Tuesday, 1 June 2021

Multicolour printing on Creality CR-10-V3 with Cura

This is a detailed guide on colour printing with a single extruder.


Multicolour printing can really lift some prints, especially where appearance is more important than functionality.

The Cura slicer provides good support for this process.

There are lots of generalised guides on this subject, but this one may be a little more helpful, especially for newbies with a CR-10-V3 printer.

3D prints which include text can look a lot better if you can print the text in a different colour to the background. In this photo, the text is raised above the back-plate...

...so this allows us to print one colour for the back-plate and another for the text, even on a printer with just a single extruder.

The basic method is:-

  1. start printing with one coloured filament
  2. stop the print process at some stage
  3. remove the 1st filament
  4. fit the 2nd coloured filament to the printer
  5. complete the print

However, there are some important details to consider, such as the extruder x, y & z positions which must be maintained so that the printer can restart exactly where it left off printing the first colour.

Although we can just stop the printer at some random point and change filament (which is how I made this clip)...

...we also need to be able to control the nozzle temperature while changing filament, raise the height (z) of the nozzle & move it away from the print (x,y) to avoid excess 'string' from contaminating the print, and having changed the filament, we need to get the extruder back to the exact x,y,z position so we can resume printing.

I think that the best approach is to modify the objects g-code, and this is where Cura comes in.

For this example I'm going to print a Bitcoin design from Thingiverse: https://www.thingiverse.com/thing:2595156.

Printed in a single colour, its OK, but maybe a little flat.

the process

Note: to follow this process you will need to connect your Creality printer to a computer running Cura via a serial link.

Open the Bitcoin .stl file in Cura and slice with your preferred settings.

Select Preview mode and zoom in to enlarge the view of the Bitcoin object.

Operate the right-hand vertical slider to a point where the coin base just stops changing (i.e. the final base layer before the text) and note the layer number.

Note that you can use the up/down arrow keys to increment/decrement the layer.

Navigate menu Extensions > Post Processing > Modify G-Code > Add a script > Filament Change

Enter the noted layer number + 1 (e.g. 16 ) as the Layer, and close the dialog.

This is because the printer will be instructed to stop before the entered layer is printed, but we want it to print layer 15 and stop before layer 16.
Then slice once again.

Now you can Print via USB

After printing all layers including #15, the print head will move back to the Home position and display a series of incomprehensible screens (...at least on my CR-10-V3, but this may be firmware dependent);

While you are trying to work out what they mean, the printer will be busy ejecting the current filament from the print head (i.e. backwards, not forwards).

 Just to instill more confusion and panic, the controller will periodically scream at you via its bleeper.

But once the filament has been ejected, you can load the next colour filament by pushing the end of the filament as far into the extruder as it will go. Then press the controller button and the nozzle will reheat.

this screen displays both the current & target temperatures

Once back up to the target temperature, the extruder will automatically wind the filament in and extrude some plastic. Then you should see the final screen...


...and as long as you have installed the next coloured filament and it has oozed out of the nozzle, you can remove the ooze and press the controller button to Resume Printing.

My firmware is so maybe if you have a newer version you will let me know if the screens have been improved!



Despite these strange screens, once you have used this multicolour method a couple of times, it becomes really easy.

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