Cut the filament end cleanly and straighten the first few centimeters. A bent, swollen or sharply angled tip is more likely to catch in the PTFE path.
For the rear spool holder, place the spool so it unwinds smoothly toward the guide. Insert the filament through the guide and into the toolhead inlet, then use the printer’s Load function. Keep light forward pressure until the extruder grips it. The nozzle heats automatically; wait for the screen rather than pushing cold filament through the hotend.
With AMS lite, put the spool on a holder that fits its inner diameter and feed the filament into the matching inlet until the feeder takes it. Confirm that the spool can rotate without rubbing the stand or another spool. Map that AMS slot to the correct material and color before slicing.
To unload, use the Unload command. The printer heats, cuts or retracts the filament according to its routine, then tells you when it can be removed. Pull only when prompted. If the filament will not move, stop pulling and inspect the screen for a cutter, feeder or temperature error.
When changing material types, purge at a temperature suitable for the hotter of the old and new filaments until the new material flows cleanly. Avoid running very soft TPU through AMS lite unless Bambu lists that exact filament as compatible; use the direct spool path when required.
Secure the loose end through a spool hole after unloading. Letting it spring under another winding is how a tangle appears hours into the next print.
Once filament is loading reliably, the next step is making sure Bambu Studio matches the physical setup — the Bambu Studio profile guide covers nozzle, plate and filament preset selection in more detail. If you are running AMS lite, the AMS lite setup guide walks through mounting the stand and routing all four tubes before you load anything. For general storage habits between prints, see how to store filament so it stays dry.