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XL enclosure discussion and new issue....  

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MME
 MME
(@mme)
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Topic starter answered:
RE:

I forgot the Nevermore Air Scrubber kit. With extra activated charcoal . $79.00

The Amazons basic heater was $21.00

 

Posted : 26/12/2023 5:51 pm
MME
 MME
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Topic starter answered:
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So all and all the cost to do this enclosure with all the accessories I added would be somewhere in the neighborhood of $1100.00. Is it worth with it I believe so. I am at roughly 875 hours now on this printer and have enjoyed it even though it has a few issues to work around.

Posted : 26/12/2023 5:58 pm
MME
 MME
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Topic starter answered:
RE: XL enclosure discussion and new issue....

 

Posted by: @rickj19zeta8

I'm chasing this issue as well in an enclosure, but I'm thinking its heat creep.  I can consistently get PLA to heat creep jam at above 43C heat break thermistor temperature.  And PETG to heat creep jam above 52C heat break thermistor temperature.  Although that varies a bit down to 45C depending on enclosure temperature.  

Even with an open top and doors (but sides installed), its right on the edge printing a full bed PETG print during low flow fill areas.  

No luck with fan shrouds trying to pull in air further away from the build plate.  Thermal paste helped slightly, but not enough to run the enclosure closed at the start.  Once the build is 25mm or so off the plate, its better.  I also thought it was the PTFE tubes initially, and tried both 3mm ID and 2mm ID tubes but no luck.  

Machining an aluminum stack on heat sink to place under the fan to try and gain some heat rejection from the heat break.  But it will be a balance of how to tie it in to keep the strain gauge working correctly for nozzle touch off.  I think that side of the tool changer extruder wants some support, as the fan shroud is tied into the tool changer and then spans to the back bolt on the heat break to allow the nozzle section to still flex upwards.  

I pretty much print PLA at 30-38 C and no more. I haven't printed PETG. Most of my prints are ASA.

Posted : 26/12/2023 8:05 pm
RickJ19Zeta8
(@rickj19zeta8)
Active Member
RE: XL enclosure discussion and new issue....

I run a lot of PETG and PC.  PLA rarely.  So I like to run in the enclosure for large prints to prevent warping.  

The additional heat sink idea did not work.  I machined a 10mm thick heat sink that matched the slot pattern in the nextruder heat break and then stacked it between the fan.  Without the fan shroud, it increased the heat break thermistor temperature by 1-2C, which tells me that the source of the issue is the hot air being pulled in off the top of the build plate.  Make sense, since smaller prints with only part of the build plate heated don't have this issue even with a chamber temperature of 40C.  

Going to chase fan shroud designs again.  

Posted : 26/12/2023 8:54 pm
MME
 MME
(@mme)
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Topic starter answered:
RE: XL enclosure discussion and new issue....

 

Posted by: @rickj19zeta8

I run a lot of PETG and PC.  PLA rarely.  So I like to run in the enclosure for large prints to prevent warping.  

The additional heat sink idea did not work.  I machined a 10mm thick heat sink that matched the slot pattern in the nextruder heat break and then stacked it between the fan.  Without the fan shroud, it increased the heat break thermistor temperature by 1-2C, which tells me that the source of the issue is the hot air being pulled in off the top of the build plate.  Make sense, since smaller prints with only part of the build plate heated don't have this issue even with a chamber temperature of 40C.  

Going to chase fan shroud designs again.  

Did you put a air circulator/ air scrubber in your enclosure? It seems to keep a pretty consistent temp throughout the enclosure. Mine keep within 2 and 5 degrees between the top and the bottom of the enclosure.

Posted : 26/12/2023 10:48 pm
RickJ19Zeta8
(@rickj19zeta8)
Active Member
RE:

Yes, I added an air scrubber and pull air from the top of the enclosure and dump it lower.  Top to bottom, i have a little more than 5C, but my enclosure has quite a few leaks.  I might add a fan to increase airflow over the bed.  I increased my part cooling fan speed and it dropped my heat break temperature a few C.  That was already with the heat break fan at 100%.  So its reinforcing my hunch the stagnant air over the bed is driving my issue, combined with the 1st layer zero cooling fan, and short low volume extrusions.  

Edit://.  yeah, re-did that part cooling fan test and maybe got 0.5C heat break fan drop.  I'm going to say thats inconclusive.

Posted : 26/12/2023 11:54 pm
reidry
(@reidry)
New Member
RE: XL enclosure discussion and new issue....

MME - is the PTFE tube deformation at the mid span clamps (orange clamps), the black clamp, or where the ptfe tubing couples to the extruder?

If it’s at the extruder, would something like this perhaps with a flared top keep the tubing from developing a kink?

https://www.printables.com/model/569956-prusa-xl-series-ptfe-guide-support

Posted : 29/12/2023 1:58 am
MME
 MME
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Topic starter answered:
RE:

 

Posted by: @reidry

MME - is the PTFE tube deformation at the mid span clamps (orange clamps), the black clamp, or where the ptfe tubing couples to the extruder?

If it’s at the extruder, would something like this perhaps with a flared top keep the tubing from developing a kink?

https://www.printables.com/model/569956-prusa-xl-series-ptfe-guide-support

Something like that would work if it had a gentle flare at the top. Over time plus the heat the PTFE on mine were kinking right where the PTFE entered the connector on the extruder. I was thinking about coming up with some type of a springy part to go over the tubing at the end sort of like what you can get for a hose or electrical wire to keep them from kinking at the end.

Posted : 30/12/2023 12:38 pm
MME
 MME
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Topic starter answered:
RE: XL enclosure discussion and new issue....

Something like this.

Posted : 30/12/2023 12:44 pm
LewnWorx
(@lewnworx)
Eminent Member
RE: XL enclosure discussion and new issue....

So here's the odd bit:  My XL5 head semi assembled came with 2.5x4 vs 2.0x4.  Apparently they've figured out the 0.2 was just too tight for that long of a run.

I still ordered some more 2.5, as will need it for spares, but also have one of the new Sunlu 4 spool dryers on order (already have one of the 2.x version single jobs) and will be moving all the filament sensors to one side to be able to use the two sunlu's to cover all 5 heads while printing.    That'll still make for a VERY long run by the time it gets to the extruders. 

In comparison my existing enclosure for my I3 MMU2 had MUCH shorter runs as the gravity winders were on top the printer enclosure and were specifically arranged in a semi circle to get the PTFE paths to the MMU as short as possible (like 15"), which you can see in the project I linked in the original reply post, and that worked out very well.

Posted : 05/01/2024 4:57 am
MME
 MME
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Topic starter answered:
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That's interesting. I also have some 2.5 x 4 on order just to see how it works compare to the 3 x 4. The 3 x 4 has been working well so far but I have some reservations about how long it will hold up with the thinner walls. Glad to see Prusa change to a larger ID PTFE tubing. Thanks for the update @lewnworx. 

I have a 27hr print going right now so we will see how the 3 x 4 holds up?

Posted : 05/01/2024 7:36 am
MME
 MME
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Topic starter answered:
RE: XL enclosure discussion and new issue....

I have a design to eliminate a lot of the PTFE tubing and shorten the runs. I just haven't had time to really look at it closely to see how practical it is or if it is worth the attempt to try it. The filament would go up the side on to a guide track with a series of 5 rollers on a gentle curve entering the enclosure on the top. The filament would enter at the center of the Nextruder travel path.

Here is the mockup on my design. The XL is so tall that putting and changing the spools on top would be interesting. Putting the spools on the side would work better for my shop setup.

Posted : 05/01/2024 7:52 am
Chimney13
(@chimney13)
Member
RE: XL enclosure discussion and new issue....

:)))

Posted : 17/02/2024 10:42 am
Durhamray
(@durhamray)
Active Member
RE: XL enclosure discussion and new issue....

 

Posted by: @lewnworx

So as part of getting my MMU2 to run as flawlessly as possible, and having ran into having the same kinds of binding issue on the MMU2, I switched out to 0.3MM ID PTFE feeders from my gravity rack and pinion spool rewinders to the PC4 mod plate I did no on the back of the MMU2, which did indeed cure the problem, initially.    The caveat is the PTFE tube walls are SO thin that they are quite susceptible to kinking, and once they do the binding issue is back with a vengeance.  I found I could typically go 6-7 months if I was super careful to be aware of the tubes at all times when changing spools in the autowinders, detaching them from the MMU for cleaning, etc, but invariably I’d forget at some point and would kink them up.    While waiting for the 5 head XL to finally ship before I go on social security, I figured I may as well upgrade the MK3S(half plus) to a MK4 and pick up the MMU2-3 kit upgrade as the MMU2 had so many hours on it at this point that it was starting to get dodgy as well.

That was before Prusa stopped shipping the MMU2-3 kits for the MK4 which I’m still waiting on and havne’t upgraded the MK3 > MK4 as 90+% of my stuff uses the MMU2 if nothing else for parts labeling.  So that upgrade is DOA until the MMU3 for MK4 finally ships.   Since I’d’ been having more binding issues due to more frequent cleanings etc on the MMU2, I figured I should swap out all the PTFE from the spool winders to the MMU2 just to get it back up to snuff while I waited for both the XL and the MMU3 for the (as yet unused) MK4 upgrade kit.

Being as I was nearly out of 0.3ID PTFE, this time around I tried to locate 0.25MMID PTFE, with the thought process being it’d still be better than 0.2 for the binding issue but that extra half MM of wall thickness might make the stuff more durable and less kink prone just due to the necessary service stuff that just occurs.     It proved more difficult to find than I’d have thought, as while there’s boatloads of 0.2MMID stuff and somewhat less of 0.3MM ID stuff, there’s not a lot of decent sources for 0.25mm, particularly in length.   I ended up having to settle for 6’ chunks of the stuff, and the packaging left a LOT to be desired.   This stuff was wound so tightly it was close to kinked right out of the box.    Some coaxing and straightening with light applications of a heat gun has helped, and I’m just now redoing the silicone modified nyloc job on the bed before I redo the live Z.   Hopefully that’ll cure the binding issue for the MMU2 until the upgrade kit gets here and will be reused on the MMU3.   It does seem less kink prone than the 0.3MM stuff was though.

My XL came with 4 mm x 2.5 mm PTFE and I am still having the binding issue with an enclosure.  My next step is to try the 4 mm x 3 mm PTFE.

Ray Durham, [email protected]

Posted : 17/02/2024 2:21 pm
MME liked
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: XL enclosure discussion and new issue....

my mmu3 for mk3.9 came with 3mm id ptfe for all tubes 
regards Joan

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 17/02/2024 3:19 pm
MME liked
tg73
 tg73
(@tg73)
Member
RE: XL enclosure discussion and new issue....

Regarding a reliable source of 2.5mm ID PTFE in decent lengths: I've asked Prusa to start stocking 5m or 10m lengths, but who knows if they ever will. Having bought what turned out to be rubbish from Amazon (super-high friction, probably not actually PTFE), I resorted to buying from "the company that shall not be named" - they sell 4m lengths of reliable quality PTFE as a "custom cut" option for the AMS.

Regarding filament drag: has anyone in this thread truly localised the issue to drag caused purely by the PTFE tubing? I had big issues with friction in the side filament sensors, which would then increase the filament tension in the PTFE tube between the sensor and the toolhead. Maybe try feeding some filament through the sensor to the toolhead (with PTFE detached) and "feel" the drag. Then do the same, but bypass the filament sensor (ideally on a different toolhead so you can compare). It can vary by material, and by speed or pattern of pull/push (eg, retractions) leading to increased binding. Consider this mod if you want to hugely reduce filament sensor drag:

https://www.printables.com/model/700838-xl-side-filament-sensor-with-reduced-force-magneti

 

Posted : 20/02/2024 4:28 pm
MME liked
Kickstart
(@kickstart)
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RE:

@MME   - I was thinking about this over the weekend - now that my Prusa XL arrived 😀 

 

I was wondering if the high temperature issue was actually a combination of two issues. Maybe in addition to the additional drag from the PTFE tubes heating up, you're also losing tension on the idler in the Nextruder due to the idler/tension parts starting to get soft?   (I think someone in another thread mentioned how MK4 users who print at higher temperatures where having this problem).

I was thinking it may be a combination of issues causing the under extrusion, and maybe if you upgraded the idler parts to ASA (or PC or Nylon) then maybe this would be enough to overcome the friction in the PTFE tubes.   Just a thought.

Posted : 04/03/2024 9:12 pm
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