Putting the science in fiction - Dan Koboldt, Chuck Wendig 2018
Printing the far future
Star wars and the far future
By Jamie Krakover
When looking at far future technology, one of the most popular pieces from science fiction is the replicator from the Star Trek franchise. The idea of printing anything from a meal to a needed item on demand, in a matter of seconds, is incredibly appealing. While 3D printing is exploding in popularity across numerous industries, how realistic is this technology application?
How 3D printers work
To answer that question, we first need to look at how a 3D printer works. Most 3D printers use some kind of material for a base, either a plastic, wax, or metal in the form of powder, wire, resin, or filament. Then a heat source such as a laser or electron beam is used to melt the material in a pattern designated by a design file typically from a computer-aided design (CAD) program. The material is laid out or fed along a pattern. The heat source then melts the material to the part being built. It sounds relatively simple in theory, but in reality there are a lot of concerns that go along with 3D printing.
As material is added to a build structure, there are a variety of ways things can go wrong. Everything from warping to gaps in the structure can occur. This makes for messy and damaged parts. When heating the material on the part build, stress can build unevenly, which causes cracking or other deformation in the part. Depending on the material and method of 3D printing, there are ways to prevent this from happening, but it involves careful planning and monitoring throughout the setup, printing, and even post-processing of the parts.
Another concern with 3D printing is the ability to repeatedly and reliably print parts. The smaller printers that in-home users purchase are not highly calibrated like the larger industrial printers used for more mainstream applications. Even with the same print program on a finely tuned printer, the end result can vary from print to print or even across different printers much like two Xerox printers at FedEx Office. Similar to how colors can slightly vary, or paper might jam more in one printer over another, no two 3D printers are exactly alike. And guaranteeing the same result from the same printer, let alone two different ones, can prove difficult. Depending on how finely calibrated the printer is, the user may get more variation in the part than desired.
If you can get past the possibility of deformations and part variability, the next concern is the surface roughness. For some applications a jagged surface isn’t a problem, but you aren’t going to get a smooth and/or shiny surface from a 3D printer. Parts coming out of a printer frequently have the consistency and roughness of sandpaper. Just as sandpaper has different levels of grit, 3D printed parts vary in surface roughness. Plastics tend to be smoother than metals, but printed parts usually have to be post-processed with some form of machining to reduce the roughness.
The part construction aside, there are additional issues with 3D printing. In Star Trek, a user requests an item from a replicator and within a few moments it appears. In real life, 3D printing isn’t nearly that fast. It can take hours or even days depending on the size of the part and the speed of the machine. It can take up to an hour to print one small plastic trinket a few inches tall. The larger and more complex the part, the longer it takes to produce it. In addition, parts are constrained by the size of the 3D printing chamber. Small in-home printers can be purchased for as little as a few hundred dollars. But parts are limited to about a square foot in size. The bigger the chambers, the more expensive the printers. And while multiple parts can be printed at once if the chamber size allows for it, the speed and size restrictions make for an expensive, lengthy process to print things in mass. Adding more to the cost is the fact that it’s not cheap to constantly heat material to the temperatures required to melt and build up a part for hours on end.
How long until we have replicators?
In theory 3D printers are similar to Star Trek replicators. You are taking one material and changing how it is constructed, but there are currently limitations on how you can go from one form to another. 3D printers don’t rearrange molecular structure like replicators do. Currently, 3D printers take some form of solid material and “melt” it into another shape. This not only changes the original format of the material but also its durability and strength.
In addition, you still have to store all the material to print things. So while a printer could be relatively small, the amount of material required to feed a whole ship and create various supplies via 3D printing wouldn’t save much space from actually storing and carrying the fully formed items themselves. Plus, most 3D printers currently only function with one material at a time, so if you were printing food it would be pretty bland and boring. Looking back at the consistent and repeatable issue, if you want food to taste the same every single time, getting that balance could be tricky. On the flip side, with a ship full of different tastes buds you may want to customize what you are printing, in which case getting the right balance could also be tricky with all the 3D printer settings.
At this point, some of you are probably thinking, hey, they’ve 3D printed a car, why can’t we just print a whole spaceship or other stuff already? It can’t honestly be that hard. But it is in fact very difficult. The cars that have been 3D printed are mostly just the frame, with additional parts added. This is perfectly fine because the cars do run, but they run much slower than your average vehicle and are typically much smaller than a standard car.
So what is 3D printing actually good for today? 3D printing is currently useful for one-off parts, trinkets, smaller parts, and parts that aren’t required to support huge loads. If you have something that will experience limited use or is solving a function other than weight bearing, 3D printing might be the right route. It’s also great for complex shapes and/or reducing part count. Many times, other machining techniques make complex shapes difficult or expensive to manufacture, which can drive up part count and assembly time. But if you can 3D print something, you can do difficult shapes in one run instead of building multiple parts and then assembling them.
We’re still a ways off from a lot of far future science fiction applications, but with the current interest in 3D printing and the amount of research going into it, we may get there one day. Not exactly to the replicators seen in Star Trek, but we may be printing products on demand from our own homes or somewhere across the universe.