AMS Purge Waste Calculator
Figure out how much filament your Bambu AMS (or similar multi-material system) is actually wasting on color changes. For multi-color prints, purge can easily exceed the weight of the part itself, and most filament cost calculators ignore it entirely.
How this works
Every color change on a Bambu AMS, Prusa MMU, or Mosaic Palette requires purging the old color out of the hotend. The material that gets flushed is wasted. For a print with 40 color changes at 8 grams per swap, that's 320 grams of filament dumped into the purge tower, which is roughly $6 of PLA or $10 of PETG.
Most hobbyists never calculate this. Bambu Studio shows flush data but buries it in the preview panel. This tool surfaces the real cost of multi-color printing so you can decide whether it's worth it for a given part.
Frequently asked
- Why does Bambu AMS waste so much filament?
- Every time the printer changes colors, it has to flush the previous color out of the hotend before the new color prints cleanly. Bambu's default flush is around 8 grams per swap. A print with 40 color changes wastes 320 grams on purge alone, which is often more than the actual part weight.
- Can I reduce purge waste?
- Yes, to a point. Lower your 'flush multiplier' in Bambu Studio (default is often 1.0x, tuned users go to 0.4x-0.6x). Use the 'Flushing volumes' matrix to set lighter purges for compatible colors (white to white flush less than white to black). Reduce the number of color changes in the print itself by grouping same-color features.
- Where do I find the color swap count?
- In Bambu Studio, slice the print, then click the 'Flush data' or 'Filament change' panel in the preview. It shows total swaps and exact grams flushed. Orca Slicer shows similar data.
- Is multi-color printing worth the waste?
- For small prints, usually not. A 30 gram part with 40 swaps uses 320 grams of purge, meaning multi-color costs 10x the base material. For larger prints, the purge percentage drops. Worth asking: could you paint the part instead of printing in color?
- Does this apply to non-Bambu multi-material systems?
- The math works for any multi-material setup (Prusa MMU, Mosaic Palette, etc.), but purge-per-swap values differ. MMU2/3 often purges 15-25g per swap. Palette uses transition lengths measured in mm of filament, not grams. Use the custom profile and enter your system's known purge weight.