Many of us have watched, mouth watering, as confection creating machines have appeared on the web. The price of admission in the chocolate printing club, however, has far exceeded our desire to have such a single purpose machine. However, those of us who already have a 3D printer might just be in luck. As it turns out, creating a quick and dirty chocolate extruder isn't that difficult!
As you can see in the video, the chocolate extruder consists of a syringe, a bit of hose, an empty water bottle, and a bicycle pump. You can use the bicycle pump to fill the water bottle with air. The pressure is released into the syringe which forces the molten chocolate out. Printing onto a cold plate allows the chocolate to re-solidify between layers. However, as Jonathan points out in his blog, this doesn't work after the prints get too tall. The layers just don't cool enough to harden. If you want to print taller things you'll have to rig up a cooling system.
For what could easily be cobbled together in a few minutes, I'd say this is a very cool addition to any 3D printer.
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Some of the best chocolate in the US can be found at See's candies. I happened to know someone who once worked at the chocolate company that supplies chocolate to Sees: it is the Guittard chocolate company. The don't sell direct so you can't buy their chocolate by itself, though looking at their website I think you can buy it direct from them.
I mention this in case anyone wants to try this 3D printer idea out. Engineering projects should use the highest quality materials! I'll happily volunteer to test your final product.
antedeluvian I live in the US. I'm a big fan of Cadbury's Dariy Milk. (Hopefully, the recipe will not be "improved.") And, I got my children hooked on Aero bars when we visited the Canadian Rockies last summer. I'll look for the things you've suggested. :-) I'm also a long-time fan of McVite's Milk Chocolate Homewheat biscuits from the UK. American chocolate, for the most part, tastes like wax to me. A nice belgian raspberry truffle would be kind of nice right now...
The same brand of chocolate is made to different recipes around the world. Cadbury in Canada is different to Cadbury in the England. (Who knows what will happen now that Kraft owns Cadbury?) Often we are conditioned by the taste we are used to, but if you want a great taste experience you should try and get hold of Cadbury's Top Deck from South Africa (it is a milk chocolate base with a white chocolate upper layer)- I don't know where you live, but there are sources of South African products around North America.
Also the greatest "cookie" (biscuit) is the Tim Tam from Arnotts in Australia. You can certainly find it in supermarkets here in Canada. It is a chocolate covered wafer. They tell me (I don't drink coffee) that the very best way is to bite off both ends and drink your coffee through it as if it were a straw.
When it comes to chocolate, as far as I am concerned the shape is irrelevant. In fact the passage from bulk to my mouth may bypass the extruding process altogether. However here's a thought- it could be used to change the texture to something like Aero. I could be interested in that.