kulfuerst

in cura I also enabled "equalize filament flow" which helps sometimes. the setting is extremely moody though. sometimes it does nothing, other times the difference is huge. it's really strange. the preview in cura also shows this but I've stopped trying to understand cura a long time ago 😄

Hi Camaro, I have started rigorously drying all my Filament before every print! this solved the issue almost entirely. with some filaments that tent to ooze strongly no matter what, I disable "fill gaps between walls". this solves it in even the most stubborn cases 🙂

I think I may have solved it! In all my prints that show these defects, a section was made up of very fine lines with which cura fills gaps between walls. I believe that during these very fine lines, filament oozes away DURING printing because extrusion is so very low, causing ever so slight overextrusion in the structures prior to the retraction! So after the next travel move, the nozzle is empty and has to first fill up before the print can continue as normal. Usually, these defects occur in infill and are not visible in the finished print. This is unless there is no infill, either because the print is very thin and consists of only walls, or because a part of it is narrow and made up of only few lines to begin with! That is also why this issue shows up besides holes so often. I can't believe I may have finally figured it out

I think I may have solved it! Is it possible that there was a section of very fine lines before the retraction that causes your issue? I believe that during these very fine lines, filament oozes away DURING printing, causing ever so slight overextrusion in the structures prior to the retraction! So after the next travel move, the nozzle is empty and has to first fill up before the print can continue as normal. Usually, these defects occur in infill and are not visible in the finished print. This is unless there is no infill, either because the print is very thin and consists of only walls, or because a part of it is narrow and made up of only few lines to begin with! That is also why this issue shows up besides holes so often. I can't believe I may have finally figured it out

Shouldn't the extra prime amount roughly be equal to the coasting volume? To normalize the pressure again.

I have also found some other threads in multiple forums, but nobody I talked to has found a solution or even a cause! Most have given up. Currently I am also out of ideas what could be causing this. In the meantime I have switched from stock to a titan extruder, but the issue persists. I therefore rule out the extruder as a cause with relative confidence. If anything, my current working hypothesis is that retraction distance could have something to do with it. Still figuring it out.

My current topic. Maybe we can troubleshoot together, I'm sure you already know some things about this that I don't. I took a video of the problem, maybe that can help. you can see the video here https://photos.app.goo.gl/G3TLKveMsLNRQmgv7

here is just one example of this issue occuring previously for other people. In this thread, which was unfortunately discontinued, a lot of parameters were also changed with no noticeable results. From my observations I can second the statements made in it. In my case though, I even have a video which unmistakably shows what exactly the problem is, not just a picture.

yes I have. And according to other entries in other forums and also this one, variations in speed made no difference for them either. If it had anything to do with speed, then I believe this stuttering would also occur constantly, not only at specific points. I'm not saying that I know what it is, I really don't, but some things can be ruled out and speed appears to be one of them.

Not limited to a specific printer as far as I can tell, but don't quote me on this.

Hello Quack3D, have you found a solution since you posted this? I have encountered the same problem recently and would love to hear if you were able to solve it.

The problem occurs in all line types, it doesn't matter what the kind is. The only thing that matters is that a retraction took place beforehand. what baffles me is that the spacing of the dots decreases until it becomes a steady line. Esteps are constant though, aren't they? What causes the frequency of the stuttering to increase? Also, the fact that these dots are placed shows that there is indeed filament in the nozzle, otherwise nothing would be extruded. Long story short, this makes absolutely no sense to me. I am not the first one to discover this issue btw. A google search yields many entries in forums of people having the same issue, but no solution anywhere. I find it surprising that this somewhat common issue appears to be so difficult to find a solution to...

Since the problem only occurs after a retraction, I am confident that it is also somewhat caused by it. As you can see in the video, the speed is no problem for the extruder after it has established a steady flow. The problem is also occuring in the wall, not the infill. There is no infill in that part of the print.

Another example, this time fortunately only in the support, the print itself shows no sign of it this time. The cause for both is probably the same tho, so I'd like to figure it out. I am using Cura 3.6.0 as a slicer btw.

It's an Anycubic i3 Mega. Sorry for not clarifying that right away.

Hello everyone, I am having trouble with some strange underextrusion. In some prints, maybe 1 out of 10 and in only certain parts, the PLA is extruded in little pulses that increase in frequency untill they turn into a smooth line. This always happens at the beginning of a new layer, after z-hop and retraction. Due to this the print is massively weakened at these parts and shows striations on the surface. I managed to capture this on video and also have a picture of it, but I have no idea what could be causing this, especially because it only shows up every now and then. I would be very grateful for tips and help regarding the issue. Here is the link to the video: https://photos.app.goo.gl/G3TLKveMsLNRQmgv7 Thank you very much! [edit by gr5: note solution was found by the original poster - see 2 message far below by author with "heart"/like icon]