
In this report I take a look at CETUS2 color change in the normal print process.
I designed a small test bowl with eleven horizontal stripes. Then I created a second version where I divided the bowl into quarters creating 44 sectors where I could alternate the colors within each row.
The lead picture displays the three variations of prints that were created.
The bowl on the left (#1) is a standard alternating color change in layers. This is the easiest print as there is no color purge required between layers. The short transisional color change can never been seen.

On The Fly
One of the selling features of the CETUS2 two filament 3D printer is its ability to change colors On The Fly (OTF). That claim is entirely true. But it took me some time to figure out how to do it well.
The primary ingredient with the CETUS2 is its very short “combined filament path" within its special extruder nozzle. The two filaments are introduced to each other (for single nozzle extrusion) very near the exit point of the nozzle.

In other articles, I mentioned the stringing, strands of light filament threads that are dragged out from the FDM print as the printer nozzle makes a non-printing jump move away from the printing surface to a new start location. It is caused by hot plastic flowing from the nozzle after it has been commanded to stop the flow.
Several adjustable factors are used to prevent this extra undesired flow. Retraction (reversing filament feed briefly) is the primary method to reduce or eliminate stringing. Temperature settings, retraction speed, retraction amount, pause, wipe, early stop, the list of “tweaks” seems endless. Sometimes it is an art rather than hard science to get the correct combination.

Is it ugly? It’s at least very LOUD. Red and Yellow seem to be circus colors perhaps. In any case it catches my eye.
It is the colors I had so it was the colors I used. I’ll call it a party bowl.
The print was made on the CETUS2 and ran for almost 24 hours. Each one of the vertical color post are printed in layer sequence, one at a time. then switch colors and repeat on the same layer (0.2mm high).