the mystery of the unexpected blobs

[mariocoppolaunina 0]

Hi eveyrbody,

I have a very VERY strange issue.

 

When printing, it comes out a strange disturb in the outer perimeter: it seems like too much filament extruded or too high temperature but I played a lot with both of these parameters and nothing, I have exacty the same disturbs in exactly the same places, as the machine (Modix 120x) in those points actually did some strange over-extrusion. And, the strangest, there is no ending or starting points in these parts. They are absolutely normal points.

 

If you look the different images you can find exactly the same disturbs in 2 different pieces printed with completely different temperature and extrusion multiplier (I changed filament amount).

 

Who knows something??? :))))

[Slashee_the_Cow 454]

That is... pretty mysterious. If you could post the Cura project files for both of them (.3mf, get it set up then go to File > Save Project) and the gcode files for the ones you've already printed, we can begin an investigation.

 

I mean sure, it's theoretically possible your printer has issues at certain combinations of X and Z positions but that's probably not the case. Hence the need for an investigation.

[mariocoppolaunina 0]

Here we go!!

 

But... could it depend from the type of mesh? because I imported the obj from Maya and it was without triangles and with 4 or 5 edges...

 

Thank you!!!

trino_MODIX_151024.3mf trino_MODIX_def_1370g_1d8h_N2.gcode trino_MODIX_new_1430g_1d3h.gcode

[Slashee_the_Cow 454]

The model file is valid... which is something I don't get to say enough 🙂. I think any format Cura can read gets exported as triangles anyway (splitting a face with more than three edges into triangles is easy).

 

The first thing I can see about the model which makes me go a little bit 🤨 is this bit on the side where the model actually comes back around on itself and creates a second closed loop, which requires travels, But that doesn't seem to be where your problem is, either the loop or the Z seam so that's probably not it:

 

There are a couple of awkward bits where a seam comes out a bit horizontal:

(zoom view):

 

There's also a couple of awkward bits in the model but they get mostly smoothed out by the Mesh Fixes > Maximum Resolution setting:

 

Looking at it from the right angle you can see there are a few bits in the slice which are a little 🤨 but it's hard to tell if those correlate with the locations of your defects:

Top view:

 

I'm sort of stabbing in the dark in the dark here, but if you could edit your model to remove little bits which jut out like these it might help:

My other stab would be to change Mesh Fixes > Maximum Resolution:

If you set it to something lower (like 0.1mm) then it'll more closely follow the model (so the difference between layers on the the sorts of bits I've highlighted won't be as much) - also your gcode file would probably be friggin' huge, but that's not the end of the world.

Conversely, if you set it to something higher (like 1mm) it smooths out the whole thing so you lose detail but the bits that jut out a bit will get sorta averaged out and not be as prominent which might make them easier to print (printing 0.25mm layers on a 1mm nozzle is impressive to start with though, so grats on that).

 

If it was me, I'd do edit the model file and lower (technically increase, but anyway) the maximum resolution to 0.1mm, try and print that. If setting the maximum resolution to that makes the hex borders too obvious, then I'd try setting the maximum resolution to 1mm, unless that makes the whole thing too blurry, in which case I'd leave that as it is.

 

Also, and I know this might seem weird, but question not the vagaries of a 3D printer: try rotating your model 90° on the build plate (some printers perform better along certain axes) and move it a couple of mm - doesn't really matter which direction (so long as it's not up or down) in case your printer has problems around certain spots.

 

But other than that not sure I can explain it 🤔. The gcode doesn't seem to have anything which would cause defects.

[mariocoppolaunina 0]

Hi @Slashee_the_Cow

first of all, thank you for the time you dedicated for me.

 

The point I forgot to say is that I previously tried to print this vase on my wasp4070 machine and it printed perfectly for the first part (then the organic filament I am using choked the 0.7 nozzle and for this reason I tried to print with modix 1mm nozzle). This should in some way negate any problem between cura and the mesh. But, are we sure there is no issue between cura and the modix 120x? Because what I see is that during the print I have something like little, punctual over-extrusion, so it is something that has not to do with the pathway but with the extrusion itself. Is this a valid theory or not?

 

 

[Slashee_the_Cow 454]

On 10/20/2024 at 1:41 AM, mariocoppolaunina said:

This should in some way negate any problem between cura and the mesh. But, are we sure there is no issue between cura and the modix 120x? Because what I see is that during the print I have something like little, punctual over-extrusion, so it is something that has not to do with the pathway but with the extrusion itself. Is this a valid theory or not?

It's certainly not impossible. The best way to find out would be to slice it in another program (like Prusa Slicer), get the settings as close to what you've used in Cura and see if the same thing occurs.