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Grid infill printing with gaps  

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perky890
(@perky890)
New Member
Grid infill printing with gaps

Hi all,

I am trying to print using a 40% grid infill, however I have noticed it is missing parts of the grid leaving gaps. Please see the picture attached. The grid started out perfect, i was watching it because a part I printed a couple of days ago also had these gaps. I thought all was ok but on a passing glance the gaps are back.

Does anybody have any idea what could be wrong and how to fix it?

 

Thanks

Posted : 16/03/2023 8:39 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Grid infill printing with gaps

Its the nature of grid infill.  Grid crosses itself on the same layer, this means it hits already laid down filament.  This has a scraping effect on the filament coming out the nozzle which can then leave a gap on the other side of the line it crossed over.  If you listen you will hear it bump over each line as its printing.

Basically don't use grid for anything except quick draft prints.  Use one of the newer infill patterns, Cubic and its various derivatives or if you must gyroid.  The problem with gyroid is its all curves, which means bigger gcode (which on some printers can cause instructions per second issues) and constant changes of direction of the extruder.  That's going to add up to more wear and tear.

Posted : 17/03/2023 7:39 am
jseyfert3
(@jseyfert3)
Reputable Member
RE: Grid infill printing with gaps
Posted by: @neophyl

Its the nature of grid infill.  Grid crosses itself on the same layer, this means it hits already laid down filament.  This has a scraping effect on the filament coming out the nozzle which can then leave a gap on the other side of the line it crossed over.  If you listen you will hear it bump over each line as its printing.

Basically don't use grid for anything except quick draft prints.  Use one of the newer infill patterns, Cubic and its various derivatives or if you must gyroid.  The problem with gyroid is its all curves, which means bigger gcode (which on some printers can cause instructions per second issues) and constant changes of direction of the extruder.  That's going to add up to more wear and tear.

Because it's the default, and because Prusa speaks so highly of it, I've never used anything except gyroid so far, and so I have two questions:

Firstly, the Prusa blog and Prusa help site both say that cubic crosses itself each layer. How does cubic differ from grid if both cross on the same layer, besides cubic not crossing as much?

Secondly, why would gyroid cause constant changes of direction of the extruder? I was just watching a print this morning and gyroid, at least when not filling a tiny area, does not cause constant extruder changes. The gyroid is laid in a continuous layer if the fill area allows, and the extruder keeps smoothly pushing filament through at the same rate, and doesn't reverse. It reverses way more printing stuff that's not infill.

Or do you mean constant changes of direction of the print head, not the extruder motor?

Posted : 20/03/2023 3:24 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Grid infill printing with gaps

Gyroid is made up of curves, therefore it’s a constant change of direction.  The extruder feeds filament smoothly naturally, that not the change I was talking about, Just try different patterns an observe what happens. Get your own experience and make your own judgements. It’s the only way to really learn. 

Posted : 21/03/2023 6:00 am
jseyfert3
(@jseyfert3)
Reputable Member
RE: Grid infill printing with gaps
Posted by: @neophyl

Gyroid is made up of curves, therefore it’s a constant change of direction.  The extruder feeds filament smoothly naturally, that not the change I was talking about, Just try different patterns an observe what happens. Get your own experience and make your own judgements. It’s the only way to really learn. 

Hmm, okay.

Also I'd argue there's no issue with extra wear using gyroid. The gyroid curves have the print head move in nice and gentle movements. Comparing that to other movements the print head does when not infilling, which have very rapid accelerations, as well as watching various inkjet printers yank the print head back and forth way faster than my 3D printer does, I personally see no issues with using gyroid. Assuming you don't have issues with commands per second you mentioned some older printers have, but I don't think that'll be an issue with the MINI+ running on a 32-bit controller.

Posted : 21/03/2023 3:37 pm
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