AP projects 2015
The 3D printer modification
As said in a previous post we are using the custom made 3d printer available at the applied labs for the printing of the chicken breast. This printer was used to print PLA and therefore made several modifications. First of all the original printing head was removed and we placed our custom made, 3D printed, head in place of it.
The motor makes the gears turn. The Gears make sure that with the little power of the motor the material can be printed. The last gear (the biggest one) pulls the transitional belt. Because the transitional belt becomes shorter on the side of the syringe, the syringe is pulled down. This is done fluently with the use of the belt holder with a bearing inside.
Next to this the software used for the printing is modified for this food extruder.
Now the first organic chicken breast will be 3D printed. To do this we use the 3d model we obtained from the 3d scan and we use the lupine/Alginate recipe with 30% less alginate than set. The first print will be made with three outer layers filled with an infill with a linear cross infill of 98%. After each layer manually the saltwater concentration (double as prescribed in the recipe) was added using a plant sprayer.
At the beginning the print did not work out correctly. We changed the layer height, the printing speed and the extrusion rate settings to make the printing more accurate. This worked out. In total the printing time was about 50 minutes for the chicken breast with a size of 50*105*15 mm. At the end the extruder was not printing straight lines anymore and clogs arose in the print. Probably this was due to the incorrect height of the extruder in comparison with the printing bed. The real line thickness was not the same as the expected one. Possibly as well the resistance grew inside the nozzle which caused a delayed print. As a result we got the following:
The good things about this print are that the layers are not visible from the outside. Further the side has quite a smooth surface. The biggest downside is that the top was not printed correctly.
More important the inside had a really fibrous structure as can be seen below.
A small part of the ‘chicken breast’ is tasted by one of the team members and as he responded: “You could really feel the fibers in your mouth. Further it was completely solid.” So luckily there were no parts where the mixture could be squeezed out. The food had no good taste yet. It was neutral and a little bit salt, but not too much.
For the second print we mainly changed the infill pattern. Now we used a concentric infill. The bottom part was really nice and fibrous. But in next layers strings melted together and bobbles appeared. Therefore we stopped the print.
Now we used again the concentric infill pattern. Now we changed the infill density from 98% to 90%. In this way we hoped the lines would clog less likely. Unfortunately this did not work out the way we hoped it would be and again clogs appeared. Probably the concentric pattern is not efficient for the printing of the organic meat.
This time we tried to print the chicken breast again with the cross linked infill, which we used for the first print. Now we used again the 90% infill density (same as print 3). The start went fine but the needle constipated after a while. First it was letting through much less material which caused material concentration at certain places and later on no material at all was extruded and the printer jammed. In this print we saw that the layers did stick to each other. This could be due to an overflow of saltwater added. Otherwise we must think of using a binder for the different layers.
In the incoming days we will go on experimenting with 3d printing. The modification will be during making the mixture. We will blend the mixture longer than in previous trials. This way we hope to get rid of lumps which cause the needle to clog.
We will as well try to add some flavour to the food. We will try to do this with mixing some ‘chicken flavour’ species with the salt water solution.