this post was submitted on 30 Mar 2026
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Note: the original thread title was "how do i fix overextrusion on infill in orcaslicer?". we've since deduced that's not what's happening. i'm leaving the rest of the op as is so you can follow the process.


So i'm doing a test print for a hot wheels track i'm making for a friend's kid on my snapmaker u1, and i'm hearing scraping noises. when i look at the in-progress print, i see this horribly mangled infill. obviously the nozzle is hitting the previous layer, right? so that's overextrusion, i think. too much material. but i let the print run, thinking maybe ironing will save it. but the surface finish is absolutely awful. all of the bumps and ridges of the infill pattern transfer up through the solid layers. not to mention now there's ringing from the nozzle hitting the bumps, so there's even more bumps. bummer.

also yes i fucked up the overhangs by trying to cheap out on supports. at least that one i know how to fix.

so, how do i deal with this? snapmaker ships a specialized version of orcaslicer (it's called snapmaker orca, it's on github) to deal with the u1s four separate print heads, and as far as i can tell there's no setting in there for infill flow? should i just try to slow everything down? i thought it might be vibration-related so i added a 20kg concrete slab and a thick anti-vibration rubber mat to the setup but nothing changed. i also dried the filament out for six hours. the hygrometer in the snapdryer got down to 12% i think.

i'd hate to not be able to print this for the kid, it's such a cool plaything.

Edit: to clarify, the grey filament is snapmaker matte PLA. the spool has an rfid chip in it so i've not changed any settings, the printer just detects it and sends it to orca.

Edit 2: i've done another test using gyroid infill and a lower flow rate, as recommended in the thread, but the surface finish is all bubbly. i cut a part out to check if the infill was the problem but it looks fine, while the surface is fucked. this is after ironing, by the way.

Edit 3: okay, i've now dried the spool out overnight and made a test disk with tweaked parameters, and i'm still seeing bubbles on top. here i increased the ironing flow from 8% to 20% so the surface is a lot smoother, but the bubbles are still visible. also getting some weird blobs on the side? could be related to the ironing. the middle circle is for a multicolor test but the dot was so small that the filament amount came out to 0.00 grams and the printer didn't really know what to do. it just put in a single dot of (the wrong) filament and avoided the area.

the changed parameters are

  • flow ratio: 0.95 -> 1
  • nozzle temp: 215C -> 220C
  • max volumetric speed: 22mm^3^/s -> 15mm^3^/s
  • seam position: nearest -> random
  • scarf joint: off -> contour and hole
  • ironing flow: 8% -> 20%
  • infill: gyroid 15% -> TPMS-D 10%
  • infill combination: off -> on, 80%
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[–] maxwellfire@lemmy.world 2 points 8 hours ago* (last edited 8 hours ago) (1 children)

As a separate note, you definitely want to do testing/tuning with ironing disabled. It will hide a lot of the features/defects that you are trying to observe/tune away.

Once things are working you can then tune the ironing

[–] lime@feddit.nu 1 points 8 hours ago

yeah i figured that out. i ran some intermediates without and i thought the bumps were small enough that the ironing would smooth them out completely, but no.

[–] shelf@lemmy.dbzer0.com 3 points 21 hours ago (1 children)

I had this issue and could hear it thudding against each line of infill as it dragged what fixed it for me was increasing temp and/or reducing max volumetric flow.

[–] lime@feddit.nu 1 points 10 hours ago

i did that for my latest test and i don't know if it helped, but the default flow for this filament is insanely high compared to the default pla settings.

[–] Bluewing@lemmy.world 3 points 1 day ago (2 children)

Grid infill often leads to the nozzle dragging across the infill. You will always get those little bumps as the nozzle passes over each intersection. It can cause clogs and actually knock a print loose sometimes.

Choose a different infill. For this model, since it's a light duty part, I might choose 5% to 10% adaptive cubic to save some print time and filament. This will still provide good support for your top layers to get that nice top surface finish.

[–] dual_sport_dork@lemmy.world 1 points 3 hours ago

Cubic typically has the same issue. Where the lines cross the extrusion is not paused, so you wind up with little bumps at each intersection which can become visible in the top layers (and in extreme cases knock your part off the bed via impact with the nozzle).

Gyroid is the right call.

[–] lime@feddit.nu 1 points 1 day ago

good to know, i switched to gyroid for the next test and while the infill looks better the top surface still looks like ass. i'll attach a photo to the op.

[–] B0rax@feddit.org 2 points 1 day ago (1 children)

I don’t see overextrusion in this print. But it is also hard to tell if there are no solid infill sections.

Why are you using that much infill? Is it a high stress part?

[–] lime@feddit.nu 1 points 1 day ago (1 children)

it's 15%. it's for a kid, needs to be solid.

but also, part of the issue is that the infiill just crumbles. i cut up the top surface and poked a screwdriver in there, and what come out was just powder.

[–] B0rax@feddit.org 1 points 1 day ago (1 children)

These are not signs of overextrusion… What is your line width on infill? It looks very thin.

[–] lime@feddit.nu 1 points 21 hours ago (1 children)

it's .45mm. it's fine on gyroid it's just on rectilinear that it breaks easily.

[–] B0rax@feddit.org 2 points 14 hours ago (1 children)

That is too low for rectilinear. Because most of the time, they are printed at twice the layer height and come out much thinner than the setting in the slicer. Try setting them to 0.6 or even higher

[–] lime@feddit.nu 1 points 12 hours ago
[–] Acklavidian@lemmy.world 2 points 1 day ago (1 children)

I know nothing about 3d printing and subbed to this community because I hoped to one day try. That said almost every post I see like this turns out to at least be partially humidity/moisture related.

[–] lime@feddit.nu 1 points 1 day ago

i thought so too, so i dried the roll for six hours before this print. but i'm also a newbie at this so who knows.

[–] maxwellfire@lemmy.world 8 points 1 day ago* (last edited 1 day ago) (1 children)

Your non-infill regions also look very over extruded. I'd try printing 20mm cubes with a variety of flow rates and see what happens. If you're using their profile, is it possible that the filament you have is larger than specified?

edit: looking a bit more, things seem really blobby too. Something is not right. Is it possible the temp is wrong for this filament? What is it?

[–] lime@feddit.nu 3 points 1 day ago* (last edited 1 day ago) (1 children)

oh hey this message federated, finally.

so this is snapmaker matte pla, the snapmaker orca fork has a profile built in for it... but it looks weird. the temps are off, the build plate is a little hotter than they specify on their page... i don't know if it's right. i'll do some cubes.

Edit: also, how can you tell the walls are over-extruded?

[–] maxwellfire@lemmy.world 1 points 23 hours ago* (last edited 23 hours ago) (1 children)

Okay my new guess is moisture in the filament causing inconsistent extrusion, leading to the bubble on the surface. And also causing over extrusion.

For the walls, your picture is a bit too blurry/low res to really see, but I get the vibe of over extrusion with the small part that's sticking up in the center of the perimeters in the lower right. Also the top of the anchors for the supports looked over extruded, with plastic kinda curling up at the top.

Your new print is now definitely under extruded with those gaps on the top surface.

I think flow rate is not the culprit here. Your bridges on the first print are also extremely suspicious. They should be solid lines, not the blobs you're getting. Something is wrong with the flow of filament out of the nozzle. Could be moisture or temperature or issues with the extruder. It's hard to tell.

[–] lime@feddit.nu 1 points 21 hours ago* (last edited 20 hours ago)

you know the weirdest part? i've now seen the exact same surface pattern on two test prints. it's not just that there are bubbles, it's that they are the same size and shape. and that's with different infill patterns; one rectilinear and one gyroid.

i sort of figured the gaps with the lower flow rate were underextrusion. i've already dried out the filament though. first for six hours on low heat in a snapdryer, then into my home-made dry box overnight. the dry box just a plastic bin with a hygrometer, a one-way valve so i can pull some air out with my vacuum, and one of those big-ass reusable desiccant bags for cars. the snapdryer read 10% humidity when i pulled the spool out, and the drybox is at like 11%. is that still too much?

as for temp, the official specs say it's good for 190-230C, and the preset runs it at 215. could that be too cold?

another think i've thought about when looking through the settings is that the preset for matte pla runs very fast. the "generic pla high-speed" preset runs at 18 mm^3^/s, "snapspeed pla" runs at 20, and the matte preset runs at 22.

[–] faebudo 4 points 1 day ago (2 children)

You could use gyroid infill. It is more tolerant to flow as there are no crossings.

[–] MrQuallzin@lemmy.world 2 points 1 day ago

Second gyroid infill. Doesn't take much longer, and doesn't scrape against itself while printing.

And also general tuning with a calibration cube. Verify temps and extrusion values, the usual.

[–] lime@feddit.nu 2 points 1 day ago

i did gyroid on my previous test and got the exact same patterns, weirdly.

[–] couscous@mamot.fr 0 points 1 day ago (2 children)

@lime
also if you can, check your filament density and compare to what is specified in orca

[–] d_k_bo@feddit.org 2 points 1 day ago

This only affects the calculated weight of the printed part.

[–] lime@feddit.nu 1 points 1 day ago (1 children)

what, weigh the spool, dunk it in water, weigh the water?

what exactly am i looking for there, manufacturing defects? moisture?

[–] couscous@mamot.fr 1 points 1 day ago* (last edited 1 day ago) (2 children)

@lime
I meant the information that comes with the filament, density of the material is given on the label on your spool or on the website, like here for example in this page https://www.elegoo.com/products/petg-translucent :

A web page giving different information on a filament, like printing temperature or density

[–] lime@feddit.nu 2 points 1 day ago

ah i see. in that case it's the same, because it's a snapmaker spool with an rfid chip and they have presets for that exact filament in the slicer.

[–] couscous@mamot.fr 0 points 1 day ago (1 children)

@lime
I've had issues with PETG that were fixed by giving precise density to orca for example

[–] lime@feddit.nu 2 points 1 day ago (1 children)

are you sure about this? it says in the tooltip for the density field that it's "purely for statistics", to figure out how many grams of plastic will be used.

[–] couscous@mamot.fr 0 points 1 day ago (1 children)

@lime
I did it some time ago, and I likely did it in Cura (it fixed extrusion consistency and stringing for sure, especially with some special matte PLA)
I thought it made sense that extrusion pressure would be related to material density, now Orca may handle it differentlyn, or i'm totally wrong (and fixed it without knowing how 😄 )

[–] lime@feddit.nu 1 points 1 day ago

aaaah yeah that makes sense. orca seems to miss quite a lot of settings, there's nothing for infill flow for example.