MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
holy crap....that is a lot of new parts!
My escape room friend kept my printer busy for days, but I finished the last of his parts yesterday afternoon. So, I am back at it as of this morning.
I did have a few other thoughts after re-reading your posts and thinking our setups and some observations from past testing.
try less weight....I suspect that a bolt and two nuts will be required, but it would be interesting to try just one. Definitely do not start testing with three nuts.
see if the spool is balanced or not before testing....I've had some very unbalanced spools to PLA in the past, but nothing that would keep the rewinder from working. But, TPU might require the spool to be -mostly- balanced. I played with spool balance a bit in the early days of design and came up with a way to test for and correct it.
My test is to put the filament spool on the shaft/cap/nut assembly and to place that on an empty stand (no track and better if no gears also). The spool should rest in any position you place it and not move. If the spool starts to turn when you remove your hand, it is out of balance. Whenever it stops moving, the heavier side will be down. At this point, I attach some weight (paper clips, etc.) to the top of the spool (lighter side will be facing straight up) and test again. Once the spool is fairly balanced, you can attach the weights to the outside of the spool with tape of glue stick.
again, I found that spool balance was not an issue for any normal, stiffer filament. But, it would be interesting to know if you failing spool is unbalanced and if balancing it corrects the issue,
The PTFE tubing I use between the spools and MMU is some really cheap stuff (varying OD and likely varying ID, etc.) and has been reused across multiple designs and now has many "kinks" that have only been mostly straightened out. It is definitely not a glass smooth and low friction solution. I plan to buy some new tubing and replace it soon. But, I am now wondering if the additional if the additional friction in my setup might perhaps be helping with TPU. It certainly seems counter-intuitive. but, it is a variable that i need to test and eliminate.