After I upgraded my h2d software to the last version ( 3 weeks ago) I have a problem with the left nozzle at the start off the print. When is doing the purging line nothing is extruded, also the problem continues even after it starts printing a few lines and after extruding it becomes normal. I don’t know if the problem is caused by the new software installed on the printer or by the Bambu studio - latest version- that I installed before. Did everyone encounter this problem?
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check nozzle temperature readings during print. If you see abrupt changes in readings.
also it can be a dirty nozzle. if you printed fiber and you let the dirty nozzle sat for days, it is better to exclude that cause with a cold pull
it can be a wrong flow ratio also
Today I tried to change something but nothing happened with that print. I changed left nozzle with the right one and still nothing was printed on that purging line - also I changed some parameters on bambu studio. The problem appears with files that contain two colours but to be sure I have to do more test to see if is happening only on two colours printing.
After, I printed a part with in one colour with the left nozzle and an improvement appears, the line was not complete but from the middle the filament start to extrude and also the art had no issues with the first layer.
The temperature of the nozzle is stable during printing.
So, to see what happens I will make more tests.
I written here because I thought that someone else had the same problem, because on my printer started to appear after I made software upgrade to the latest.
It’s probably not the fault of the latest software, i’ve had this issue before. I actually forgot about it since I haven’t checked it in a while, as I mostly print with right nozzle now.
Hi mate. I encounter exactly the same problem as yours. Do you manage to solve this issue?
Hi. Unfortunately I didn’t solve anything. Lately I only used the right nozzle. I also didn’t try anything else. What I noticed is that the problem is worse with translucent pla and petg hf. With mate pla, carbon and glass fibers, abs, asa the problem is not that bad - still the purging line is not complete but is starting from the middle of it. Maybe the extruder motor should start spinning earlier but this should be done by bambu with their software.
hello. yeee. same problem ;( we will wait for fix
in my opinion your flow ratio is too high for the given temperature. try reduce that, don’t change temperature otherwise you need to redo all the evaluations of everything
I had the same issue with asa cf until i reduced the flow from 0.95-0.98 to 0.9-0.92. (275°c nozzle over a max temp of 280°c as indicated by the filament’s producer (eryone) but I call them hermione 
Hi mate,
I believe I have identified the root cause of the left nozzle’s extrusion failure.
After closely observing the printer during several print attempts, I noticed that when the left nozzle moves to the purging line—located at the bottom right corner (the furthest distance)—the filament PTFE tube becomes extremely tight with a very sharp bending radius. This restricted radius creates high friction, restricting filament movement and causing unsuccessful purging. This explains why initial layers lacked extrusion, even though the nozzle prints perfectly fine at all other bed locations.
This issue specifically occurs when feeding filament from the external spool.
To test this hypothesis, I switched the left nozzle feed to the AMS 2 Pro. Because the AMS active drive mechanism provides additional pushing force, it successfully overcomes the friction caused by the tight bend radius. I verified this with five consecutive test prints; all five purged and printed flawlessly.
Next Steps:
I am currently waiting for a new, slightly longer PTFE tube to arrive. Once installed, it should prevent the sharp bending radius at the apex. I will then re-test using the external spool (without the AMS) to confirm the fix and will keep you posted on the results.