RE: 0.05mm layer height is possible and I'm sharing
(and yes, I realize a part like that would be a bear to print in one shot; this is a *very* early draft and all I have time for today)
Given the shape involved I think that's a bad goal. I'd go for a mount that attaches to the carriage and then the bucket mounts to that. That should make the design and printing much easier.
RE: 0.05mm layer height is possible and I'm sharing
Yeah, I hold no reservations there. it'll probably end up being a screw-together assembly, *if* it stays in this general shape. But I'd wager it may well be possible to make it clip-on so no Z-top removal is required. I'm trying to keep this somewhat universal as I currently have a skelestruder and don't want to maintain a bunch of different designs if I can help it. What I have in mind would be that the only thing to adjust for different carriages is the trip arm length. I'll split, print, and glue this on Thursday to get a better sense of how things fit and what room I have for the "activation" mechanism.
RE: 0.05mm layer height is possible and I'm sharing
I started collecting some info in my gitlab project: https://gitlab.com/gnat.org/originalprusa/tree/master/devices/mmu2/bucket
I figure it would be nice to capture the important parts of this discussion somewhere better than Wordpress... 😉
Feel free to send me PRs (or send me your gitlab user and I can just add you directly to the project as a contributor).
Oh and turning on verbosity in the gcode really didn't add anything useful 🙄
RE: 0.05mm layer height is possible and I'm sharing
Good idea. I'll set up an account later today.
RE: 0.05mm layer height is possible and I'm sharing
Surprise win today - I was able to tweak print it as a one-shot with no supports and some pretty serious bridges. Needs some fitment tweaks, but the theory seems sound - I printed from some crap PLA and lined the "bucket" with a piece of foil to keep it from sticking. Extruded plastic just slides right down the chute and to the side of the bed. I also deliberately left some space for a wiper blade of some kind to sever the purge from the nozzle.
Worth noting we probably want to avoid going to 255, my printer bumps into the X end at ~253, and actually hitting it is likely to cause skips and layer shifts (unless we can rehome X after a purge?... still seems risky though)
Now to noodle on the mechanical bit to make it rotate or pop out when the extruder gets close...
RE: 0.05mm layer height is possible and I'm sharing
Surprise win today - I was able to tweak print it as a one-shot with no supports and some pretty serious bridges. Needs some fitment tweaks, but the theory seems sound - I printed from some crap PLA and lined the "bucket" with a piece of foil to keep it from sticking. Extruded plastic just slides right down the chute and to the side of the bed. I also deliberately left some space for a wiper blade of some kind to sever the purge from the nozzle.
Nice! The foil idea is a good idea. Readily available, prevents sticking, and will also reflect some of the heat away from the bucket too which should add to it's longevity.
I've wondered about the blade idea myself. I think we want something that that can get close to the nozzle to clean it as best as possible, but we don't want it to melt and deform.
Worth noting we probably want to avoid going to 255, my printer bumps into the X end at ~253, and actually hitting it is likely to cause skips and layer shifts (unless we can rehome X after a purge?... still seems risky though)
Now to noodle on the mechanical bit to make it rotate or pop out when the extruder gets close...
Rehoming is possible, but I don't think that is ideal for a few reasons (time being the biggest).
It will be easy to add customization settings to the post processor so it can be tweaked to fit the bucket system being used (even if they use a fixed bucket on the plate itself. The important part will be knowing the size of the extruder and where it would impact the bucket.
RE: 0.05mm layer height is possible and I'm sharing
Yeah, it may be a tad tricky to get right. a wiper pad or something might be problematic because you now need to ensure the height is right, and you limit the design to certain extruders that fit the adjustment range, and while some brass bristles is more forgiving, I suspect they'd have a tendency to grab and perhaps re-deposit things back on the nozzle.
I'm thinking perhaps a V-shaped notch to the rear that traps the strand and just tugs it away. If it's been given some time to harden then the point it breaks free will be right at the nozzle.
But simplest things first, folks have reported using cardboard to wipe their special coated nozzles; I've got plenty of that around and it's an easily sourced consumable.