Make necessary calculations for designing the drawing die for this component. Determine the size of blank, percentage reduction, number of the draws required, radius of pitch and die, Drawing pressure if $σ_yt = 430N/mm^2$

Given data:

d = 50 mm

r = 1.6 mm

t = 1.2 mm

h = 50 mm

1.Size of the blank

The ratio of d/r = 50/1.6 = 31.25

The ratio is more than 20,

$D = \sqrt{d2+4dh} = + \sqrt{50X50±4X50X50}$

D = 111.8 mm

Blank diameter is theoretical in order to get a smooth edge we add 3.2 mm on each side

D = 111.8 + 3.2 × 2 = 118.2 mm

2.Percentage reduction

Percentage reduction is given by

= (1 – d/D) X 100 + (1-50/118.2) X 100 = 57.7 %

%reduction permissible for the first draw = 45 to 50%

Hence cup cannot be drawn in one draw

3.Number of draws

Ratio of h/D = 50/50 =1

Therefore, No of draws = 2

Standard Table for number of draws

4.Punch and die radii (R)

The punch and die radii is considered as 4 times the die thickness

R = 4t = 4 X 1.2 = 4.8 mm

R = 4.8 mm

5.Die clearance (C)

The die clearance is considered as 1.25 times the blank thickness

C = 1.25 t = 1.25 X 1.2 = 1.5 mm

C = 1.5 mm

6.Drawing pressure (F)

F = πdtσt(D/d -C)

= π X 50 X 1.2 X 450 X (118.2/50 – 0.69)

$F = 142 X 10^3 N = 142kN$