Is Multi-Colour 3D Printing Actually Worth It?
The purge waste is worse than you have been told, and the answer still might be yes.
Multi-colour printing sells printers. Every product page shows the same thing: a bright, complex, many-hued model that looks nothing like what a single-colour machine produces. It is genuinely impressive, and the marketing is not lying to you.
It is, however, leaving something out.
How single-nozzle multi-colour actually works
An AMS, a CFS, an ACE Pro — they all do the same thing. There is one hotend. To change colour, the printer retracts the current filament, feeds the next one in, and then extrudes until the new colour has fully flushed the old one out of the melt zone.
That flushed material is waste. It goes into a purge tower, a "poop" chute, or an infill sacrifice, and it is gone.
The numbers nobody puts on the box
A colour change costs somewhere between 20 and 100 mm³ of filament depending on the colour transition — dark to light is far worse than light to dark, because black pigment lingers.
A model that changes colour a few times per layer, over three hundred layers, does not perform ten colour changes. It performs a thousand or more.
The result is routine and startling: a 40 g multi-colour model can consume 150 g of filament. Most of your spool becomes purge. The print also takes two to four times longer, because the machine spends much of its time swapping and flushing rather than building your part.
When it is absolutely worth it
- Display models, figures, signage and anything decorative. The result is not achievable any other way, and nobody minds the waste on a showpiece.
- Text and logos. Embedded lettering in a second colour is transformative on a nameplate or a control panel.
- Soluble supports. This is the underrated case. Printing supports in PVA or a break-away material gets you clean overhangs and internal geometry that would otherwise be impossible. Even here, the purge cost is real.
When it is not
- Functional parts. A bracket does not care what colour it is.
- Large models. Purge scales with colour changes, and a big model has a lot of layers.
- Prototyping. You will iterate ten times. Do it in one colour and save the multi-colour run for the final piece.
The alternatives worth knowing
Filament painting / pause-and-swap. For models where colour changes happen at distinct heights — a two-tone vase, a sign with a coloured base — you can insert a manual filament change at a specific layer in any slicer. Zero waste, zero extra hardware, thirty seconds of your attention.
Dual nozzle. The Bambu Lab H2D has two independent hotends. Two materials with a fraction of the purge, and it makes soluble supports genuinely economical.
Toolchangers. The Prusa XL takes this to its conclusion: five independent tool heads, each parked when unused, essentially no purge waste at all. It also costs four thousand dollars.
So, worth it?
If you are choosing between an A1 and an A1 with AMS lite, and the difference is around $130 — yes, buy it. You will use it, and you will enjoy it.
If you are stretching your budget to afford multi-colour on a machine you otherwise cannot quite afford — no. Buy the better printer. The AMS is an upgrade you can add in a year, once you know from experience whether you actually want it.