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closedcircuit

Anyone knows how to get rid of those?

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I'm printing an architect's model. One of the bathroom's walls has a mirror. When printing, two new bands appear on the right of the mirror (but not on the left, nor anywhere else). Everything else in this long print (circa 60 hours) looks quite good.

Does anyone know what happens here and how to get rid of the problem?

How it should be (print screen from Cura - nice flat wall)

Cura Screenshot

 

How it is (the two bands surrounded by a red line shouldn't be here):

Close Up   Mirror

 

I'm printing this using the following:

Cura 14.07

Printer: UM2

Layer height: 0.1

Shell thickness: 1.6

Enable retraction: ticked

Bottom/Top thickness: 1.6

Print speed: 25mm/s (@100%)

Support type: None

Adhesion: Brim

Nozzle: 0.4

Travel speed: 200

Minimal layer time: 7

Enable cooling fan: ticked

Filament: PLA Pearl white from Faberdashery

Temp.: 230°C

Bed Temp: 60C

Thanks!!!

Phil

 

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There's probably something wrong with your model. If you look at it in X-Ray view (top right button in the 3d view window and then choose X-Ray from the drop down), do you see any red areas then? If you do, it means there's a problem with the model. You can try playing with the "Fix horrible" checkboxes in the expert settings and see if those help. Switch to the layer view in cura and look at what the layers look like in that area as you change the settings.

If that doesn't help you can try Netfabb's cloud service for repairing models: https://netfabb.azurewebsites.net/

 

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Yes--try fixing any errors, but I've actually had cases (in Kisslicer) where the netfabb "fix" was worse than the problem, because it caused new perturbations in the tool path, though the model passed error-free after the "fix."

I would also try another slicer. You can't have too many of them! ;) You could also cut this problematic area out of the model to reduce test print time, but the problem might go away from just doing that. (You can cut the model with the free to download netfabb.) To eliminate test print time altogether, load the gcode and preview the tool path in Cura (View mode >> Layers) or Repetier Host (Preview tab).

Please report your findings here. It might be a Cura issue or bug.

 

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@calinb and @IRobertI: Thanks for your comments. There is one small red area, but it's in a completely different part of the model.

I don't know if it's a Cura issue or not. I've enclosed below a link to the stl in case someone with better skills than I have want to have a look: https://dl.dropboxusercontent.com/u/109695611/2014-08-14%20---%201ST%20FLOOR.stl

The model was scaled down to 0.12 in Cura.

 

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FWIW I loaded the file into InStep which reported 1514 errors. I then exported it to a step file and Instep said it output 9 of the 10 bodies in the model due to errors. I then imported to Solidworks. This imported the 9 bodies, with errors. The 10th body that was not exported by InStep is all the walls.

So a duff file it seems.

 

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@yellowshark: Thanks for having done all that. It's much appreciated.

Bearing in mind that Cura only shows 1 problem area, I was very interested to read that InStep reported 1514 errors. Do we know why this is the case?

This model is one of several floors designed with MOI and then exported to STL. All other floors print perfectly well and I'm puzzled as to why this file would be a duff and not the others... I'll look further into it tonight.

Thanks again!

 

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Thanks for the model. It greatly helps us to help you!

Here's what I did:

1. Opened with netfabb (you can download the basic Studio version for free still, I think, or you can try the online version).

2. Default repair.

3. Cut out just the problematic bathroom (in the middle of the walls).

4. Default repair + remove degenerate faces.

5. Scaled to fit on Ultimaker bed.

6. Exported .stl.

7. Opened .stl and sliced with Cura.

In examining the gcode with both Cura and Rep-Host, it looked okay!

With this large model, you might want to cut-out the rooms as separate models, print them separately, and bond them together later too (easy to bond ABS, but not as easy with PLA, and impossible with nylon). However, if a strong mechanical bond is not required, you can probably just use silicone sealant to "bond" the parts--even if printing with PLA or nylon.

Next I tried your entire model:

1. Opened with netfabb.

2. Default repair (no degenerate faces this time).

3. Exported .stl + repaired (split) manifold edges (this is the operation that can cause problems with Kisslicer).

4. Opened with Cura and scaled to fit on bed.

5. Sliced with Cura.

A cursory viewing of the gcode toolpath revealed no problems.

Based on my relatively brief experiments, I think I could print this model just fine. Don't give up! Despite what many 3D printer marketers would like you to believe, 3D printing ain't like printing your family vacation photos on an inkjet (and I don't see that situation changing anytime soon). Relatively recently in life, I've learned to fairly competently run a lathe, milling machine, and 3D printer (Ultimaker Original). The 3D printer had (has) the steepest learning curve--at least for me. And I'm a "computer guy" too.

Keep us informed of your progress and good luck!

-Cal

 

@calinb and @IRobertI: Thanks for your comments. There is one small red area, but it's in a completely different part of the model.

I don't know if it's a Cura issue or not. I've enclosed below a link to the stl in case someone with better skills than I have want to have a look: https://dl.dropboxusercontent.com/u/109695611/2014-08-14%20---%201ST%20FLOOR.stl

The model was scaled down to 0.12 in Cura.

 

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It's pretty common for CAD tools to export meshes that cause problems with other tools and it's why netfabb offers repair tools and Cura has "fix horrible." You can try meshlab for repairs too, but I've never mastered it.

I've had pretty good luck exporting from Geomagic (formerly Alibre) and I've exported some very complex models. The more complex the solid model (or the more quick and dirty "hacking" that's been done on a model), the more likely one is to encounter problems in an exported mesh. The solid operations that are most likely to cause problems are the direct editing functions (push/move faces/surfaces, delete faces/surfaces, etc.) or boolean operations. I still use them, but I'll redo or create a bunch of sketches to avoid doing these operations on a solid model, if possible. Sometimes a problem associated with these operations doesn't pop-up until much later--after the model "grows" larger during development.

 

@calinb: Thanks a lot for your help. Your comments definitely gave me a lot of food for thought as I try to understand why and where MOI would generate a broken STL model when exporting solids. I'll keep on digging and let people know if I find anything interesting to report.

 

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