Block travel outside of print footprint?

[m12lrpv 0]

Is there a way to stop travel outside of the base footprint of the part?

I've been printing for years and thought I would finally tackle one of the biggest issues i face in my prints. I want all travel to stay within the base footprint of the part to stop all of the ugly stringing and artifacts caused by travel. I've just upgraded from 4.6 but it seems that there is still no combing setting that works.

 

By example this simple part with some holes in it that are going to be drilled and tapped. The holes split the part and cura takes it upon itself to then travel outside of the part in the worst ways possible. All travel should jump the shortest distance (across the hole) but as can be seen it wants to travel through the outer skin regardless of any combing settings.

 

For PLA it's bearable because the retraction can handle it but for PETG it's terribly stringy and ruins the surface.

 

Is there a setting i'm missing???

 

 

 

[MariMakes 206]

Hey @m12lrpv,

 

That's a really interesting challenge 😄

Do you have a project file for us?
To save a project file go to File -> Save project.

On the top of my head I would say that the Within Infill combing option would help you here.
You can read more about it here. https://github.com/Ghostkeeper/SettingsGuide/blob/master/resources/articles/travel/retraction_combing.md

[m12lrpv 0]

Thanks for thinking about it.
None of the combing options work because the whole part is split by the hole which is where things go awry. Sometimes I will design in a line that I have to drill away just so there's no break in the external wall to allow combing to work.

Drill holes are the most common case where this occurs but anything that splits an otherwise straight walled part will cause wild travel and subsequent stringing artifacts.

 

Perhaps another way to look at is as trying to select a minimum external travel distance for each layer and another option could even be a "same as previous unbroken layer" travel option.
 

The part here is a clip for a celestron telescope tripod if you're curious.

 

leg_clip.stl PETGE5_leg_clip.3mf

[MariMakes 206]

Thanks for sharing!

I believe I have the solution for you!
If you move the Z Seam postition to front you get this:

 

I've also noticed that the type of infill has a lot of influence on this model.
So if you are not married to the infill pattern/density that is something else you can play with.

Good luck and happy printing! 😄

[m12lrpv 0]

Thanks. Maybe I should have gone with the more complex one first. Once I add a few more cutouts no z-seam setting can handle it.

 

[MariMakes 206]

Hey @m12lrpv,

 

Ah, I can imagine that the travels change if the geometry of the model changes.
I've noticed that increasing the Travel Avoid Distance helps in this model to clear the 

What is the reason you want to prevent these travels? Are you experiencing stringing?
Do you have a picture of the stringing you are seeing? 

These travels are light blue, so they should be retracted.
If they are not you can consider tuning your retraction settings.

[m12lrpv 0]

It's not an issue with PLA. The retraction works cleanly with no stringing. Even with the travels.

 

But for PETG I am running lowest practical temperature (255C) and retractions aren't as effective and the stringing is terrible. It's the nature of the material. If I want the strength it offers then I have to put up with the stringing unless I can keep the nozzle within the part in which case I can get a perfect print.

 

Maybe with an all metal hotend I could run a lot hotter and make retraction more effective but it's too much of a fuss for me right now.

[Gero 54]

255°C is quite a lot for petg. If I am still printing PETG, then it is more likely to be at 230-235°C. This definitely reduces stringing. 

PETG also absorbs a lot of moisture from the air, so I would also recommend drying the roll at about 60°C for 4 hours before printing and storing it in an airtight box.