coolant and small cnc mills

[DMS]

I run my mistless at about 20psi, but I have a small (5gal) compressor. It switches on every few minutes. It's also not the quietest of compressors. With the spindle going, and the hiss of the mistless, and the compressor... things can get a bit loud. I have plans to build a dedicated (quite) compressor for the mist setup, but it's still in the backlog.

 

[09kevin]

It seems that the paint on the Tormach base and chip tray is not as tough as the paint on the machine itself. This doesn't appear to be limited to Tormach, as I've seen similar threads for other machines also. The coolant tends to soften the paint. I've done a lot of research on the topic and will try some of the coolants that were mentioned specifically or being easy on the paint. On my particular machine, the paint is perfect, but the chip trays are bubbling and peeling.

Eric[/QUOTE]

I thought I read that Tormach fixed the paint issues on the series 3 machines? I didn't have any problems with my paint using the coolant Tormach sold, but when I switched to Tech Cool 5052 the paint started to bubble.

I prefer flood coolant for lubricating and flushing chips out, I let the chips sit overnight so the coolant runs off then use a shop vac to clean up. I did modify the Tormach enclosure to help keep the coolant and chips inside because it will make a mess really fast :whistle:

 

[echesak]

I had heard the same thing about the Tormach paint. But like I said, the paint on the machine is perfect. It's the chip tray that's peeling. So if they changed the paint on the chip tray, it's probably on a later unit of the base/chip tray than what I received. I removed and repainted the chip area on the base. But I doubt that it will hold-up to much heavy coolant use.

Like J Ferguson, I'm looking for alternatives. For me it will probably come down to money (spent my CNC wad). I have the flood coolant system and would have to buy/build a droplet system. I'll probably try flood first, since that is what I have. I read about a couple coolants that perform well. I know nothing about them, but the ones I was reviewing were TRIM E206 and Hangsterfers S-506 CF and Rustlick WS-5050. Other forum posts have indicated that these work well, are easy on the paint, have a low odor and don't seem to get rancid (the top 4 on my list). Enco has the Trim coolant and free shipping over $50 currently. So That's probably what I'll try first.

 

[j ferguson]

I'm leaning toward flood system. Shop will be in garage. Landlord requires that car be parkable at any time because of deal they (well, the developer) made with local zoning. This means shop is workbenches and tool chests arrayed at end away from car-door and on one side. No ventilation except by gravity with big door open. Rack storage system on other wall with usual family treasures in bankers' boxes.

So the concern is eventual film of coolant residue on everything. And I suspect it would happen quicker with a misting system.

Obviously, I could buy some ducting and build an extractor (5 1/4 inch muffin fan) to convey the vagrant mist from the mill to the outdoors - cheap and likely effective and maybe I should just do it. Residue film everywhere seems equally likely if I just brush on cutting oil like I did 55 years ago in the wonderful shop where I worked and should have learned all of this stuff.

O/T but ... The place was set up in 1914 north of Chicago, mostly ran on a single motor with overhead shafting, leather belts, etc. Newest machine (only one with coolant system) was horizontal band saw. Second newest were War Production Board South Bend, some Hardinges,. and a Delta Drill. Everything else had been there in 1918.

Unfortunately (well fortunately for me) I'm the only one who worked there in 1960 who is still alive so I can't find out what we used for cutting oil. The smell is imprinted on me somewhere, but I haven't run into it in years - probably suppressed by EPA. But its use did lead to film on windows - whose cleaning annually was one of my jobs. Might also have been Pipe tobacco fumes -- Oscar Trumbull Scalbom. So it sounds like an exhaust duct will be part of the scheme. I really don't want to have to clean the walls.

BTW, if you think anything I write is nuts, I won't take offense. I spent most of my career doing things I didn't understand and am used to criticism. In fact if I don't get any, it really bothers me.

 

[Ray C]

I'm leaning toward flood system. Shop will be in garage. Landlord requires that car be parkable at any time because of deal they (well, the developer) made with local zoning. This means shop is workbenches and tool chests arrayed at end away from car-door and on one side. No ventilation except by gravity with big door open. Rack storage system on other wall with usual family treasures in bankers' boxes.

So the concern is eventual film of coolant residue on everything. And I suspect it would happen quicker with a misting system.

Obviously, I could buy some ducting and build an extractor (5 1/4 inch muffin fan) to convey the vagrant mist from the mill to the outdoors - cheap and likely effective and maybe I should just do it. Residue film everywhere seems equally likely if I just brush on cutting oil like I did 55 years ago in the wonderful shop where I worked and should have learned all of this stuff.

O/T but ... The place was set up in 1914 north of Chicago, mostly ran on a single motor with overhead shafting, leather belts, etc. Newest machine (only one with coolant system) was horizontal band saw. Second newest were War Production Board South Bend, some Hardinges,. and a Delta Drill. Everything else had been there in 1918.

Unfortunately (well fortunately for me) I'm the only one who worked there in 1960 who is still alive so I can't find out what we used for cutting oil. The smell is imprinted on me somewhere, but I haven't run into it in years - probably suppressed by EPA. But its use did lead to film on windows - whose cleaning annually was one of my jobs. Might also have been Pipe tobacco fumes -- Oscar Trumbull Scalbom. So it sounds like an exhaust duct will be part of the scheme. I really don't want to have to clean the walls.

BTW, if you think anything I write is nuts, I won't take offense. I spent most of my career doing things I didn't understand and am used to criticism. In fact if I don't get any, it really bothers me.

FWIW, In my experiences, I cannot relate to the concept of a film of residue from mist cooling. Maybe if I had many machines running with full PSI misters blaring away -all day long... it would increase the humidity level. Running at lower pressure, my kool mist systems use about 1-3 ounces of liquid stock solution after several hours of continuous operation. About one ounce of that solution accumulates on the part, vise or table and gets sucked-up by the vacuum cleaner when you clean-up the swarf.

If I had to guess, the shift in humidity after a light rain or morning dew on a temperature transitional day produces 1000 times more moisture leading to eventual dirt, dust and residue development on the walls and ceiling.

-Not meant as a criticism but as a data-point to aid your understanding and perspective on the issue. ... I have no vested interest in which method you chose... -Just passing along my experiences.


Ray

 

[echesak]

Made me chuckle, out loud. I worked the Corporate Engineering a few years ago, and didn't understand most of what I was doing, or why I was doing it. But I must have done it right, as I climbed the ladder in my 13 year career there.

Again, this topic is beat to death, on the web. But I also read that Carbide end mills, prefer not to be used with flood coolant because of the thermal shock to the material (when machining heavy cuts or harder materials). So there's probably a place for both in the shop. I'll probably make a droplet misting unit, as I probably have all the materials in the shop (including a cool 316 stainless tank that was used for Coke syrup).

The car is probably the least of your worries, since it will get a regular wash. But like you, I'm not interested in having the other machines and everything else covered in coolant residue grime.

Eric

 

[Ray C]

Made me chuckle, out loud. I worked the Corporate Engineering a few years ago, and didn't understand most of what I was doing, or why I was doing it. But I must have done it right, as I climbed the ladder in my 13 year career there.

Again, this topic is beat to death, on the web. But I also read that Carbide end mills, prefer not to be used with flood coolant because of the thermal shock to the material (when machining heavy cuts or harder materials). So there's probably a place for both in the shop. I'll probably make a droplet misting unit, as I probably have all the materials in the shop (including a cool 316 stainless tank that was used for Coke syrup).

The car is probably the least of your worries, since it will get a regular wash. But like you, I'm not interested in having the other machines and everything else covered in coolant residue grime.

Eric

I personally have never experienced any thermal shock problems with carbide endmills and I use them almost exclusively -and did so with both flood and mist coolant systems on both the lathe and mill. Things didn't seem to remain very cool with just trickle flow coolant. Possibly with high pressure coolant and multiple nozzles, it comes close to the cooling effects of mist systems... I don't know.

What I do know from experience is that with mist systems, the part and bits (be it lathe inserts or endmills on a mill) never get above a slightly warm feeling -maybe 100F or so. Most of the time, the parts remain cold. This has vastly simplified things as I no longer need to worry about coefficients of expansion offsets when making a final pass on a critical cut.

In the realm of high-speed "hard machining" -usually with very hardened materials or materials like titanium or Inconel that work-harden to extreme amounts, folks use ceramic inserts. I recently did a project here and used ceramic inserts. You cannot use any form of coolant with those as they rely on generating heat. The insert gets glowing orange hot and doesn't start cutting well until it gets that hot. One drop of coolant on that and it will shatter. "Hard Machining" is a whole different ballpark and largely out of the hobbyist realm. It is fraught with safety concerns regarding oil fires and nasty swarf burns that leave immediate 3rd degree burns -small ones but painful nonetheless.


Ray

 

[j ferguson]

Thanks much Ray, I can see i need to think about this some more.

 

[DMS]

The problem with carbide and intermittent cooling comes when you bury the cutter dry and then think "hey, that looks like it's getting hot, I better spray it down". With carbide the the rule is all or nothing, either use coolant constantly, or run it dry. Worst thing you can do it's spritz it periodically.

 

[jererp]

When I started in manufacturing 40 yrs ago, we used only 2 types of coolant. First was a soluble oil, which was 5-7% oil, the balance water. The other was straight oil. Bacteria growth was always a problem in the soluble oil systems, fire a concern for the oil systems, and oil mist in the air a problem for both. Just because it is 'flood coolant' doesn't mean no mist.

Synthetics solved a big part of the bacteria problem, but they were a very effective paint stripper for oil based industrial paints.

I'm not familiar with the current products on the market...just thought I'd share a little history.