EML4321 Quiz 5

Which of the following is not the type of deformation encountered in sheet metal forming?

• deep drawing

• rod drawing

• bending

• stretching

In the blanking (punching) of a circular sheet metal part, the blank diameter equals which of the following?

• the punch diameter

• the die diameter

The cutting force in a sheet metal blanking operation depends on:

• modulus of elasticity

• shear flow strength

• compressive strength

• yield strength

True or False? If the shear flow stress is unknown, about 70% of the ultimate tensile strength can be used in its place to calculate the cutting force.

• True

• False

What is bend allowance?

• amount by which the die is larger than the punch

• amount of elastic recovery experienced by the metal after bending

• safety factor used in calculating bending force

• length before bending of the straight sheet metal section to be bent

Springback in a sheet metal bending operation is the result of which one of the following:

• elastic modulus of the metal

• elastic recovery of the metal

• overbending

• yield strength of the metal

What is the range of spring back degree in general?

• 1-2 degrees

• 2-4 degrees

• 4-6 degrees

• 6-8 degrees

If Young’s modulus increases in a bending operation, the springback

• increases

• decreases

• remains the same

• is independent of Young’s modulus

Express the springback factor Ks using a_f (final angle) and a (bend angle under bending)

• (a)   af/a

• a/af

• a-af

• none of the above

If there is no springback, the springback factor Ks is

• 0

• 1

• 2

• 3