BHF (Blank Holding Force)

Q. In deep drawing of sheet metal, spring loaded stripper clamps the work until;

1. The punch penetrates twice the stock thickness
2. It removes wrinkles on the product edges
3. Shedder removes the work from the tools
4. Punch is completely withdrawn from the work material

Q. The function of draw bead in the deep drawing operation is to

1. Produce a balance between the amount of stretching and drawing
2. Produce a circular groove on the flange
3. Reduce the drawing load
4. Reduce the wrinkles on the flange

Q. Identify the stress strain in the flange portion of a partially drawn cylindrical cup when deep drawing without a blank holder

1. tensile in all three directions
2. no stress in the flange at all, because there is no blank holder
3. tensile stress in one direction and compressive stress in other direction
4. tensile in two directions and compressive in third direction