A compound die will be used to blank and punch a large washer out of aluminum alloy sheet stock 3.2 mm thick. the outside diameter of the washer = 65 mm and the inside diameter = 30 mm. determine: (a) the punch and die sizes for the blanking operation, and (b) the punch and die sizes for the punching operation.

a) The sizes of punch and blanking are equivalent to its diameters. The blanking die diameter is Db = 65 mm

Diameter of the blanking punch is,

dpunch = Db - 2c

Here, c = Ac (thickness)

For aluminium, Ac = 0.06

c = (0.06) (3.2 mm) = 0.192 mm

dpunch = (65 mm) - 2 (0.192 mm)

= 64.616 mm

b) The diameter of the punching punch is equivalent to the interior diameter of the washer.

Thus, diameter of the punching die is, Dh = 30 mm

Diameter of the punching die is,

ddie = Dh + 2c

= (30 mm) + 2 (0.192)

= 30.384 mm