What is a 3D printer?
A 3D printer is a machine that prints cross-section slices of an object on top of each other to build a physical object from a computer model.
There are many different types of 3D printers that print with a variety of materials, such as plastic, metal, or even sugar.
What does this one print with?
The 3D Mineral Printer uses hydraulic minerals such as cement and plaster as a print medium. These materials are available at any hardware store at a low price. These minerals can be mixed with sand and other materials to make a good concrete mix for 3D printing.
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.
The wet parts of each layer will cure into rock-hard concrete, and the rest remains in a powder form which can be brushed off later. Concrete cures via 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 over and over, stacking layer upon layer, building up a solid object inside the pile of dry, powdered concrete mix.
The dry concrete mix acts as a support structure during the printing process, so objects with protruding sections and disjoint parts can be printed.
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.
But there are only so many things you really want to make out of cement....
A major goal of this printer is actually to print molds for casting. Instead of directly printing the object, the machine prints a mold to cast the object from another material.
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.
How big is it?
The current 3D Mineral Printer prototype has a print area slightly smaller than 1 meter in each dimension. The design is scalable and can be made much larger in any dimension. See the hardware section for more information.
How did it begin?
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 a small team formed to build the printer.
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.