A Study on the Clearance Decision of Fine Blanking Tool for Eco-Al Special Parts with Various Inner Corner Shapes

Abstract

Fine blanking is a press-working process that permits the production of precise finished components which are cleanly sheared through the whole cutting surface. It can be eliminated secondary operations, such as milling, grinding, etc. Recently, many studies on the weight reduction of automobile for fuel saving were underway. Especially, there are many examples in which light metal like Al were applied for automotive parts. Eco-Al is the new material which is replaced Mg of aluminum alloy with Mg+Al2Ca, therefore Eco-Al material has improved mechanical properties and formability. The clearance between the punch and die of a fine blanking tool is an important design factor that affects the sheared surface of a product. In a fine blanking process, the clearance is typically assigned a 0.5% material thickness. If the clearance is too big, a fractured surface would occur in the product while if it is too small, bulging would occur. In this study, a setting for optimum clearance was proposed for inner corner shapes by checking shear characteristics and bulging effects according to various clearances. After designing a special part with various corner shapes possessing Eco-Al5052 (thickness: 4 mm), a fine blanking tool was constructed and fine blanking experiments were conducted. The result could be usefully applied in fine blanking processes for Eco-Al automobile parts with corner shapes in the future.