I just finished a design and fabrication project. Along with the sense of completion comes a whole host of other emotions. Relief, first and foremost, that the job is done. But with it regrets that maybe it should've been done better.
Over the years I've done a number of design and fab projects, as well as straight fabrication projects. I get more satisfaction out of the former, though the latter are never any easier. Projects I do on my own for my own self tend to be over-engineered, and sometimes under-manufactured. The old adage of design to the micron, measure with a caliper, cut with an axe, and repair with a sledge hammer isn't too far of the mark. But at work I tend to strike a better balance.
This last project involved a heat transfer problem. I had a fixed amount of heat input, and a heat exchanger regulated to a given temperature. I needed to make a heat pipe to move the heat off of the source and over to the heat exchanger. This boils down to a cross-section you need to maintain over a given length for a given material.
Unfortunately that's never quite how things end in real life. The first one, made out of copper, was deemed too heavy for the mechanical elements in the system. Back to the drawing board. The second, made out of aluminum, but with the same thermal characteristics, weighed half as much. Even so, it was still deemed too heavy and was rejected.
The third and final design was a compromise. It's half the weight of the second one, but has half the cross-section. It won't be able to perform to spec, but it's better than what's there right now. The engineers involved in the project all agreed this was the course to take, so we took it.
The final parts looked ok. Certainly they're better-machined than the earlier ones, which were prototypes at best. Even so I can't help looking at them and wonder, could I have come up with something that would give me everything I need within the weight limits? From a theoretical standpoint I have to say no: It's all about cross section times length, so no matter how I cut it I'd have the same amount of material. But I still feel dissatisfied that I couldn't deliver, even if I was trying to deliver the impossible.
Still, even with the design and fabrication end of things winding down, I can't wait to see how they perform. These are an attempt to mitigate an overtemp condition in some electronics. The proof will definitely be in the pudding. If the parts continue to fail, I lose. If the failures stop, I win.
Maybe that's what I like so much about design and fabrication projects. They're not that different from the structure of a novel. You have a problem that needs solving. The climbing action is the set of events that bring you from the statement of the problem, through the R&D, to the final design and fabrication. The declining action is the testing, tweaking, and installation of the final parts. Each step of the way there are problems to solve, tasks to complete, choices to be made. Each is a chapter in and of itself, and each one closes with a cliff-hanger that pulls you into the next problem, the next task, the next choice. And even at the very end you're wondering if this is it, or if there's going to be a sequel.
-- Pencil
