Top cover

ahem, Motordude, Guy: Sorry!  :ph34r:

Having back a top cover (before I was running with a not so artistic version of motordudes cover but I had to remove it for other cabling and filament support) I immediately restored the better warp and split resistance of ABS prints.

The print on the pic has outer areas for clamping it to the bed, had to do this before and even then it lifted from the bed.

It's almost at the outer limits of the M200 printable area (193 mm) and right now I do not use clamps and if it should lift later it would not harm the print anymore.

The ABS used is not Z-ABS means it shrinks a lot more than Z-ABS (causes more warping normally).

I've paid about 150AUD each delivered for Clark's (gadgetstogo) covers for all 3 of my machines, and I've certainly got no regrets.

I'm not trying to achieve super high temps, just keep it at a nice constant 40 degC, which means fan running almost continuously in summer and occasionally in winter.

I've only got the control box and filter set up on one of them, just been too busy/lazy to set them up, but I will.

They're a good solid design, and are quite functional.

If only he'd supply them with metric bolts, not this medievil BS.....

I'll get them finished Clark, and send you a nice pic of 3 of them in 3 zortrax colors all along my bench....one day

You should have included a choice for $0.  That will give you a feel for the ratio of people interested or not.

I can see the possible value of temperature regulation but you would have to prove it before I would spend money for it.

I don’t worry about particle generation… here’s why…

 

I headed up a 6 month project to study VOC and particulate generation by 3D FDM printers and filament recycling systems.  We found that if you desiccate ABS or Nylon to 25% or less RH at 70F then there are no detectable VOC's and the particle generation is near zero.  The problem occurs when the filament has a higher moisture content.  Our hypothesis is the water in moist filament turns to steam in the hot end which creates a large volume expansion causing the equivalent of micro-explosions as it exits the extruder.  Particle counts for ABS and Nylon filaments stored at 60% RH were extremely high.  We didn't check VOC generation at that level though.

 

If you want to drop particle generation down to near zero, store your filament below 25% RH.  If you are still concerned tape a small 5 Watt blower to a vacuum cleaner HEPA filter and recirculate the air inside the print volume (assuming enclosed sides).  Even when we had very high particle counts, modest recirculation through a HEPA filter was enough to bring particle counts to zero, which was much lower than the ambient room air counts.

Regarding temperature regulation... In my experience, it requires a lot more work than just a temperature regulating top cover to truly avoid ABS warpage.  I didn't see much benefit by raising the temperature from 85 to 105F.  I had to get closer to 190F (90C) to get past the warping issue for large ABS prints with long straight walls.

I built a heated enclosure for a previous FDM printer I owned and didn't see much benefit until I got close to that 90C mark.  At that point you have to take special measures to keep the filament cool until it reaches the hot end, as well as keeping the temperature of your electronics and steppers low enough to prevent damage.  It gets pretty involved.  I bought my Zortrax shortly after getting that printer going and the Zortrax is so reliable I haven't used the other printer since.  I can usually design parts in a way that prevents warpage so its something I can work around.

You should have included a choice for $0.  That will give you a feel for the ratio of people interested or not.

I can see the possible value of temperature regulation but you would have to prove it before I would spend money for it.

I don’t worry about particle generation… here’s why…

 

I headed up a 6 month project to study VOC and particulate generation by 3D FDM printers and filament recycling systems.  We found that if you desiccate ABS or Nylon to 25% or less RH at 70F then there are no detectable VOC's and the particle generation is near zero.  The problem occurs when the filament has a higher moisture content.  Our hypothesis is the water in moist filament turns to steam in the hot end which creates a large volume expansion causing the equivalent of micro-explosions as it exits the extruder.  Particle counts for ABS and Nylon filaments stored at 60% RH were extremely high.  We didn't check VOC generation at that level though.

 

If you want to drop particle generation down to near zero, store your filament below 25% RH.  If you are still concerned tape a small 5 Watt blower to a vacuum cleaner HEPA filter and recirculate the air inside the print volume (assuming enclosed sides).  Even when we had very high particle counts, modest recirculation through a HEPA filter was enough to bring particle counts to zero, which was much lower than the ambient room air counts.

You might want to have a look at this paper, published last month:

http://pubs.acs.org/doi/abs/10.1021/acs.est.5b04983

2930

printer emissions.png

If you are still concerned tape a small 5 Watt blower to a vacuum cleaner HEPA filter and recirculate the air inside the print volume (assuming enclosed sides).  Even when we had very high particle counts, modest recirculation through a HEPA filter was enough to bring particle counts to zero, which was much lower than the ambient room air counts.

That's exactly what a cover is good for: providing mounting space for the filter and fan, making the remaining inside volume dense for catching up all particles.

I would feel like an idiot staying with a filter and taped fan at the printer while it's printing (generating and releasing the particles by extrusion and movement).

That way I prefer to spend some money for a cover over the (so called) zero cost 'solution'. It saves me a lot of money doing business while my printer is doing multi hour jobs.

You might want to have a look at this paper, published last month:

http://pubs.acs.org/doi/abs/10.1021/acs.est.5b04983

attachicon.gifprinter emissions.png

That study has a fatal flaw... they didn't measure filament moisture levels of the filaments they tested which are absolutely key.  Their results would vary by many orders of magnitude depending on the moisture level of the filaments tested.  They only logged RH for the ambient air during printing which is pretty much irrelevant.

They also do not report what health consequences are expected.  I didn’t spend enough time to try to connect the dots but they mix a lot of units such as #/m3, micrograms/gram and #/min then mix and match to make claims.  I suspect if I looked long enough I would find that these tests don’t represent levels you would measure in a typical room with a 3d printer running but concentrations closer to the enclosed printer. Remember, if a researcher doesn’t find something scary they don’t get continued funding.

Another important point to make is that if they ran the same tests in your kitchen when you make breakfast or in your car or closet, the results would make the ones reported for printing look like nothing.  The particles and VOC's you breathe from car exhaust driving to work, cooking, carpets, clothing and other textiles, cleaning products are likely in much higher concentrations than what your printer creates.  Its common for PhD's to focus on finding issues with expanding markets to try to create a buzz which stimulates further funding.  They could make a case that UFC's encountered while living near or driving on the freeway will likely knock several years off your lifespan and increase your chances of cancer and heart disease very significantly but they are less likely to do so because it isn't likely to garner future funding.  They also know that people are less likely to accept this kind of conclusion regarding cooking or clothing compared to an upcoming technology like 3D printing.

We tested with the printer inside of an enclosure and found particle counts (particles >0.5 microns) for ABS and Nylon filaments stored below 25% RH were in the 5000/ft3 (0.18 particles per CC, very good air quality) during printing compared to normal room ambient levels of 30,000 to 60,000 (2 to 3 particles per CC)… I.E. the air quality inside the printer enclosure was much better than the ambient room air during the printing process.  30,000 particles/ft3 is generally considered good air quality depending on the shape and size distribution of the particles.  Its not uncommon to see counts over 100,000 in ambient air outside on a clear day.

Our tests only included ABS and Nylon materials so I don’t make claims outside of those materials.

We also tested VOC generation using Drager tube measurements for every VOC listed on the ABS and Nylon SDS’s (formerly MSDS).  We recorded ZERO VOC’s for every material except one and it was well under safe limits according to EPA guidelines.

As I mentioned before, a very small blower recirculating through a HEPA filter inside the printer enclosure would be enough to eliminate any concerns about particle generation.  Add an activated carbon mesh in front of the filter if you are worried about VOC’s.

After spending six months studying this issue I still don't believe there's any need to use any type of filtering or venting for my printers as long as I store filaments at 25% RH or lower.  I can't make claims for all materials for all situations but I will say that I don't worry about it.  I just make sure my filament is kept below 25% RH. 

That's exactly what a cover is good for: providing mounting space for the filter and fan, making the remaining inside volume dense for catching up all particles.

I would feel like an idiot staying with a filter and taped fan at the printer while it's printing (generating and releasing the particles by extrusion and movement).

That way I prefer to spend some money for a cover over the (so called) zero cost 'solution'. It saves me a lot of money doing business while my printer is doing multi hour jobs.

You make a point that I hadn't considered... if you are printing all day long every day and have multiple printers then it may be worth investing in having a test run in your facility to see if you need filtering for your printers.  You will likely find that you have some other sources of air quality issues that are worse than your printers.  Testing and identifying real issues is better than fearful reacting to the unknown.  People trying to sell printer hoods may not be the most objective sources for information on this subject.  I don't have any motivation other than providing objective information.

  1.  Keeping your filament stored at under 25% RH is the best thing you can do to improve air quality in your 3D printing area.

2.  After that, if you are still concerned about air quality, have your facility tested by a qualified professional.  They will likely identify issues you didn't know you had and printer hoods are very unlikely to be the ultimate solution.

They also do not report what health consequences are expected.

Section 3.5, covering a page and a half, is titled "Implications for Human Exposure and Health Effects". Regarding typical environmental levels, they say "... an increase in UFP concentrations to ∼58 000 cm−3 would be approximately 10 times higher than what we typically observe in indoor air in our office and laboratory environments and what has been reported as a typical average indoor concentration in schools. However, it would only be moderately higher than typical time-averaged concentrations in homes but lower than what is often observed in other microenvironments."

It seems pretty level-headed, thorough (apart from I suppose the filament moisture content issue, which it seems they didn't consider) and un-sensationalistic to me. As to the moisture issue, I suspect that the majority of printer users don't control their filament's storage humidity carefully - I know I sure don't - so maybe that's not a great argument for absolving printing of all heath risks.

The big takeaway for me was the styrene emissions, present in relatively high levels in all ABS printing in their tests, and entirely or almost entirely absent with PLA. They do mention that styrene is considered a possible human carcinogen by the IARC. Make of that what you will.

I'm probably a little "anti-PhD" biased after seeing up close and personal how much they distort their findings over the years.  Biasing results to increase funding is too much of a temptation for most to avoid.

My tests with dry (25% RH storage) ABS and Nylon filaments showed no issues with either VOC or particle generation (particles over 0.5 microns).  

I guess a filtering hood may be a safer option for public use printers where filament moisture levels are less easily controlled.  Personally, I'd rather dry my filament than spend $100-$200 on a hood that doesn't work any better or may even cause more issues.  There may be a case for filaments other than ABS or Nylon which I haven't tested.

Keep in mind that HEPA filtration efficiency is rated for particles 0.3 microns and larger.  Filtration efficiency goes as low as 10% for some particle sizes so a venting hood may actually be a dust pump for those size particles.  Capturing VOC's using activated carbon requires matching the filter surface area and flow rates to ensure the output VOC's are reduced sufficiently.  A recirculating filter system would be much more effective.

Has anyone selling these hoods actually tested to prove they are solving and not actually exaggerating the problem?  The test equipment can be very expensive.  I’m sure HEPA will solve the problem for particles 0.3 microns and larger though, even for a non-recirculating system.

If anyone wants to do some of their own testing just to ease your mind, you can get a Dylos laser particle meter for around $250.  There are a few models.  It would be best to get the Pro model which measures down to 0.5 microns vs 2.5 microns for the standard model.  You can find them on Amazon ( http://www.amazon.com/Dylos-DC1100-Pro-quality-monitor/dp/B004AWEG0Y/ref=sr_1_1_a_it?ie=UTF8&qid=1456506364&sr=8-1&keywords=dylos+pro)  The readings correlate pretty well with meters costing $4000 and up.  They don’t compensate for humidity so high RH levels can affect their readings because water vapor is seen as a particle.

Interesting discussion.  I don’t have all the answers for sure.  Hopefully my comments stimulate some critical thinking though.  IMO, its possible to make a $40 product (sale price, $10 build price) that would alleviate any lingering concerns for untested filaments.

 

You make a point that I hadn't considered... if you are printing all day long every day and have multiple printers then it may be worth investing in having a test run in your facility to see if you need filtering for your printers.  You will likely find that you have some other sources of air quality issues that are worse than your printers.  Testing and identifying real issues is better than fearful reacting to the unknown.  People trying to sell printer hoods may not be the most objective sources for information on this subject.  I don't have any motivation other than providing objective information.

  1.  Keeping your filament stored at under 25% RH is the best thing you can do to improve air quality in your 3D printing area.

2.  After that, if you are still concerned about air quality, have your facility tested by a qualified professional.  They will likely identify issues you didn't know you had and printer hoods are very unlikely to be the ultimate solution.

No it would be definitely not worth investing in a test. You wrote you have been busy 6 months on that issue, for this I would either tell that you are a big enthusiast or have been paid for doing it.

I do not get paid for testing it, therefore if in doubt (and this theme actually is) I just pay that money and have:

- better thermal conditions in the print chamber

- less smell in the rooms

- less doubt about air quality

As Julia mentioned (and told a bit bolder from me): Your measures are only valid if filament is stored at 25% wich actually is not a healthy RH for a house. That way probably your report is of value for people that have professional storage abilities for all the others it's useless.

No it would be definitely not worth investing in a test. You wrote you have been busy 6 months on that issue, for this I would either tell that you are a big enthusiast or have been paid for doing it.

I do not get paid for testing it, therefore if in doubt (and this theme actually is) I just pay that money and have:

- better thermal conditions in the print chamber

- less smell in the rooms

- less doubt about air quality

As Julia mentioned (and told a bit bolder from me): Your measures are only valid if filament is stored at 25% wich actually is not a healthy RH for a house. That way probably your report is of value for people that have professional storage abilities for all the others it's useless.

Here's what I use...

Rechargeable desiccator http://www.amazon.com/gp/product/B000H0XFCS?keywords=rechargeable%20desiccant&qid=1456512958&ref_=sr_1_1&sr=8-1

Sealed container http://www.amazon.com/IRIS-Airtight-Container-25-Pound-Clear/dp/B007RBB6UI/ref=sr_1_10?ie=UTF8&qid=1456513006&sr=8-10&keywords=airtight+container

Hygrometer (optional) http://www.amazon.com/gp/product/B00A9W41GI?psc=1&redirect=true&ref_=oh_aui_search_detailpage

Right now the RH in my filament container is below the measurable level of the hygrometer (probably under 10%).  I never smell anything when I print because my extruder isn't spraying particles everywhere (because I use dry filament).  

I don't have anything against hoods.  My guess is that they help.  I just want others to know that keeping their filament dry is the best way to keep emissions down and it is easy and it also improves print quality.

Why not invest $40 in a sealed container and rechargeable desiccant that has been proven to work vs. a hood that may or may not help or hurt?  Your prints will be more consistent and higher quality and the odor should drop to nearly nothing.

If you think printer emissions may really be a health issue and you have multiple printers operating in a facility then you probably owe it to yourself and your employees to have a test performed.  Hoods with no documented test results aren’t any guarantee.  They will certainly help but its not known they increase or decrease ambient particle counts for particles 0.1 micron and smaller where filters are much less effective and can even become Ultrafine particle pumps.  

The project I worked was a 6 month study testing feasibility of recycling filaments for long term space missions.  You can buy a Dylos Pro for $260 and test particle counts (not VOC's)  in your facility yourself.  IMO, a test result in your working context is worth a thousand claims.

 

Cheers,

Tony 

Here's what I use...

Rechargeable desiccator http://www.amazon.com/gp/product/B000H0XFCS?keywords=rechargeable%20desiccant&qid=1456512958&ref_=sr_1_1&sr=8-1

Sealed container http://www.amazon.com/IRIS-Airtight-Container-25-Pound-Clear/dp/B007RBB6UI/ref=sr_1_10?ie=UTF8&qid=1456513006&sr=8-10&keywords=airtight+container

Hygrometer (optional) http://www.amazon.com/gp/product/B00A9W41GI?psc=1&redirect=true&ref_=oh_aui_search_detailpage

I have about 30 spools (out of manufacturers bags) laying around here, other have more.

It would save me nothing to buy all your boxes and dryers for 30 spools, no print would have better results.

How about extending your measures (give them some more real life relevance,) and do a study how much increase in filament humidity is raised when doing a 30+ hour print job having the spool at regular RH?

I have about 30 spools (out of manufacturers bags) laying around here, other have more.

It would save me nothing to buy all your boxes and dryers for 30 spools, no print would have better results.

How about extending your measures (give them some more real life relevance,) and do a study how much increase in filament humidity is raised when doing a 30+ hour print job having the spool at regular RH?

30 spools isn't that much.  Just get a larger container.

You indicated that you are are worried about particle generation.  Desiccating your filament would resolve that issue.

Particle generation, as you indicated in an earlier post, is even more "real life" relevant than nice prints.  However, desiccating filament improves both.

We didn't notice any particle generation during the hour or two that we were printing for each test.  I assume that means that filament takes a while to absorb moisture after it has been dried.  However, the absorption rate is dependent on the ambient RH and temperature.  The further over 25% RH the ambient air is the faster the filament will reach a level where it starts spewing fine and ultrafine particles via steam generation at the hot end.

I don’t come to this forum much.  I just popped in to see if anyone knows why Zortrax is practically giving filament and printers away with their latest deal.  My intention is to inform, not to agitate.  I think I’ve passed on all of the relevant information I know about the subject.  I hope it proves helpful for some of the readers.  I’ll bow out now.

Cheers

Wow... ordering some desiccants. Thanks Tshulthise

Yes,

I keep all my open filaments in sealed plastic buckets with this rechargable dessicant units in them, always have.

The humidity must be quite low, as they stay blue for ages unless I accidentally leave the lid off a bucket.

That said I still smell fumes, and strongly if all 3 are running, and am concerned enough to go ahead with the hoods.

I print a LOT of abs products, and have for almost 4 years now, and can assure you that an enclosure does reduce (I do not say eliminate) splitting and warping, and I see nicer prints at an enclosed 40 deg C.

I am going to modify Clarkes filter boxes to allow a hose up to my ceiling exhaust fan and aim for a very slight suction effect on the hoods, just enough to keep the fumes travelling up the hose, not out through the gaps into the room.

I'll still have the thermostat fans to kick in if it reaches my trigger temp.

No fumes are good fumes. If I can smell them I'm not happy.

I don't believe this humidity stuff has that effect, I had some filament stored in vacum cover (as it arrives from zortrax ) but whenever I take them out and start printing I start smelling  bad odor. Anyway, next printer that I'm going to buy will have to be closed with filtration like the Cubicon single or Upbox.

With 3+ printers constantly running, I'm seriously considering one of these:

http://inovaairpurifiers.com.au/home-air-purifiers/airclean-e20-plus/

As well as hoods, fans, etc.

Not to say that Tshulthise is wrong, but I also smell fumes heavily despite dehumidified storage.

I don't believe this humidity stuff has that effect...

Not to say that Tshulthise is wrong, but I also smell fumes heavily despite dehumidified storage.

Tshulthise (I am always tempted to spell that originally German name right :-) is completely right and I do not doubt his test results that with 25% RH you don't experience noticeable particles in the air.

But this is of almost no relevance for the regular use of 3D printing with the M200 (home / office printing).

Most users don't have that low (and unhealthy) RH while printing, and assumed the spool is not feeing the printer out of that drying boxes that's why the filament will soak up at least for long running prints. TShulthise mentioned that it depends on RH and temperature, I would add that it depends on filament type too.

And of course TShulthise's tests do not count for VOC and if you take this and add some other points I wrote about earlier, you alway are better off with a covered printer that scrubs the air inside thru a filter.