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Water resistivity sky high after cutting Inconel

RJT

Titanium
Joined
Aug 24, 2006
Location
greensboro,northcarolina
Changed resin bottle and filter about a week ago , everthing was fine. Cut some D-2 , all was well,then cut splines in 2 pieces of 8 Inch thick Inconel and now the resistivity is triple what it usually is. Im going to change resin bottles again so i can use the machine, but wondering what caused this? First time I have cut inconel. Seemed to cut fine ( slowed down as resistivity went up) , but cut to size and finish was good. Is this a symtom of cutting inconel? Such a thing as a bad resin bottle? Also noticed a white powdery scale on the parts and fixture after cutting.
 
We cut Inconel exclusively on our wire machines and we don't have any trouble with resistivity.

If I were to guess I'd say maybe you got a bad resin bottle or maybe the bottle is hooked up backwards??

To answer your question, cutting Inconel shouldn't have any affect on the resin bottles.
 
Well I wouldn't swear to it, but my EDM guy is pretty conscientious and has 25 years experience, so hooked up backwards is a very slim possibility. But I see where it is possible, same fitting , just marked in and out. We have already replaced it, so no way to check.
 
Check your filters for a tear or blow out.

Sounds like you just cut quite a bit of inconel.

In my experience inconel ( and aluminum) clogs filters much faster than steels and ss.

If that happened and you blew a filter it will take the DI down (up?) real fast.
 
Hi RJT:
The loss of conductivity (high resistivity) means you've removed more ions from the water than you normally would have.
A bad bottle is usually one that is less efficient at stripping out ions, so I'd expect a bad bottle to give persistently high conductivity, not low conductivity.
(De-ionized water is an electrical insulator; the ions present are what give it it's conductivity, and the job of the DI bottle is to bind up those ions in the resin thereby lowering the conductivity to where you want it)

The two main ways abnormally low conductivity can happen:
1) The water is flowing through the DI bottle continuously, stripping out the ions faster than your cutting can replenish them.
This will happen if your conductivity probe is falsely reading high conductivity, which of course triggers the DI pump to divert water through the bottle all the time.
Maybe cleaning the probe will do the trick.

2) Some contaminant in your water (or maybe on your inconel blocks??) is precipitating the ions out by making insoluble salts.
You'd need to make a lot of precipitate to drop the conductivity of such a big water volume a lot; so just how much white powder was there on the parts and fixture?

The third possibility, of course, is that the actual water conductivity is fine or even high and the probe has glitched.
Do you have a conductivity meter that is separate from the machine so you can check?

A crude and dirty way to find out is to piss in the water tank (just kidding) and see if the DI pump comes on.
Cheers

Marcus
Implant Mechanix • Design & Innovation > HOME
www.vancouverwireedm.com
 
Our sensor was giving false readings about a month ago, Swapped it out on our other machine and it read fine, diagnosed a bad PC board which we replaced and it has been fine since. The filters are fine, good readings and no signs of blow out. Resin supplier said high Nickel content of Inconel will cause increased resin usage. Not sure I'm buying that 100%. We put a new resin bottle on and everything is back to normal. We are paying $162.00 to recharge resin bottle, is that in line?
 
We experienced the same while cutting some (not every) Inconell pieces. Don´t exactcly remember the alloy, but it was THE SAME. Also with molibdenum, and in a minor scale with aluminium. I´m not a chemist to know the reason, but it just happened! We just plugged off the conductivity probe to avoid killing the ion exchange resin and then just trew away almost all the water in the tank. It ain´t no elegant solution, but definitly cheaper as resin exchange.
Good luck!
 
Thank you for this post as my Mitsubishi fx20 has been having some issues with high numbers- new resin bags- but cutting mostly D2. Can't figure it out. Tried testing some of the water using our other machines sensor and sensor is fine. Going to look into maybe a sensor not telling machine to circulate through resin or something like that if that exists.

To add to the comment about aluminum and inc. clogging filters, with new filters it's ALWAYS best to run something like D2 material parts for at least 4-6 hours before running aluminum or softer metals. This helps to minimize the clogging for some reason. Just a suggestion that works for us anyways.

Thanks,
Tvalen
 
Check your filters for a tear or blow out.

Sounds like you just cut quite a bit of inconel.

In my experience inconel ( and aluminum) clogs filters much faster than steels and ss.

If that happened and you blew a filter it will take the DI down (up?) real fast.

8" thick parts, those filters were having a tough time.

I wonder if nickel's suitability for both electro and electroless plating is somehow a factor inside a filter?

Aluminum does indeed physically clog filters. They used to sell powdered aluminum as radiator stop leak. (In recent years they went to ginger root but added some mica so that it looked like powdered aluminum)
 
I'll second the "bad bottle" statement.
Seen this a few times with regenerated resin.
You can avoid this by using virgin only, but that isn't very green or financially responsible.

I would also ask the question, "Did you fill the machine with straight tap water"?
If so, how is the water in your area?
I recommend a separate DI bottle connected to your fill water line.

Jay Crumb
Advanced EDM, LLC
440-567-5808
 
The only time I saw "bad resin" was with some recharged bags back from Ameriwater that seemed to do nothing at all.

Turned out that Ameriwater got my resin for recharging but didn't feel the paperwork was the way they wanted so they simply SENT THE RESIN BACK UNTOUCHED WITHOUT SAYING A WORD and left it to me to notice that what I assume was recharged resin wasn't working and call them to find out why.
So that was the last time I ever dealt with that pathetic company. The next machine I bought I had them replace anything ameriwater related and I've never seen bad resin again. Now I use the bottles from ABA.
 
With 6 wires and a drill we use Mueller out of Houston.

They have each machine set-up with a dual bottle system.

Every 3 weeks they come out and switch the #2 bottle to the #1 postion and put a recharged bottle into the #2 position on three of our machines.

If we have one go out on us for some reason, I call and they are there the next day.
 
Never saw that last post, and I would be hard pressed to figure that out now.

We are running the same job again and after cutting about 3 hours have killed another resin bottle. Looking more like some kind of problem with Inconel. We have a very consistent resin life with cutting tool steel, this is the second time the exact same thing has happened. Going to run with the probe out and replenish water after we finish this job. No way to test it, but those of you that cut lots of this stuff, do you alternate cutting other material with the same resin bottle?
 








 
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