Tiny Tiny bumps

[Hops 3]

Hi all, Ive some issues with tiny dots while printing and im hoping you can help!

 

on the two photos you can see the walls printed beautifully but the half dome on the top has some very noticeable defects. As this is for a client and needed to be close to perfect I decided to take the long road and used 0.15mm Visual preset with the only change being to add supports. I was sad to see after waking up on the morning the print finished to see the small dots on the top of the dome.

 

I checked cura and found that there are travel lines that exit from the dome and go around to the other model. I tracked down that the travel lines are exiting from the outter shell because Travel> avoid supports while traveling is ticked. Why is this? it seems to be partially responsible for the dots i think and it seems odd to me that the hotend would travel over the outer layers, especially on a visual setting.  Is there a valid reason for this?

 

Once i took that setting off i printed another part of the same type and found that there were still dots! after zooming in very close i found there are also small black loops that exit and enter from the outer shell back into the model! Its literally a travel line that for no apparent reason goes to the edge of the model and does a little loop..... 

 

Please let me know how i can get rid of:

A Travels over the edge

B The small loops that seem to server no purpose other than making small dots on the outer surface.

 

Ive attached the 3mf file also in case someone wants to check it out.

 

Thanks!

Scanner Covers.3mf

[Torgeir 280]

Hi Hops,

 

The small dots, its really from the travels Cura sometimes makes due to some issues..

I've been experimenting so much with domes and curves over the times in order to trying avoid this to happen, so here is some tip.

 

I've found that Cura need a model with a high number of triangles in order to do slicing better (Cura is somehow sensitive here).

Over times I've tested so many curved and coned models in order to understand how to "prepare" a model for Cura to be sliced as good as possible in order to make a good 3D print of my object.

 

So here is how I'll do curved and "dome" prints;

 

1)

Increase the number of triangles in your model, just put a high number up... Do not think about megabyte size, think more about your model quality!  -You can always delete a big temporary file.

 

2)

Use the "finest" (0.006 mm if you can) height resolution you have!

 

3)

Select adaptive layer height in Cura (search in the menu for this setting).

 

The above should make a much better surface outcome for curving and high "overhanging angle" part of your print.

But you use support, -do you?

 

And sure no warranty here.. 🙂

 

Sure I've tested your model.. So just increase the number of triangles in the stc file of this model. Cura work much better with enough number (resolution) of triangles.  But do not forget the rest of settings..

 

This is just my experience.

 

Good Luck.

 

Thanks

Torgeir.

 

 

 

 

 

[Hops 3]

Hi and thanks for the detailed reply!

 

I raised the poly count from 6,000 to 42,000 and am unable to increase further in Fusion 360. and indeed the number of loops reduced. However they are not gone 😞 

In this case and basically any im in where there is a client waiting for the product printing time is important. at 0.15 this takes 1,5 days. at 0,1mm its 2 days and 13 hrs. As this had to be done over the weekend i could not have printed at this resolution and made the handover. 

 

I was hoping for a setting something like "Do not make small travel loops on the wall" 

 

@ultimaker team Is this a known issue thats in the backlog? Will this be fixed? It seems that these loops should not be there regardless of poly count. Do they have a function?

Edited September 16, 2020 by Hops

[Torgeir 280]

 

What printer do you have?

 

Can you share your gcode file here?

 

Thanks

 

Torgeir

[Hops 3]

56 minutes ago, Torgeir said:

 

What printer do you have?

 

Can you share your gcode file here?

 

Thanks

 

Torgeir

 

S5 with air manager. i cant seem to add the output from cura which is a ufp file 

 

EDIT> Added the 3MF file that should include the models and exact settings i used to print them

Scanner Covers.3mf

Edited September 16, 2020 by Hops

[Torgeir 280]

Ok. Great and you are using Cura 4.7.0 right?

 

 

Torgeir.

[Torgeir 280]

Hi, sorry for late reply..

 

You'll need to change two settings to remove this extra travel issue.

First, turn off combing mode.  Then set Z seam to "user specified" and select "back".

That's all needed.

 

Here's a picture of settings and result.

 

 

For testing just the "affected" top parts, you can do this;

 

You can drag the object down and just printing the upper part (just skip support for such test). Set a brim or skirt for just that part of the object.

 

All in all very easy to do.

 

Good luck.

Thanks

Torgeir

 

 

Edited September 16, 2020 by Torgeir
Text error.

[Hops 3]

The combo seems to have fixed it, can’t find any more dots. Thanks! Maybe ultimaker should update the visual profile  

[Torgeir 280]

Thanks for the feedback, glad it's worked for you.

 

Regards

Torgeir