Articles on: Filament & materials

AMS auto-refill and filament tracking in SimplyPrint

SimplyPrint can track filament usage when your printer's AMS (Automatic Material System) switches to a backup spool mid-print.


SimplyPrint does not control AMS auto-refill. The auto-refill feature is handled entirely by your printer's firmware - SimplyPrint can only observe what the printer does and track usage accordingly.



What SimplyPrint can and cannot do


SimplyPrint can

SimplyPrint cannot

Set filament color and type on your printer's screen

Trigger or control when auto-refill happens

Track which spool is being used

Decide which backup spool the printer picks

Calculate usage when the printer switches spools

Override your printer's auto-refill settings


The auto-refill matching logic lives entirely in your printer's firmware. When your AMS decides to switch spools, SimplyPrint sees the tool change and updates its tracking - but the decision is made by the printer alone.



How usage tracking works


If auto-refill isn't working as expected, the issue is with how your printer matches spools - not with SimplyPrint.


When your printer switches spools mid-print, SimplyPrint detects the change and tracks usage based on print progress.


Example: If Spool A was used for 0-60% of the print and Spool B for 60-100%, SimplyPrint calculates usage proportionally for each spool.


The filament info SimplyPrint sends (color and type) is what the printer uses for matching.



Setting up auto-refill on Bambu Lab printers


These steps are for reference only. Auto-refill configuration is handled by your printer firmware - consult Bambu Lab's official documentation for the most up-to-date instructions.


Requirements


Bambu and third-party filaments are never considered "the same" - even if the color and type match. Bambu filament must be backed up with Bambu filament, and third-party with third-party.


The AMS will only auto-switch to a backup spool if it has exactly matching properties:


  • Same brand (Bambu or third-party)
  • Same material type (PLA, PETG, ABS, etc.)
  • Same color
  • Same nozzle temperature


Enabling auto-refill


For Bambu filament, RFID is read automatically. For third-party filament, manually set the type, color, and temperature to match.


  1. Load your primary spool and backup spools with identical properties
  2. Enable "AMS Filament Backup" in Bambu Studio or AMS settings on the printer
  3. Verify all spools show correct filament information


AMS 2 Pro note


On the X1E with AMS 2 Pro, backup spools must be in an AMS unit connected to the same extruder - left AMS units back up left, right backs up right.



Troubleshooting


SimplyPrint only sets the color and type visible on your printer's screen. Make sure those values match between spools you want to use as backups - the rest is up to your printer's firmware.


If your printer doesn't auto-switch when a spool runs out, the problem is with the printer's matching logic - not SimplyPrint.


Common causes:


  • Properties don't match exactly - even small temperature differences will prevent matching
  • Mixed brands - Bambu and third-party filaments won't match each other
  • Filament info not configured - third-party spools showing "?" need manual setup
  • Print was paused/unloaded - this can disrupt the backup function




Updated on: 23/01/2026

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