We had been skeptical of the utility of 3-D printing until we saw this video:
This came from Mike Shedlock: 3D Printer Builds 10 Small Houses a Day for $5,000 Each. It turns out we had been thinking inside the box – the printer cartridge box. The problem we had seen was that a printer can deposit a single material and that material must be of a nature that can be sprayed out of a standard printer nozzle. Most devices are made of separate moving parts of different materials. How could you possibly print a spring made form a specialty steel alloy or duplicate a part that is dependent on a material’s crystal structure?
Then we saw this video. Our problem? We didn’t understand the paradigm, partly because we had viewed it as a 2-dimensional process, the deposition of a thin homogeneous layer on a substrate, controlled by a computer. In other words, a mechanization of the centuries-old pen and ink.
In actual fact, the precursors of the 3D printer have been around for decades. Consider the cake decorating bag. Although it can be used to create 3-dimensional shapes, the common use is to produce lettering on the surface of a cake. The process of forcing a viscous sugar/flour mixture, possibly coloured, through a nozzle or opening in the bag in a guided manner is the basic process of the 3D printer. Another common application that falls within this paradigm is the soft ice cream cone machine. Again a viscous mixture of sugar, fats, and other ingredients is forced through a nozzle in a manner controlled by the operator to produce the characteristic cone-shaped extrusion.
Interesting extensions of the paradigm have emerged such as the 3M two-part epoxy system which mixes binary components before they are forced through a nozzle.
The paradigm then is the application of a material of suitable viscosity to a substrate in a controlled manner. The height and width of the deposit are a dependence of the properties of the material chosen. Although current machines move in two dimensions, the problems of depositing in three dimensions are probably limited to materials and computational control. Given materials with appropriate thermal resistivity, there is no reason why we could not use lava from a volcano to build structural products.
Material science will be the area that generates the most interesting possibilities. If 3M can mix epoxy components before extrusion, why not mix carbon fibers with concrete and extrude a reinforced concrete shape. In house construction the joints where wooden components are fastened together are the weak point. How would a carbon fiber reinforced concrete house that is a single unitary structure withstand a tornado? What about developing a “concrete” that has high thermal insulation characteristics to build the shell of a house – in the colour of your choice? How about printing roads?
We can see now that the applications are limited only by ingenuity and discoveries in material science.