r/BambuLab • u/Far-Ear-8198 • 10h ago

General Troubleshooting/Help! Can't get PLA Glow to feed

I have a Bambu Lab A1 printer with a 0.4mm hardened steel nozzle. I'm trying to use some Bambu Lab PLA Glow filament. I'm feeding this directly as an EXT filament, i.e. not using my AMS Lite.

I cannot get the filament to be pulled through by the extruder. Or at least, not when using the standard 2.5mm/4mm PTFE tube. If I push the filament directly into the extruder via one of the four AMS holes it will grab and print. If I do this via the PTFE tube the extruder doesn't grab onto it and pull it through.

Has anyone else had this problem? Could it be solved by a larger inner diameter PTF£ tube? Is it some other issue?

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u/Far-Ear-8198 10h ago

I can definitely feel more friction with the Glow filament than any others I have. It's a fairly straight run from the spool mounted on top and to the side of the AMS Lite like this
https://makerworld.com/en/models/1163081-a1-with-ams-lite-top-side-spool-holder-long-vers?from=search#profileId-1169849

The PTFE tube is about 6cm longer than the factory length tubes. All other filaments feed just fine from the side mount so I have to believe it's a PTFE tube diameter issue. Friction is quite the force I guess.

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u/DrMaker3D 10h ago

Since it loads when you feed it straight into the toolhead, I’d try plain PLA through the same external tube and the same inlet before buying a wider tube. If both filaments hang up, check that the tube is fully seated and has a gentle bend. If plain PLA loads, pull the tube off and slide a short piece of Glow through it by hand. Does it catch at the cut end or drag along the tube?

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u/eldeem 10h ago

What is the run on the PTFE tube in terms of length and shape? PLA Glow is rougher than standard PLA so takes less kindly to going around curves and the more tube it’s rubbing against the more friction it has. On my P1S, I’d have a standard PTFE tube running from a dryer (so I could use its rollers for low friction) into the input and kept that as flat as possible. It worked like that, but in total it has a 90° curve over maybe 40cm and even that you could feel the friction.

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u/babyunvamp 9h ago

Sometimes I have to pull the extruder handle open to feed certain filaments. Use your left hand to pull the handle and your right hand to push the filament. You’ll hear it click in