Need help understanding settings.

The company I work for has a edm "hole popper". The machine is a KTC EDB-435 (CNC). We use this to drill holes in carbide. The machine was purchased new in 2008.

I am currently being trained on this, but the person training me doesn't know what the conditions in the conditions table stand for. This is a Korean machine, and the manual that came with it doesn't explain much. Plus, the translation from Korean to English is horrible.

This is the only EDM that I have seen operate, and any advice or education about EDM will be appreciated.

The following are the variables in the conditions table: Work Pc, thickness (material), diameter (electrode), pipe mat'l, fluid, P(Kgf/cm2), T on, T off, lp, Vs, R/S, C, V, wear rate.

What does each of the following stand for: P(Kgf/cm2), T on, T off, lp, Vs, R/S, C, V

We use copper electrodes for drilling carbide, and brass for drilling steel.

Currently, the setups we do will run the entire program, but the holes do not drill true the entire way through. 25 - 50% of the holes end up cone shaped and have to be redone.

We use electrodes from 1.7 mm in diameter to 3.1 mm in diameter, with distilled water as the fluid.

Any info about this machine, or about the process will be greatly appreciated.

Taper in holes

Your taper problem is consistent with hole popping. The electrode sacrifices itself on the way in and hence the cone shape. When the electrode breaks through the machine essentially stops burning and the electrode does not go deep enough to take out the taper. What I do is put a dummy piece of material on the bottom side (breakthrough side) and let the electrode go through that also. Depending on the amount of taper on the electrode, add enough thickness to the dummy part to make up for the taper. When your 'trode' breaks through this you will know that the hole is to size all the way through.

Sorry, I can't help with the settings. My machine is totally different.

TMD

Thank you for the advice about the tapering.