Metal Sheet Air Bending Model And Experiment Research

Air bending and bottoming are two main metal sheet bending methods. On one hand,comparing to bottoming, air bending is popular for its less requirement for equipment andenergy consumption, while with high efficiency in small batch manufacturing. On theother hand, due to its inherent flexibility and diversity in sheet bending, the precise controlof process parameters (especially the punch penetration) has always been a conundrum inthe sheet bending industry. In this study, systematic research and analyses of punchpenetration theoretical model, springback compensation and correction methods areconducted.In the research, starting from the process of two theories of air bending, punchpenetration simplified models before unloading existed are analyzed respectively in detail.Then a novel simplified model is proposed based on the relationship between bendingradius and up die fillet radius. Secondly, an experimental study of the influences ofprocess and mold parameters on springback is conducted. And finally, based on processdata base and linear interpolation method, a punch penetration compensation andcorrection method is proposed. To verify the applicability and industrial effectiveness ofthe model, actual experiments of sheet bending are conducted.The experiments are implemented in two equipment, Sheet bending machine (PR6C60×2550) manufactured by Jiangsu Jinfangyuan NC machine company Ltd. and Sheetbending machine (PPEB100T/30-4) provided by Hubei Tri-ring metal forming equipmentcompany Ltd.. In validation of the experimental result, the zero point, repetition andpositioning accuracy of machine and molds are examined. Experimental arrangements areas follows: comparison of the simplified punch penetration model before unloading andthe mature numerical control system (DELEM DA65W and Cybelec880S); Influentialfactors of springback analysis applying ABAQUS simulation and machine vision onlinemeasurement; and process data base correction experiment. The experimental resultsshows that the final bending angle error is within±0.5°adopting the proposed model. Andit satisfies the industrial precision requirement.The theoretical research and experimental results have been successfully applied inthe self-developed numerical control sheet bending machine software called HNC-SPB60,and relevant process experiments had been approved by the engineers of the HubeiTri-ring forging apparatus company Ltd.