Generative Design Podium
What is Large Format 3D Printing
Most 3D printers sit on a table or desk and have a build plate area of maybe one or two feet by one or two feet. Large format 3D printing relies on the same technology while greatly increasing build size. Such printers can be any size, ranging from Dr. David Florian’s DIY printer with a 42”x42”x42” build volume to the Thermwood LSAM1540 which can print a whopping 10 feet by 10 feet. Such large volumes allow things like tables or chairs to be 3D printed. Of course, printing at this scale can present technical challenges, some of which will be discussed below.
What is Generative Design
Generative Design leverages AI to optimize part design. More practically, a variety of parameters are defined, and the resulting part should require minimum material while boasting maximum strength. FormLabs has a great article about generative design which includes a motorcycle with a body that is the result of generative design.
How does Generative Design work?
The generative design process can be broken into three major steps
- Determine the constraints of the design | That is, define the elements which have to be in the design (in this case, the shelves and the logo on the back.) Then, define the forces which will act on the podium, such as a person leaning against it or a heavy book on the shelf. Finally, tell the computer which material the product will be made of and what manufacturing methods are available. For this project, PLA and large format 3D printing were used.
- Let the computer generate potential designs | Generative design passes all of these parameters into an artificial intelligence model which then produces an “ideal design” for the part. In this case, the ideal design was one which minimized the material usage and the weight while still being safe for use.
- Choose a design and edit it | A final design must be chosen and evaluated. Often, the design will require small changes to ensure it is manufacturable. This is especially true when using a technology that is still in its infancy, ie. large format 3D printing.
Below, the first picture shows the result of the first step. The blue arrows represent forces that must be withstood, the green bodies represent components which must be in the file design, and the red box represents space that must be left empty in the final design. The second photo shows the result of the third step.
What makes a model manufacturable?
The criteria vary depending on the method used to manufacture the model. Here, there were three:
- No support material One benefit of large format additive manufacturing is that minimal post-processing is required. Unfortunately, due to the constraints of the printer, support material would need to be machined off, likely with a power tool. This is not viable.
- No overhangs greater than 45 degrees Since the large format printer extrudes such a large amount of plastic at a time, it takes longer to cool than extrusion from a normal 3D printer. Moreover, more plastic means more weight. Taken together, this means that material printed at an angle greater than 45 degrees will likely experience significant sagging.
- No islands of material less than 35 mm As with any 3D printer, the extruder must be able to switch between extrusion and retraction in order to both print and move between discrete areas of the print without leaking material. However, because this printer must output so much material at one time, it takes a non-trivial amount of time for the nozzle to begin extrusion again after a travel move. Thus, if any “island” of material has a smallest diameter less than 35mm (a value based on empirical evidence) the extruder is not guaranteed to extrude which could cause an entire portion of the print to fail.
How was this model made manufacturable?
After the creation and selection of the generative design model, the model was edited manually in Fusion360. The mesh of the supports generated by the AI were measured and edited. In some places, the model had to be thickened to meet the 35mm island requirement. In other places, the angle of supports had to be changed. This can be a time-consuming and monotonous process, and the more complicated the model, the longer it takes.
Of course, making these sorts of changes to the model can alter its ability to withstand the forces it has been specifically designed to withhold. Therefore, it is good practice to run the edited model through a simulation to determine whether it still meets the requisite strength requirements. Hopefully, it will, but multiple iterations may be necessary.
Applications of Large Format Printing: Planetary Surface Construction
A few years ago, there were a number of articles that came out discussing 3D printed houses. These structures were seen as potentially revolutionary in the housing market, although it was also clear the technology was still in its infancy. However, a large variety of such homes were built, and [designwanted has compiled a great list of them] (https://designwanted.com/3d-printed-houses/). The article also lists a few benefits of this sort of construction, including fewer worker injuries, decreased construction time and costs, and minimization of material usage.
Of course, while this technology can benefit humans on Earth, it also has the opportunity to facilitate the colonization of other planetary bodies like the moon and Mars. Indeed, the ability to print a structure like a house or an office in place on the surface of another planet could significantly increase the feasibility of humans settling there. In fact, as far back as 2020, NASA awarded a contract to a company to “expand 3D printing of livable and workable structures.”
Beyond the convenience of printing structures in place, the ability to 3D print anything from tools to structures in space would greatly increase the efficiency of such efforts. Instead of manufacturing components on Earth and packing them for transport on a rocket, raw material could be sent. This material might take the form of pellets or cubes which could be densely packed in order to preserve space on the spacecraft.
Of course, the benefits of this technology are only enhanced by the simultaneous usage of generative design. Efficiency is the name of the game for planetary surface construction, and generative design’s main benefit is that it can maximize strength while minimizing material usage. In other words, every pound of raw material sent to a planet can go further if it is used to print parts that are the product of generative design.
Generative design may also hold the key to getting materials to other planets in the first place. Each pound of weight added to a rocket requires more rocket fuel to launch a craft into orbit. Thus, minimizing the weight of any pre-built structure is necessary. Indeed, NASA’s JPL and Autodesk have partnered to address exactly this. JPL has begun to use Autodesk’s generative design capabilities to explore new manufacturing methods for space exploration. The effort has already yielded fruit: JPL has used the technology to reduce the weight of the external structure of a planetary lander by over 35%, to say nothing of the gains made by optimizing internal components.
In case it was not already clear, here it is worth explicitly noting the particular symbiosis between generative design and large format 3D printing. The growth-like structures that are the hallmark of generative design are particularly suited to additive manufacturing techniques such as large format 3D printing because material can simply be added in the required configuration instead of removed from a solid piece.
Still, this does not mean that this technology is ready yet. Generative design is in its infancy and still requires some optimization. Additionally, printing such a large volume of material comes with technical challenges and design constraints. Moreover, research is still being done on how best to print materials like metals which would be especially useful in planetary-surface construction. Advancements and specialized technology in all three areas is likely needed before this technology is ready for showtime.
Even if the technology were ready now, it’s an open question whether astronauts are ready for it. Wikipedia’s page about planetary-surface construction breaks the practice into three phases: 1) modules ready to be used upon delivery; 2) a kit of pre-fabricated parts that can be assembled upon delivery (think IKEA furniture); and 3) in-place manufacturing with components from Earth. Large Format 3D printing is solidly positioned in the third and final phase and therefore likely only makes sense after humanity has established a meaningful presence on another planetary body. Namely, humans have to go back to the moon for the first time in over 50 years before this technology can be utilized, even if it were already perfect.
Once humanity is ready, this technology does appear to be the key to expanding beyond Earth. It will scale with the needs of future populations, and it can create itself. A number of 3D printers these days are in fact made of mostly 3D components. This is critical to being able to build a self-sustaining colony on the moon, Mars, or any other planet.
CAD Model of Device
Manufacturing
Photos of Podium Print Coming Soon