Flood coolant

[vidio1]

Attached are some pics of a coolant collar and an enclosure I put together over the last couple weekends. Inspired by CNCCookbook: Milling Machine Coolant Collar
The collar is a piece of 3/4 Mic6 scrap sealed and covered with a piece of 1/8. It has an 1/8 slit with a countersunk 1/4x20 allen bolt to pinch it to the quill. The input side is 1/4npt with 4 1/8npt outs. The drains are 1/2npt with pieces of garden hose running from each side to a 15 gallon tank(old anti-freeze drum) A sump-pump provides more flow than the table will drain at a very good pressure(soon to be tested).
The enclosure is made from 2 pieces of 2'x4', 26ga. courtesy of Lowes. Thinner than I would like, but I don't have a brake. I reenforced it on the front and back of the table with strips of 3/16x2" to help seal it.

[HimyKabibble]

Having just converted to flood myself about a month ago, I'd guess you're going to find you have a few problems:

First, the coolant will very easily splash, and throw wet chips and coolant over those walls in considerable volume. My table is enclosed to a height of 24", and still things make it over - not many chips, but the flood will hit things on the table (vertical faces on the workpiece, vise, clamps, etc.), and splash back a good distance (8 feet or more), and height.

I had to put a telescoping way cover between the back of the table and the under-side of the ram, to prevent chips from piling up on the Y ways behind the table. Some still get back there.

When you do heavy cuts with larger tools (1/2"), you'll find it takes *pressure* to clear the chips from slots and pockets. Volume alone simply won't do it. I've got a 1000GPH pump on mine, and it's just not enough to clear the chips when I'm roughing. So, I'm about to swap out my pump for a "shallow well pump", which is a small pressure pump and pressure tank, that will pump about 900GPH, and put out up to 60PSI. At that pressure, coolant will be splashing EVERYWHERE. These are about $100-150 from home centers, Harbor Freight, etc.

Just so you're not surprised, you're going to find a LOT of coolant simply disappears when you're using flood. I "lose" 3-4 gallons a day. Not through leaks, but the coolant clings to the chips, and doesn't make it back to the tank. The coolant on the chips evaporates away overnight. So, I have to add several gallons of new coolant to the tank every day. That, I did not expect! I typically add water one day (figuiring it's the water that's evaporating off, not the coolant), and coolant mix the next, estimating coolant concentration by the color of the coolant. Someone suggested getting an old washing machine, and throwing the chips in there on the Spin cycle to recover the coolant, but with the volume of chips I'm creating (at least a garbage can full per day), that's just too much trouble, given that the coolant concentrate (I'm using KoolMist 77) is pretty cheap.

Regards,
Ray L.

[vidio1]

Thanks for the heads-up. Wow I never expected coolant to splash that far. I guess that shows with the 10" walls. Basically I was tired of squirting coolant, cutting oil, and WD40 by hand. I stumbled on the coolant collars from the link provided (among a ton of other good info) so I decided to built one. It works really well for the 1 off type stuff I've been piddling with, but I needed some sort of enclosure. I might have to rethink my enclosure for small production run stuff, but I think it'll work in small doses for now.

As an afterthought how do you deal with the flow/pressure you have now? Mine fills the table slots in about 6 or 8 seconds if left wide open and I have to reduce it for it to drain.

[HimyKabibble]

My tray is not in any way water-tight, so once the table fills up (just a few seconds), coolant pretty much spills over everywhere, and falls into the big trays underneath. If you're constrained by the flow out the drains, you're going to have to throttle WAY back on the flow, because they simply don't allow much flow. your other option is to plumb in a second pump specifically to PULL coolant out through the drains in the table. You *might* get enough suction using another sump pump, and making an enclosure around the pump, so it can only draw through the hoses to the table drains. But, centrifugal pumps are not ideal for that application.

My setup drains, by gravity, into the hollow base of the mill. I have a sump pump in there that pumps the coolant from the mill base back into the external coolant reservoir. It's important that pump have a flow rate HIGHER than the highest flow I'll ever use on the coolant going into the machine, otherwise, the pump in the reservoir will eventually run dry. At any given time there will be at least 3-4 gallons of coolant "in-transit" throughout the system.

Regards,
Ray L.

[llmeyer1000]

"I typically add water one day (figuiring it's the water that's evaporating off, not the coolant), and coolant mix the next, estimating coolant concentration by the color of the coolant."

You are correct in estimating that much of your coolant loss is due to evaporation, but it is probably not a good idea to add plain water. It will not readily mix with the existing coolant. This can cause rust on the table and other places on the machine. A rule of thumb is to add coolant everyday mixed at 1/3 % as compared to the percentage that you want to maintain. You should also invest in a refractometer so that you can measure the actual concentration every other day or so.

Your coolant's biggest enemy is tramp oil. Invest in a good skimmer, or manually skim the oil floating on the surface in the coolant tank. Avoid adding any contaminants to the system.

[Deano7/11]

Originally Posted by HimyKabibble Having just converted to flood myself about a month ago, I'd guess you're going to find you have a few problems: First, the coolant will very easily splash, and throw wet chips and coolant over those walls in considerable volume. My table is enclosed to a height of 24", and still things make it over - not many chips, but the flood will hit things on the table (vertical faces on the workpiece, vise, clamps, etc.), and splash back a good distance (8 feet or more), and height. I had to put a telescoping way cover between the back of the table and the under-side of the ram, to prevent chips from piling up on the Y ways behind the table. Some still get back there. When you do heavy cuts with larger tools (1/2"), you'll find it takes *pressure* to clear the chips from slots and pockets. Volume alone simply won't do it. I've got a 1000GPH pump on mine, and it's just not enough to clear the chips when I'm roughing. So, I'm about to swap out my pump for a "shallow well pump", which is a small pressure pump and pressure tank, that will pump about 900GPH, and put out up to 60PSI. At that pressure, coolant will be splashing EVERYWHERE. These are about $100-150 from home centers, Harbor Freight, etc. Just so you're not surprised, you're going to find a LOT of coolant simply disappears when you're using flood. I "lose" 3-4 gallons a day. Not through leaks, but the coolant clings to the chips, and doesn't make it back to the tank. The coolant on the chips evaporates away overnight. So, I have to add several gallons of new coolant to the tank every day. That, I did not expect! I typically add water one day (figuiring it's the water that's evaporating off, not the coolant), and coolant mix the next, estimating coolant concentration by the color of the coolant. Someone suggested getting an old washing machine, and throwing the chips in there on the Spin cycle to recover the coolant, but with the volume of chips I'm creating (at least a garbage can full per day), that's just too much trouble, given that the coolant concentrate (I'm using KoolMist 77) is pretty cheap. Regards, Ray L.

Ray

how is your mill going. obviously well if you are creating that many chips. has your z axis proved the test of time?

[HimyKabibble]

Originally Posted by Deano7/11 Ray how is your mill going. obviously well if you are creating that many chips. has your z axis proved the test of time?

Yes, my quill drive has performed flawlessly from the first day I put it on. So are the other two I built for friends. The machine is, overall, working very well, though I really need to do a ballscrew conversion on the knee. My only big problem has been software - bugs in Mach3, which finally drove me to abandon Mach3 entirely, and move to a KFlop, running my own controller application. So far, it's been a BIG step up in reliability.

Regards,
Ray L.

[Deano7/11]

Originally Posted by HimyKabibble Yes, my quill drive has performed flawlessly from the first day I put it on. So are the other two I built for friends. The machine is, overall, working very well, though I really need to do a ballscrew conversion on the knee. My only big problem has been software - bugs in Mach3, which finally drove me to abandon Mach3 entirely, and move to a KFlop, running my own controller application. So far, it's been a BIG step up in reliability. Regards, Ray L.

that is one of the things that holds me back is mach 3. have you been able to sort out the knee and the quill. last i remember you were having issues with getting mach3 to contol both.