Manufacturing Processes I · Metal Forming · 2 marks · Numerical answer
A cold-rolling process without front/back tensions requires minimum friction coefficient 0.04. Assume large rolls. If draft doubles and roll diameters halve, find the new minimum coefficient (two decimals).
The bite condition is $\mu_{min}=\sqrt{\Delta h/R}$. New draft is 2Δh and new radius R/2, so the ratio of new to old μ is $\sqrt{2/(1/2)}=2$. Therefore **μ = 0.08**.
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