59.2 PRACTICE PROBLEMS

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1. We try an EDM process where the copper tool has a mass of 200g before beginning and 180g after. The iron workpiece drops from 3.125kg to 3.096kg, but has rounded corners.

a) What is the tool wear factor?

b) If the tool was cylindrical to begin with, draw sketches of the electrode before and after.

2. What are the selection criteria for choosing between machining and EDM?

ans. EDM is particularly useful when dealing with internal cuts that are hard to get tools into. Machining tends to work best with external cuts. EDM is suitable for removal of smaller amounts of material at a much slower rate.