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Should we NOT cover all holes? (airtight)  

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frebys
(@frebys)
Trusted Member
Should we NOT cover all holes? (airtight)

Hi. I've got the enclosure and I'm considering adding some small bits here and there to completely cover all the enclosure holes and gaps. My hope is to minimize the escape of smells (and health-hazardous fumes) coming out of the enclosure. However... is there a reason as to why this isn't already done? Would it be a bad idea for me to cover all the holes and make it more air-tight? 

PS: I already have the air filter installed. 

Posted : 11/12/2023 12:37 pm
adesir
(@adesir)
Reputable Member
RE: Should we NOT cover all holes? (airtight)

Hello,

Where the fresh air comes from? What if you close all gaps?
Where the fumes go?

You can try to visualize the air flow with some smoke.

Mes modeles publics
Posted : 11/12/2023 12:52 pm
ronnie12342003
(@ronnie12342003)
Estimable Member
RE: Should we NOT cover all holes? (airtight)

it needs to have an exchange of air other wise you will have a vacuum and the black hole will suck your printer into the void lol

Posted : 11/12/2023 2:14 pm
Thejiral
(@thejiral)
Prominent Member
RE: Should we NOT cover all holes? (airtight)

Funny answers aside. I don't think the holes are needed for anything other than maybe as mounting points. Nothing wrong with closing them. If you really want to get rid of all the fumes though, the way to go is by adding a very low flow fan, ideally with carbon pellet filter to the back with a small tubing to vent that air outside or to a well ventilated room (eg bathroom with active ventilation). You don't want much airflow, just enough to create an ever so slight underpressure that air doesn't move out through the cracks but in. The tighter the enclosure the lower that airflow can be to do the job. 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 11/12/2023 2:55 pm
frebys liked
Renze
(@renze)
Eminent Member
RE: Should we NOT cover all holes? (airtight)

Where the fresh air comes from? What if you close all gaps?

between the doors?

Where the fumes go?

Through the filtration system?

Posted : 11/12/2023 9:12 pm
frebys liked
frebys
(@frebys)
Trusted Member
Topic starter answered:
RE: Should we NOT cover all holes? (airtight)

I was mainly thinking that it would be unwise to seal all the holes due to the temperature inside the enclosure maybe being too high. But perhaps all those little small holes and door-cracks aren't doing much for cooling. 

Posted by: @thejiral

Funny answers aside. I don't think the holes are needed for anything other than maybe as mounting points. Nothing wrong with closing them. If you really want to get rid of all the fumes though, the way to go is by adding a very low flow fan, ideally with carbon pellet filter to the back with a small tubing to vent that air outside or to a well ventilated room (eg bathroom with active ventilation). You don't want much airflow, just enough to create an ever so slight underpressure that air doesn't move out through the cracks but in. The tighter the enclosure the lower that airflow can be to do the job. 

Thank you for the tip. I might end up closing all holes but one of the larger ones and mounting a little mini-fan with a mini-tube to a ventilation point. Thank you for the tip! 

Posted : 12/12/2023 7:26 pm
Thejiral
(@thejiral)
Prominent Member
RE: Should we NOT cover all holes? (airtight)

Yes with a PETG based printers, the enclosure temperature is a bigger issue. I'd be surprised if you can push it beyond 45°C though. After all the Prusa enclosure is quite spacious, there is a lot of volume to heat. You should check. If with nothing else, let the heat bed run at your settings and keep the hotend turned off and maybe at 10 mm height. Then you can get a rough estimate of the temperature development inside. 

Regarding printing itself. High enclosure temperatures are only an issue when printing PLA. But with PLA you are probably better off keeping the doors open. 

PS: The PSU is outside isn't it?

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 13/12/2023 7:58 am
frebys liked
Thejiral
(@thejiral)
Prominent Member
RE: Should we NOT cover all holes? (airtight)

 

Posted by: @renze

Where the fresh air comes from? What if you close all gaps?

between the doors?

Where the fumes go?

Through the filtration system?

Without design centered around air tightness it is basically impossible to create a truly airtight printer. There are always gaps. The fewer there are, the lower the air flow will be when you put an exhaust/outlet fan onto your enclosure. You cannot really achieve much underpressure and you don't need to, all you need is reverse the airflow through the gaps. Your fans will move less and less air the bigger the  pressure difference it has to overcome. So there is an equilibrium, the tighter the enclosure the lower it is and except for PLA you want minimal airflow. 

The fumes go through the exhaust filtration system but ideally afterwards through a venting tube out of the window and if that is not an option to an actively ventilated room like eg a bathroom. 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 13/12/2023 8:04 am
frebys liked
frebys
(@frebys)
Trusted Member
Topic starter answered:
RE: Should we NOT cover all holes? (airtight)

 

Posted by: @thejiral

Yes with a PETG based printers, the enclosure temperature is a bigger issue. I'd be surprised if you can push it beyond 45°C though. After all the Prusa enclosure is quite spacious, there is a lot of volume to heat. You should check. If with nothing else, let the heat bed run at your settings and keep the hotend turned off and maybe at 10 mm height. Then you can get a rough estimate of the temperature development inside. 

Regarding printing itself. High enclosure temperatures are only an issue when printing PLA. But with PLA you are probably better off keeping the doors open. 

PS: The PSU is outside isn't it?

 

I found thisPRUSA Blog post and I interpreted it that we don't want to print e.g. PETG at higher than 36°C, but maybe that was wrongly interpreted by me? High ambient temperatures are only a problem when printing with PLA? 

PS: You can place the PSU inside or outside of the enclosure, it's up to you! But I believe the recommended (by Prusa) way was to put the PSU outside of the enclosure. 

Posted : 13/12/2023 10:21 am
Thejiral
(@thejiral)
Prominent Member
RE: Should we NOT cover all holes? (airtight)

I think you are reading those values wrong. In the blog they state that those are temperatures that can be commonly reached with the according print settings. It doesn't necessarily mean you can't print at higher enclosure temp. For PLA already 33°C might be an issue due to clogging. PLA is the only filament type I know of with this peculiar ambient temperature related issue. 

39°C is certainly not the optimal enclosure temperature for e.g. PC-Blend, it is the temperature you can reach. For the material itself it would be better to print at 70°C enclosure temperature or even higher but that is out of reach for a printer that will start to deform at that temperature already. 

 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 13/12/2023 11:42 am
frebys liked
Renze
(@renze)
Eminent Member
RE:

I can’t imagine that the Prusa team didn’t think this enclosure through. They must have thought of all the problems described above. The little holes are mounting options and you can find several solutions to cover them on Printables. Like this one
However I keep wondering @frebys: in your opening post I don’t see you mentioning an actual problem at this moment. Or do you actually notice smells coming out of the enclosure even with the filtration system on?

If not, I would keep the enclosure as it is and along the way make the changes. There is al lot of tweaking possible so I’ve seen on Printables… I’m getting my MK4 & enclosure in a few weeks and look forward to building it. 

Posted : 13/12/2023 1:31 pm
Thejiral
(@thejiral)
Prominent Member
RE: Should we NOT cover all holes? (airtight)

I am not saying that Prusa did not think that enclosure through. Very few if any commercial hobby printer enclosures put fume management at the top of their priorities. 

Freby is approaching the issue possible from a similar perspective as I am. It is possible to reduce the fume emission into the room to almost zero, at least to a level where otherwise perceptible emissions became impossible to detect by smell (I tried VOC sensors but actually just smelling is more reliable unless you put incredible amount of effort in method development, as long as you keep it relative, for testing you need a positive control scenario where oyu can dedect the smell easily enough, without extra fume management). 

 

Mk3s MMU2s, Voron 0.1, Voron 2.4

Posted : 13/12/2023 2:51 pm
Renze
(@renze)
Eminent Member
RE: Should we NOT cover all holes? (airtight)

I am not saying that Prusa did not think that enclosure through.

I wasn’t referring to you or anyone in particular ☺️

Just asking myself what exact problem we were talking about and if this is a real problem or a possible problem. 

Thanks for all the input until now. 

Posted : 13/12/2023 3:04 pm
frebys
(@frebys)
Trusted Member
Topic starter answered:
RE: Should we NOT cover all holes? (airtight)

 

Posted by: @renze

I can’t imagine that the Prusa team didn’t think this enclosure through. They must have thought of all the problems described above. The little holes are mounting options and you can find several solutions to cover them on Printables. Like this one
However I keep wondering @frebys: in your opening post I don’t see you mentioning an actual problem at this moment. Or do you actually notice smells coming out of the enclosure even with the filtration system on?

If not, I would keep the enclosure as it is and along the way make the changes. There is al lot of tweaking possible so I’ve seen on Printables… I’m getting my MK4 & enclosure in a few weeks and look forward to building it. 

Posted by: @renze
Just asking myself what exact problem we were talking about and if this is a real problem or a possible problem. 
This is a real problem for me. For three reasons!
 
With the air filtration on and the enclosure doors closed, there is a weak but very present smell in the room (when printing PLA). This is made worse by there being no proper ventilation in the room, but it's the only room I can place the printer in. 
 
It's also slightly about money. The air filtration filters must be replaced sooner or later. And whilst the approximately rated 600 hours entails that each print costs only a little due to "air filtration wear", it's still something I would like to minimize and only use when printing actually toxic-fumes-producing filaments. I.e. not having to "waste" the air filter on PLA or PETG. 
 
Finally, having the air filter on makes the printer like 2x as noisy. 
Posted : 13/12/2023 3:17 pm
Renze
(@renze)
Eminent Member
RE: Should we NOT cover all holes? (airtight)

there is a weak but very present smell in the room (when printing PLA)

Could it be PLA quality? I have my printer in my living room for a while now and I never noticed any smells when printing PLA or PETG. Neither did I get those complaints from the rest of the family. I mostly print with Prusament. 

Posted : 13/12/2023 3:24 pm
Zappes
(@zappes)
Estimable Member
RE: Should we NOT cover all holes? (airtight)

I printed quite some Prusament PLA in the last days, and I did notice a smell escaping my enclosure. It's very faint, and it's also not exactly unpleasant, so it's something one might not notice if you aren't explicitly looking out for it.

That being said, I don't see the small holes in the enclosure as the problem here. The enclosure doors being wide open whenever I print PLA are a more probable explanation. 😉

My models on Printables
Posted : 13/12/2023 3:33 pm
Renze liked
frebys
(@frebys)
Trusted Member
Topic starter answered:
RE: Should we NOT cover all holes? (airtight)

 

Posted by: @renze

there is a weak but very present smell in the room (when printing PLA)

Could it be PLA quality? I have my printer in my living room for a while now and I never noticed any smells when printing PLA or PETG. Neither did I get those complaints from the rest of the family. I mostly print with Prusament. 

I don't know. I've only printed with Prusament at home. At work I've printed on a MK3 with another PLA brand (don't remember), and a powerful smell covered the entire office floor (I wasn't popular that day). I think it might have to do more with filament blobs getting stuck to the nozzle and being heated for a long time. I occasionally see some yellow blobs stuck to the nozzle after a long print when I've been printing "pure" white filament, almost as if I've "burned" the filament or something for it to change color. 

 

Posted by: @zappes

The enclosure doors being wide open whenever I print PLA are a more probable explanation. 😉

Is there some reason for you doing this? I've only printed Prusament PLA with the enclosure doors closed and I haven't noticed any problems. Ambient temperatures are around 29-30°C for me. 

Posted : 14/12/2023 2:06 pm
Zappes
(@zappes)
Estimable Member
RE: Should we NOT cover all holes? (airtight)
Posted by: @frebys
Posted by: @zappes

The enclosure doors being wide open whenever I print PLA are a more probable explanation. 😉

Is there some reason for you doing this? I've only printed Prusament PLA with the enclosure doors closed and I haven't noticed any problems. Ambient temperatures are around 29-30°C for me. 

I'm just being careful here because I don't want to risk clogs. I forgot keeping the doors open a few times, albeit only for really small prints - nothing bad happened then and the enclosure ambient temp didn't rise above 30°C. Better safe than sorry, though. 🙂

My models on Printables
Posted : 14/12/2023 2:12 pm
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