Round shapes is not in spec

Hello fellows.
I’m having a strange problem with Luban.
When i’m designing a linear shape like a square, when printet it’s right on the spot regarding size.
But when i’m designing round shapes like holes or cylindrical shape, the printing size is not right.
Like a hole designed Ø: 7,5 mm is printet Ø: 6,8 mm
A cylnder Ø 2.0 mm is printet Ø : 1,8 mm

It seems that when Luban is slicing round shapes is like 10% smaller ?
Do anyone experience the same?

Does the bracket coming out of the linear module the print head is attached to feel loose?

I had a similar issue on my snapmaker 2 and that was the source.

Do we talk about laser, cnc or 3d print?
If it is cnc, you could create on, in or outline paths, the radius is depending on the tool in this case.

No not at all.
Everything is firmly assambled.
I quit sure it’s something that happends when Luban is slicing the 3D model.
It’s the issue on every print i have made with holes.

The 3D print.
Sorry i should have clarifyed it in the post.

You should calibrate your e-steps, you are about 10% off, I bet your e-steps as well.

Search for extruder calibration is a must in the forum!

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Does that apply to original snapmaker?

edit: Wait, why did i think he had original snapmaker. sorry. must be mixing up my posts.

Now i have done calibration of e-step.
As in the “guide” Calibrate E-Step
My A350 needed to be corrected almost with the same number as the other ones.
But it has not helped regarding the size og a hole in a printet plate.
I have used the same 3D model as in my first print. I didn’t expect it to do any change as i can’t see how length of extrusion could affect a size of a hole.
I’m still sure that this issue is to how Luban interpret a .STL file

I suspect you have excessive backlash in your linear module personally

Holes being the wrong size can be attributed to anything from slicer settings/limitations to filament diameter to overextrusion or under extrusion or many other things,

but having a hole thats not round is a big red flag (assuming it is horizontally printed)

regardless, On luban you are a bit limited in corrective actions, but other slicers have a lot of things you can use to compensate with.

There is another setup test you can do without evolving to cura though

Try the linear advance section of this guide

Teaching Tech 3D Printer Calibration (

This test will show you how unevenly the line thickness is on the extrusions, and then allow you to fine to a value to make it better.

this test had a night and day transformation on my print quality.

Additionally, maybe you would be interested in trying an alternate slicer to see what power it can unlock. I made a short video for a member that you might benefit from:

What are the rules of thumb with various calibration and 3D print settings in Luban? - Getting Started - Snapmaker: where creation happens

The hole is round,
I have printet holes on the flat surface and also in vertical.
They are round but the size is 10% smaller than in the design.
I’m not sure that A350 is using Linear advance because if i’m type in M900 in cmd line, it returns “ok” and no K-bumber as in the video.
I think i need to make a test with Cura and see if the problem persist.

Snapmaker will not respond over wifi, you have to connect via USB

Now that the extruder is calibrated, the next step would be size compensation or flow rate reduction, neither of which are possible via luban.

Oh… I forgot about the Wifi. :relieved:
I must have my laptop connectet again.
I’ll do that tomorrow.
Still i’ll make a test with Cura as slicer, to see if it will be better.

sorry, i must have misinterpreted your original post.

OK, if you get cura i would say to do the test on this page:

Teaching Tech 3D Printer Calibration (
Slicer Flow Calibration

and then… adjust the flow rate to the recommended value.

there are more advanced settings for hole compensation and so forth in cura as well, but thats probably an easy fix with the flow rate adjustment.

if you need help with cura setup just ask. there are a lot of posts on the forum about it but frankly the snapmaker provided configuration is wrong.