pricing
Pricing Multicolor & AMS Prints: Don't Forget the Purge Waste
Multicolor 3D prints waste filament on every color change. Here's how AMS purge works, why it can exceed the model's weight, and how to price it.
Multicolor prints sell. A two-tone nameplate or a four-color figurine commands a much higher price than a single-color version of the same model — and customers happily pay it. But there's a cost hiding in those color changes that wrecks the margins of sellers who don't account for it: purge waste.
If you run a Bambu Lab AMS (or any multi-material system), you've seen the little piles of "poop" — short stubs of mixed-color filament ejected on every color switch. That's filament you paid for, turned into trash. On a print with lots of color changes, it can weigh more than the model itself. Price only the model and you're giving the wasted filament away for free.
Why multicolor printing wastes filament
A single-nozzle printer can only hold one color at a time. To switch colors, it has to flush the old color out of the hotend before the new one comes through clean — otherwise your bright yellow would print as a muddy yellow-green for a few millimetres.
That flush is the purge. The printer extrudes filament until the nozzle runs pure, then resumes the model. Every color change does this, in both directions. A print that swaps between four colors layer after layer can trigger hundreds of purges.
The wasted material goes into one of three places depending on your setup:
- Purge "poop" ejected out the back or chute (most common).
- A purge tower / prime tower printed beside the model.
- Infill or a sacrificial object if you've set the slicer to flush into them (which recovers some of the waste, but not all).
How much waste are we talking about?
It depends entirely on how many color changes the print has and your flushing volumes (how much the slicer purges per change). But the numbers surprise people:
| Print type | Model weight | Typical purge waste | Total filament used |
|---|---|---|---|
| Single color | 20 g | 0 g | 20 g |
| 2 colors, few changes | 20 g | 5–10 g | 25–30 g |
| 4 colors, layer-by-layer | 20 g | 25–40 g | 45–60 g |
| Hue-blended / many swaps | 20 g | 40–80 g+ | 60–100 g+ |
In that third row, a 20 g model actually consumes 45–60 g of filament. If you priced the material at "20 g × spool rate," you under-charged for material by more than half.
Worked example: what purge does to your material cost
Say your filament costs $22/kg ($0.022/g), and you print a 20 g multicolor model that purges 35 g.
Pricing the model only (the mistake):
20 g × $0.022 = $0.44 material cost
Pricing the real filament consumed:
(20 g model + 35 g purge) × $0.022 = 55 g × $0.022 = $1.21 material cost
That's $0.77 of filament thrown straight in the bin on a single small print. Run twenty of those for an order and you've quietly eaten $15 in waste you never billed for — on top of the extra print time multicolor adds, which costs you electricity and machine wear too.
How to reduce purge waste (so you can charge less and win the sale)
You can't eliminate purging, but you can cut it:
- Lower your flushing volumes in the slicer for color pairs that are close in hue (dark-to-dark needs far less flush than light-over-dark).
- Group color changes — design or orient the model so colors change less often per layer.
- Flush into infill or a sacrificial object to reclaim some waste as useful structure.
- Order your colors smartly — going light → dark generally purges less than dark → light.
- Reuse the poop — some sellers grind and recycle it, or save it for prints where color doesn't matter.
Even after optimising, budget for some waste on every multicolor job.
How to price it
The rule is simple: charge for every gram that leaves the spool, not just the grams that end up in the model. Two ways to do it:
- Measure it. Your slicer reports total filament used (model + flush) and often the flush weight separately. Use the total.
- Estimate it. If you can't get the exact figure, add a purge percentage based on the print's complexity — roughly +25% for light multicolor, +100% or more for heavy layer-by-layer color work.
Then add the other multicolor costs on top: longer print time means more electricity and more machine wear, and the extra fiddliness is real labour. Multicolor should be priced as a premium product — because to you, it genuinely costs more to make.
The free pricing calculator has a dedicated purge weight field right next to the model weight, with a toggle for whether to bill it — so you can plug in the flush figure from your slicer and watch the true material cost update. For the full cost picture, start with How to Price 3D Prints: The Complete Guide.
Key takeaways
- Every color change purges filament to flush the nozzle clean — and you paid for it.
- On heavy multicolor prints, purge waste can equal or exceed the model's own weight.
- Pricing the model only can under-charge material cost by 50% or more.
- Cut waste with lower flushing volumes, smart color order, and flushing into infill — then charge for whatever's left.
- Multicolor is a premium product: price the extra material, time, electricity and labour, and sell it as one.