Calculate Size of Blank Required for Drawing

A flanged cup shown in Figure is to be produced by deep drawing. Calculate the size of the blank required for drawing.       

                                                                                                  Material : Al

Sheet Thickness : 1.5 mm

All dim. in mm

Solution

Neglecting sheet thinning/thickening,

Area of flanged cup = Area of blank

The cup shape is divided into 3 primitives as under

Annular Disc

Area

A1 = ∏/ 4 (15²  - 10² )

= 125 ∏ /4 mm²

Cylindrical Part

Area A₂  = ? DL

= ? × 10 × 8 = 80 ? mm²

Circular Disc

Area A³ = ∏ / 4  D²

 = (∏ /4 )× 100 mm2

Area of flanged cup

A = A₁ + A₂  + A₃

= 545 ∏ / 4

                                  = 545/4  ∏

Diameter of blank, D_b  = √545

                                 = 23.35 mm

Diameter of blank can be chosen to be 25.00 mm to account for material properties, die clearances and trimming allowances.