Collapsible tubes are made by

At the last hammer stroke the excess material from the finishing cavity of a forging die is pushed into .............

In a wire drawing operation diameter of $$6mm$$ is reduced in stages to a diameter of $$1.34mm.$$ Assuming ideally rigid plastic material and ideally lubricant condition,
$$i)$$$$\,\,\,\,\,\,\,$$ The minimum number of passes required by assuming max reduction per pass
$$\,\,\,\,\,\,\,\,\,\,\,\,$$ is obtained with $$\mu = 0.2$$ and half die angle as $${6^0}$$. If the flow strength of the
$$\,\,\,\,\,\,\,\,\,\,\,\,$$ material is $$60$$ $$MPa.$$

$$ii)$$$$\,\,\,\,\,$$ The diameter of wire after $${2^{nd}}$$ stage

Flatness of slip gages is checked with