Try pressure molding the resin with a balloon inside the box, with a cover attached on the open bottom. It wouldn't need much pressure to squish the carbon fiber fully into the resin. A problem with using a balloon is that latex rubber causes cure inhibition with some resins so a compatibility test of spreading some mixed resin on a deflated balloon would be needed. Could possibly use a plastic bag. You're not making aircraft parts, just trying to not have huge bubbles and voids. I'd make the mold box a full box. No need to have the cutout on one side, cut that out later to precision fit around the weapon parts. Rounding the corners to a fairly large radius would help fend off attacks from horizontal bar spinners, and also increase corner strength. For impact resistance the resin should have some flex so that the robot can be bounced away from weapon strikes rather than the armor cracking. Attaching the shell to flexible mounts would prevent breaking it free from the frame, which would likely include breaking parts off the frame. PLA is not a good choice for the frame because it is too rigid. Very strong but will snap instead of flexing any. PETG might be a better choice.
@TimeExpander
2 жыл бұрын
I'll probably choose a simpler shape next time - and probably try vacuum bagging at the same time.
@tmdybvik
3 жыл бұрын
In order to optimize use of the weight budget, rather add an additional saw blade rather than a small diameter fly wheel. You want to turn every gram into maximum rotational inertia.
@TimeExpander
3 жыл бұрын
Thanks for the tip. I'll pop out and source more saw blades and redesign the rotor later today :)
@greggv8
2 жыл бұрын
@@TimeExpander a benefit of using two saw blades instead of that toothed pulley for inertial is the blades should be far better balanced so you'll have less vibration. What would be really slick is if you could take the blades to a shop with a water jet cutter to have the anti-kickback bumps trimmed off the back sides of the teeth. That would let the blade better hook into anything sticking out from another bot. That's another reason to not use PLA. A good hard hook from your blade could snap the weapon supports or the frame. I'd want to include some sort of slipper clutch (or switch to a V belt) to give you time to let off the weapon switch in case it gets jammed. A lot of toothed belt driven weapons in fighting robots fail because of zero tolerance for getting the thing stuck into the opponent. Get in a lot of driving practice. :) Especially moving with the blades at full speed. Gyroscopic precession will be a pain to deal with.
@TimeExpander
2 жыл бұрын
I ended up ditching the flywheel and stacked 4 blades together instead (same weight, but more mass at the edges). Only the base plate is now made of PLA. The brackets that hold the rotor shaft is now made of polypropylene (which doesn't shatter). That said. PLA is way more durable than you would think. I used the same strategy with my previous bot. This went head to head with a rather nasty drum bot and took a rather heavy beating, but it was still structurally intact after the fight (even though a few chunks were missing :))
@dumdidumdumification
2 жыл бұрын
Jesus dude, love the work, but that blade test spinning next to your hands...
@TimeExpander
2 жыл бұрын
What can I say? It felt perfectly safe at the time :) I didn't really realize how crazy it looks until after I watched the footage myself.
@HenryTriplette
2 жыл бұрын
Nice idea, I'm curious how the taser will work in the end. Also, it's always difficult to balance a saw rpm vs time-to-bite. Sometimes slowing the blade gives more time to "catch" into another bot armor.
@TimeExpander
2 жыл бұрын
The taser is mostly a gimmick, but I might get lucky as well :)
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