this post was submitted on 28 Feb 2024
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How do I fix these god-awful seams? (sopuli.xyz)
submitted 2 years ago by DreadPotato@sopuli.xyz to c/3dprinting@lemmy.world
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I have trouble fixing the terrible seams I'm getting. I've followed Elli's print tuning guide and calibrated extruder, tuned PA (it's now 0.035) and extrusion multiplier.

I've tried adjusting both retraction length and speed, but it doesn't seem to have much impact. I'm not using "wipe on retract" or "retract on layer change", I only retract if travel distance is longer than 3mm. Retract is 0.3mm @35mm/s.

I've tried reducing PA smooth time too, but this also doesn't seem to have a noticable impact.

I've tried reducing seam gap from the default 10% in Orca all the way down to 0%, but the bad seams persist.

I've tried with "wipe on loops" both disabled and enabled with no difference.

I've tried with both arachne and classic wall generator, no difference.

I've tried different wall orders, inner/outer, inner/outer/inner and outer/inner, all with the same bad seams.

Filament in the picture is matte PLA, it is without doubt dry and generally prints well aside from the seams. It's stored vacuum sealed with silica, and I use a filament dryer to dry if I suspect wet filament.

I'm running out of ideas for where to tweak to get a decent result.

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[–] callcc@lemmy.world 9 points 2 years ago* (last edited 2 years ago) (1 children)

Most probably PA. You should try adjusting it while printing using some g-code console. This way you get immediate feedback. What they often don't tell you is that pressure advance is not something you can calibrate once and forget, it's dependent on material, temperature, nozzle diameter and also a lot on feed rate and extrusion rate.

The need for PA and precise tuning is more pronounced the higher changes in extrusion rate you have eg, you print very fast or with wide or high layers.

Just play around with it a bit and I'm sure that you'll find a better value after some layers.

There are even macros that try to remove the feed rate dependency by effectively replacing every g-code that adjusts feed-rate by a combination of the original g-code pre-ceded by an adjustment of PA. I haven't tried them out yet though.

What's weird is the differences of the effect between the layers. Is the every layer the same or is the path different for different layers? Maybe post some images of the inside of the model.

[–] dual_sport_dork@lemmy.world 5 points 2 years ago

This is a good idea. I will further add that Klipper lets you dick with the linear/pressure advance parameters mid-print via GUI with its Fluidd interface. Other systems probably have similar capabilities.

A good test model for this might be a thin walled hollow cylinder with the Z seam facing the user (i.e. out the door or front of the machine) only 2 layers thick or so. That sounds like it ought to make the issue visible quickly, and with minimum of wasted time and filament on infill (not to mention ruined parts).

[–] ShadowRam@kbin.social 7 points 2 years ago (1 children)

_ I’m not using .... “retract on layer change”_

There's your problem.

[–] DreadPotato@sopuli.xyz 4 points 2 years ago* (last edited 2 years ago) (4 children)

No, I've tried with that enabled as well, same issue. This isn't before a layer change, it's when it goes from extruding the walls to extruding the infill.

But even without infill this happens. It's the end of the outer wall that doesn't connect to the beginning of the outer wall and it's not really fixed by reducing seam gap, so I'm not sure what's actually causing it.

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[–] bigredgiraffe@lemmy.world 4 points 2 years ago (1 children)

So I stared at this for a while, particularly the pattern of the seam, I have a few questions. What type of infill are you using? how many outer wall loops? How much infill overlap (or whatever it is called)?

Also what happens if you rotate the part on the bed 90 degrees so the seam is on a different axis? Or maybe 45 degrees? This will make sure it’s not some sort of mechanical issue in one direct that shows up in this specific situation.

I know that all seems random but those are what I would check hah.

[–] DreadPotato@sopuli.xyz 2 points 2 years ago

Issue seems to be following the seam when I rotate parts. in this particular example I am using 5% gyroid, if I switch to grid the defect is uniform along the part. This is just 2 walls, can't remmber infill overlap, I'll check tonight.

[–] ShepherdPie@midwest.social 4 points 2 years ago

Have you tried checking the belts and all the bearings/rails for tightness and smoothness? It almost seems like layer shift at the seam, and if you compare both seams side by side, layer by layer, it almost seems like the print head shifts equally on both prints for any given layer (e.g. left print looks over-extruded while right print is under-extruded, next layer up, it flips and right print looks over-extruded while left print looks under-extruded).

If not the belts or other hardware, perhaps it's a flow issue. Do you know if the gross looking seams are the start or the end of the layer?

[–] ThePantser@lemmy.world 4 points 2 years ago (1 children)

There is a setting in super slicer called Seam gap, do you see a setting like that you can play with?

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

Yes I've already tried that, and it doesn't make much of a difference.

[–] ThePantser@lemmy.world 4 points 2 years ago (1 children)

Wiggle the nozzle is there any slop?

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

Nope, it's rock solid.

[–] CluckN@lemmy.world 9 points 2 years ago (1 children)

Does the nozzle taste normal?

[–] DreadPotato@sopuli.xyz 10 points 2 years ago

No clue, the heat completely numbed my tastebuds /s

[–] dual_sport_dork@lemmy.world 4 points 2 years ago* (last edited 2 years ago) (1 children)

That retract distance seems a bit low to me. My (direct drive) printer is happier around 1mm to 1.5mm. I'm not convinced that has anything to do with your particular problem, though.

Anyhow, to my untrained eye that looks like underextrusion at layer change and/or the perimeter lines not actually hitting each other. Are you sure your pressure advance/linear advance values are correct for that filament?

Also, does Orca Slicer allow you to specify a negative value for the seam gap? If so, that might be worth fooling with to see if it has any impact. That's probably a band-aid, though. I think your issue lies in pressure advance tuning still.

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

This is the filament I've tuned PA with, and to my best ability this is what Elli's guide suggests is the optimal value 🤷‍♂️

But I agree, it does actually look like PA is tuned incorrectly and stopping extrusion too soon/starting it too late.

[–] rambos@lemm.ee 3 points 2 years ago (2 children)

Try without PA, also try another filament

[–] rambos@lemm.ee 2 points 2 years ago

Also try normal brass nozzle and check if your new hotend is not loose

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

Tried without PA but there was no difference, going to try different filament next.

As I mentioned somewhere else in this post, it seems to relate to the infill. I'm using gyroid, and the seam lines up with the anchor point for the infill.

[–] rambos@lemm.ee 2 points 2 years ago

You can also try without infill 😉

Im throwing many things to try, but not in any particular order

[–] Creat@discuss.tchncs.de 4 points 2 years ago (2 children)

In what can only be described as "perfect timing", the 3d printing channel teaching tech uploaded a video about just this problem literally a day ago: https://youtu.be/vl0FT339jfc

[–] DreadPotato@sopuli.xyz 2 points 2 years ago* (last edited 2 years ago)

Yeah I can see that the seams of his "before" models is actually look like what I've been able to achieve on mine now. I guess I was trying to fix the last bit with standard seam options which might not have been possible.

I'll download the noisyfox orca slicer and test the scarf seams out.

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[–] mildbeard@linux.community 3 points 2 years ago

Duct tape.

[–] Betch@lemmy.world 3 points 2 years ago (1 children)

That's a really weird looking z-seam, something is going on there that I'm not quite sure the cause of.

However, in this case I think you could try randomizing z-seam position. It's not gonna fix the issue completely but it might help you with this particular part.

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

Yeah I've tried that, but it's still really bad, almost worse, with these scattered all over the surface.

[–] Betch@lemmy.world 2 points 2 years ago* (last edited 2 years ago) (1 children)

Yeah I thought that might happen too. I've never seen seams like that before. What temp are you printing at?

[–] DreadPotato@sopuli.xyz 2 points 2 years ago* (last edited 2 years ago) (1 children)

It's printing at 200C with fan at 100%, using a 0.4mm hardened steel nozzle.

[–] Betch@lemmy.world 2 points 2 years ago (1 children)

Have you ever done a PID tuning?

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

Yes, I recently switched the hotend from a proprietary one to a regular volcano hotend and did PID tuning.

[–] Betch@lemmy.world 2 points 2 years ago* (last edited 2 years ago) (1 children)

Did you notice this kind of thing happening before you switched your hot end? I'm assuming you've tested printing at a higher temp already but I have to ask anyway. 200C is kinda low for some PLAs.

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

Yeah I've tried 190-220C, which is the range specified by the manufacturer of the filament.

I don't remember seeing this issue before the change, but I'm still new to the hobby and may just have overlooked or accepted it earlier.

[–] Betch@lemmy.world 2 points 2 years ago (1 children)

Is there a way I could see the file you're trying to print?

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

This is just the basic cylinder that's part of orca slicer that I'm using to troubleshoot the issue because it's quick to print and the issue is clearly visible.

[–] Betch@lemmy.world 2 points 2 years ago (1 children)

Hmm, I've never tried OrcaSlicer. I'm curious, installing it now.

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (3 children)

I did also switch to orca around the same time I changed the hotend...I'll give my old slicer a go as well, maybe it's a slicer issue.

[–] Betch@lemmy.world 2 points 2 years ago* (last edited 2 years ago)

Could you tell me where in OrcaSlicer you found this cylinder? I can't seem to find it in the calibration tests.

Edit: Nvm found it hahah

[–] Betch@lemmy.world 2 points 2 years ago

Yeah that's definitely a possibility. I'm just finishing up my start g-code, gonna see what happens if I try to print that cylinder. Hopefully my printer doesn't blow up or something 🤞

[–] Betch@lemmy.world 2 points 2 years ago (1 children)

Well, I just printed a cylinder and my seams are just fine with "default settings".

I say "default" because originally I saw some weird stuff in the preview but it turned out to just be because for some reason spiral vase mode was on by default.

[–] DreadPotato@sopuli.xyz 2 points 2 years ago (1 children)

I just noticed, after intensely staring at my print from an awkward angle to see the nozzle while printing, that the gyroid infill has an anchor to the wall at the seam line. What kind of infill and infill settings are you using?

[–] Betch@lemmy.world 2 points 2 years ago (1 children)

Actually noticed my settings were not "default" at all because I had selected options in the calibration test section. I just started an actual default print with a top, bottom, multiple walls and infill hahah.

I'm printing with grid infill. Gonna cancel and try with gyroid.

[–] DreadPotato@sopuli.xyz 2 points 2 years ago* (last edited 2 years ago) (1 children)

I'm getting a 100% uniformly bad seam with grid infill, instead of the one in the pictures that kind of "switches side", which in guessing is because of the direction changes relative to the wall made for gyroid throughout the model, but grid always moves away from the wall at the same angle.

Edit: tried without any infill, same result as grid infill. So it's would seem it finishes the wall before it actually fully connects the wall-end to the wall-beginning on the outer walls, before changing to next layer or infill.

[–] Betch@lemmy.world 2 points 2 years ago (2 children)

Yeah I got the same thing where it seems to pull when it's switching direction but it's nowhere near as bad as how it is on yours. I'm thinking it might be a physical issue with your printer.

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[–] Imgonnatrythis@sh.itjust.works 3 points 2 years ago (4 children)

I have one just like that on my scrotum and was told it's normal so I wouldn't worry about it too much.

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[–] maxwellfire@lemmy.world 2 points 2 years ago* (last edited 2 years ago) (1 children)

Is the bad side of the seam where it stops or where it starts printing the outer wall? I assume it's where it stops and then it cross the wall to form the infill?

To add to the PA questions, are you sure that your PA setting actually are changing anything?

What printer is this and what firmware?

Does a spiral mode print work fine?

What if you print the part significantly slower (to rule out rigidity/acceleration issues)

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[–] _haha_oh_wow_@sh.itjust.works 2 points 2 years ago* (last edited 2 years ago) (2 children)

Randomize Z seam and make sure your flow/retraction settings are as good as you can get them.

Messing around with your nozzle temperature might help too: Keep in mind that the thermistor in the heat block might be off by a few degrees so if you can measure the temperature directly as a comparison, it can help you figure out how much it's usually off by and adjust accordingly.

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