Calculate the Length of Developed Blank

Part shown in Figure is to be produced from flat sheet by bending operation. Calculate the length of the developed blank. Assume k = 0.3.

                                        Figure

Solution

Reference to Figure 15.5 the part is a case of straight Bend with the following parameters :

Bend Angle  : 90 degree Bend Radius : 5 mm Lengths        

L₁ : 20 mm

L₂ : 15 mm

Bend Allowance = θ (r + kt)

BA = ∏ /2  (5 + 0.3 × 2)

= 8.796 mm

Bend Compensation = - BA

BC = - 8.796 mm

Blank Length = L₁ + L₂ - BC

= 20 + 15 - (- 8.796)

=  43.796 mm.