Mist collection solutions for partially enclosed machines?

I have an 1984 Fadal VMC40 with a half-height enclosure and an oil mist lubricated spindle. It creates a terrible oil haze in the air after running for 30 minutes or more. I primarily use a Trico Micro Drop system for coolant. This system doesn't contribute to the mist problem as much as the spindle, but I would also like to be able to use flood coolant without creating a coolant fog.

My machine shop is in the corner of an 8000 sq ft building with 25ft ceilings, so my thinking is that it's only worth trying to collect the mist at the source rather than trying to ventilate the whole shop. I have a powerful fan which helps a little, but pushing the mist around doesn't solve the problem since it then contaminates other workspaces, storage etc. Building out a smaller interior machine room is not an option right now.

I'm designing a full enclosure that could be added to this machine but there are a few obnoxious aspects of the machine design that complicate this. Basically, I can't just "build up" from the panels that are already there and need to rethink the whole thing in order to be satisfied with access, safety, mist collection, coolant/chip flow etc. It's a project that will require significant time and consideration, but I need to reduce this mist problem ASAP.

So, I'm wondering if there are others here who have solved similar mist problems without adding a full enclosure. Ideally something using an off the shelf mist collector, so later on I could mount the same unit to my full enclosure. I sometimes plumb vacuum hose near the spindle for milling wood, using 2.5" Loc Line. Would just hooking up a mist collector to this work well? Maybe I need to make something like a kitchen exhaust hood?

Alternately, has anyone already built a full enclosure for an old Fadal where the factory enclosure "telescopes" in and out with the Y axis? If so I'd love to see your design.

A cheap and dirty way would be to hook up a centrifugal duct fan to it through about 25' of flex duct. With that much duct not much mist will get to the fan. A shop I worked at had this type of arrangement to vent a sinker EDM, ducted outside, and it worked very well with 4" duct. A 4" fan will flow around 150 cfm.

Might be worth looking at the oil flow rates for the spindle, sounds like its using way too much.

I have one of these Honeywell air cleaners in my shop to clear the whole shop. It's intended for fab and body shops I think but it does well well with mist too. You could just hang it above the machine and draw the mist up into it. It moves a good bit of air on high speed, draws in the bottom and exhausts out the upper sides all around.

I suspect the Trico micro drop IS adding most of the problem oil mist to the air, particularly if the material you are machining is coming off hot (like steel chips) because they will sit there and smoke the lube residue into the air.

Face milling can really raise a lot of mist in a flood situation, too, but I'd rather work dry, or with flood, than with Trico micro drop on a continuous basis.

It takes a big mother mist removal system to be effective on a machine that is not well enclosed.

Thanks for the input everyone.

Hu, unfortunately it is the spindle that creates the majority of the mist. It's obvious when doing dry cutting or even just running a warm-up. You can see mist being puffed out and it will fog up the shop area even if the Micro Drop is off.

DavidScott, after reading your post I researched some big duct fans as the idea of venting everything outside is tempting due to the simplicity and low cost. But ultimately I decided against it as I do not want to be responsible for putting oil mist into the outside air. Even if the immediate impact is minimal, I'd like to establish "clean" practices now while my shop is small and relatively quiet so I'm not undoing bad habits later.

adama, that hadn't occurred to me but I will check it out. I need to go through my fadal manuals to see if there are recommended rates and how to calculate.

Right now I'm thinking of buying a used Royal Filtermist, either the 900 or 1200 cfm unit and ducting it to near the spindle on the Fadal as well as into the enclosure on my Mazak QT8. Ducts will have gates so that I can pull as much from the Fadal as possible when I'm not running the lathe. I read a testimonial on PM from someone who had the 900cfm Filtermist successfully servicing two open surface grinders. Even my little 137cfm dust extractor will noticeably cut down on the mist when ducted near the Fadal spindle so I'm optimistic. This solution is also attractive because it could be adapted in the future to support multiple fully enclosed machines and it is much lower maintenance than a filtered/electrostatic air scrubber like Mud suggested.

I'll be posting a WTB soon on PM for one of the Royal units and I'll report back with the results once it is all set up.

adama said:

Might be worth looking at the oil flow rates for the spindle, sounds like its using way too much.

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Agreed. My Haas has oil mist lube in the spindle and it doesn't appear to put out anything like a visible mist cloud. If it sits over the weekend, a single drop of oil may condense and accumulate on the spindle nose. Your Fadal must have a pool of oil beneath the spindle after sitting?

I don't know if it will help here but we solved our plasma dust problem with a pair of swamp coolers with their motors reversed.

HuFlungDung said:

Agreed. My Haas has oil mist lube in the spindle and it doesn't appear to put out anything like a visible mist cloud. If it sits over the weekend, a single drop of oil may condense and accumulate on the spindle nose. Your Fadal must have a pool of oil beneath the spindle after sitting?

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There's not a regular drip from the spindle. If I leave it for a week or more, I may see a few drops puddle up on the vise but no major oil loss. Mostly it's a very very fine atomized cloud that puffs out from the spindle only when running. It's a bit annoying in other ways, since the oil mist dampens the spindle nose area and causes fine chips to stick.

It's a Bijur Mist Lubricator system running Velocite #6 oil. I really do not know much about this system and have not messed with it since the spindle runs well, but I'm now very curious to find out if the flow rate is correct.

With 25 feet of duct ending in a centrifugal fan you won't exhaust anything in the air, probably no need to vent outside. I currently use far less duct to an air filter and it stays clean for years.

I have a few Airflow systems MP14 mist collectors I should part with. They are a little tall for my 12' ceilings but your 25' height would be fine for them. I'm on the wrong side of the country for you but I only want $500 each. They are 3 phase 1.5hp. I think one with a hood might be enough for your fadal, 2 certainly would.

Whatever system you chose be sure it's safe with regard to the oil mist or collected residue not being a fire risk. So motors and controls should be fully sealed, "pool points" should have a drain into a steel bucket (which should be emptied frequently), and any ducting should be impervious to oil soaking into it (no fabric ducts).

carbonbl said:

Right now I'm thinking of buying a used Royal Filtermist, either the 900 or 1200 cfm unit and ducting it to near the spindle on the Fadal as well as into the enclosure on my Mazak QT8. Ducts will have gates so that I can pull as much from the Fadal as possible when I'm not running the lathe. I read a testimonial on PM from someone who had the 900cfm Filtermist successfully servicing two open surface grinders. Even my little 137cfm dust extractor will noticeably cut down on the mist when ducted near the Fadal spindle so I'm optimistic. This solution is also attractive because it could be adapted in the future to support multiple fully enclosed machines and it is much lower maintenance than a filtered/electrostatic air scrubber like Mud suggested.

I'll be posting a WTB soon on PM for one of the Royal units and I'll report back with the results once it is all set up.

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I have an older Filtermist F-1200 model, I bought it used, and have found subsequently the drum pads were only a few hundred hours old. Put simply it doesn't work. It rarely deposits any coolant back into the sump, about the only time it has worked well was with a 1/2 drill at 3000rpm that had a large ball of swarf flining off mist. My coolant usage hasn't changed in the slightest.

I talked to a shop owner recently who had 5 Filtermist units. he said the 2 units on the lathes worked ok. The 3 units on his fadals didn't. He said even with all 3 units on the fadals running he still had to have the roll up door to exhaust the mist.

The other downside is that the units are very noisy. If you buy from a distributor if I were you ask to go to a shop who he's supplied units to to get an idea of effectiveness and noise.

I'm about ready to pitch the F-1200 and get a Mistaway, which is what I should have got in the first place.

triumph406 that's a disturbing anecdote. The reason I settled on the Filtermist unit was that it seemed to have a good reputation on PM and has been basically the same design for a long time. Do you have the after-filter on your unit?

There's a lot I like about the mistaway (120v, 1200cfm, way more affordable), only concern I have is the extra maintenance of multiple filters and being tied to one company to replace them.

I have a Filtermist 1200 on a lathe which is not well enclosed. It does capture something when the chuck is really getting soaked. But a lathe chuck produces a tremendous volume of coolant mist which is likely quite large droplets. I wonder if maybe an electronic air cleaner (for weldiing smoke primarily) wouldn't be better for your application? All these things are noisy because they are gulping huge volumes of air.

A thought which occurred to me about your Bijur spindle lubricator: does it have a metering port on the injector? Maybe it's stuck wide open? Is there not a timer on the Bijur as well, to reduce the frequency of injection? If you have a used machine with an unknown history, you just never know who has monkeyed with what.

carbonbl said:

triumph406 that's a disturbing anecdote. The reason I settled on the Filtermist unit was that it seemed to have a good reputation on PM and has been basically the same design for a long time. Do you have the after-filter on your unit?

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That's why I suggested to talk to a distributor and see if you can get to see some units in action. I would take the experience of somebody with and older unit (me) with a pinch of salt, on the other hand the experience of the guy with 3 units on 3 Fadals was similar, they were newer units which are better sealed.

I don't have the after filter.

carbonbl said:

There's a lot I like about the mistaway (120v, 1200cfm, way more affordable), only concern I have is the extra maintenance of multiple filters and being tied to one company to replace them.

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Other advantages of the Mistaway are it's lighter and getting it up on top of the machine is much easier than the Filtermist. (I can't get a forklift or any type of lift to the back of my machine, so it was a concern for me)

Also the Mistaway is going to use less power, so will cost less to run. The Filtermist is 3HP 208V 3ph and uses (can't exactly remember) 6-7A/leg.

My Filtermist I originally attached it to the top of the fadal sheetmetal enclosure. When it was running you could feel the control unit and monitor vibrating slightly. That went away after I put some vibration isolators between the sheetmetal and the Filtermist. That won't be a concern with the Mistaway.

I don't know if there is much maintenance required for the filters. I shouldn't think the Metal Mist/Baffle filter require any maintenace what so ever, their availible from vendors who supply filter systems (and Mcmaster), but you'll never need to replace them.

Also I would think the Merv 14 ASHRAE and Carbon filter are availible commercially, so you will not have to rely on Mistaway for replacements. When I was looking at different units I did look at Mistaway replacement filter costs and thought they were very reasonable. Also replacing the filter would only be a matter of minutes as well.

One thing you will need to do is seal the machine the best you can. No system is going to work very well if there are large air gaps on top of the machine. I have sheets of plywood/aluminum crudely trimmed to cover the top of the machine. I'm going to redo those sheets to see if I can get the Filtermist F-1200 to perform better.

HuFlungDung said:

A thought which occurred to me about your Bijur spindle lubricator: does it have a metering port on the injector? Maybe it's stuck wide open? Is there not a timer on the Bijur as well, to reduce the frequency of injection? If you have a used machine with an unknown history, you just never know who has monkeyed with what.

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The Fadal Bijur unit has a window for monitoring rate of oil consumption, It should be 1 drop per second.

I checked the flow on the Bijur mist lubricator, it is indeed around 1 drop/sec. It runs constantly while the spindle is turning, there is no on-off timer I can see and no Fadal parameter for adjusting that.
Here's a photo showing the mist around the spindle. This is running at 700rpm and what you are seeing is mist actively puffing out, not a pre-existing haze:



This spindle is 10k rpm and the Fadal manuals I have only mention a 15k air/oil spindle, with 10k being grease-packed according to the manual. The manual mentions that the 15k air/oil spindle has a vacuum pump designed to catch any oil mist blow-by at the spindle bearings. I don't believe this machine is equipped with that. Like I said it is a very early machine and some other oddball aspects of it have even stumped Fadal parts/service people I have talked to.

triumph406, I'm looking into the mistaway system more. The primary pleated filter and the carbon filter are on McMaster too so that's one less concern about alternative filter availability. I really do like the idea of a 1200CFM machine running on 120v with less power use. No matter what I will have to deal with some gaps, so I'm trying to get the most airflow possible. The enclosure on this machine is not like normal Fadals which can be "capped" on top. The control console sits over the table right next to the spindle and the enclosure stops below chest height. The front of the enclosure and doors move in and out with the Y. So enclosing the whole mess with minimal air gaps but still good access is fairly complicated and I would like to delay it as long as possible by mitigating the spindle mist problem with the current enclosure configuration.


Hu, I'm thinking that the full-shop air cleaner may be a later purchase if I still have air quality problems. At this point I'm set on trying at-the-machine collection on my Fadal and Mazak lathe, especially since that kind of system could easily transfer to a fully enclosed VMC some time in the future.

HuFlungDung said:

A thought which occurred to me about your Bijur spindle lubricator: does it have a metering port on the injector? Maybe it's stuck wide open? Is there not a timer on the Bijur as well, to reduce the frequency of injection? If you have a used machine with an unknown history, you just never know who has monkeyed with what.

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It might have a nut to control the flow.

EnderDRM said:

It might have a nut to control the flow.

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It does have an adjusting screw for the flow valve, but I don't think I'm going to mess with it if it is supposed to be at 1 drop/sec which is what I'm seeing now. It's not worth shortening the spindle life.

The bijur lubrication unit is essentially the same as this modern one, just without the blue shroud around the lower pressurized vessels
http://www.bijurdelimon.com/fileadm...atasheets/35512_LUB_Mist-Lubricator_DS-R4.pdf