The effect of punch-die clearance on blanked edge quality in fine blanking of steel sheets

In precision shearing there are different working principles oriented on good quality of blanked edge surface quality. In the case of fine blanking, indentation of the ring tooth at the blankholder into stock portion of material causes larger dishing than conventional shearing and the dishing can be changed from convex to concave according to the amount of indentation. Moreover, the amount of dishing changes during shearing owing to the working force and results in various topography of the blanked edge. This paper analyzes the effect of the punch-die gap on blanked edge quality in fine blanking. The objective is determination of basic mechanical properties of galvanized multiphase steel sheets with a thickness of 0.75, 0.80 and 0.85 mm under the uniaxial tensile test, examination of the effect of the punch-die clearance on plastic zone height of stamped part edge and, finally, determination of the effect of material properties of blanked sheet metal on blanked edge quality.

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