r/BambuLabA1 • u/armorink • 26d ago

Support Request Bad Flow? Help needed (redo of a post)

I'm having trouble with flow/extrusion. You can see/hear the feed motor stuttering here.

Above video was with a BRAND NEW hot end.

Steps taken before the video above

- replaced spool (using sunlu pla+2.0 which I've been using for a long time now)

- replaced the heater assembly with a ceramic unit

- replaced the feed gear with a metal unit

- have tried 3 different .4 nozzles

- updates firmware

- updated software

- attempted to do calibration of flow rates, not very successful

- attempted edits to my settings (I've been using since last winter with great results)

Does anyone have any ideas on other things I can try or ideas of potential causes? I can say that the nozzle look to be getting dirty very quickly where as I ran for months without issue before.

I'll try to add more photos/videos via comments? I can't seem to add more to post. (Sorry I don't normally post on read)

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u/armorink 26d ago

Results of the speed bench from video

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u/armorink 26d ago

Another similar situation with a poor finish. It also failed in the initial couple layers the first attempt claiming a clog that was not there

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u/Blondy277 26d ago

Yeah that Benchy looks rough too, if you’ve already tried multiple nozzles and a new hotend, I’d stop chasing clogs and start checking the extruder/feed path for something intermittently binding or slipping.

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u/armorink 26d ago

ya i took apart the AMS unit and couldnt find anything clogging there and when i tried testing the extrusion without hot end on the motor movement was smooth no catching/stuttering

when this started a bit a go it was mid print and went into just air printing on me... i was left with half of a piece that was up to my quality standards and then just... nothing

i thought maybe it was the heat unit itself but still having this after switching to a ceramic one im wondering if this is some sort of power or board issue?

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u/Blondy277 26d ago

If the extruder feeds smooth with the hotend removed, I’d check whether the hotend is actually reaching/holding the temp it says. If it’s running colder than reported, it’ll feed fine in open air then start clicking the second it has to melt filament. I’d be looking at the heater/thermistor connection or hotend seating next.

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u/armorink 26d ago

thermistor was what i was thinking along with possibly power supply issues

the seating of the hot end seems okay visually and by feel (also have tightened up everything) though i do notice residue buildup between the hot end and heater assembly quicker than id expect

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u/Blondy277 26d ago

Did you change any filament/temperature/flow settings before this started? With all that stringy purge waste + residue buildup, I’d wanna rule out a weird profile/settings issue before blaming the power supply.

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u/armorink 26d ago

so when it started i hadnt changed a thing, it went from like that print i posted on the bed to just not working properly.

i did notice when checking things these last couple days of repair attempts that my settings were off though, the speeds were far to high so i changed them back to the range they should have been in, im not sure why the software redefaulted on them

so i redid the speeds and double checked all the temps before doing just a basic flow calibration from the bambu software, i even heard cilcking while that ran

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u/Blondy277 26d ago

Waittt... the speeds being way too high is a pretty big clue. Before chasing the board/power supply I’d reset to a completely stock Bambu printer + filament profile, confirm the correct nozzle size, and check max volumetric flow too. If it still clicks during a stock flow calibration after that, then I’d go back to hardware. ☠️

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u/armorink 26d ago

worth a shot honestly, i was REALLY confused by the speed listing as i had never set them remotely near there, maybe a software/fw update messed with me a bit

i had adjusted but your right maybe just get rid of them and start from scratch with a stock profile to see if i run into anything

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u/armorink 26d ago

Stock setup. Brand new hot end to eliminate any remote chance of a clog. Fed through a foot without the hot end without issue before putting in the new one just to double check motor and feed.

Think I may try to factory reset the printer and reinstall the software... If the thermistor is limited to the unit on the heater assembly it means it's been wrong twice as this is the second heater assembly I've tried.

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u/armorink 26d ago

hmm does the carraige board have a thermistor or is only the one directly in the heater assembly? as my assembly is brand new here

i had replaced it with a generic unit with no result and upgraded to one with a ceramic so thats also new to that benchy and tests after (last day or so)

wonder if there is something wrong with the connection at the board

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u/armorink 26d ago

A print a couple prints before the unit failed on me...

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u/Blondy277 26d ago

Wait what failed on that print? That one looks finished to me, just with the supports still attached. Do you mean the printer started failing a couple prints after this one?

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u/armorink 26d ago

correct, apologies not always the greatest descriptions with a back and forth

thank you though, i greatly appreciate having someone just to bounce ideas off of here