How to multi color print on single extruder ( Ender 3 + Cura )

thingiverse

I wrote this tutorial to share my experience about how to easily make multicolor prints with a single extruder (Ender 3) by manually changing the filament, resulting in the highest possible quality. The keyring examples on the pictures were made in TPU using this procedure. I've uploaded a simple cube that's useful for testing and getting familiar with the procedure: Load your file into Cura and then click on Extensions->Post processing->Modify g-code. Add Pause at height script (first picture on gallery). Set Pause at Layer no. at the layer where you want to start the new color (the print will pause before making that layer). Set Park printer head X and Y at 10 to get the nozzle stopped in a convenient position for clearing it from color purging. Don't set it to 0 because after resuming, it will lose bed calibration. Set retraction to 0 (this is a feature useful only for pausing prints because after resuming, right before starting the new layer, it will extract the same length retracted and it's not possible to insert the new filament at the exact position of the previous one). Leave "Extrude amount" and "redo layers" at 0. Set standby temperature at the same print temperature (it's essential to set this because you won't get over extrusion right before starting the new layer caused by the nozzle heating up). Start your print and wait for the pause. Wait for approximately two minutes for the extruder stepper being disabled, then retract all the filament while paying attention not to move the extruder/bed or z-axis height position. I suggest using an extruder knob to unload/insert the filament for this critical procedure; I'm using this (https://www.thingiverse.com/thing:3373315). Insert the new color and purge the nozzle until you can clearly see the new color. Leave it untouched for a couple of minutes to let all the over-extruded filament drain from the nozzle. Clear the nozzle, press the printer button to resume the print with the new filament, and pay attention that the script will be saved into Cura for all files you will open. When you don't need it, I suggest setting the layer to a greater value (ex: 9999999) in order to disable the script instead of just deleting it. When you'll need it again, click on the tools icon that will appear on the left side of the Cura slice button and set your desired layer to activate it. Hope this helps!