Multi-colour printing, honestly

Multi-colour machines are genuinely brilliant and nobody tells you the trade-offs before you buy. Here they are.

What it actually costs you

Every colour change flushes the old colour out of the hot end, and that plastic is thrown away. On a colour-heavy model the waste can weigh more than the print itself. That is not a fault — it is how the technology works.

Cutting the waste right down

• Purge into the model's own infill instead of a waste block — free, and it is inside the part anyway
• Purge into a small useful object printed alongside
• Re-model or re-orient so fewer colours meet on the same layer
• Tune the flush volumes per colour pair — dark into light needs far more than light into dark

It also takes much longer

Every swap costs time as well as plastic. A four-colour print can take three or four times as long as the same model in one colour. Worth knowing before you set one going on a Sunday evening.

When bleeding happens

Muddy transitions mean the flush volume is too low for that colour pair. Print a colour-swatch tower once and you will have the right numbers for good.

What it is brilliant at

Text and logos in a contrasting colour, models that would otherwise need painting, and printing supports in a different material so they snap off cleanly. That last one is the underrated trick.