Problems with filament jambs

[RobH2]

Very interesting. I've always had my spools unwind on a dowel (actually, a small section of PVC water pipe) and never ever had a twist issue. I'll keep an eye on it now that I know it can happen.

[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

[3D OZ]

CalifDan,
Glad we could help with your twisted filament issue. I have encountered this issue with every roll I've used (dozens), some more than others. A good spool holder that feeds off close to the extruder drive helps a lot. Guides that keep the filament as straight as possible between spool and extruder help too. Not always practical.
I don't think it's caused by twists built into the filament during manufacture or large spool-small spool transfer. I think it is an inherent behaviour of the filament having been wound tightly around the relatively small diameter of the spool hub. This is why a new spool with the first 70% wound around the larger diameter of the remaining filament doesn't display this problem.

As to problem No2, do you check your Cura slices by changing to the "Layers" view before saving the G-Code? (Top right corner of the object view) I have discovered many Cura oddities before printing by performing this step. You would have spotted the missing cutout and could have corrected it. Check the expert settings and experiment with the "Fix Horrible" settings as these often cause strange results in Cura G-Codes. Use the layer view to check what Cura will do before you export your g-code or print.

Problem No3, the Y-Axis shift is hard to diagnose without more info. Does it happen often? Loose belts? Has it happened only once? Ignore and carry on.

[CalifDan]

3dOz,

The shift only happened once. Last print job. The belts don't seem loose enough to have slipped. In fact, I checked that first. I did not check the slices in Cura. I will repeat it and see what that looks like. I appreciate the advice.

I would like to figure out how to effectively use Cura. It seems to me that it is a lot more efficient than Slicr. However, I do prefer the support material that Slicr produces more than Cura. When I create a slot (rounded edge rectangle for example) Cura puts in so much material that I find it hard to remove without marking the part.

CalifDan

[3D OZ]

I'm no expert in CURA or Slic3r and I tend to use both. You will probably find one better than the other depending on the model being sliced.
CURA seems a little more intelligent regarding the order that it prints different elements but Slic3r is far more configurable (at least for me).
I'm no fan of the way either one of them adds in support material and I tend to model my own support into the object I'm printing.
This obviously takes time but gives you some more control over where and how the support is used.

[RobH2]

Have you played with Meshmixer? It's pretty easy to get started with it (however it took me 20-minutes to figure out how to delete a model in the panel) and I liked the ability to add my own supports. You have to get used to them but the control is pretty amazing. I happen to like both Cura and Slic3r but I too find their supports hard to remove. That's why I started playing with Meshmixer last week. I have had some interesting results. It might be worth a try.

[CalifDan]

I started with MeshMixer. Maybe I will go back and give it a try. Modeling in the support seems like a good idea. That might take some experimenting.

CalifDan

[RobH2]

It definitely takes some experimenting. Sometimes they come in at extreme angles that you know won't print or stand up. But there are controls to modify that. It allows you to add bracing between supports which was interesting. I got lost in just building crazy stuff and forgot all about a real print. I just had fun making a crazy support scaffolding for awhile. It was kind of fun. Who new you could have fun making supports?

But seriously, experiment with it. I was able to print a few things with minimal supports in comparison to Cura's supports "everywhere."

[printbus]

What version of Slic3r are the support comments pertinent to? The Slic3r release notes mention how support functionality was rewritten from scratch in v1.0.0.

[CalifDan]

Interesting. I did a print this morning using Slicr 1.1.7 and it completely missed the support for a long opening. It was a rectangle with rounded ends about .3 inches high and 2 inches long. Slicr put in the support at each rounded edge but completely missed the rest. It managed to bridge after a few passes on top, but unfortunately, an otherwise great print is not usable.

I loaded 1.1.7 yesterday. Otherwise, I have been going back and forth with Slicr 1.1.6 and the last .9 whatever version. I sure will be happy when they get 1.2 working where you can review the entire print. I tried 1.2 but it failed with a bunch of errors trying to output the g-code file.

CalifDan

Edit: Never mind, I had the don't support bridges box checked. Something new learned. I don't even remember seeing that before.