F16-like Control Stick Assembly Grooves

 

Added some what I called "assembly grooves", or "assembly features" on the F16-like control stick body for the one solid body stick. The two-halves body does not need this "feature."

Here's why and what it is.

You see, when I bought a genuine OTTO U2-16 trigger assembly (about USD $150+, see picture below), and 3D modeled it for designing the control stick, I did not model the two small rivets, and the large hollow rivet that also serves as the pivot point. They actually extruded out of the side faces by something like 0.3mm. I didn't think it significant to model. Plus, I chose the two halves split as you see in the picture below. That... once I tighten the two halves with some M3 stainless steel screws... will compress the soft PLA body to accommodate the "extra" thickness of the rivets. Well... not quite... pivot rivet got compressed... sure the assembly went well... but... due to the compressive forces, now the trigger get stuck. So, I had to modify the design to accommodate the thickness of the "pivot" rivet. Print again, assemble again, test.. good... works... done and done... or was it?

So, now the test fit is done... in PLA... and seems to function well... how about other better materials? Say, forged carbon fiber? Basically, it's chopped carbon fiber strains, called chopped tows, and you dabble epoxy on the one of the molds, and you compress it down with another mold, squeezing out excess epoxy in the process, and end up with a fully filled epoxy carbon fiber composite part. Mine... has a bit of the problem with the two part mold for the "forging" action. I have a hollow core. So, the idea was to print a negative shape of the hollow with Ultimaker Breakaway filament... put it in the mold and then compress... blah blah blah... Didn't quite work out... so, change plan to use vacuum bagging for forming the inside hollow. That produced a kind of forged carbon fiber stick body... in one piece.... see picture below.

There are some defects... so some improvements are needed, mold design, composite skills, better vacuum pump, new machines for sealing the plastic bag... new bagging material, like Stretchlon 8... order, wait for delivery, try out... fail... improve.. etc. etc.

So, eventually I bought a new 3D printer with hardened gears and nozzle... a Bambu X1 Carbon. So, I decided to print it with the Nylon12 Carbon Fiber filament... in one piece of course. That was a smashing success! 100% infill, strong, feels weighty and substantial in my hands, unlike the hollow 20% infill PLA which feels cheap and breakable although I would be hard pressed if you could break it by squeezing it like a egg. No, it's not that weak... it would be workable, but might have trouble on connecting to the shaft of the controller base. It would probably need some glass/carbon fiber enforcement for the shaft (as was originally envisioned), but it would work.

But the fit test of the OTTO trigger encountered a problem. With PLA printed one piece controller, I can squeeze in the trigger and the PLA wold yield "properly", but Nylon12 Carbon Fiber would not yield enough to the trigger to go in. Squeeze hard enough, it will go in, but the trigger would get stuck.

Hence, the added design feature of the assembly grooves for the trigger to go in, see the two "grooves" on the inner side wall of the controller right next to the trigger.

This feature, obviously is only needed for the the one-piece controller. The split halves version doesn't need it.

I might design my own trigger with optical sensors, so I don't have to debounce the trigger. After all, the trigger is THE part most critical of latency. If I had to soft debounce the trigger signal, that would drag the latency of the rigger signal to the range of tens of ms...