Wire EDM machine

**m_c** · 31-08-2017

That cuts far quicker than I thought it would.

For video purposes, would slowing the pump flow make the work area more visible?

**Neale** · 01-09-2017

Cuts a lot faster than we expected! Faster than a blunt junior hacksaw blade...

Pump flow is something we might look at. If you start without it running (which is what I normally do for demonstrations) you hear the spark quality go down after a few seconds and pick up once the pump is started. So, some flow is needed. At the moment, we probably have too much flow for this thin material, but I'm not sure that there is enough for the thicker cut like the HSS toolbit. The debris can build up in the cut behind the wire and almost weld the waste material back to the bulk. A nozzle to direct the flow would help. Commercial machines tend to blast liquid at to and bottom, I believe, but that's for much thicker cuts than we anticipate.

**m_c** · 01-09-2017

Originally Posted by Neale

Cuts a lot faster than we expected! Faster than a blunt junior hacksaw blade...

Pump flow is something we might look at. If you start without it running (which is what I normally do for demonstrations) you hear the spark quality go down after a few seconds and pick up once the pump is started. So, some flow is needed. At the moment, we probably have too much flow for this thin material, but I'm not sure that there is enough for the thicker cut like the HSS toolbit. The debris can build up in the cut behind the wire and almost weld the waste material back to the bulk. A nozzle to direct the flow would help. Commercial machines tend to blast liquid at to and bottom, I believe, but that's for much thicker cuts than we anticipate.

If you're just using a basic impeller pump, can you add a flow control valve? A pair of mole grips/small g-clamp/pipe clamping pliers would also work for testing purposes.
Or would increasing the depth of water work, so there's not quite as much disturbance from the flow?

**Neale** · 01-09-2017

Originally Posted by m_c

If you're just using a basic impeller pump, can you add a flow control valve? A pair of mole grips/small g-clamp/pipe clamping pliers would also work for testing purposes.
Or would increasing the depth of water work, so there's not quite as much disturbance from the flow?

It's actually a diaphragm pump intended for use in caravans with a pressurised accumulator to damp out pressure pulses. We do have a control valve - a little clamp with an adjustable screw! The pump output splits; part goes through a deionising filter to keep the conductivity of the water down and the rest goes through the jet playing on the cutting area. It's possible to juggle the relative flows but it's an adjustment that I have not played with. Depth of water is a bit critical - too low and it doesn't flood the work (sparking is much more effective under water or the right kind of oil, believe it or not), too high and the splashing ends up in the electronics. Bad news - the machine's first outing came to an end during the first cut when spillage on to the control panel shorted out something critical which meant a new PC board was needed. A good question to which I do not have the answer is, "but why did non-conductive water short something out?" It just did!