Cura will sometimes "travel" on the print surface.

[jamieo 0]

In most cases cura works just great for me, but on certain shapes it will "travel" (I think we call it travel - when the head moves without extruding to another position to start its next level or area) along the face of the surface or just too close to it, damaging the printed area. It only happens for me when doing a certain type of shape, like a semi sphere subtracted out of a wall. I have had it a numerous occasions for different prints. Widening the print doesn't help. I do alot of forms like this and I hope to find a fix or workaround.

Here is a screen grab of what I mean:

http://www.facebook.com/photo.php?fbid=10200858538935987&set=a.10200858540576028.1073741826.1539726292&type=1&theater

Big thanks for any help!

 

[jamieo 0]

It just came to me, I should try retraction. Though if there is a setting somewhere or a workaround so that it doesn't travel near the surface that would be great, because when using retraction I found other issue arose. I like to keep it simple as its printing great for me in general, except in these area.

I only care for the one side of the print, the curvy side. I will try adding more geometry or less on the straight side to see if that makes it run in another way.

 

[jamieo 0]

I'm not sure if its bumping the wall as it travels pass these thinner areas or its leaving some filament behind as its passes. Anyway, I'm trying retraction with jumps only off. If not, maybe wall thickness or the sequence? Anyone know what 'loops' are in sequence?

Retraction didn't help.

 

[gr5 2,024]

You should try kisslicer.

In Cura you could try changing the print order. Default I believe is "perimeter - loops - fill". You would want perimeter last.

Perimeter is the outer edge. Loops are inside circles such as a hole through your part - you don't seem to have any loops in this part.

 

[illuminarti 18]

I think that loops are not just (the innermost part of ) interior holes, but also any layers of the outer skin apart from the outermost one. If, say, you are doing wall thickness = 0.8 and nozzle size = 0.4 in Cura, to get two concentric passes around the outside edge, the innermost one is a loop also, and the outer one is the perimeter.

You might also want to try having the head lift above the print during travel moves. Cura has an option for this in the expert settings, and Kisslicer can also do it.

 

[Daid 304]

Your example isn't that bad, I've seen much worse. It comes from the Skeinforge code which is still behind Cura. Which does some strange things and as with all odd code, things sometimes go wrong.

I'm working on replacing Skeinforge, which is quite a tough job, but can be done.

 

[jamieo 0]

Thanks a million guys. I'm going to try the sequence now and will let ya know. Though I can't find that option to lift the head.

When I tried kisslicer, I couldn't find the options I need to position the print where I wanted it. Something else scare me off it also, might've been just the name.

Cheers

Nah, the sequence made it worse.

Adding an extra wall didn't help either. Lifting the head sounds very interesting now, but still can't see it. Thanks

 

[illuminarti 18]

It's 'Enable Hop on Move' - the last option at the bottom right of the 'Expert Settings' dialog.

Be aware that hop on move has it's own issues - it tends to move more than needed, and if you combine it with the half-height perimeters feature 'Skin' it seems to do bad things at layer changes.

(See: https://groups.google.com/d/msg/ultimaker/BLX8RDC-qv0/xzcsB9oxqaQJ)

Also see Erik's comment in that thread, and the link to my post about the potential to optimize z-moves so there's less time for blobbing etc.

 

Lifting the head sounds very interesting now, but still can't see it. Thanks

 

[jamieo 0]

Thanks mate. I didn't have the latest version of cura. Its obviously easy to find now.

I'm going to try different infills if this doesn't work.

 

[jamieo 0]

Nothing worked to fix it. I normally don't mind some artifacts on the surface, as it can be cleaned up but this prints has alot of fine detail that cant be cleaned up.

I'm trying kisslicer now, but will stay with cura for most work - I love the update with the print dimension display, very handy.

 

[gr5 2,024]

Did you consider turning off infill altogether?

 

[jamieo 0]

What a great call dude!! It worked perfect, best print for me yet. Done super quick time and I even lowered the layer height. I will probably fill them with plaster to solid them up a bit.

Loving cura even more now.

 

[gr5 2,024]

Glad that worked.

Consider also doubling the wall if the part doesn't seem strong enough. Your nozzle diameter should be .4mm so 2X that would be .8mm so consider making the walls .8mm which is two passes around. That will give you more strength without hurting print quality too much.

Or try a different infill pattern - hex instead of lines.