This instructable follows a new set of adventures 3DigtalCooks food printing adventures with multimaterial food pastes. This was born with the idea of being able to blend flavors during a print. But for that. We need first to be able to control it ;)

My inner critic told me keep it easy bro, that is why I decided to test everything first using colors. Simpler to spot how well is printing.

The printer used for the experiments is Pinya3.

Instead of using different nozzles, I decided to workout my newbie machining skills to made nozzle/s that handle the same material without offsets.

Step 1: Nozzles

The first nozzle tested is a coaxial nozzle. This is a nozzle withing another nozzle where the materials are not in contacted until they are extruded.

Shout out to Will Patrick for sharing his idea with me an making this possible!

It uses 1/8" barbed threaded (10-32) connector for the tubes.

Please check the video for a better look at it!

Step 2: Extruder Tests 1st Day

I used this extruder for the first run of tests. The only difference is that this time the cartridges were connected to the coaxial nozzle with tubes. This removes the weight from the printer head.

I did a dry run and everything worked perfectly. I was able to print air without problems! Pretty fast I realized that the extra forced needed to push materials through the added tube would required and update for the extruder.

Step 3: New Extruder Design

So without thinking much (wroooong), I decided to get a stronger motor. If I could go back in time, I would had got this bigger Nema 23. Since the weight of the motor are not an issue any more that would had been better. Although that would required to update the power supply for higher voltage (which I ended up doing anyways).

Parts needed:

4 x M3 8mm
4 x M3 60mm
4 x M3 nut
4 x M3 locking nuts
Laser cut parts

The new motor uses a 6.35mm shaft so I had to make a special coupling to connect the shaft and the piston of the cartridges.

Step 4: Tests 2nd Day

Day two and ready to test the new extruders.

This time I was so concern about the consistency of the puree used that I added too much water. Still that helped to start playing with some basic shapes and configurations to get some results.

I do not think the coaxial nozzle is the best choice for simple tests. Is good because no material gets wasted purging the nozzles, but since it has a quite flat end, this creates and undesired mixing effect from color adhered to the it.

Soo... Lets make a simple nozzle!

Step 5: 2nd Nozzle

This nozzle was made to try to reduce the extrusion force needed by using a tube with bigger diameters. From 1/8 to 1/4.

Making this test nozzle was fun . Specially because it was my last part made using my beloved lathe at the Pier!!!!

The design is simple. As inlets I used barbed fits for 1/4" tubing. the nozzle diameter is 1.5mm (0.060 inches). And the M5 screw on top is to hold it to Pinya3.

Step 6: Testing It

It has taken, only 6 months for me to give it a try ;)

But finally during our last workshop at Messe Erfurt in Frankfurt I managed to test and record a video of the new nozzle printing.

This is a big journey that just has started. Not just from finding the right consistencies for the printed food. But also to create the right tools to generate designs that make sense.

And specially effort to be able to control the extruders in a more organic way aka synchronizing them.

Hopefully more experiments soon here, at 3DC and at our youtube channel!

Some app ideas for the future.

Spiral tool path