Assessment of influence of some process parameters on sheet metal blanking

The blanking of thin sheet (0.1-1 mm) of mild steel has been analysed using an elastic-plastic finite element method based on the incremental theory o f plasticity. The blank diameters are considered in the range 1-4 mm. The s tudy has helped to evaluate the influence of tool clearance, friction, shee t thickness, punch/die size and blanking layout on the sheet deformation. T he punch load variation with tool travel and stress distribution in the she et have been obtained. The results indicate that a reduction in the tool cl earance increases the blanking load. The blanking load increases with an in crease in the coefficient of friction. These observations are very similar to the case of blanking of component of large size. Further, these effects are very similar in the case of both single and double blanking. An interbl anking site distance of about twice the sheet thickness is good to reduce t he thinning of sheet at the intermediate regions between the two blanking s ites. For a particular sheet thickness, the blanking load requirement reduc es as the blank diameter increases. (C) 2000 Elsevier Science S.A. All righ ts reserved.