Question

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.

Answer 1

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