Printing the Extraordinary
Just a few months ago, MIT released a video showing a printer that created objects out of molten glass, and the Oak Ridge National Laboratory has a printer the size of a small car that can extrude carbon fiber. However, many of these new printers are specialty; they cost thousands of dollars or more and are confined to printing in their specific medium. Thankfully, there are many filaments that can be used to expand what consumer 3D printers can make. Here are four different unconventional filaments that can be used with ordinary PLA/ABS consumer printers. They are all “composites”, meaning that they work by suspending particles of the desired material in a plastic normally used by the printer.
Two figures printed in wood composite. Image courtesy of LulzBot.
Organic composite 3D printing filaments aim to replicate the features natural materials in the form of a printable plastic. The only handful organic composites I'm aware of that work with consumer printers are wood, cork, and bamboo. What’s interesting about these filaments is that once they’re printed, users can sand down models and even stain them like they would regular wood or bamboo. In terms of strength, organic composites aren’t terribly impressive. Their strengths lend themselves to aesthetics more than function, so users should expect to use these filaments for things like model making. For now, most of the wood composites are simply labeled as “wood”, but in the future look for filaments modeled after specific types of wood.
Several busts printed with copper composite filament. Image courtesy of ColorFabb.
There are lots of different types of metallic composite filaments made by different suppliers, and they cover a surprisingly large range of metals. Aluminum, Brass, Copper, and Bronze are all available, just to name a few. Again, it's surprising how many aspects of the original material are embodied in the composite. In terms of aesthetics, the composite oxidizes similarly to normal metal. A copper composite will actually turn green in time. All of the composites can be polished like normal metal, and patina can be applied for different effects. Aluminum or other light metals are the only ones that contribute to the strength of the material, as most other metals are too heavy to help. One important aspect to consider about these composites is their ability to conduct heat better than normal plastic; makers could print their own heat sinks or other heat transfer devices.
An RC car printed with carbon fiber filament. Image courtesy of ColorFabb.
Carbon fiber is an extremely versatile material in any context, and 3D printer enthusiasts should seriously consider including carbon fiber filament in their next project. Even a filament that is only carbon fiber by mass is significantly lighter than normal plastic. This feature makes it perfect for projects that need to cut down on weight, like quadcopter builds. Additionally, the filament is substantially more rigid than normal plastic, which is important for parts that have a lower tolerance for error. However, this material does come with a major downside: it ruins your extrusion nozzle. The filament acts like sandpaper on the inside of the nozzle, wearing it down much faster than normal plastic, so only use this plastic if you’re willing to get a new nozzle afterward.
A simple circuit made with conductive filament. Image courtesy of Adafruit.
One of the newer composites on the market is a conductive filament. While it isn’t as conductive as normal copper wire, it's good enough to work for most basic circuits. Printing with this on its own is certainly interesting, but it truly shines when used by a dual extrusion printer. Imagine being able to print with both the conductive filament and a normal plastic (insulating) filament at the same time! Users could make three-dimensional circuits in solid objects, and could even pause the printer at certain times to embed components directly in the circuit. Printing in conjunction with other filaments on this list could yield interesting results; imagine a figure that looks wooden on the outside but has a bunch of internal wiring.
The market for specialty 3D printing filament is just starting, so don’t limit your search to this list. In the near future, look for a wax-like filament that would allow makers to cast resin or molten metal objects. For more organic composites, look for “edible plastic” filaments that could be used to make cake toppers or other novelty edibles. All types of makers should keep an eye on this market, because it’s only a matter of time before a filament comes out that is invaluable to their field.