Cura Improvement Suggestion - Travel Speed Variable with Overhangs

[Gerrardh 1]

Hi All,

 

Not sure where to post suggestions, so I'll leave this here - please let me know if it belongs somewhere else.

 

I'd like to suggest a setting that allows the travel speed to decrease (user settable) in areas where the overhang gets above a certain value. I found with my printer, if I left the travel speed at the usual setting (40-50mm/sec) then my overhang tests would only get about 50-55 deg, but if I dropped the speed to about 10mm/s then I could get results much closer to 75-80deg overhang meaning I could print much more complex parts with less support material. Unfortunately printing a  whole model (especially a large one) at 10mm/s is out of the question... So it would be super cool if Cura could allow me to reduce the travel speed immediately above areas (for say... 4 or 5 layers) that have overhangs above a certain value in much the same way as supports are added now if overhangs are over a certain value...

 

Hope I'm not the only one who'd find this helpful.

 

Regards

[burtoogle 516]

Hi @Gerrardh, I am intrigued by your request. What difference does the speed of travel moves make in overhung regions? Could it simply be that because the moves take longer, the layer time goes up and so the part cools more (which helps the overhang performance)?

[Gerrardh 1]

That's what I think... while the print head is moving slowly, the fan is blowing on the extruded filament to help it cool... Once it's cool it's strong enough to prevent sagging... There are still limits of course... Each layer needs to be supported somewhat by the layer below, but a single thread of filament WILL support some small cantilevered overhang with minimum sagging.

[EE_guy 0]

Hi, since we're on the topic of improvements (maybe this is hidden somewhere) ?  I'd like to see an option to ZigZag alternate layers.  Odds and evens if you like.  The reason for this is that it will give better stability/strength.  Ie an angle of 45 degrees only gives a consistent sheer line whereas 90 degrees alternate layers significantly improves the strength of a part.  I personally think this should be the default configuration too!! If you rotate every layer by 90 degrees you will have a cross hatch from alternate layer builds.

 

I must comment that this software is excellent BTW.  ?

Edited August 31, 2018 by EE_guy

[gr5 2,269]

zig zag already does alternate layers.  Oh wait - you want 4 directions instead of 2?  No I think you want zig zag.  It's already a feature in cura.

 

I'm not a fan of zig zag already. It extrudes the right amount on intersections but underextrudes in between because it only extrudes every other layer.  So it's very weak.

[EE_guy 0]

Thanks for the response.  Yes, I actually discovered that ZigZag does alternate layers and it's exactly what I wanted.  Sorry for not realizing this.  As I'm sure you guys know, there's a lot of features in Cura and it takes time to understand what they all do.

[burtoogle 516]

If you want to print layers at funny angles, you can do that too. I have a part that I print the infill using the sequence 0,-45,0,45,0,-45,0,45,...

[Gerrardh 1]

FYI, This setting now exists in Cura as "Overhanging wall speed" under the "Experimental" Section.