GregValiant 1,370
I print mostly PETG. Stringing (Angel Hair) is always an issue. Also an issue is the curling of feather edges as they warp upwards. That is a severe problem when large horizontal holes start closing up. There must be z-hops to clear the part or the print can be hit hard enough to break it loose. The hops make the Angel Hair a lot worse.
When you enable z-hops in Cura, there are going to be z-hops from the beginning to the end. My solution was to cancel the z-hops except for those layers that need it. Setting the new z-hops height to '0' effectively negates the hop.
When a hop occurs the code is often something like this...
G1 X132.477 Y129.811 E1854.34812 >> Last extrusion before travel
G1 F2100 E1847.34812 >> Retract
G1 F600 Z16.0 >> Z-hop
G0 F7200 X143.424 Y129.432 Z16.0 >> Travel destination
G1 F600 Z15 >> Z-drop
We know where the nozzle is, and where it's going to, so it could be post processed to produce this...
G1 X132.477 Y129.811 E1854.34812 >> Last extrusion before travel
G1 F2100 E1847.34812 >> Retract
;G1 F600 Z16.0 >> Lose the Z-hop
G1 F7200 X137.951 Y129.622 Z16.0 >> Add this line. The X Y are the mid-point of the original destination line.
G0 F7200 X143.424 Y129.432 Z15.0 >> Original destination but now the Z is the drop-to height.
;G1 F600 Z15 >> Lose the Z-drop
That is doable without too much work.
Combing moves, whether they are at the end of a layer, or mid-layer, will be a problem. You have a non-linear travel move that might be 10 or 15 lines of gcode (or a lot more if you are circumnavigating a large round print). Trying to increment the Z-hop across 1/2 those lines and then incrementing it back down across the next 1/2 would be a PITA.
I'll stick with my solution. I suppose effectively having a wipe at the start of every travel would have some advantage, If the "Feather Edge" is close to the start of the travel and the nozzle isn't yet be up to the full z-hop height, it's gonna hit.
And then there are multi-extruder printers with different hop heights per extruder.
Using this post to negate the z-hops except for specific portions of a print works well for me. Using the "Advanced Cooling Fan Control" post-processor along with "Alter Z-Hops" can help reduce stringing. It isn't eliminated though.
Edited by GregValiant
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Supramaker 0
I found this:
I will give it a try, although I would prefer a postprocessor script that runs automagically after slicing in Cura.
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