April ambitions
Added 2023-04-24 14:57:07 +0000 UTC
Heyo folks - update time! A bit later in the month than I'd hoped, but for a reason...
The BigRig is construction is done and ready for testing!
Jebus what a journey it's been. As usual with these things it ends up looking way simple, but y'all know the process has been quite a thing.
Results/status:
- The overall design holds up, and can just barely (~3cm to spare) fit in the workshop height-wise. Woopwoop!
- The mechanics are up to spec, albeit very basic. No electromechanics yet, and the tolerances are a bit wack all over the place. Should be fine for manually tended casts though.
- The weight system works! By which I mean 'did not cause a catastrophic failure'. 4*5kg weight disks, with another 2 to spare if needed. Should be enough to counter the bouyancy of the mold if my napkin math is correct, and I've still got the option to shift the mounting point for them further down the lever of the cradle for more angular momentum.
- Swapped the heavy-duty liner for a slightly more fragile construction plastic sheet. Turns out that surface friction is important. Since I'm not cutting/gluing the sheet this time around, the folds will get stuck if the friction is too high. Causes problems when compacting it, and more or less guarantees wall contact for the mold. Swapped, and that fixed it. A bit more scared of punctures now, but c'est la vie, can't have everything.
- The filler's good enough. Despite lofty ambitions of custom casts I ended up going with stacked styrofoam, which can be easily adjusted and/or swapped out. I suspect I'll have complete 'puzzle blocks' of styro that fit each mold.
- The mold seems functional enough, but we'll have to cast before we can say for sure. The detachable arms/legs work perfectly (as noticed during a construction accident where they detached). The 'replacable' parts may need some further adjustments in later designs. Ended up perma-attaching the feet for now, tricky mechanical weak spot from the foot 'lever action' kept breaking the weaker adhesives I used for swappability. The head could probably use an attachment point redesign too, it's prone to fracturing the edge seal with its jiggling. I'll try this round and see how it goes.
What's left before the maiden cast?
- I've got a 210L rain barrel to assemble. In all likelihood this rig will need a tad more latex than that, but just being able to store everything in one big barrel should make life a bit easier. Considering building a stand for it so as to be able to tap the latex directly into the vat.
- Water test. Fill up the system with water instead of latex, verify quantities and functionality. Going to try to do it asap during the upcoming weekend. Definitely a full-day project.
- I need to re-up my latex supplies... by a lot. I've got a good chunk left over from my preparation order last spring, but not enough. Gonna' cost €2k or thereabouts, so will get it in once I've verified the quantities with the water test (and salary has dropped on the 25th). This is a big reason why I'm always gushing about being grateful for your support! Jfc the scale of this thing... Honestly a bit nervous.
Other leftovers:
As usual, there's a few musts and a few maybes queued up from this. Let's start with the musts that I know I'll have to deal with before any kind of serialized production is possible:
- I will 100% have to redesign the pulley attachment system. The current "quick first version" design is blocking me from being able to easily remove the mold from its cradle after casting. The way it is now means I'll have to empty out the vat before I can safely remove the cradle.
Fine for the first tests and the misc fixes between runs, but not for any kind of streamlined production. I've got some loose design ideas but they need a bit of latent work (aka waiting for heureka in the shower) before I'm ready to start building.
- I'll need to wire up electromechanics once I've redesigned the pulley system. For proper quality the mold needs to be pulled from the vat slooowly and at an even pace, not really viable to do with manual winching. The linear actuators I've got for the small-scale vats aren't useful here, so I'll need to sort out some worm geared winch setup. Details pending.
- I'm going to have to wear-test the casts quite a bit before letting them loose in the world. Even if I'm going to lob the first protos cheaply it's still going to be a decent amount of money. Can't have them breaking or failing, so gotta' make sure they're up to spec. Not gonna' complain about that though, goals.txt :p
Then there's the maybes:
- Probably going to redesign + reprint the arms. The current spread-out design is in part due to issues from the spray-casting process - can't spraycast areas you can't reach. With vat-casting I can compact the posture down a lot, which leads to more compact equipment + savings in e.g. latex vat quantities. With the modular design I can simply print+prep new arms while still using the existing ones for casting though.
(I really should've thought about this earlier, but but... C'est la vie. Better late than never.)
- May redo the head-to-neck connection, which means a slew of reprints. The current one may be okay, but I'm not quite happy with the level of jiggling it's giving me. Will see after the first round of tests.
Wrapup
All-in-all this should soon result in the first cast with a rig and tech that'll be viable for production. Good times! Besides being psyched as hell for the suits themselves, I have to admit equally psyched about doing something other than this goddamn hardcore carpentry for a bit. I started the new rig project around 18 months ago, and it's kind of eaten my life during this entire time... So - new 3d models/designs! Hood/suit features! Chemistry stuff! Media! Fancy stuff for the store! Not sure how I'll roll this, so stay tuned for when we actually get past the first casts.
Speaking of which - there's may+june updates ahead, then usual july vacation. Thinking retro (and rig updates) in june, future plans in august? Will see how the rig testing goes. I'm probably going to try to get the 'roadmap visualization' concept back up and running after summer when I'm no longer 100% consumed by One Single Big Carpentry Project. There'll actually be smaller things to pick and choose from project-wise, omg!
You know the drill - anything I missed? Glossed over? Ping me, comment, etc! Y'all know how much I appreciate the support, and by jove we're almost to the first working fullsize rig now!