Cura 5.3.1: slicing issue with very small part of .stl model

[Erik84750 0]

In the .stl file the two tiny sloping bars are not being shown in the example after slicing. Settings: fine (0.1mm), no support structure (already included in the .stl model).

And printing does not give these two bars neither.

 

What can be done to get this right?

Thanks for any reply and/or help.

Erik

 

Track_Bumper_Buda.stl

[obewan 36]

Using a 0.2 nozzle and a 0.2 line width seems to give good results.

Or just setting 0.2 line width might work ok,ish

 

[GregValiant 1,112]

The model needs repair so that needs to be taken care of first.

 I see problems with a 0.4 nozzle and with a 0.3 nozzle so I think you're stuck with the 0.2.  

 

This is with the 0.3 and there are still gaps here and there.  They go away with the 0.2 nozzle slice.

I think it would be better if this had been designed in "Fun Scale" instead of "To Scale".  Those vertical posts are tough.

 

 

 

 

[Erik84750 0]

Thank you the both of you for that help; I will be testing this right away.

 

Something else shows up, I don't know if a different thread is best but: how do I get rid of these blue horizontal tiny threads?

They also show up on the file I posted in my opening post.

 

 

 

[obewan 36]

They are travel moves shown by cura, you can turn the option off in the 'colour scheme' menu 

[GregValiant 1,112]

They come in two flavors.  Heavy lines are "no retraction" and can indicate that there will be stringing.  Light lines are "retracted" moves.

On the last image I would suggest playing with the Retraction settings.  You will want a retraction before the print head moves from island to island or all those blue lines could end up being strings.

[Erik84750 0]

Retraction already is active, with retraction distance set at 6.5mm as well as "z-jump when retracted".

 

Indeed light lines; when retraction not set the color changes to dark blue (heavy lines).

 

Would retraction distance have an influence on the actual print? On Cura simulation the light blue lines do are not reduced.

[GregValiant 1,112]

"Retraction distance" (the actual amount of filament moved during a retraction) should not have an effect.  The "Retraction Minimum Travel" and the "Max Comb Distance with no Retract" do have an influence.  You would need to set the "Max Comb distance..." to a number smaller than the distance between the "wings" on that model.

This is with those two settings set to there is no retraction before traveling between the "islands".

 

Here I changed the settings so that there IS a retraction for the travel moves.

 

[Erik84750 0]

Hi greg, many thanks for that valuable answer.

But I see on your picture (and in my resulting slicing) that there still are strings, even very tiny.

How can these be eliminated altogether, if at all?

[GregValiant 1,112]

If you have the "Max comb distance..." turned down to 2.0 or similar (shorter than the distance between the wings) then you might have to re-visit your "Retraction Distance" and "retraction speed" and maybe your printing temperature.

Most bowden systems have a maximum of about 7.0mm retraction distance.  Any more than that and the hot plastic can get pulled up into the heat break of the hot end where it can form a plug that makes for a partial blockage.

If the retraction speed is too slow, it takes forever.  If the retraction speed is too fast it can snap the filament backwards faster than the melted plastic at the nozzle can react.  That can cause other issues like incomplete retraction and/or air being pulled up into the nozzle opening.

PETG is pretty soupy at higher print temps whereas PLA is all-around much easier to deal with.  

That's a small piece so another thing you could do would be to print 2 (or 3) of them at once rather than just one.  That would allow your layer cooling fan to have a lot better chance of actually doing some good.

If you simply can't get rid of some stringing then a hobby knife is your friend.

[gr5 2,071]

light and dark blue lines are TRAVEL MOVES.  As opposed to EXTRUDING MOVES.

 

You need to understand what those two terms mean.  Extruding moves means plastic comes out.  Travel moves are mandatory.  You can't get the print head from place A to place B without moving the print head.  Travel moves should not create strings but sometimes they do.

 

red, yellow, green, teal lines on the screen represent PLASTIC.  blue lines represent movements (no plastic).

 

Are you following me?

 

In general DARK BLUE = BAD (in that some plastic will leak out.

LIGHT BLUE = GOOD (no plastic comes out - hopefully)

 

If you understand nothing else, know that dark blue moves *might* create strings.  Light blue moves should not.  Sometimes they do anyway but that is a hardware issue, not a cura issue.

 

 

[GregValiant 1,112]

And speaking of hardware...what printer are we talking about here?

 

[Erik84750 0]

On 8/4/2023 at 4:14 PM, GregValiant said:

And speaking of hardware...what printer are we talking about here?

 

It is a Anycubic Vyper; bought just a month ago, started experimenting a few weeks ago.

As for filament: I use Fibrelogy PLA.

 

EDIT: the strange thing is that with Cura default settings I cannot remember having had these hairline strings. Maybe I should get a default reset of Cura?

 

EDIT #2: I seem not to get email notifications from this forum on my thread; although account settings are default..

Edited August 6 by Erik84750
clarification

[Erik84750 0]

The stringing issue is solved.

 

I replaced the entire hot end, heatbreak and feed tube section.

 

This had become clogged with a bad quality of PLA, purchased from Sakata 3D filaments, a Spanish producer.

Now I only use Prussa and Fiberlogy.

 

Thanks anyway for all the suggestions in this thread!