Purge Tower Filament Waste Calculator
Calculate total filament waste from a multi-material purge tower.
Enter purge volume per color change, number of changes, and filament price to find total waste cost.
Multi-material printing systems (Bambu AMS, Prusa MMU, ERCF/Happy Hare) purge the previous filament color before printing with the next. The purge volume — how many cubic millimeters of new filament to push through the nozzle until the old color is fully cleared — directly determines how much material is wasted in the purge tower.
Typical purge volumes. For a standard 0.4 mm nozzle, a good starting point is 100-200 mm³ per color change for same-family filaments and 300-500 mm³ when switching between very different colors (white to black being the worst case) or between transparent and opaque materials.
The default Bambu AMS flush volume is around 450 mm³ per change (before their adaptive purge optimizations). Custom profiles tuned for specific color pairs can reduce this to 80-150 mm³ with careful calibration.
Converting mm³ to grams. Filament density varies by material:
- PLA: 1.24 g/cm³
- PETG: 1.27 g/cm³
- ABS: 1.05 g/cm³
- TPU: 1.20 g/cm³
mass (g) = volume (mm³) x density (g/cm³) / 1000
Reducing waste. The most effective strategies are: calibrating exact flush volumes for your specific color pairs, using the “purge into infill” option (Bambu/OrcaSlicer), and printing infill-adjacent purge objects rather than a standalone tower. Some systems support “tip shaping” to reduce the mixing zone length.