Metal Sheet Air Bending Model And Experiment Research

Two main bending methods of sheet metal numerical control bending machine areclose-die bending and air bending. Because of its low requirement for press brake andforming flexibility, air bending has already been the most common bending method forthe entire metal sheet bending industry. However, the advantages of air bending also bringsome shortcomings for the sheet bending process, such as the lack of machining precision,more than two try-outs needed in order to get the fine result workpiece. This thesis doessome critical research on the air bending process for numerical control metal sheetbending machine.The thesis starts with a brief introduction of principles of the air bending process,analyses the related parameters of the air bending process, and focuses on the research ofpunch penetration model before unloading. According to the dimension variations of thetools in different models, a bending radius and punch radius relationship punchpenetration model is proposed. In order to stabilize the precision problem brought by thesimple calculation model, a database based interpolation method of punch penetration isbrought to apply in the machining procedure. Some feedback experiments are conductedto prove the adaptability and validation of the model.The experiments of the models mentioned above are conducted on three differentkinds of press platforms with a various specifications, a10KN precise servo control presssystem, a30KN single cylinder hydraulic press system and a600KN(3+1axis) numericalcontrol sheet bending mechine system. For the validation of the experiments, the precisionof returning to zero and positioning repetition of these systems are thouroughly analysed.The expriments for punch and die radius simplification model, punch radius simplificationmodel and database based interpolation model are conducted successfully to validate theutillty fo the punch penetration model.The research and experiment results are successfully applied on the sheet bendingmachine process planning software developed by our laboratroy on our own, and isadopted in the cooperation project with Hubei tri-ring metalforming equipment company,LTD.