Study On Approriate Blankholding Force &Ideal Clearance For Drawing Formation Of 8″ Brake Cylinder Cover

Wrinkle and Crack are the main obstacles in sheet forming. Prediction and prevention of the flange wrinkling (external wrinkles) and side-wall wrinkling (internal wrinkles) are not only the reliance in design of tooling and process parameters in sheet metal stamping, but also are the theoretical basis of the intellectual control in sheet metal stamping. Therefore, the research of wrinkling is very significance both for the development of forming theory and the practice of curved parts production.On the specific case of the flange wrinkling and the wall wrinkles in deep drawing, using the simplified Hill's yield criterion, the distribution of the main stresses is gained. And then the analytical blankholding force for flange wrinkling is gained the based on of the wrinkling criterion of conical part deep drawing.Numerical simulation research on forming of 8 inch brake cylinder indicates that simulation technology not only performs smooth simulation calculation in multi-step forming, but also plays a role in material optimum selection.On the basis of the criterion for the wrinkling under the real condition, the experiment research for wall wrinkling of conical part deep drawing is carried out and the results which provides the data indicates the theory analysis is reliable and effective. The experiment research proves the theory analysis for the wrinkling in deep drawing can abo be used to design the tooling determination on ideal free clearance of concave module & convex module,make the process parameters and to be the basis of intellectual control in sheet metal forming.