[themedulla]

Hi guys,

I have a Taig CNC mill and have a home-made flood coolant system. I have been using a submersible pond pump to drive the coolant out of a 5-gallon bucket. I've used this setup for a while with no problems.

For a couple of weeks I had been working in plastic and hadn't used the coolant. I was doing some cuts in delrin and I decided I would use the flood coolant for kicks to see if I could maybe do some deeper cuts. I started the flood coolant and it went fine for a few cuts. At some point the motor stalled out and I was only cutting 0.1" DOC in delrin with a 1/4" end mill. At first I thought maybe I was just cutting too much so I dropped it down to 0.05" DOC which I have done many times before in delrin without any issues at all. I started it back up with the flood coolant and it went fine for a few seconds but then stalled out again. Hit the e-stop and finally made the connection - I started it back up again with no flood coolant and it cut fine for hours.

That was a few days ago. I cleaned out the filter and made sure there wasn't a lot of buildup in the reservoir and everything seemed fine. I ran the coolant for a while and alone it has no issues at all. I gave it another shot and again it cuts fine for a little while but then the motor stalls.

I really have no idea what is going on. Could it be a problem with ground? Maybe the coolant is transferring a charge to the spindle and the motor is losing voltage? I would think that if the issue was with the power limitation on the garage circuit then I would trip the breaker. Anybody have any ideas?

Thanks for any help,
Matt

[SSN Vet]

I am nooooooo expert, but whenever we cut UHMW or HDPE on our CNC machines at work, we never use coolant. Somehow I had the impression that it wasn't used for plastics.... but as said.. I am noooooo expert.

[themedulla]

Well I repeated the experiment with aluminum to the same results.

Most plastics do poorly with coolant and don't really need it. I believe delrin can take the water-based emulsion that I use - that's why I gave it a shot.

At any rate, it doesn't seem to matter much what it is cutting - just really confusing as to why the power of the spindle seems to be really limited when coolant is on.

[mactec54]

themedulla

It seems you have a power problem as you have found out, it does not matter what you are cutting, you must be drawing to much, from the one circuit, this will not trip a breaker, unless you have a fault, If you have a meter test & see how much voltage drop you are getting when you have both running

& yes you can use coolant/ cutting fluid for cutting plastic, for a better finish, better tool life & stress free cutting of your part, I would not do it any other way