Spool Size Questions - What's your largest for a 1KG?
Ok, but have you got any numbers?
Whatever’s your largest hub?
I respool everything to Prusament spools just for that reason.
Spool 200 mm diameter / 66 mm width
Filament 100 mm diameter
Axle 50 mm
Thanks. Thus far my widest is 68mm (overture PLA), largest flange 200mm, and smallest hub was 70mm. 50mm hub is VERY small and will increase the revolutions needed for an 18” retract to 3 from just short of 2 for a 70mm hub. What filament had that side hub (axle)?
I've never respooled any filament, but I expect I'll need to one day. Do you have an easy/automated method to do this reliably? Seems it could be a really boring job without some type of automation.
Well that’s bigger on the flange and width size but not the smallest on the hub size (50mm). Looks like I’ll need to add another 8mm to the width of the stand if I want to use ninja.
What do you use for respooling? I line a couple of my auto rewinders minus the gravity weight back to back and go that route but it’s not ideal. Would love to have something that does a good job of the back and forth weaving as part of that process as despite my best efforts to get a dead on spooling all it takes is a split second of losing tension on the filament and I have to unwind a lot of work and redo it, which takes a long time when I get a knot or something in a pretty much brand new spool (overture, matter hackers, I’ve given up on both of those outfits due to too many tangles).
The spool width will drive the axle size and subsequently the width of the entire rewinder assembly. I’m hoping to be able to fit this in a dry cereal box (starting to look less likely) but definitely want to keep all 5 side by side under 29”, ideally less to they’ll line up on the enclosure top to minimize the PTFE tubing length going down to the MMU.
Hub size (smaller is worse) drives how many revolutions the rewinder will require to do color changes at the end of a spool. At 68-70 MM (most of what I have, which is Prusa, overture, Matter hackers and CC3D) it takes just two revolutions on a 70mm hub to retract the 17” needed for a color change using the stock feeder PTFE tube length from the MMU to the extractor (also includes the length INSIDE the MMU on the selector side of the pulley gears).
If the hub drops to 50mm that goes up almost a full additional revolution which in turn drives the required height of the vertical rack gear that drives the rewinder. I can do some clever stuff with the stacked gear ratios to offset this, but in doing so will change the torque exerted on the spool at the tail end of the travel, and I’m afraid if I get to radical with the gearing it’ll yank the filament right out of the feed into the MMU. Then again, by the time it’d be doing a full 3 revolutions most of the mass of the filament will be gone, so maybe this isn’t as big of a concern.
And finally, the flange size drives the height of the entire device. If I can stay around 200mm for the spool flanges I can shave off some height from the existing mechanism I’m deriving this design from, which will make filament spool changes easier when the rewinders are on top of an enclosure. Migrating the PC4-M50 connection to the top side of spool vs. the bottom of the frame should help this as well.
Armadillo is Ninjateks hardest TPU with a durometer of 75D same size spools as the Ninjaflex and Cheetah.
One oddball I have is the RepRapper spool, which is about 58mm wide with a center hole of 72mm.
That is an oddball. It’s narrower (most of mine run in the 65-70 range, hub size is decidedly larger, although I’ve got zero problems with that from the rewinder design standpoint. I had read someplace that some materials require larger hub diameters due to being more brittle and they’d break on smaller hubs.
I think you misunderstood me.
The filament is wound onto a 100 mm diameter cardboard cylinder (use this measurement for your rewinder).
The plastic spool flanges have an axle of 50 mm.