Problem with artifacts on thin walls at seam lines  

RE: Problem with artifacts on thin walls at seam lines

I've seen similar.  I've written it off to speed and trying to print certain filaments too fast.  New extrusion starts don't adhere at first and pull along until they do stick, leaving a small gap at the beginning of layers.   Try slowing down the perimeter speeds, see if that makes a difference.  The other settings that will affect this is jerk - or initial movement speed, and retraction.  You can reduce or even zero the retraction as a test.

ps: you can also try random seams, but that also makes the overall appearance less satisfying.

RE: Problem with artifacts on thin walls at seam lines

Tim's right about speeds.  The other one you might want to try lowering is actually travel speed.  I've had one model where it transitions from the last bit it was laying down on a perimeter to a high speed travel move which also pulled filament from that spot leaving a gap there with a string to the area it moved to.  

RE: Problem with artifacts on thin walls at seam lines

I know this thread is old but it's the most relevant post I've been able to find online. I'm battling with this exact same issue and am going crazy.

I'm printing at 0.2mm resolution and I've halved the speed of all perimeters and it still occurs. I've also lowered retraction from 0.8 to 0.3 and it's still occurring.

OP, were you able to solve this issue? If so, how?

Thanks in advance.

RE: Problem with artifacts on thin walls at seam lines

@vaclav-b11,

I had a new brand of filament to dial in, so I figured I would try out the models you posted to see if I was going to have the same problem.

I didn't have any Issues at all, I'm wondering if your Issue might be related to a partially clogged extruder, if not perhaps your idler tension is the problem, or some friction somewhere in your system that causing the filament not to extrude at a proper rate? 

I included some images.

I sliced these in Prusa slicer 2.2.0 I used the PLA 0.15mm SPEED preset with generic PLA settings. the only thing I changed was the bed temp and filament temp to get in the right range for my PLA and I changed TOP & Bottom layers to be 5 & 5 that's it.

I didn't try them in PETG, I'd be willing but I don't think the PETG was your problem.

Hopefully you have your problem has been solved, if not I would look at the extruder maybe 2 or 3 cold pulls or an idler tension adjustment and see if that helps

Good luck

RE: Problem with artifacts on thin walls at seam lines

For me, this problem only occurs with PETG. With PLA this doesn't happen.

RE: Problem with artifacts on thin walls at seam lines

Hi all,

I am having the exact same issue as the OP and am wondering if this is something to do with PETG? I have been printing ABS for over a year now and how no issues. Just started with PETG (due to the warping and am trying to print the Wall Mounted Drybox link: https://blog.prusaprinters.org/dryboxes-and-alternative-spool-holders-not-only-for-multimaterial-upgrade_30525/) and seem to have this issue with these prints. It also seems to happen on the retractions. 

Below is the screenshot from PrusaSlicer (v2.2.0)

Here is what the print looks like (still printing). All these blobs appearing in the same location. All other corners of the print are fine, with no artifacts.

I have reduced the print speed down to 30mm/s for internal perimeters, 25mm/s to external. I have gone through a couple of PETG guides on how to print and applied all the settings, including removing Z Lift and slowing down retraction speed.

At this stage, I am not sure what else to do with this and need some help please.

Happy to try other setting or provide more screenshots of my current settings as I need to print 3 more of these and would prefer to have at least some come out better than currently. 

Thank you for any help provided in advance. 

RE: Problem with artifacts on thin walls at seam lines

@evgeniy_parail

Have you tried moving seams to aligned or rear? If those aren't seams, they might be steam pocks - moisture in the PETG.  

RE: Problem with artifacts on thin walls at seam lines

@tim-m30

Thanks for helping out. I really appreciate it.

I believe these are seams, based on the software. The interesting part is that they only go up to a certain distance, then stop for the remainder of the print.

The filament I am currently using is brand new (bought a week ago and opened for this print) eSun PETG. It was vacuum bag sealed and the seal was good.

Image of the final result including the remainder of the print. There are no seams, blobs or anything for the remainder of the print, came out perfect for the last 20% (top section).

It is interesting because the printer does not move to the right side of the print for the seams and retractions as per above, but continues up on the left side all the way to the bend in the print. I feel this is something to do with either wipe while retracting, non print movement speed (travel speed) or something to do with this. 

The print above was printed with 3mm retraction length, 0mm Z lift, retraction speed of 25mm/s, retract on layer change on and wipe while retracting on. The setting retract amount before wipe was left as 0%.

Extruder temperature is set at 245 with extrusion multiplier of 95%. I was thinking of reducing extrusion multiplier even further, however will not touch it for this test. Am I also correct in assuming that PrusaSlicer Filament Settings extrusion at 95% and printer settings of 95% means the actual extrusion is about 90.25% final extrusion value?

I am going to start printing another dry box now, but will remove the wipe setting only to see what if any change there is. 

Once again, thank you for all the help. 

RE: Problem with artifacts on thin walls at seam lines

3mm retraction is too much on a mk3 printer.   2mm is the generally agreed on safe distance otherwise you risk pulling molten filament too far up which can cool and cause a jam. 

Also much earlier in this thread I did suggest to the original poster that he try reducing travel speed as I find that can pull filament away from the part and cause print artefacts in some cases. 

RE: Problem with artifacts on thin walls at seam lines

@neophyl

Hi mate. Thank you for your response. 

The 3mm retraction was a type, I triple read the post but must have missed it. It is set to 2mm, I have just double checked. 

For the current print, I have left the travel speed at 130mm/s as this is the default speed, and just removed the wipe while retracting setting. 

As per @tim-m30 suggestion is also made the change from Nearest to Aligned for the seam position setting. I will see what results this generates (happy to share here) and then will try reducing the travel speed as per your advise. What would you recommend to reduce the travel speed to?

Thank you for your help. 

RE: Problem with artifacts on thin walls at seam lines

Im not at the pc at the moment but the last time I looked the Prusa travel speed was default to 180mm, I knocked mine back to 120mm so if yours is already at 130 then it’s probably not that. 

RE: Problem with artifacts on thin walls at seam lines

Hi Guys,

So by removing the Wipe settings, the result has come out better than before, however the blobs are still there, and only for some of the print. Yes I am printing all these boxes in different colours, this issue is the same apparently irrespective of the colour printed. 

Comparison between with Wipe and without Wipe setting enabled

This is the actual close up.

What I do not understand is why this only happens sometimes. As can be seen from the photo, there is no change in the print from the first bottom half to the middle section that has the blobs. Apparently, the only difference is where the start point is (if that) and where the layer finishes printing. 

As another test (second half of the dry box) I have lowered print temps to 230 degrees and set the extrusion to 90%. My original settings were 95% and 240 degrees. Might be a big jump, want to see how it comes out.

Any other advise will be greatly appreciated. Thanks.

RE: Problem with artifacts on thin walls at seam lines

@evgeniy

Hi

I know it was a while ago but where you able to dial in the settings ? I think I am having the same problem as described in your pictures

Kind regards

RE: Problem with artifacts on thin walls at seam lines

I was able to go from the first picture to the second one by removing "detect thin walls " in the slicer setting's. Hopefully it helps someone else 

RE: Problem with artifacts on thin walls at seam lines

Can you post a Zipped up .3mf project file? you can add it after its zipped using the above, and to create the .3mf file you simply choose "save project as" name it and zip and send. this well show us the settings you are using so that we can best assist you. the pictures are helpful as well.

Good Luck

Swiss_Cheese

RE: Problem with artifacts on thin walls at seam lines

@zaso

I was able to resolve my issue. It turned out that the pre-assembled hotend was actually not assembled properly at factory and although it appeared to be correct, it was in fact leaking from the top causing filament to run down the heat block at the back (not visible as my printer is in an enclosure) and leaving particles all over the print. It was also obviously slightly under extruding due to the leaking. By the time I found this, I had almost given up on the printer as I was lost for any other ideas and at no point was this even a possible consideration. 

I hope that you are able to sort out your issues, but usually, the stock profiles and settings should print fine. If you are having issues with these, then these is a high chance you have an issue with the hardware. Temps and speed do play a part in this, but usually only if they are at either end of the extreems. 

The only recommendation I can also offer is do not print with Z Hop if you can avoid it. This seems to add issues especially the same as the horizontal line I see in your print.

Let us know if you are able to resolve your issues.

evgeniy

RE: Problem with artifacts on thin walls at seam lines

@ryker

PETG is more sensitive to print speed and thinner layers in my experience.  

RE: Problem with artifacts on thin walls at seam lines

@ryker

It has more to do with wall thickness, extrusion width and slicer settings e.g. detect thin walls, then material type.

RE: Problem with artifacts on thin walls at seam lines

@swiss_cheese

Could be, but it could also be the PETG.  I would change filaments and see if it prints fine.