Question

As the cutting speed increases, how do the machining cost and tooling cost behave?

• A. Machining cost decreases while tooling cost increases
• B. Both machining cost and tooling cost both increases
• C. Both machining cost and tooling cost both decreases
• D. Machining cost increases while tooling cost decreases

Hint:

- High cutting speeds $\rightarrow$ Shorter machining times $\rightarrow$ Machining cost drops. - High cutting speeds $\rightarrow$ Accelerated tool wear rate $\rightarrow$ Tooling cost rises. The minimum point of the combined cost curve defines the economic cutting speed.

Answer 1

The Correct Option is A

Total cost per piece in machining is basically machining cost plus tooling cost, plus handling. As cutting speed goes up, the machine removes material faster, so each piece takes less time on the machine, and the machining cost that is tied to time comes down. But going faster also wears the cutting edge out sooner, so tools need to be changed and reground more often, which pushes tooling related cost up. These two costs move in opposite directions with speed, and that is exactly why the total cost curve has a dip at an economic speed instead of just rising or falling together. So with rising speed, machining cost falls while tooling cost rises.