Multicolor Case iPhone 15 (Kastelruther Spatzen Edition)

This model was made for a close friend of mine. I used a generic iPhone 15 case from Printables, flattened the backside + integrated the sparrow of Kastelruther Spatzen.

Took a decent jpg from the web of the “Spatzen” and imported into CorelDraw!. Then traced the jpg so that I received a good vector graphic. This was a quite lousy part of the job, as the bird consisted of many colours, much more than my MMU2s could bear.

Cut and combined the colors to individual layers of 0.6mm and integrated into the iPhone case. Used black for case TPU, then red, orange, yellow and brown. I did not dare to use the black TPU for the body, as there were too many little and tiny fragments (dots) of TPU to spread to the build plate, this would have ended in a chaotic stringing festival, LOL.

So I started my MK3S+ with the slice. As (my) MMU does not really like TPU I applied a little trick:

1. First I untightened the bondtech gears screw, so that the gears did not squeeze the TPU when introduced into the extruder. Note: When you print with moderate speed and low temperature, the gears will make it. My experience!
2. Started with white, then yellow, then orange, the red PLA filament 
3. Black (TPU) as fifth and last color/filament.
4. PLA was printed first, then came black TPU. This was not in my buffer nor in the MMU.
5. Trick: when last PLA was retracted in to the MMU, I quickly removed the PTFE bowden tube from MMU to extruder! The selector went to position 5 (TPU), then I introduced a dummy filament piece (ca. 120mm) into the Finda, so the push motor ran faster, then manually introduced TPU into the extruder, push motor slowed down and idler was dis-engaged.
6. Layer #1 is printed with TPU (go slow!!) and layer #2 is printed with TPU next. When you see that the layer is almost done, get prepared to act: when TPU is pushed OUT of the extruder, grab it and put it out interference (just put it away). Remove the dummy filament and replace the bowden tube quickly, because the selector goes to the next color and starts feeding out filament, quickly connect the bowden to the exrtruder too. It is not difficult, but you need to act quickly. What has helped me most s that I replaced the pneumatic nipples by ECAS04 nipples, which are less aggressive and thus much easier to take the bowden out).
7. So printer continued with colors 1 through 4 (PLA) or vice versa, and when it comes that selector chooses bay #5 (TPU) you just remove the bowden as described before. This is then layer #3, finish with TPU and go back to bowden style with filas #4 through #1. 
8. I usually use three 0.2 layers for logos or pictures. So PLA is done after last PLA on layer #3, you can now use TPU until the very last end.

This procedure seems more complicetd as it is indeed, I have some experience in acting so. The important thing is to be quite quick with removal of the PTFE-bowden, as said the ECAS04-nipples helped me a lot.

Note: PLA does not really melt with TPU, so be careful to bend the case more than necessary, normally it is not necessary to bend it at all, as the phone goes over the plain TPU areas.

Good luck with it and create your own phone case or whatsoever.

Explore my other Printables: https://www.printables.com/de/@Tritschi