MQL (Minimum Quantity Lubricant) questions

Hey guys. I'm in the market for another mill and my tooling salesman suggested looking in to MQL instead of a 1,000 psi thru coolant system. This seems to be a pretty new thing since I'm struggling finding much information on it. I understand the concept, but I'm looking for every day experience with this type of system. I am NOT talking about a $200 mister for band saws and manual mills here.

- Does this work for small through coolant twist drills? I just finished a job that had a total of 3700 ø.028" holes .705" deep and 1920 ø.093" holes the same depth in 6061 (and these were prototypes ). Used Mitsubishi MWS drills for this and they worked well with my 320psi through coolant, but it seemed like I could have really cranked the feed with more pressure (or flow). MQL makes sense in my mind for this application. The holes in the drills are something like .003-.004" diameter.

- Does this work well with larger drills? And coolant through face mills? And would it work with running through coolant with a standard ER collet (flushing out a pocket, etc.)?

- I have a Royal mist collector on my current mill and will get one for the next mill. Will they suffice for the fog that I assume these systems create?

- What about for general milling? I use HSM for damn near everything so lots of heat in the part isn't too much of a concern, but I'm curious if these systems actually remove chips from the part or if they tend to get stuck in the oil film on the part. I'm thinking finishing passes and 3D stuff here. I suppose I could have the standard coolant come on as needed to rinse the part?

Any other thoughts or input?

Very good questions ...now you've got me thinking...we got one system on test from the rep but haven't even taken it out ofv the box. Imo it looks weak and not very user friendly, some use the existing coolant lines for the mql ours has an external one gallon tank. The pocketing question is a good one, titanium plus minimum coolant plus heat equals crispy vmcs

I use a Acculube MQL system on my Bridgeport, its no $200 system either, these things start at like 600 and go up from there, mines a 4 way and retails well north of $1K. IMHO it works great, the other day milling hardox 450, cutter life with coated carbide is great. Tank size really is not a issue, acculube use just a few ounces tops over 8 hours. You get none of the shock issues of coolant, but you also don't get the heat removal. Mist is not a issue, they use practically no oil at all. STD test is to hold a piece of paper in front of the nozzle, takes damn near a minute to get a wet patch the size of a penny.

That said, again IMHO it's not going to work worth a damn on through the spindle type applications like you want it for. At the end of the day you only have your air line for pressure. Yep the lube may be great, but there's going to be no comparison to 1000psi coolant jets! That said, i belive some people have had luck using it for gun drilling, but again, you lose the advantage of the hi pressure fluid supporting the cutting tool which matters at greater lengths. Equally you lose the heat removal.

Unless you can get them to demo it for free i would stick with through coolant on a real VMC!

http://www.grouphes.com/lubemec/Vogel/dateien/us/pdf/izs_pdf/1-5102-US.pdf

Might help too, its the vogal way of doing it, but its the same net result as my acculube system, a very fine very minimal quantity of oil droplets. It works great on certain things, like the saws and open machinery you want to not hear about, but imho its just not in the same league for small through the spindle applications. 100psi air only removes chips so well, 100+psi of coolant flow has way more moving mass hence exerts way more momentum when it hits a chip blowing it up the flutes.