3DP has quite a variety of 3D printing materials. On this page will be a list of possible materials. Some of these materials are already being used in Plan B, others are materials tested in research or in available in commercial printer. A veritable treasure trove of information is: http://depts.washington.edu/open3dp/category/formulas/. They do a lot of research on powders for 3DP printing and binders. Materials that have been investigated include: Rice flour, several gypsum mixtures, salts and sugar. They also have a binder you can make. Most powders are based on 4 parts powder, 1 part Maltodextrine and 1 part powdered sugar. Go take a look.
Zcorp gypsum and binder
The materials shown in all of the prints right now is Zcorp gypsum and a ZD-16 binder. I got this stuff from a friend who owned a Zcorp printer, so right now I don’t have a steady supply of this stuff. A quick search on the interwebs show that ZD-16 makes Zcorp compatible 3D printing materials, mostly sold on ebay. The powder goes for $399 for 30lbs (13.6kg) of the material, excluding shipping (an additional $136 to the Netherlands). This would make it around $40/kg. comparable to expensive FDM filaments, but expensive when you consider it’s main ingredient. The binder is also fairly spendy, at $300 per gallon (3.8l) excluding shipping.
The exact formula is a trade secret, which is no surprise coming from Zcorp and partners, but there is one place to start. The material safety data sheet:
Going from these files, some of the composition can be traced. The powder has 3 main ingredients. Plaster (50%-95%), Vinyl polymer (2%-20%) and sulfate salt (0%-5%). All of these values are very vague and poorly described, but there are some safe assumptions to make. Plaster is plaster, it simply is what it is. Vinyl polymer leaves a lot to guess, but it is safe to say that that is PVA powder, since it is cheap and perfectly matches what the powder is supposed to do, bind. Only the sulfate salt is a bit of a mystery.
The binder is a bit more complicated. It has 5 ingredients. Glycerol (1%-10%), Preservative (sorbic acid salt) (0%-2%), Surfactant (<1%), Pigment (<20%) and water (85%-95%). Beginning again with the simplest component: water. Used to solve all of the other things. Pigments can be used to color the binder. Plan B uses the remaining pigments from the cartridge, but cartridges have been completely flushed, leaving the possibility to add any color pigment possible. From what I can find, glycerol would most likely be used as a thickening agent, though I can’t know for sure. Surfactants lower surface pressure, probably to aid inkjet printing. Dish washing liquid is a nice example of this. The Sorbic acid salt seems only to be there to prevent bacteria from doing their thing. All of these are assumptions though, I only poses an engineers/high school amount of chemistry.
Homemade Gypsum and binder
With all of the above limitations and information, it should not be impossible to recreate the powder. The binder is a bit more of an issue, but I know from the people I got the powder from that rice wine (sake) also seems to work. Their machine smelled incredible for weeks because they filled the main binder tank with this sake. It did print with more issues than original binder though, so it is not a perfect replacement.
There is also a
few documents on the internet (this link died) suggesting that USG Hydroperm is an out of the bag printing powder, that combine with rice wine would be a decent printing material. It seems to respond to humidity though and should be a bit hit or miss. The part needs to be baked at around 90°C for an hour to get the part to strength. This material can also be used to make metal casting molds. Look up the article to get all the information.
3D printing ceramics is a real possibility. I know this because it has already been done with 3DP printing. It even came with full recipes and proportions (which makes me very happy). Plan B is perfectly capable of printing in this way, It will be one of the first experiments I want to run.
The possibilities are real. I have seen too many FDM printers fitted with a paste extruder extruding parts at big layer thicknesses. It works and proves the point, but the surface finish seems a bit too rough to be really used. Also not all shapes are possible with paste extruded parts. The amount of liquid in the ceramic paste used means that the parts need some sort of support to print large heights. 3DP has none of these disadvantages, being capable of printing in high resolution with no limitations.
3D sugar printing had potential for maybe a week. the-Sugar-lab posted amazing results printing in sugar. Then 3D systems acquired the-sugar-lab, and any possibility of an open source material with food grade properties was gone. Now the Chefjet exists, which is in deed capable of 3D printing full color in sugar, but it is a bit sad that it had to be acquired by one of the large 3D printing companies, none of which I like even a bit.
But I digress. Sugar. Printing in sugar could be food safe, though not on Plan B (aluminum, cartridges, steel). When the-sugar-lab first posted their result, I immediately mailed to see if I could get more info. They were working with patents, so they could not share much (they even discouraged the use of it) but this they did share: It is 3DP printed, Cheap, very fragile, cant be post processed and melts when wet. I don’t know the exact way to use it, but high percentage alcohol in pure sugar or a mixture of sugar and maltodextrin seems the right place to start experiments.