Experimental Examination of Effects of Punch Angle and Clearance on Shearing Force and Estimation of Shearing Force Using Fuzzy Logic

A significant challenge faced when using blanking/piercing to machine sheet metal is the handling of the shearing force required for high strength and thick stock. Increased shearing forces lead to the requirement of higher performance expected from the pressing machine and result in increased wear on the punch tool and die. Clearance, employed to increase precision and quality in blanking/piercing operations, affects the shearing force as well. One of the techniques used to reduce the force required is the employment of a punch shear angle. In this study, the effects of punch shear angle and clearance on the forces required for blanking/piercing were examined on a grade of steel broadly used in the manufacturing industry, DC01. Experiments were carried out using five different punch shear angles, namely 0°, 2°, 4°, 8°, and 16°. Six matrices with varying clearance rates (0.4%t, 0.5%t, 0.6%t, 0.7%t, 0.8%t, and 0.9%t) were used in this study, and these clearances were altered by modular matrices on the die. This study shows that shearing forces can be reduced by 80% when 16° punch angle is used. The results of the experiments were transferred to a fuzzy logic model to obtain extrapolated results for intermediate values which had not been obtained from the experiments. The results obtained from the experiments and the output from the fuzzy logic model were compared and found to be highly similar. These results have showed that the model developed using fuzzy logic can be used to determine different shear angles and clearance values