Weird striping effect


#161

Are the lines only it the upper (farthest from the build plate) part of the print?


#162

that is very weird, it looks like seams in the toolpath (the same you see on FDM printers). Can you show what cura options you are using?


#163

Hi @nbltsgndpfrdbrms. I got curious about this. Why a pause before tilt and not after. Not possible or not better? I always thought that Moai rushed a bit on the tilt, I think it should let the resin set a bit more. If not mistaken tilting process on form printers are a bit slower on the tilt process.


#164

@glassTransition, the upper area is the worst but i can see the same effect on other areas of the model.

@matt3o, i used the new 100um default Moai profile.

Here are the settings:

quality

material

speed

travel

cooling

adhesion

mesh

extrusion

experimental

Thanks

PS: Should that “Outer Wall Wipe Distance” be activated???


#165

Add the same thought talking with Leonardo before. It seems the same effect that S3D costing and wiping settings control. In Cura if not mistaken this are applied in a automatic manner scattered through the model. and not a matter of peeling forces in play.


#166

try to zero outer wall wipe distance (it’s an option I’m experimenting with)

also set skin removal and skin expand to 0.402

z seams alignment “sharpest corner”

Seam corner preference “hide or expose”

Do the glitches appear on the preview in Cura? You may need to activate the helpers to see them.


#167

It doesnt look like it!

See here:

I will try your settings and see how it turns out!

thx


#168

please activate the travels in the preview (sorry by helpers I intended those too)


#169

Here you go =):


#170

yeah there are no weird travels there. it shouldn’t be a slicer issue. more likely lack of support maybe?


#171

Didnt wanna fill that area with more supports so i could keep a good resin flow…

I will try more supports then and the settings you mentioned.

Thanks


#172

Hi @matt3o, tried the settings you said, also added more supports to the areas where i had those lines…

Results are the same near the same spots… even worse, now the problem is showing in some areas it didnt before…

I added more supports and the angle was not exactly the same as the last print. This one was tilted more.

Here are some pics…

And this weird texture is still present in some areas:

I dont wanna get off-topic here, dont know if this is related to this issue or something else…


#173

unfortunately having changed the angle we can’t really compare anymore. what laser power are you using? I assume you can’t share the 3d model?


#174

Here is the model: https://drive.google.com/file/d/17RAGx3-twgwflPAxeBVPYwD-kYbTXYjO/view?usp=sharing

Even not having a direct comparison… i dont think i should have those issues…

The thing is… i have perfect prints sometimes… lol Could this be a problem with the STL? What i’ve noticed is that prints that are smaller usually print out great.

And this model… the lower section is better than the upper section, but that could probably be explained by the lower section not being as complex… dont know… kinda lost here.


#175

First, what I think you are seeing is caused by the model flexing. The resin is not fully cured and can be pulled apart by suction forces. The layers provide a natural line of fracture. I had a similar issue with a scaled-up maquette model.

I will admit to have not read the full thread, so I apologise if this has been answered: is the model hollowed and properly vented? This could help with the pull forces. However, you must crosslink the long supports in order for them to work. Think of them having the consistency of lightly cooked spaghetti, they are not as mechanically strong as you think.

I think that the texture is a symptom of the model flexing, essentially squeezing the layers together until you get that odd alligator-skin pattern.

As stupid as it sounds, I would add more supports at the head and cross-link all of the supports across the model.


#176

Hi @Paradoxical_Cat… thanks for the help.

The model is hollow with 2mm walls. It is wide open on the base and has two holes on the top.

I could try cross-linked supports to hold the model better, because i cant see where more to put supports… but its like you said… they are not cross linked and that may play a role here. I could also add some more to the head…


#177

no, you should not have those issues, but we can’t say if the options you changed had any impact on the print resolution.

the model is very big. Moai is good on medium-to-small objects… that being said your result is pretty bad and you can surely do better.

the 3d model is not very good and would require retopology, you can see it looking at the borders

that is the kind of topology that drives the moai and cura mad, but honestly at 0.1 shouldn’t make that difference.

The best would probably be to cut the model in 2-3 pieces and glue them together later (base, bust, head). If that is not possible I would try to angle the model better (rotating it on multiple axis or even upside down).


#178

I could slice the model and print it yes… But right now my concern is to understand whats going on here…

If its a stability issue, for the purpose of testing, would it be better to print the model straight of the buildplate with minimal supports? It would flex less, right?


#179

I’m afraid you’d create some suction that way


#180

The walls may be too thin as well. I have printed thinner structures, but never this large. I suggest using thicker walls, maybe double thickness from what you have now.

You could try printing perpendicularly to the build plate, with additional vent holes in the back, neck, and head, but I don’t think it will solve the problem. You would still need stabilizing supports for the head, regardless.