FR-4 Material Filtration

Is there anyone out there who could provide me with specific documentation that 0.3 Micron HEPA filter would work to filter FR-4 (Printed Circuit Board Material) Dust. I can’t seem to find anything.

All of the dust Collector manufacturers that I talk to say that their collectors are only rated for wood dust, I think a cyclonic wood dust collector with 0.3 Micron HEPA filtration will be okay, but my bosses are looking for something very direct.

Even OSHA and the CDC say that this is something that should be taken up with the dust collection manufacturer although obviously this is quite impossible.

anyone want to help out?

You may want to look at bathing it. Similar to what this person did:

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I can’t and won’t offer any advice myself, but this thread might be of interest:

@mbellon knows his stuff when it comes to dust collection safety.

I also heard somewhere about milling underwater to avoid the problem altogether.

EDIT: sounds like “milling underwater” is my Frenglish speaking, and “Bathing” is the correct term :slight_smile:

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Yeah, so the CNC machine that we are going to use to cut it is open and does not have an option for any type of water use.
-Thanks though

Yes, I have read this. @mbellon does not give reason as to why 0.3 Micron HEPA filtration is okay or needed for that case. Is this just an opinion he has?
-Thanks

I’m incompetent on these matters, I really have no idea. Hopefully Mark will see the message and respond, and/or other people will chime in.

here IS A REASONABLE WEB SITE - .3 micon is very small and should catch and all dust form the nomad. You would certaily need some prefilter setups to preserve the .3micron Tom

FR4 and Garolite are some of the most dangerous materials to machine, with respect to air safety. Carbon composite materials are. “right up there” is danger with respect to air safety too.

Where does the 0.3 micron HEPA filter requirements come from? SCIENCE!

Seriously, the EPA and many industrial studies over the last 50 years show that particles need to be filtered out down to 0.3 microns so as to remove as much of the associated risks as is practicable. Only being on a totally separate, isolated air supply is safer (which you see, for instances, in paint shops).

The filters in a fire fights mask? 0.3 micron HEPA.

mark

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A messy but workable method when working with FR4, Garolite, and carbon composites is the bath. Mill a flat surface under distilled water. I’ve seen this done several times. I use the bath technique, myself, rarely, and do so to handle some difficult materials where then need to be submerged in cutting/coolant fluid. Very, very rare to need to do this.

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Remember that CNC machines do not create “saw dust”! They create particles of many sizes. The ones you cannot see with you eye - 5 microns and less - are the dangerous ones.

The EPA and industry scientific research over the last 50 years is where the numbers come from. 5 micron particles aren’t too dangerous, but they will make you choke and cough, almost instantly. As we get down to 2.5 microns there is HUGE body of peer reviewed scientific evidence - collected over the last 50 years - to show how dangerous these particles are. There are even strong links to Alzheimer’s! The more exposure, the more more frequent the problems.

When we get below 1 micron, we’re starting to talk about particles that enter the lungs and stay there. Now we’re talking about things that make asbestos look health.

The 0.5 micron size - for filtering - is where the data shows the risks dramatically drop off. Many HEPA filters are 0.5 microns for this reasons. HOWEVER, there is data to show that the 0.3 micron filter size is superior, and this why fire fighters masks use it.

If people want pointers to papers, I’ll be happy to provide additional references.

https://www.health.ny.gov/environmental/indoors/air/pmq_a.htm
https://www.canada.ca/en/health-canada/services/publications/healthy-living/guidance-fine-particulate-matter-pm2-5-residential-indoor-air.html


https://www.cdc.gov/air/particulate_matter.html

Air safety in CNC is an area that is often ignored, to the detriment of the health of its user.
Caveat Emptor!

I’ll reiterate, as I have in many places, that ANYTHING is better than nothing, as this is all about minimizing risks. Any reasonable budget and circumstance can dramatically decrease any air safety issues.

If anyone has any questions about how to deal with this, or brainstorm about how to get the best outcome from a particular budget, just let me know. There is always something that can be done.

mark

P.S.

Let me remind everyone that one can deal with the particles in air problem in several ways. If the air is dumped inside, where people are, the best filtration you can afford is required. The ideal and industry requirement is 0.3 micron HEPA filters. Next best is 0.5 micron HEPA filters.

HEPA filters are EXPENSIVE! It’s a good idea to have dust separator (e.g. a cyclone) in front of the dust collector with HEPA filter. This will remove over 90% of the particles before they hit the filter, dramatically extending their functional life.

If one can dump the air OUTSIDE and be sure that the air doesn’t easily/quickly come back INSIDE this is a much less expensive way of solving the problem. All that is needed is a 5 micron filter (to prevent “snow” for accumulating underneath the output port).

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Hey Tom, what is the actual website that you found this on?

Would it be ethical/legal to just exhaust it outside, without any separation or filtering? Scrimping on filtration would be “penny wise and pound foolish” IMO.

Isn’t this backwards?

Yep, but cyclones and HEPA filters cause drops in static pressure (suction). This new dust collector would help with that because it has far more static pressure than most dust collectors with more than adequate air flow for most/all hobbyist uses.

As pointed out here, folks shouldn’t rely on just the dust collector because it won’t collect all of the dust and they’ll need protection when emptying the collected dust. A HEPA respirator would be a wise investment (if you can find one these days!)

In the US, asbestos requires special disposal procedures. Is that true of fiberglass dust too?

Isn’t this backwards?

Yes, that was backwards, a mistype. My bad. Fixed in the original posting.

Would it be ethical/legal to just exhaust it outside, without any separation or filtering?

No.

Scrimping on filtration would be “penny wise and pound foolish” IMO

Very much so.

As I’ve pointed, here and elsewhere, if the air (from the vacuum for particle collection) exhausts back into the room where people are, a HEPA filter is called for. The best one can afford; 0.3 microns is the standard.

Can the air be dumped outside, avoiding HEPA filters? Yes… but there are still gotchas.

One still needs a dust separator, so as to dramatically reduce the amount of particles dumped outside. This removes well over 90% of the particles and concentrates then in the dust separator, making for easy disposal. Remember that these particles are NASTY to your health.

In general, it’s a good idea to use a respirator whenever one empties their dust separator. This should be done OUTSIDE well away from a residence, when standing up wind. The 3M 5000 respirators with a HEPA filter is a good choice.

So now the air is being dumped outside. It still have some NASTIES in it. One must prevent the air from easily returning to the work area and from entering other places in a residence (where people are). It makes no sense to exhaust it from your basement, only to have enter your house from the open window near the exhaust port.

Now one should have a 5 micron filter to prevent the accumulation of “snow”. These are inexpensive cloth bags. One would have this outside the exhaust port, covered to prevent getting wet from rain.

Finally, one has to deal with NOISE. Vacuum systems are noisy and the exhaust port will really upset a close neighbor. It’s best to exhaust far from others (due to noise), or at least pointed away from others. Yes, it is possible with a little bit or care to build the little structure over the 5 micron cloth bag to act as a muffler. Just remember that the source being emitted here can continue to HOURS. Be sensitive about your neighbors!

Yep, but cyclones and HEPA filters cause drops in static pressure (suction).

Correct. This can easily be addressed with properly addressing by adjusting the “strength” of the dust collector and using proper tubing techniques.

This new dust collector would help with that because it has far more static pressure than most dust collectors with more than adequate air flow for most/all hobbyist uses.

This is really cool! I hadn’t seen that one yet. It’s also way outside the cost range of most of the people on these forums. There is also the issue of NOISE. These devices, if inside with people, make a real racket. Proper design calls for a small room or enclosure, with sound suppression materials, if necessary, to not exceed the safe levels of sustained noise requirements.

Yes, long term sound, even at modest volumes, can be detrimental. CNC machine are near perfect generators of sound that can drastically and negatively affect ones health and well being.

iu

I regularly have jobs running for as long as 12 hours. The 85 dBA level is easily generated by most CNC machines. The Nomad, with its enclosure, keeps the sound levels quite well. Even so, my Nomad enclosure pushed for even lower levels, because the sound can be irritating.

As pointed out here, folks shouldn’t rely on just the dust collector because it won’t collect all of the dust and they’ll need protection when emptying the collected dust.

Bill is considered a bit of an extremist I’m afraid. He clearly states that he has allergy issues which would hyper sensitive him. I trained in Physics and have gone through the math. I don’t, in general, disagree with him, however, few in these forums can afford the level of safety he is advocating. This is all about risk reduction, the better the protection the better… but the reality of budget must enter into the equation.

What he doesn’t state, is how well something a bit less “fancy”- and much less costly - does. Which is remarkably close to the level he is asking for.

I’m available to discuss how to achieve very good levels of safety, but be aware that the requirements, have some stiff costs associated with them.

A practical tradeoff, extremely effective, is to build an enclosure, and let the vacuum run for a few minutes after the job completes. Lining the enclosure with sound suppression materials really helps, especially for larger machines and longer running jobs. Having a spindle, over a router, also helps as spindle as inherently quieter than routers.

A HEPA respirator would be a wise investment (if you can find one these days!)

For sure!

Yes, they have become hard to find, ironically due to COVID, since a HEPA filter will not stop the virus, which is some 10X smaller than the filter. If people do want them, please let me know. I can point to industry sources where they are much more likely to be available.

As I pointed out, one should use them to emptying their dust separator.

As a general solution for being around CNC machines, they fail pretty badly:

  1. Wearing them (which I have done) for extended periods of time is very hot and uncomfortable.

  2. The particles get into your clothes. If one doesn’t change after being around the CNC
    machine, they bring “second hand” particles home. Not good. Even learning how to
    handle particle contaminated clothes takes some doing and discipline.

In the US, asbestos requires special disposal procedures. Is that true of fiberglass dust too?

Yes. This gets into wearing “Tyvek space suits” and respirators. This isn’t practical for CNC machine use.

As I’ve said, ANYTHING IS BETTER THAN NOTHING, this is about risk management. The more one can do, the better. When I design for commercial customers, a nearly universal complaint is… THIS IS BLOWING OUR BUDGET! It sure is… because the CNC companies don’t make it clear how dangerous things are with respect to air and noise safety.

Besides the dust collector and dust separator, there are tubing requirements. Routing, dust explosion prevention, cleaning and safe cleaning… the list goes on.

Few in this forum are going to run the minimum tubing necessary to achieve near perfection (4 or 5 inch tubing, very powerful blowers with very high air velocity and pressure capabilities, near optimal routing, etc.).

Machining friable materials (e.g. FR4, Garolite, Carbon Composite, MDF, woods, etc.) generate particle problems very different than the safe cleanup requirements for a building. even plaster and spackling dust is nor understood to be dangerous.
mark

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Some of them should do a better job than the N95’s, which reportedly are effective, though. I use an Elipse P100 (for my protection) with a disposable fabric mask on top of it (for the protection of others from its exhaust).

Isn’t that a myth?

How did you modify your Nomad enclosure to enable dust collection and what do you use to do it?

Can’t dust exposure cause such allergies? Doesn’t he provide a lot of useful information, a nice calculator, and numerous useful links to references?

Any air exhausted from the workshop needs to be replaced, so exhausting air outside may not be practical for some.

Yep, much simpler and less expensive options are likely adequate for most.

Isn’t that a myth?

Most certainly no.

In CNC ducting, dust can accumulate. Static charge builds up and a discharge can cause a poof or fire. One uses grounded conductive tubing or runs a grounded wire down the middle of their ducting to ensure no possibility of state discharges (into their “dust”).

Can’t dust exposure cause such allergies? Doesn’t he provide a lot of useful information, a nice calculator, and numerous useful links to references?

I’ve pointed the dangers of dust exposure in numerous postings (fell free to search for them). The particles can contain viruses (particularly exotic hard woods), teratogens, carcinogens, toxics, and irratants. These can cause all sort of health issue (many quite serious, especially if exposure continues), including allergies.

As I stated (please reread what I wrote) I basically agree with this numbers, but Bill’s numbers are also over-the-top. What he doesn’t do is say how well other schemes work. Many, much cheaper and easier, come very close to his numbers. Also, his numbers force one into a budget that is beyond what most “here” can afford. It’s all about risk management vs. budget. Practical advise, while acknowledging what’s near perfection, then the user gets to manage their risk (and/or ask questions).

Any air exhausted from the workshop needs to be replaced, so exhausting air outside may not be practical for some.

I pointed out the practical difficulties with outside exhaust. I clearly stated that one must be careful to not allow the exhaust to reenter, at least not too closely. Commercially, shops that exhaust outside often do so through one wall and take air in from the opposite wall or “far away”.

Yep, much simpler and less expensive options are likely adequate for most.

Festool (EPA/DIN/EU approved (even for asbestos)), amongst others, are unquestionably good. There are many others. Unfortunately, most as dangerous crap. Having a “HEPA” filter doesn’t make the unit acceptable for air safety. Any ole shop vacuum is likely to be ineffective. Check with the vendor and ask for their HEPA and vacuum testing certificates. If they say “what?” or “we don’t do that” or “we tested ourselves”, something is likely not good. Reputable vendors get outside lab testing.

Real equipment that really works isn’t likely to be the cheapest or low cost. Modest cost up is more likely to provably safe.

A shop vacuum, if the air can be dumped outside, is effective… but then one has to deal with all of the issues I pointed out.

How did you modify your Nomad enclosure to enable dust collection and what do you use to do it?

Numerous others have added dust collection to their Nomad enclosures. Search around. You can find my postings and see what I did as well. I replaced my Nomad enclosure with one of my own design. It had additional sound suppression.

There is sufficient room to obtain a “decent” amount of dust collection. Given the size of the Nomad, one has to compromise. Running the vacuum for some time after the job ends provides a good level of protection.

mark