Research Of The Combined Fine Blanking And Extrusion Process On Sheet Metal

As a kind of precision form technology, fine blanking has characteristics of high quality,high efficiency and low expenditure, which has been widely used in many fields such as automobile, motorbike, instrumentation, light industry machine, home appliance and office facilities. The Fine-blanking Forming Stamping (FFS) technology combining the contour fine-blanking and other forming processes such as extrusion, precision forging, bend and coining which integrates respective advantages will be an inevitable trend of fine-blanking technology development.The combined fine blanking and extrusion process of sheet metal which effectively integrates the sheet metal extrusion and the contour fine-blanking is a typical process of FFS. Currently, the research of the sheet metal extrusion as well as the combined blanking and extrusion process of sheet metal is very limited. In this paper, the rigid finite element software is adopted to simulate the process of sheet metal extrusion firstly and then analyze the mesh distortion and material flow field of the process, through which the distributions of velocity,effective stress and effective strain are obtained and utilized to reveal the deformation features of the process. Meanwhile, the influence of extruding speed and extrusion ratio on the metal flow,the occurrence of shrinkage cavity and the force energy parameters is analyzed, which sets up a foundation for the process optimization.Based on the study of sheet metal extrusion, the mesh distortion and material flow field of the combined blanking and extrusion process of sheet metal was also simulated in this paper, through which the distributions of velocity,effective stress and effective strain are obtained and utilized to reveal the deformation features of the process. According to the simulation result and the fracture criteria proposed by Hancock. J. W and Mackenzie. A. C, the main factors affecting the occurrence of fracture are analyzed and the fracture location is predicted. Moreover, measures are proposed to prevent the defects.The moulds are designed and applied in process experiments which are carried out on YT32-315C oil hydraulic press and Y26-315 fine blanking press. Through experiments the influence of the main parameters on the result is observed and the fracture in the combined blanking and extrusion process of sheet metal is obtained. The rigid finite element method is verified to be a effective way to simulate the process,predict the defects based on fracture criteria and reveal the deformation features of the process, which provides a guidance for the application of the combined blanking and extrusion process of sheet metal.The success of manufacturing the combined fine blanking and extrusion product proves that the FFS technology can effectively broaden the application field of fine blanking.