Foldable Articulated CubeSat for Additive Manufacturing

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Summary- Technology : SLS or SLA Materials : Nylon (SLS) or ABS-Like (SLA) Cost : $190 (Nylon) or $400 (ABS-like) Mass : 53g (Nylon) or 47g (ABS-like) Part Count : 6 Key Features : Flat print, printed hinges, printed threads, low part count Description- This 1U cubesat frame was designed to offer a new and novel way to simplify the fabrication of CubeSat frames through additive manufacturing. The main feature in the design is the flat print configuration. This low Z-Height is optimal for additive manufacturing, since print time is highly dependent on part height. Hinges are printed into the structure that allow it to be articulated into the standard cube shape once the print has been completed. As each panel is raised, a snap fitting will connect it to its neighboring side panel. This fitting will hold it in place during the rest of assembly. Once the frame is fully assembled, a counter-sunk screw is used in each corner to securely fasten the sides together. This will allow the CubeSat to withstand the vibrations of the launch environment. There are 6 total components in this assembly, 5 countersunk screws and the printed frame itself. This significantly reduces the part count from traditional manufactured CubeSat frames (typically between 30-50). This design will print well using either SLS or SLA technologies. The standoffs for the CubeSat push the main frame away from the build plate, thus requiring support material underneath the entire frame structure. Since both SLS and SLA are self supporting techniques, this is not an issue. Nylon would be an excellent choice for the SLS technology while an ABS-like material would be the choice for SLA. Both of these materials are strong and light, making them excellent candidates for spaceflight applications. Since most CubeSat missions are short duration, the effects of radiation and UV-hardening on these materials would likely not be an issue. To evaluate the cost effectiveness of this design, quotes were gathered from a 3D printing house (Protolabs-Fineline). The price for the SLS print came in around $190 while the SLA print was around $400. Both of these costs came down dramatically as the quantity ordered was increased. These prices are very favorable when compared to the cost of purchasing the skeleton frame from current suppliers. For example, from CubeSat Kits the cost for a skeleton frame is around $1700 ($925 Walls PN703-00289, $375 Cover Plate PN710-00296, and $425 Base Plate PN710-00294). The mass for this design is also much lower than commercially available frames, allowing more mass to be devoted to science instruments. Using nylon as the build material, the total mass for the system is 53g, three times less than the 158g for the CubeSat Kits frame from above. A 100g weight saving is very significant when the total mass of a 1U CubeSat is capped at 1330g. Since this concept is designed for additive manufacturing, the mounting features for science instruments could be customized for every new iteration. As such, these features have been omitted from this design. Whether they are simple mounting holes or rails for PCB cards, they would have no effect on the feasibility of this concept. The concept proposed here is an excellent alternative to the traditional manufacturing methods for CubeSat frames. Using additive manufacturing, the part count for a CubeSat from has been reduced from 30 to only 6, the cost for a skeleton has been reduced by nearly a factor of 10, and the mass has been reduced by a factor of 3. All of these advances make it clear that additive manufacturing and this concept should be utilized to further the science capable of CubeSats.