Problems with filament jambs

[CalifDan]

Here is what I did for a test. I took the roll of filament which was giving me the problem and unwound it out about 25 feet and turned the roll to takes the twists out of the filament (mostly). I then ran a 1.5 hour print and it ran with no filament feed issues (more on another issue in a moment). Based on that, and the fact that I have done about 20 hours of printing over the last five days on a different roll, I think the problem is the twist in the filament as I get towards the end of the roll. The problem filament is from Ultimachine (recommended by Makerfarm) and so is the newer roll I have used over the last four days.

If the same problem shows up in this second roll (might take a few more weeks to get down towards the end of the roll), then I am going to have to find a different filament vendor.

All of that said, the print was not problem free. About 3/4 of the way through, the whole print shifted about .1 inches on the y axis. I have never seen that happen before. I was using Cura. Also, Cura completely missed a rather large cut-out which starts at the first layer. I later bridged, but not without losing some of the part below where it finally bridged. I am not too worried about that, I can adjust the part to compensate for that, but the .1 shift on the y axis I do not understand. Bug in Cura? Or, did my Y axis suddenly shift by that much?

CalifDan

[clough42]

but the .1 shift on the y axis I do not understand.

As others have pointed out, this is difficult to diagnose. It's possible that it's s software problem, but that's not where I would start. It's usually skipped steps on the motor or a skipping belt.

If you can precisely measure the amount of the shift with calipers, see if it's a multiple of *exactly* 2mm. If so, it may be a belt skip. If it's not exactly a multiple of 2mm, it's not the belt. Friction or inertia (or an outside force) probably overcame the motor's holding torque and it skipped some steps. By "outside force" I mean things like bumping the printer or getting your finger caught between the bed and the Y idler while trying to feel the belt tension. Not that I would know anything about that.

If it only happened once, ignore it. If it keeps happening, you can try making sure your mechanics are moving freely and try slowing down.