RAPID is the name of a 3-D Printing trade show and conference. The 2015 edition was held last week in Long Beach, California. While there was little on display with a direct relationship to composites and architecture, there were several things that had interesting implications.
“3D Printing” is exploding in uses, in a variety of fields. Its technology and applications are changing so quickly that it has really outgrown its name already. “Additive manufacturing” is also in use. Considering the numerous rumblings in the press about various entities and partnerships trying to 3-D print houses, perhaps “additive construction” would be more appropriate to cover the range of industrial and architectural uses. But because of the way popular culture works, we’re probably stuck with “3D Printing” for a while.
There are several different methods of 3D Printing at this moment. Fused Deposition Modeling (FDM) is the one probably most familiar to the general public. A moving “print head” lays down a tiny trail of molten plastic, layer by layer, guided by a 3-D computer model.
That is the method that is most compatible with composites, at the moment. A dual-head desktop FDM machine that lays down either pure plastic or resin-impregnated fiber was profiled here a few months ago.
Now, composite raw material – plastic with short glass fibers mixed in – is available. According to one printing service at the show, these fibers tend to orient along the extrusion path, making it possible to achieve a rough control over the orientation of fibers throughout the 3D build by controlling (and engineering) the direction in which the print head is moving across successive layers.
One of two robotic arms that were engaged with building something out of carbon fiber. It looked like an oddly-shaped section of ductwork. Unfortunately, there were neither printed nor live human explanations available for this display.
The printed orange thing becomes a table-pedestal with the addition of a glass top. Displayed on it is a working bolt-and-nut that was 3-D printed as a single build. (They should have put a head on each end of the bolt if they really wanted to show off.)
The other types of 3D printing are also guided by a 3D model, and they all tend to build in layers. There are several types of powder-bed printers: a box holds a loose powdery material, which gets joined together one layer at a time, a layer being defined by the granular size of the powder.
Metal powders and silica sand can be fused using a laser (laser sintering). (A really great visualization of this method is provided in a video where a large lens concentrating solar energy is substituted for the laser.) The laser can focus on very tiny areas, making it possible to create parts with a fine degree of detail. The laser fuses a thin layer, the bed drops a tiny bit, and then another layer of powder is fused.
Powder beds can also be used with a chemical binder that is jetted into the material from the print head (instead of laser sintering). Sand can be bound with a silicate compound that reacts chemically with silica (glass). Another binding method on display involved a photo-polymer that is fused using light.
There were even three machines demonstrating a wetbuild method, where a laser is used to fuse a solid out of a liquid bath, with the “print-out” being gradually pulled up out of the bath layer by layer as it is built.
Another method – not seen at the RAPID show but readily visible in online videos – involves extruding wet concrete from a moving head to 3-D print buildings. This method has reportedly been used to build 10 houses in a single day in China. Architecturally speaking, the appearance of the walls resembled giant worm castings, but the proof of concept was nonetheless there.
Perhaps the most intriguing achievements at the show were the printed moving parts. Whether by extruding plastic or fusing metal powder, a variety of single-build moving parts were on display, objects which could not be assembled, nor disassembled without breaking them apart. Many of the ones on display were made just for that purpose: to show off the possibilities of the system. But there were certainly numerous practical examples, especially multipart objects that were hinged together, but made in a single build.
This colorful object was built in a single build, simply to demonstrate what you can do with FDM 3D printing. All the parts move. There is no known practical use for this thing, except to stimulate the imagination.
Another multi-part object that could not be assembled from individual parts. Each ring is a center-section from a hollow sphere. They were built in a single build, and cannot be taken apart.
The real breakthrough represented by these moving parts was expressed well by one of the vendors at the show. “Most of industrial design, until now, has been driven by the need to assemble simple parts to make complex objects. When you don’t have to assemble it, it utterly changes the way you design.”
This is where the implications for architects may be the greatest. Does the freedom from assembly issues make possible new ways to deliver the on-going, universal needs of architecture? For example, what could you do better if you can build houses with HVAC ducting and plumbing pipes integrated into the very fabric of the walls and floors? Could plumbing in the walls double-function as radiant heating, making air-driven HVAC unnecessary? (You take it from there…)
Architectural offices are already using 3D Printing to make architectural scale models. It is only one of probably dozens of professions that have adopted a technology that was once solely the domain of rapid prototypers. (A woman at the show mentioned her company’s business making 3-dimensional, patient-specific “guides” for surgeons to properly plan and instrument surgeries.) And several high-powered entities in the architecture/construction world have announced their intentions to 3-D Print buildings. It seems like a natural time for composites to emerge more fully into the construction world, too, using additive technologies that can leverage the composite advantage.
Imaginations are hard at work today, creating new applications and new technologies in this area. Imagining the possibilities requires a major re-adjustment of your thinking… but what possibilities!