Missing outer wall line

[Hops 3]

Hi all, So this happens on alot of models on my S5 and so here i am looking for a solution. At the point where the model has an abrupt change or goes from "C"shaped lines to "O" shaped lines(that go from back and forth to all the way around the model) there is often what seems like a missing outer wall line or that the print head is no longer where it should be for one layer.

 

Please see the attached picture & 3mf file. This is using Cura 4.8 and latest S5 Firmware 

 

Thanks!

IMG_0241.pdf Small Black Scanner Cover.3mf

IMG_0245.pdf

Edited January 30, 2021 by Hops

[Torgeir 248]

Hi @Hops,

 

you can see the issue by opening ufp file of the model in Cura, -I'll assume you're using version 4.8.0. (Just zoom in).

The missing/hided line in one of you pictures, I cannot see, maybe check the Z  shaft greasing.

Just upload the new Cura version: Arachne_engine_alpha.

You will see a big difference in the affected area..

No need to change any of your project settings.

By the way, this is really a smart way to save PVA!

 

Thanks

Torgeir

 

Edited January 30, 2021 by Torgeir
Text error.

[Hops 3]

Hei. Thanks for the advice but im not sure what you mean by new version of cura. I am indeed on 4.8, is there a newer one? The printer is well maintained and everything greased / oiled.  

1 hour ago, Torgeir said:

Just upload the new Cura version: Arachne_engine_alpha.

Not sure what you mean here :S

 

ive added a picture of the whole model currently printing and it has the same issues. 
 

thanks!

[Torgeir 248]

Hi,

 

here you'll find the new version, an alpha version of Cura (kind of experimental).

 

https://github.com/Ultimaker/Cura/tags

 

I can't remember if this version want to "delete" previous versions of Cura, but if you have to answer no.

 

PS., it might also help to increase the numbers of triangles in the model before exporting the file to Cura.

 

Here is two pictures of your model sliced with Cura 4.8.0 and the new alpha version of Cura (issued 22 Des 2020).

 

First, Cura 4.8.0.

 

 

And here is the new Cura Arachne engine alpha.

 

Good luck

Thanks

Torgeir

 

 

 

Edited January 30, 2021 by Torgeir
More info.

[Hops 3]

downloaded the alpha, will give it a try. Here are some pictures of what was printed overnight. Unfortunately this is not something i can handover to client. interesting note that i think it is indeed software related and not a layer shift as the inside is printed beautifully and without the errors....... if only i can find out how to swap outside for inside.

[Hops 3]

Ok so heres the finished reprint on the alpha software. Not sure if its the software or that i doubled the triangle count or that i lowered the outerwall speed to 20 but its better. Still has a nasty band at the top and at the bigger change near the middle, none of which are visa le in preview

[Torgeir 248]

2 hours ago, Hops said:

Ok so heres the finished reprint on the alpha software. Not sure if its the software or that i doubled the triangle count or that i lowered the outerwall speed to 20 but its better. Still has a nasty band at the top and at the bigger change near the middle, none of which are visa le in preview

Hi,

 

this is strange, I've been looking at the model in the previous posting and found thous three lines around not seen at all in preview mode or in "ufd" preview mode. When looking closer to those lines, they all appear when there is a "sharp" change in horizontal movement at those levels. There is three such areas, the first overhang, the second overhang and the last is the "unsupported" roof (you are using support block here).

So I'm just wondering if you have a little play in X or Y, or maybe both axis? Should be easy to feel by just trying to move the head, without actually moving it, but you will feel if there is a lot of slack/play. Just a very little play is normal..

 

I've tried to slice your model with different versions of Cura and they are slightly different, but the issues that your print have is not seen in any of them.

 

I'm curious if you find too much slack in the print head, as I cannot see that this is a software problem..

 

Do you experienced this issue in other prints?

 

Thanks

Torgeir

 

 

 

Edited January 31, 2021 by Torgeir
Text error.

[Hops 3]

Yes unfortunately this is on every print where there is an abrupt change. There is play in the head, guess ill have to contact my reseller and see if its considered “too much”. To be honest I really hope thats the issue cause then at least there is a possibility to fix it

[Torgeir 248]

Hi,

 

thanks, for replay -and sure I've been testing this issue with my UM2E+.

I'll think that the last print you made with the "alpha" version of Cura is much better and the doubled numbers of triangles plus speed reduction contributed as well..

A head -that's have to much play, sometimes make every second line offset some -and this very much depend of the model plus how it is sliced.

 

Good Luck

 

Thanks

Torgeir

[Hops 3]

Thanks for all your help! I think you are right that the Alpha version was better, this makes me think its down to line heights and thicknesses and if they add up to a height thats divisible by the height. For example if the change is at 10mm  and you have the layer height at 0.1 then it would be at the right height when it hits this change, But if you had the layer height at 0,15 then it would not be correct and would cause this problem more. 

 

This is just a guess and ive yet to test it. Will see if i get the chance...

[Torgeir 248]

You're welcome, -and you're right doing the math always matter..  🙂

 

Wish you good luck.

 

Cheers

Torgeir.