Hi,
I got my new H2D three days ago and I am / was very happy with the initial printing results.
The main reason for buying the H2D for me was the second nozzle, where I can use support filament for my technical models.
After about 15 prints I am now getting the message:
“Extruder Wechsel fehlgeschlagen; bitte wenden Sie sich an den Assistenten.”
(German)
Probably translates to:
“Extruder switch failed; please contact the wizard?”
Whatever I try, I can not overcome the message for prints with support filament!
Prints with filaments from the AMS are working fine…
(So now I am basically back to the same functionality I had with my X1C)
Anyone out there with the same problem and a suggestion for a fix?
Sup PLA … ideally right nozzle. It softens at such a low temp that the up-down motion is akin to large retraction on the older X/P machines and will balloon the filament, causing jams right before it enters the hotend.
Thank you for this suggestion. I will switch the Filament and try again.
Do you have any sources that I can read and learn from which show the differences between the right and left nozzles and how to use them best?
I don’t know if there is a restriction for Support PLA on the left nozzle. Generally, the restrictions are for softer or brittle filaments (they go in the right nozzle). Have you checked for debris in the switching mechanism?
Technically**, it’s suggested to use the left nozzle for support filaments. However, I have a special place of hate for the Support for PLA in my heart. That thing just clogs left and right, unlike it’s cousin Support for PETG/PLA.
I guess I should have asked if the chamber temps were creeping up towards 45C, as that’d definitely exacerbates matters. But I’ve had it misbehave in the high 30s just because of the latent heat of the hotend.
** unless the phrasing is off under “Recommendations for materials used for the left and right hotends” — “3. If you want to use the second hotend to print support materials, it is recommended to use the lifting hotend for printing.” Is printing referring to main printing filament?
This is what I was waiting for … what the problems were going to be with the H2D. I guess I was thinking in there would be some with early deliveries. I haven’t had any issues with the X1C I couldn’t solve myself so far, as I bought after it had been out a while.
Brittle filaments are to be used in the left nozzle according to the wiki. The right nozzles ptfe tube gets bent up pretty good when the tool head goes to the far right side of the bed.
Yup left nozzle is ideal for brittle filaments. Had a nasty extruder clog today running polycarbonate in the right nozzle after a piece of PC filament broke off and jammed in the extruder gear. Thankfully due to the open skeletonized design I was able to get the piece out with some tweezers without needing to remove the extruder assembly.
Sorry, that’s correct. I was thinking I saw it mention the left nozzle’s raising and lowering would create a problem for the brittle filaments. But I guess I was mistaken.
I switched the filament, so that the left extruder is connected to the AMS2 and the right extruder is “fed” by the single spool of “support for PLA/PETG filament”.
Also, I removed and cleaned the hotends (they were not really “dirty” after only 15 prints).
But all of this did NOT solve the problem!
The “extruder switch” continued to fail.
Then I disassembled the filament cooling fan duct and took a look at the “flow blocker”
This flow blocker with a magent mounted on top seems to be the problem!
The blocker seems to “hinder” the travel of the mechanism “deep inside the hotend” which moves the left extruder down and up.
When I “help” the flow blocker with my fingers to reach the end positions, the error message “goes away”.
As a temporary fix, I just unscrewed/removed the flow blocker, and now all works fine and printing works flawlessly.
I will investigate the impact of the missing flow blocker on the quality of my prints.
This is certainly not the final solution, but it works temporarily.
I have the “feeling” that the magnet on the flow blocker hinders when “blocking” the right extruder, the full travel inside the mechanism.
It seems to me that the magnet “sticks out” too high and makes contact with the other side too early, so that the switching mechanism can not fully push out the left extruder.
(Note: the message always only came when switching from the left extruder back to the right extruder)
No, but my “hacked” fix is so war working for me.
I just “unscrewed” the moving lever and since then I have no error messages anymore.
But sometimes a little blob or strings of filament on my models.
Please tell me when you get an answer.
I still think it is a production “mistake” of the glued magnet on the lever.
The magnet just is sitting a little too high I think.
Anyway, I think the lever is not a real solution to that, what Bambulab wanted to fix. One left / right moving lever is not a good solution, they should have implemented two separate levers moving forward and backward individually.
Yes, I have EXACTLY the same issue. When moving to Right nozzle, the mechanism behind the rubber part that blocks the nozzle hits the magnet support area and won’t move all the way over. I can manually rotate it over, and it is ok, but when the nozzles try to switch again as part of calibration, the issue repeats itself.
I also removed the lever, and notice the magnet is high and may be the reason for the obstruction. As in your case, with the lever removed (pic attached of what I removed), printing proceeds as expected with no nozzle switch/extruder switch errors.
After looking at several close-up videos of how the flow blocker got jammed when moving to the right nozzle, I radius-ed the edge that was catching a bit using a Dremel tool, followed by a ceramic file and finally some rouge to make it smooth. The radius-ing includes both the holder that the magnet fits in and the side of the magnet too. See picture. I put it back on the H2D and so far the switching between left and right nozzles (and extruder switching that goes along with it), appear to be working well. It is interesting that not all H2D’s have this issue. I wonder if there is some very minor variance in the mechanism that moves back and forth that causes this binding on some machines. I haven’t gotten a response to my support ticket on this, but I’ve sent very detailed descriptions of my issue and testing with pics and videos. Hopefully Bambu will respond by slightly modifying that radius on the flow blocker going forward and provide those to us. Without the flow blocker, you can do multi-color dual nozzle prints, but the purge/clean up cube is pretty messy and there is always the chance that some excess filament from the currently unused nozzle will drip or get caught on the print underway.
I have the same issue. Anyone found fix for that?
Support recommended me to basically randomly troubleshoot things like nozzle blocker for being bent and blockages. But printer is litterally new, I disassembled parts of it and everything seem to be fine but nozzle blocker stops right a few mm before blocking the right nozzle, it blocks left nozzle with no problem though!
I read the wiki and watched the video on the nozzle flow blocker and it says it is very fragile and shows how to bend it back so that it works right. After some filament came out and the flow blocker closed on the spewed filament too late it got bent and I had to bend it back into position because it was able to close the right nozzle but didn’t align to the left nozzle. I had to bend it upwards.
