I had difficulty with the mk19 spool adapter, so I thought I'd just knock up a simple adapter myself. It turned out to be really effective in the AMS so I thought I'd share it.

Features:

• 20mm outer diameter, matching the Bambu Labs spool diameter, for maximum AMS compatibility
• Precise fit for the spool - doesn't crush the cardboard, isn't loose on the spool, reducing AMS issues

FAQ:

• Why no filament retention holes?
  • The cardboard is really flimsy, poking filament through the holes on the cardboard can damage the cardboard, making the wall weaker and causing AMS issues. So to maximize wall integrity, I didn't leave any holes for the filament. I suggest printing a standalone clip if you don't have any already.
• Why no retaining wall?
  • Pushing the carboard through a hole that's too small (e.g. past a retaining wall) causes the cardboard to be bent, which means the spool doesn't sit perfectly in the adapter which can cause AMS issues, therefore I opted to let the spool sit snuggly in the adapter without retention. I haven't had any issues with the spool working itself loose, the adapter does a good job of holding onto the spool without a retaining wall. No issues here so far.
• I've printed it, but it's not quite the right size?
  • For absolute best results when printing any model, you should calibrate your printer's x-y contour and hole compensation to ensure your printer is printing as close to true-size as possible. This is not strictly necessary because Bambu printers are generally very accurate out of the box, but if you're having fit issues, make sure your printer is printing true to size.