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DI water conductivity

Billyr1968

Plastic
Joined
Feb 22, 2006
Location
Panama city
On My chmer I was told to keep the conductivity at 50 KΩ.cm.
What is this measuring the water or the wire to work peace . The more material in the water would seem to increase the continuity . I am just trying to get a better grasp on what's going on. Can it get to high if so how would you lower it?

thanks
 
You need the low DI because you need to control the spark jumping between the wire and the work piece, if you have "dirty" water the spark will jump out of control, and cause your burn to be inaccurate and make your wire break.
you water is suppose to cycle through a filter system and there after through a DI system, to make sure you level is low enough.
I do not know of the brand "chmer" but on a Mitsubishi, Charmilles or Fanuc you will get a warning when your level is to high, I know the Mitsubishi will not even start if a high level is reached.

I got some information on this stuff at work, but I am on vacation this week, if you want me to email you some information Monday, drop me a mail.

HTH
Lars
 
What they are referring to is the conductivity of the water, specificly the charged ion content. Different EDM manufacturers specify the conductivity in different values (ohms, volts, etc) but the idea is the same. I'm sure somewhere on the machine is a meter, or an on screen indicator of water conductivity.

That's why it's called "dielectric" water; it's fairly non-conductive. By having a non conductive (or low conductive) medium between the wire and the workpeice, you allow voltage potential to build up creating a spark when the potential is high enough. With very conductive water, you will effectively go into something close to a short circut. Believe it or not, conductive water is good for cutting speed, but causes wire breaks, unstable conditions, and poor finishes. Designed water conductivity is a balance between speed and stability.

Ions in the water don't just come from the parts, either. Two things very bad for DI water: carbon dioxide, and carbon monoxide. In other words, people and smoking. Keeping both away from the machines as much as possible will extend your DI resin life.

Yet another reason to keep EDM's in seperate rooms ;)
 
Hmmm, if the probe was so gunked up that it wouldn't read the water, what did throwing pinches of salt into the tank do for them? It obviously wouldn't have change the machine readings...
Can you imagine throwing salt in your water?? I get pissed off when dudes walking by would dip their cigarettes in my tank to put them out.
Hey Billyr1968, are you in the Navy??
Do you do EDM for the Navy??
 
Resistance of a material is measured in ohms. Conductance (the opposite of resistance) is measured in mho's. For convenience the measurement of microsiemens is used for conductance. Most wire edm machine builders will specify the operating range of the water in microsiemens. My Agie's won't run if the water condition gets over a preset limit (15 to 25 us).
Typically I do not use my machines for a band saw, but rather am doing fine intricate work with small diameter wire and keep my water condition to 3 to 5 microsiemens. Conductance and resistance are different animals. Conductance is the reciprocal or inverse of resistance.

Conductance= 1/resistance.

http://www.tpub.com/neets/book1/chapter1/1p.htm

TMD
 
Billy,
Sorry I did not get back to you yesterday(1st. after 10 days off, things where a little crazy). I could not find the info I had in mind when posting last week, wonder if went in the garbage can at some point, sorry.
You could try to call someone like Aba water system or whomever you get your resin from, they might be able to send you some helpful material.

Lars
 








 
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