How Much Filament Does Multi-Color 3D Printing Waste?
How purge (flush) volume, the number of color changes and prime towers add up on AMS and MMU prints, with ways to cut the waste.
By CalciTools · Published · 6 min read
Every number on this page is calculated with the same formulas as our calculators. How we build and check them
Every color change pushes out old filament. With Bambu Studio’s default flush of about 280 mm³, each change wastes roughly 0.35 g of PLA. A 40 g model with 200 color changes can throw away 75 g — more than the model itself.
How the waste adds up
| Waste | Share of filament used | Waste cost | |
|---|---|---|---|
| 40 g model, 20 color changes | 12.9 g | 24% | $0.26 |
| 40 g model, 200 color changes | 75.4 g | 65% | $1.51 |
| 4 copies on one plate, 200 changes | 18.9 g per copy | 32% | $0.38 per copy |
PLA at 1.24 g/cm³ and $20/kg, default flush multiplier, 6 g prime tower.
Ways to waste less
- Print several copies at once. They share the same color changes.
- Flush into infill or supports where the slicer allows it, so the purge does useful work.
- Reduce color changes: put colors on as few layers as possible, or use a single color for hidden areas.
- Tune the flush multiplier for similar colors, and test before a long print.
The multi-color waste calculator uses the color changes and prime tower from your slicer; add the result to your filament before working out the full print cost.
Frequently asked questions
Why does a multi-color print waste so much filament?
Each time the printer switches color, it has to push out the old color until the new one comes through clean. That flushed plastic — plus any prime tower — is waste.
Does printing several copies reduce waste?
Yes, per copy. Objects on the same plate share each color change, so the purge is split between them.
Can I lower the flush volume?
Often a little, especially between similar colors. Test it on a small print first: too little flushing leaves streaks of the previous color.
Sources
Estimates for planning. Results depend on the numbers you enter — use the gram, hour and ml figures from your slicer, and your real material and power prices. Material densities are typical values; check your spool or bottle datasheet for exact figures.