Hi all, I ran into a strange problem with my H2D on the latest firmware. Though the printer prints well, it seems that when loading/unloading filament, the printer uses the minimum temperature of the filament previously loaded into the printer as opposed to the normal printing temperature, and on some filaments (the problematic filament for me is the support for PLA/PETG), the low temperature creates too much resistance for the extruder to melt the filament already in the nozzle. In this case the extruder makes clicking sounds and nothing is extruded. In one instance this happened during the preparation stage of a long print, and I was shown the dreaded ‘extruder overloaded’ error.
For example, if my last filament is Support for PLA/PETG, with a minimum temperature of 190, I can try loading another filament, and the printer will then only heat up the nozzle to 190 degrees before trying to extrude and purge. A lot of times, 190 degrees is not hot enough to allow for Support for PLA/PETG to extrude, so the extruder clicks and the loading process fails.
I initially suspected maybe the left nozzle (which this problem occured on initally) slightly colder than the thermistor reading, but after cross checking the filament with the right nozzle (and an A1 mini for good measure), I found that none of them were able to reliably extrude Support for PLA/PETG reliably at the minimum 190 degree temperature. Raising the temperature by as little as 5 degrees sometimes allows it to extrude.
The loading & purging routine on the A1 in my experience will always raise the nozzle temperature to 250 degrees even for relatively low temperatures such as PLA or Support for PLA/PETG, so there was never a problem like this.
Has anyone else experienced this issue? In my opinion Bambu Lab should probably increase the filament loading/unloading/purging temperature from the minimum temperature to the normal printing temperature, or even the maximum temperature (like the A1), which would be more reliable.
I’ve attached some photos to show the printer attempting to load PETG HF (230 degrees minimum temperature) while only heating thr nozzle to 190 degrees due to the previous filament being Support for PLA/PETG.
I’ve contacted support and they said they’ve recreated the problem and it would be fixed in the next firmware updates. I’ve found a workaround, don’t initiate loading and unloading on the screen, do it on bambu studio (I’ve not tested bambu handy), and the temperatures would be correct.
I have had just the same problem with some insane jams in the left extruder and thought the same thoughts about the temp beeing to low going from PC to PLA Good that they are going going to fix it!
ooo thanks for the tip in regard to initiating the unloading of filament using the bambu studio app as i have been doing it using the screen… i sent a support ticket since this issue happened in two different events (going from ABS to PLA) … I do hope they fix this issue from unloading/reloading from a hotter melting point filament to a lower melting point filament
I sent the following sequence of events and no one said that they recreated this in their lab but rather they sent me a new dual extruder filament guide part (maybe because I had the H2D for less than 3 weeks before experiencing these issues). I haven’t had time to replace it yet as I received the part a few days ago but I have been reluctant to print with ABS
From my support ticket:
I have attached a pic of the error as well as pics of the mechanism that was stuck and the piece of ABS plastic that was forcefully removed from that mechanism by manually removing it and pushing it up/down. Purging ABS filament from this piece on the left hotend when replacing it with PLA plastic does not seem to work well as this process failed twice and was fixed using the same technique which I have outlined below along with the chain of events. Perhaps the hotend does not get hot enough to fully purge the ABS after switching from ABS to PLA and then ir gets stuck because the PLA hotend temp is not hot enought to melt the remaining ABS inside the mechanism?
2025-06-10
Hotend swapping got stuck after unloading ABS filament and switching to PLA filament.
2025-06-10
I cleaned the extruder after contacting customer support thus restoring functionality to the hotends.There was some stuck/melted ABS plastic left behind after switching to PLA that prevented the mechanism above the left hotened from moving up/down. I was able to remove the ABS plastic by manually moving the mechism up/down after dissasembling the extruder by following your guide/youtube video.
2025-06-11
I 3D printed a keychain using only ABS plastic successfully. (multi color ABS (not multi material) using both hotends)
2025-06-12
Using the H2D touchscreen, I unloaded the ABS black filament from the left hotend (external roll), and also unloaded the ABS white filament from the right hotend using the AMS 2 Pro via the H2D touchscreen. I then loaded PLA filament into the left hotend ensuring the ABS filament was extelruded by following the instructions on the H2D touchscreen and then started a new print job using all PLA filament.
2025-06-12
The hotend swapping mechanism got stuck again. same symptoms and fix as the first time. I dissasembled the extruder and by pushing the left hotend mechanism that moves up and down, a thing layer of ABS plastic came out of the mechanism thus restoring movement.
2025-06-13
The hotened were able to switch back and forth and I was able to print a 3D model using multiple colors of PLA plastic with the left and right hotend.
Good that they are going going to fix it!