printing hollow shape gets filled in

[jvdwaa 0]

I am trying to print a hollow shape (a rectangular bin to be more exact) without a top, see the first attachment "polssteun bak.stl".

I have printed this object before in a previous version of Cura (15.x) and it came out perfectly.

However, I am now trying to print it again with Cura 3.6 and the result is a solid block of plastic 🙁

 

I had the same issue with another stl-file, "koffieschep v4.stl" (a spoon), this was also printed as a closed object.

Both stl-files look OK in Blender

 

Which setting in Cura is causing this?

polssteun bak.stl

koffieschep v4.stl

[Smithy 1,135]

The first object polssteun_bak.stl is ok in my Cura 3.6 and was sliced normally, but the wall is a little bit thin.

 

The other STL has a problem, if you check it in X-Rax view you can see that there is a problem (not watertight) in it. And I get also a solid model if I slice it. So this object needs some repair.

[jvdwaa 0]

Hi Smithy,

It is OK that the walls of the box are thin.

I checked the design in Blender and even the thickness of the bottom should be only 0,5mm. Yet when I printed it, I had a bottom of mora than 2,5 mm before I switched of the printer. Also the printing time is 2 hours and 56 minutes.....

So, how did you check the slicing?

I still have the impression I screwed up a setting, but I still don't know which one.

 

Btw, didn't know about the x-ray option, very handy, will correct the coffespoon 🙂

Edited November 26, 2018 by jvdwaa
missing info

[Smithy 1,135]

I just put your STL file in Cura 3.6 and pressed prepare 🙂 then checked the layer view.

[gr5 2,002]

If the walls are very thin sometimes Cura won't print them at all.  I assume that's a problem for you 🙂  There is a "print thin walls" option in cura.  Sometimes you can fudge the line width a bit.  A 0.4mm nozzle can go down to about .35mm line width without much reduction in quality.  Even .3 will work.  Much lower than that won't come out so well.

[jvdwaa 0]

Hi gr5,

The bin was printed before, but somehow it got lost. That's the reason I wanted it to print again...

As I always keep the STL-files I have printed, I was rather puzzled why it didn't print properly.

Still no solution why it is printing the bin as a solid mass of plastic.

Edited November 26, 2018 by jvdwaa

[Smithy 1,135]

Next step would be to post your Cura project here, then we can see also your settings.

[kmanstudios 1,120]

If it is printing solid, then it is 'capping' the non-watertight model. I am not sure if this was a feature or not on earlier versions (pre 2.x) you should be able to fix it in an online service. I have no idea where that is though. @gr5 knows such things.

[jvdwaa 0]

As requested, the Cura project file for the bin (polssteun bak .3mf).

Please ignore the spoon (koffieschep V4), that design has to be corrected anyhow.

polssteun bak.3mf

[P3D 46]

The project file slices just fine for me, as did the STL.

[Smithy 1,135]

36 minutes ago, kmanstudios said:

I have no idea where that is though. @gr5 knows such things.

This is the online service which does the job for free:

https://service.netfabb.com/login.php

 

[jvdwaa 0]

The strange thing is that the object looks OK in Cura, but when printed it seems to be printing a solid object.

If you look at the STL-file, you'll see that the bottom of the bin is just 0.5 mm, when printed I interrupted it when there was already a layer of more than 2.5 mm.....

 

[jvdwaa 0]

I tried the online service on https://service.netfabb.com/login.php, but besides the fact that the stl is 8 times larger, It looks exactly the same, just like the estimated print time of almost 3 hours (where 25 minutes should be the max given the wall thickness)

[kmanstudios 1,120]

I do not think it is 8 times larger. Unless you have turned off the automatic scaling, that means it has been scaled down by 7/8ths. This will make the walls impossibly thin. This would probably mean that Cura is trying to compensate for that and therefore will print solid.

 

seems odd that the layer view would show one thing and then print another. I have not seen that before.

[jvdwaa 0]

Hi Kmanstudios,

I was referring to the file itself, not to the object...

And I had exactly the same astonishment when the printer created the thick bottom layer. 

I still think I ticked one or another setting in Cura that generates a solid object when printed, can't think of any other option 😞

 

[kmanstudios 1,120]

25 minutes ago, jvdwaa said:

I was referring to the file itself, not to the object...

You mean actual file size and not dimensions?

 

25 minutes ago, jvdwaa said:

I still think I ticked one or another setting in Cura that generates a solid object when printed, can't think of any other option

Should print as shown in layer view though. That puzzles me.

[jvdwaa 0]

yep, the actual file size has grown. The object in the file is exactly the same size, just like the estimated printing time of nearly 3 hours.

[kmanstudios 1,120]

14 minutes ago, jvdwaa said:

yep, the actual file size has grown.

Thanks. Kinda misread that. Duhhhhh......  😛

[Smithy 1,135]

3 hours ago, jvdwaa said:

The strange thing is that the object looks OK in Cura, but when printed it seems to be printing a solid object.

If you look at the STL-file, you'll see that the bottom of the bin is just 0.5 mm, when printed I interrupted it when there was already a layer of more than 2.5 mm.....

 

It is not strange, it works as designed. I have checked your STL in Fusion 360 and the bottom of the model has a thickness of 3mm. The total height is 12mm and the inner height is 9mm.

[jvdwaa 0]

hmm, in line with what I broke of when being printed, but not in line with the design I made in Blender: there the z-position of the lower outer plane is -1mm, and the inner plane -0.5mm. hence the bottom should be only 0.5 mm thick.

Btw, I get the same value difference between inner and outer plane when I import the stl back again....

I just reduced the thickness to have another try.