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gardnert

Random infill layers?

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EDIT: the third layer I thought was infill, is actually supposed to be a solid layer/skin. The model should be three solid layers material 1, two solid layers material 2, three solid layers material 1.

 

Hello everyone!

I work with an Ultimaker 3 at the office, and only recently have I run into this strange issue. Please see the gif below:

Cura animation

I've designed a part, with two pieces and merged them on the buildplate. I'm basically filling a mortise in two parts with a tenon of another filament. The mortise and tenon are the same size. Can anyone help me figure out why there looks to be an infill layer below and above the second material (in white)?

I was thinking it should go: two solid layers of material 1, then two solid layers of material 2, then two solid layers of material 1. But looking at the slicing it's inserted an infill layer between the materials? I've seen this recently on other parts I was working on. Is this a settings issue?

Layer height is 0.2mm

Thanks for any insight.

Edited by gardnert

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How does the model look in x-ray view? I'm guessing that the model has some issues with it.

 

If possible, share a .curaproject file with us, then we can have a look at what you did (and thus, what might be wrong).

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Thanks for the replies!

Unfortunately (or, fortunately?) this was a working file, and through iterative changes, I can't get the issue to be recreated. I will reply to you when it pops back up (this model wasn't the first time this has happened).

 

Curious: what would x-ray mode show me? Honestly I've never used it as it seemed sort of confusing?

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On 9/5/2018 at 3:31 PM, gardnert said:

Curious: what would x-ray mode show me? Honestly I've never used it as it seemed sort of confusing?

1

It highlights areas in the model that are incorrect by making them red.

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I think there is a bug in Cura... would someone from Ultimaker please confirm this?

 

While single material extrusion comes out as expected, dual material extrusion (dissolvable support) causes problems with the build material (not support material). It causes the "top surface" layers right underneath the support to be treated as infill instead of a solid area. This problem manifested with both PLA + PVA, and CPE + PLA.

 

I attached a photograph of the a "Print In Place Gravitational Hook" printed part with the problem that was PLA + PVA, as well as screenshots of the relevant layer previews for the "Dissolvable Support Gearbox" part in dual extrusion mode where it messes up, and in single extrusion mode where it's fine.

 

Here are also links to YouTube videos I took using the OBS Studio screen capture software that show me scrolling through the layers:

dual extrusion bug in Cura 3.4.1-PPA? (dual extrusion mode layer preview)

dual extrusion bug in Cura 3.4.1-PPA? (single extrusion mode layer preview)

 

Operating System: Ubuntu 18.04

Software: Cura 3.4.1-PPA

STL Models:

Dissolvable Support Gearbox by tbuser (gear_box.stl)

Print In Place Gravitational Hook by lecter (PrintInPlaceHook.stl)

Dual_Extrusion_Layer_38.png

Dual_Extrusion_Layer_39.png

Dual_Extrusion_Layer_40.png

Dual_Extrusion_Layer_41.png

Single_Extrusion_Layer_38.png

Single_Extrusion_Layer_39.png

Single_Extrusion_Layer_46.png

Single_Extrusion_Layer_47.png

Hook_Closed.jpg

Hook_Open.jpg

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From the X-ray view there seem to be no problems at all with the model. If I scale the model by 2x (200%) in Z the issue goes away, so it seems that it's a rounding error? There is an option "Support Interface Resolution" but lowering it from 0.3mm doesn't change anything.

 

I'd appreciate if you'd download the model and try slicing it at 0.1mm or 0.15mm layer height for PLA+PVA dual extrusion targeting an Ultimaker 3. I think you'll see what I mean, and if not, I'd like to know exactly what settings you use!

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1 hour ago, fdarling said:

I'd like to know exactly what settings you use!

 

If you want to make it easier to reproduce the issue on our end, save the file as a project. Then we can get exactly what your configuration and settings are.

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For example, I can slice with PLA+PVA and it's fine. If I keep all of the settings the same but choose CPE+PVA, it shows the issue at layer 14. I attached the 3mf files as well as screenshots of a problematic layer for both materials. Here is also a YouTube video:

 

 

Here are a summary of my changes for the default settings for the "normal" 0.15mm layer height:

 

Support->

    Generate Support: (Yes)

    Support Extruder: Extruder 2

    Support Z Distance: 0mm.

Build Plate Adhesion->

    Build Plate Adhesion Type: Skirt

Dual Extrusion->

    Enable Prime Tower: (Yes)

CPE_Material_Selected.png

PLA_Material_Selected.png

CPE_Material_Selected.3mf

PLA_Material_Selected.3mf

gear_box.stl

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