the parts is basically consistent with the original design, the die model is finally determined, which realizes the design and manufacture of die.Finally, do experimental researches on ISF through multi-step tool-paths oftaillight supporter, considering the unification between the main evaluation indexes ofprocessing efficiency and forming quality. the selections of key process parameter,such as step size, forming speeds, the diameter of tool and so on, are studied during theexperimental researches. Then, tool-paths that makes a great impact on parts ISFthrough multi-step is studied, the transition surfaces is optimized according to sortingout the remaining problems in forming concavity and vertical wall by primary designdouble-steps method. Although this can greatly avoid the appearance of cracks instraight-wall, the problems of cracks and stacking still exist. So the forming by zoningmethod is proposed, which can greatly improve the formability of concavity andstraight-wall. As to the problems occurring at the fillet position between differentdistricts connection during the forming by zoning method, the forming by zoning baseon high partial forming method is also presented to have a good influence on thetaillight supporter forming quality.