Most die-sinker edm's use oil. The natural oil's are tough on your skin, and can easily get contaminated with bacteria. The synthetic oils have a vitually unlimited shelf life, and no bacteria issues. They also have a higher flash point and a higher price tag. The problem for your diy project is the need to filter out the debris from the vaporization and re-solidification of your work piece and electrode. The commercial machines use large capacity and flow pleated cartridge filters, typically in the 5 to 10 micron range. I have seen small edm drills using deionized water on a disposable basis, ie; buy or treat the water outside of your edm, flow it once through the gap, and dispose. The wire edm's that use di water, also have filters like the sinker, and a cation/anion resin mix to keep the conductivity stable through sensors and selonoid valves. If you are trying to do accurate, repeatable work, this is important. Assuming this has not scared you of yet, I'll give you some pointers on electrode material and wear rates!
Regards,
Roy |
Thanks for your input! You definately made it a little more interesting
I did a quick google and found out that most water purifiying companies do filters down to 1 micron. I think this should be a good option since the flow rates of a tap should be more than what I need.
Whilst where talking about Dielectric...
Should I be spraying the gap with oil or sucking it out?
It makes sense to suck the oil aout around the tool and filter it then as to catch more of the solids. Any comments?
Do you have any specific names of oils I can be looking for?
For electrodes, ESjaavik mention graphite which got me thinking.
i'm not sure if you all call them the same thing but Pacer lead's, regardless of thier name, are just small sticks of graphite. for extremely small work (down to 0.1mm) these look perfect. I have to go see if the local newsagent has bigger ones.
EDIT: Whilst studying chemistry I read that they mix the graphite with clay in pencils. Maybe I'll go pull apart a bettery instead...
Thanks again
Matt
(I'll be starting this once my exams finish
I'm half way there
)