I do print "half on the roll": I manually unwind a bit of filament, and then wind it up in the opposite direction around a skater wheel (7cm diameter). And then I let it sitting on the roll, now very loose.
My print jobs rarely take more than 3 hours, which at 1m/h requires only 3m of filament to unwind and straighten. I do this while the printer is warming up and I am waiting anyway.
This has two effects: (1) it straightens the filament and gives it the same bending radius as the bowden tube, ca. 30 to 50cm. So resistance in the bowden tube and nozzle is almost zero. And (2) it completely removes the anti-unwind resistance of the spool, which would otherwise act as a very strong spring that resists unwindind. I also have replaced the spool holder with a frictionless holder with bearings, but I am not sure how much effect this has. I just disliked the jerky movements and sound of the original too much. My UM2 (non-plus) were sensitive to variations in resistance in the feeding traject.
I am not trying to convert you :) , but for me this just works: while not perfect, it is good enough for our prototypes. The benefit is that I don't have left over ends of filament for each model.
But of course this is method would not work for long prints that take days, or for unattended printing.
See this photo where the filament is being bent in the opposite direction around the blue-green skater wheel. A couple of meters are already done and now sitting *very* loose around the spool. The yellow sliding clamp on the edge of the spool is to prevent the filament from falling off sideways. And to prevent it from "auto-unwinding" while I am straightening it.
-
1
.thumb.jpeg.0b7a05eafc09add17b8338efde5852e9.jpeg)
Recommended Posts
yellowshark 153
Well I have nearly always printed "off the roll" as I buy most of my filament loose to avoid entanglement. Now if I print Dutch Orange I do not use the rear holder and instead leave the reel on the floor but unwind a length and at the same time loosen the wind of the unwound length. This provides about 45 mins printing before getting near any danger of entanglement and so not absolutely great because it does require a visit to the printer every 45 mins or so, but does the job ? Lol I certainly would not try to change your mind.
Link to post
Share on other sites
cloakfiend 995
You know where the quality is at!
Doing a big job just isnt worth the risk on the roll and adds tons of post time messing around trying to sand out a weak layer which takes longer than you'd think to sand out!
For small jobs its fine on the roll but for the filament that isnt wound perfectly, I now wouldnt even risk it.
There must be some kind of device that clamps down on the filament from the start to prevent ANY filament skips. Its the only thing i can think of. The pressure applied needs to be consistent though to keep nice beautiful layers.
I find the the last 10-15 percent of a tightly wound roll to be totally fine on the roll. I find TR colourfabb seems to be wound tighter or simply slips less than others perhaps to the texture of the filament? Eitherway ill probably off the roll it for important jobs anyways....
Smooth/slippery filament I imagine would tangle a lot. Its all down to how its wound and surface tackiness....imo.
Link to post
Share on other sites