Large Bellows Manufacturing
The objective of this project was to increase the volume of the cryogenic fuel bellows while simultaneously mitigating manufacturing flaws such as thinner material points and “webbing.” To achieve this goal, I first standardized the production process to address these issues as best as possible. I then devised a bellows design featuring a lower (improved) draw ratio, thereby minimizing material stretching and webbing compared to the initial mold I inherited.
The ultimate aim was to produce a higher volume bellows capable of being actuated at 25 Kelvin for 5,000 cycles without any leaks.
Before
The production process for the bellows was thermoforming by necessity. Blow molding would be more ideal, however we were unable to find any manufacturer that would accept a volume below 10,000 units. As such, the only rapid prototyping option available to us was thermoforming, so we were stuck with it and had to innovate. I took this knowledge and decided the best course of action was to standardize and perfect the process.
Before the standardization of the process, it was rare to get a good result and we ended up with some pretty gnarly results most of the time. Even if we got a good result, it would not survive the amount of cycles we wanted, which was about 5,000 at cryogenic temperatures. The only ways to achieve this was to create smaller bellows, lower the volume, or strategically place the deformities so we could ignore them.
After
Following the standardization of the process, we achieved significantly improved results that demonstrated resilience to cryogenic temperatures. This standardization encompassed meticulous control over time, temperature, process, force, and various other parameters. With this process refined as possible, we successfully manufactured an almost flawless bellows featuring a smaller draw ratio and a larger volume. It served as a crucial steppingstone toward the development of the higher volume design, which are the images at the top of this page. Below, you can observe the testing of the smaller standardized bellows submerged in liquid nitrogen.
Unfortunately, I left Hyper before the large dewar that we needed to test the large volume bellows was delivered.