Jonathan Keep has already brought us a Delta ceramic 3D printer and released instructions on how to build one yourself. Now, Keep has developed a chocolate 3D printer utilizing the ceramic Delta 3D printer.
Rather than building a whole new machine, Keep simply replaced the extruder on his Delta printer with a syringe which is pressurized from a soda bottle and bicycle pump. Apparently the syringe system can be attached to any RepRap style 3D printer.
According to Keep, printing with chocolate comes with its own set of problems. “Having a melting temperature of under 30°C (above it goes granular) and then re-solidifying at room temperature it has a very narrow working potential for extrusion. However the ability to go from solid to liquid and reverse makes it a good material for extrusion 3D printing, if you can control the temperature.”
Predicting that liquid chocolate would not need much pressure to extrude I abandoned my normal studio air compressor and cobbled together a fizzy drinks bottle compressed air system. I believe a fizzy drinks bottle can withstand up to 6 Bar of pressure so with my bicycle pump and only pressurizing the system to 1 Bar it was not stressing too much. The pressure needed to extrude the chocolate as I turned up the regulator did not register on the pressure gage so I cannot say what it was but the rate of flow was controllable. One priming of the fizz bottle with the bicycle pump was enough pressure for a syringe of chocolate. I began printing onto cling film, then gloss card, on top of a ceramic tile that I had put into the deepfreeze. This was to help re-solidify the chocolate as it printed.