Multicolor prints are easier than most assume. For this example I’ll use a small travel version of a game inspired by Quarto that I designed in Tinkercad. It has internal holes in the base and figures for metal washers and magnets to help keep figures in place (i.e. places in the printing process where we want to pause the print anyway to embed metal into the print).
I’ll use the popular software Cura for the examples, but they basically apply to any slicer software.
Pick out the filaments you want to use
I start with this step because the filament can impact your slicer settings. The easiest way to get good adhesion between filaments, is if they are the same brand/type, but with enough patience and tweaking settings, you can get anything to stick together (even PLA and TPU).
Pick out the layer where you will want to change colors
In this example layer 25 is the last layer where the holes are still open, and starting with layer 26 the holes are covered. So we will interrupt the printing after layer 25, switch filaments, and then continue.
Cura has a plugin feature, and one of the provided plugins is called “Filament change”. It moves the head away from the print, retracts the filament, and waits for the user to put in a different filament before continuing the print.
To add breaks for filament changes, go to “Extensions -> Post Processing -> Modify G-Code / Add a Script -> Filament Change”. This gives you a configuration window where you can specify on which layers you want to change colors/filaments.
If you want to change the color multiple times, just list all layers the filament should change separated by commas.
Switching filaments
Once the head is clear of the print and the filament has been retracted, remove the current filament, and insert the new one. manually extrude enough filament so that the old color has been purged out of the hotend/nozzle (it doesn’t need to be a hard cut, it is sufficient to just get the new filament into the hotend and not have a gap between the old and new filament). Remove and excess filament from the nozzle, so that it is clean and can continue printing and then continue the print from the printer display.
Be creative with filament changes
For example you can use it to inlay logos or text into a print by printing 1-2 layers of a different color before switching back to the original color (here we switch filaments at layers 9 and 11 to have 2 layers of a darker color).
