While I was searching internet for cheapest hydroxyapatite offer, I stumbled upon articles, that described how to synthesize this material. At first glance it seemed as somewhat complicated process, but after some reading it became more and more doable. Maybe it would be fun to find a way to do the process at home with products being ready to use in a 3D printer. Whole process could also be automated using some pH probes and syringe pumps. Whole device could possibly be 3D printed, so it could be used as a standalone machine for creation 3D printer substrate.

If i understood corectly, one needs CaO and phosphoric solution to produce a hydroxapatite. The process is done by mixing. It also needs regulation of pH (i think). This all seems pretty much doable. The reactants should not be so hard to get (CaO is lime and phosphoric solution shouldn't be too hard to get). Then I would just use a jar as a mixing chamber with 3D printed lid. The lid would contain 2 inlets for pH regulation (2 syringe pumps with HCl and NaOH), 1 inlet for phosphoric solution, some sort of trickler for lime input and few sensors (probably just pH and temperature probes). I would als add a outlet pipe connected to a peristaltic pump to a suspension reservoir. All could be controlled using a arduino. There could also be a peltier element to heat or cool the jar for best possible output (if it would be worth it of course).

Note that this is just my thought process. It is a result of the fact that cheap hydroxyapatite is almost non existent in case of purchasing. I still want to print a whole object, but for this I would need one liter of this powder (>1 kg; approximately 600 €/100g over at sigma aldrich). If I will be able to find someone who could help me on this subject, I will definitely think of doing it.

If you have any ideas I would be pleased to know. I would be also happy if someone would be able to try creating the hydroxyapatite powder themeselves as I have quite a lot of work to do regarding the printer itself.