XL enclosure discussion and new issue....
Okay everyone thought I would start this thread for discussion and fixes. As many of you know I have been working and testing my enclosure for sometime now. I have recently completed closing it in pretty air tight so the temp will climb to about 52C and hold.
The issue is that now anything over 45-46 C the filament drags in the long PTFE tubes and the friction seems to stop or hinder the extrusion process. This is with ASA. The higher the temp the faster this happens.
There are no issues with PLA or lower enclosure temp filament.
I have tried both Nextruders and get the same result. At higher temps the higher temp filament stops wanting to feed. So what happens is the machine continues to print without any filament feeding into the nozzle.
If you look at the pic below you will see at some point the filament cannot be pulled through the long PTFE tubbing. The feed wheel just spins when it can't pull the filament through.
So what is the cure for this issue?
1. Use larger PTFE tubing between the filament sensor and Nextruders. Go from 2mm id to 3mm id ?
2. Don't use any PTFE tubing except at the Nextruders and the filament sensor.
I hate to tighten the feed gear as they have been working just fine.
You can see where the feed wheel just keeps spinning on the filament because it can't pull it through the long tubbing.
RE: XL enclosure discussion and new issue....
There are special low friction PTFE tubes available. But they are quite expensive.
https://www.amazon.de/Capricorn-Ultra-Friction-Bowden-1-75mm/dp/B07TXZJRTQ
I tried to change this tubes (factory installed) to a clear version, as I wanted to see what is happening inside the tube. But I have to change back to the original tubes. This was a bowden style extruder.
I have also seen YT videos where they apply PTFE dry grease inside the tubes.
RE: XL enclosure discussion and new issue....
Ok so this morning I am trying this to do a test. I removed the stock tube which had developed a kink where the wire tie held it at the base. This kink probably didn't help.
I put a section between the sensor and the first orange tube holder. Then I just installed some 25mm sections in the rest of the holders. I want to see if this alleviates some of the friction to make the filiment easier to pull. I will also be able to see what the filiment does outside the original PTFE tubing.
I have some of the low friction tubing, and some 3mm id tubing on the way to try that.
If these attempts do not work I will start thinking having the filament enter through the top of the Enclosure.
A pic of the kink that was under the wire tie. Both Nextruders have this kink.
RE: XL enclosure discussion and new issue....
This is what I am trying this morning I am hoping the filament doesn't kink at the little sections.
RE: XL enclosure discussion and new issue....
I will say there is a lot of stress on the filament watching the XL print without the tubing. The head has to travel a good distance front to back and left to right. Especially on a large print or a full print bed with parts.
By watching the filament I can see how there would be binding inside the small ID PTFE. I would think 3mm ID tubing or the low friction tubing would solve the problem.
RE: XL enclosure discussion and new issue....
That test did not work out!! So I reinstalled the original PTFE tube and keeping the temp between 42C-45C.
I am 2 hours into the same print that failed earlier and all is good so far.
ASA filament
Nozzle temp 250C
Bed temp 105C
Enclosure temp 42C-45C
I
RE: XL enclosure discussion and new issue....
So the filement is getting to hot and melting in the tubes?
I wonder if the enclosure needs vent holes like the Prusa prototype has?
RE:
So the filement is getting to hot and melting in the tubes?
I wonder if the enclosure needs vent holes like the Prusa prototype has?
No it is not melting in the tubes. It looks like due to the higher heat in the enclosure there is more expansion. With such tight tolerances in the tubes that is causing the binding especially around some of the tighter corners, where the wire ties are behind the docking area and where the filament goes into the Nextruders. It is more the PTFE tubes then the filament. Apparently with the long run of PTFE tubes the heat is changing the shape of the tubes just enough to cause binding in the tubes.
45C and below there are no issues. Above that the binding starts.
RE: XL enclosure discussion and new issue....
I ran another test with ASA and different temps. The 2 over 45C (50C-52C) failed due to filament binding in the tubes. The last one at 42C-45C printed perfectly.
This is the good print that was printed at 42C-45C. The ASA filament ran smoothly though the PTFE tubes.
RE: XL enclosure discussion and new issue....
Here is a pic of one of the fails due to filament binding. As I mentioned earlier this only happens with hi temp filament like ASA with enclosure temps 46C +. There is no issues with sub 46C prints of any filament.
I saved this print and you can see where the filament binding starts and it progressively gets worse till there is no filament flow. The printer will continue printing without filament flow.
RE:
So the filement is getting to hot and melting in the tubes?
I wonder if the enclosure needs vent holes like the Prusa prototype has?
I can regulate the temp just by sliding the upper front acrylic piece up or down as needed. I I have about 13cm of adjustment.
You can see where I have lowered the front about 7cm to keep the temp between 42C and 45C.
RE: XL enclosure discussion and new issue....
Still going strong.
This is a 8+ hour print and we are 7 hours into the print in ASA.
RE: XL enclosure discussion and new issue....
Well then... just get new tubes with a higher clearance and loosen the thight spots? They are cheap so why bother with a temperature-dependance?
RE: XL enclosure discussion and new issue....
Well then... just get new tubes with a higher clearance and loosen the thight spots? They are cheap so why bother with a temperature-dependance?
As mentioned above I have new tubes on order.