I've worked with beeswax, but never tried to use it for 3D printing. However, I doubt it will work very well in that application. The problem is that it has a rather abrupt phase transition between its molten and solid states. So it will either be too runny, in which case the layers won't sit up on the other layers but tend to run off, or it will be too stiff and crystalline, so there will be deep fissures between succeeding layers and they won't adhere well. There are other waxes marketed to the jewelry industry, some of which come in filament form, that might be more suitable, although the wax printers I've seen are fairly complex machines with heated lines, expensive jets, and a planer cycle that's used to flatten each layer previous to laying on the next one.

I'd suggest you do some simple tests with heated syringes full of wax, and see if you can get it to behave as desired at any temperature. If that works, see if you can find a paste-extruder head that accepts heat well. Inventing your own might be an interesting project, but it could well take more time than you've allotted for this whole machine. The trouble with trying to print one is that the temperature range of the wax is pretty close to the melting point of the thermoplastics used in the printer. Instead, think in terms of a metal syringe/extruder device that could be precisely heated at the barrel.

Andrew Werby
www.computersculpture.com