The 3D Mineral Printer is a new type of 3D printer, designed to make large objects quickly at a very low cost.

What is a 3D printer?

A 3D printer is a machine that builds computer models by stacking cross-section layers of the model on top of each other. There are many different types of 3D printers that print with a variety of materials, such as plastic, metal, or even sugar.

Neat, what does this one use?

The 3D Mineral Printer uses hydraulic minerals such as cement and plaster as a print medium. These materials are available at any hardware store for a low price. These minerals can be mixed with sand and other materials to make a good concrete mix for 3D printing.

Whoa, how does it work?

The 3D Mineral Printer lays down a thin layer of this dry, powdered concrete dust, then sprays the image of one 'slice' of the object onto it with a computer-guided water sprayer.

Only the wet parts of each layer will cure into rock-hard concrete, the rest stays in a powder form which can be brushed off later. Concrete cures using a chemical reaction that does not require air to dry, so the next layer can be deposited right after printing the last layer's image.

The cycle of laying down concrete dust and printing with water is repeated again and again, stacking layer upon layer on top of each other, building up a solid object inside the pile of dry, powdered concrete mix.

The dry concrete mix also acts as a support structure for the object, so any shape can be printed, even if it has protruding sections or disjoint parts.

Once the concrete cures, the finished object can be lifted out of the powder bed. Fast-drying materials such as drywall compound can be used in the mix so that curing only takes a few minutes.

Crazy.

Yeah... But there are only so many things you really want to make out of cement....

The main goal of this printer is actually to print molds for casting. Instead of directly printing the object, the machine prints a shell around the object. Then we vacuum out the uncured concrete dust from the center of the mold and fill it with molten metal or liquid plastic epoxy or A-B foam mix or rubber or just stick some rebar inside and fill it with properly-mixed concrete with coarse aggregates.

Then, just crack off the concrete shell and we are left with a cast bronze statue, or something like that.

Interesting...

Also, since the only concrete mix that is actually "used" is the stuff that got wet and cured into rock, the rest can be recycled. Printing a shell mold for a large, intricate cast part would only consume a few dollars worth of material.

And, since we plan to print just the shell of an object, the printer can run a vector-path of the outline of each layer, instead of raster-scanning the whole thing. This makes it very fast, even for really big objects.

How big?

The current 3D Mineral Printer prototype has a print area slightly smaller than 1 cubic meter. The design is very scalable and can be made much larger in any dimension. See the hardware section for more information.

So who are you guys, anyway?

The 3D Mineral Printer was built for the senior engineering design class at UCSC. Leif Ames came up with the idea after he was exposed to the world of DIY 3D Printing by The CandyFab Project. After doing some experiments in his back yard to prove that the concept was sound, Leif pitched the idea to his class and managed to get some help with the project.

The 3D Mineral Printer team for CE/EE 123 A/B Engineering Design Project at UCSC consisted of Leif Ames, Matthew Bowman, Marides Athanasiadis and Terrell Edwards.

The class is now over, but the project is still being maintained by Leif and Matt.