To print in several colors on a single-extruder printer, you stop at chosen layers and swap the filament by hand. In Bambu Studio you set it up by right-clicking the handle marked + on the layer slider in the Preview tab.
The method works for horizontal color bands: one color for the base, another for the body, a third on top. It will not give you two colors inside the same layer, though. That needs an AMS or a multi-extruder printer.
Setting it up
- Slice the model and switch to Preview.
- Move the layer slider on the right to the layer where the color should change.
- Right-click the + handle on the slider.
- Under Change Filament, pick the filament for the new color. The item only appears when the project has more than one filament, so add a second one first if you have just one.
- Repeat for as many changes as you want.
- Send the print.
At that layer the printer stops, retracts and waits for new filament. If you want to embed a part rather than change filament, use the pause method. Pull the old filament out, feed the new one in, purge until the old color is gone, then press Resume.
If the add options in the slider menu come up grayed out, check the Print sequence setting. The detail is in the grayed-out Add Pause option article.
Which layer
To find the right height, drag the slider in Preview: the model builds up layer by layer and you can see where you are.
The slider shows both the layer number and the Z height. If you want the change at a specific height, 10 mm say, go by Z.
Pick the layer one early. The change happens at the start of the layer you choose, so that layer prints in the new color. Confirm in Preview exactly where the boundary lands.
How much filament it saves against an AMS
With an AMS the printer changes color itself, but that costs something: it has to clear the old color out of the nozzle, and it dumps the waste into a purge tower printed beside the model. Why that tower comes out so large, and which setting actually shrinks it, is in the prime tower article.
| Manual change | Automatic with AMS | |
|---|---|---|
| Human intervention | At every change | None |
| Purge tower | None | Yes |
| Filament spent | Little (manual purge) | Noticeably more |
| Several colors in one layer | No | Yes |
For a few horizontal bands, swapping by hand uses noticeably less filament. On a model that changes color every ten layers, the filament an AMS spends on the tower can exceed the part itself.
The trade is that you have to be at the printer for every change, which rules out an overnight print.
The AMS side has a friction of its own: even with the slots loaded, if the slice is tied to a single material, three of them come up grayed out in the print window. The cause and the fix are in the grayed-out AMS slot article.
Keeping the color change clean
After a swap, residue of the old color is still in the nozzle and the first few centimeters come out mixed.
- Purge enough. Keep extruding until the new color runs pure. Light to dark is easy; dark to light takes a long time.
- Avoid black to white. That is the hardest transition, because black pigment lingers. Order your colors light to dark.
- Make the purge useful. You can put a small sacrificial part at the edge of the plate and purge into it.
The alternative: split the part
Sometimes splitting the model beats changing color. If the two pieces need different materials, say PLA and ABS, why one print will not do it is in printing PLA and ABS together. Print the two pieces in different colors, glue them together, and:
- The color boundary is perfect, with no mixing
- Both pieces print at once
- You do not have to stand over it
If the boundary is horizontal and flat, this is nearly always cleaner. Changing color earns its place on complicated boundaries, or on parts that cannot be split. If you split a painted model with Bambu Studio's cut tool, which versions keep the paint is covered in cutting without losing paint.
