What is gap in vertical layers referred to?

[rkondakjian 1]

Hello,

 

I'm trying to search this forum for other scenarios before I post , but most searches are only successful if you know what key words to use. What is the gap between these vertical layers referenced as? I'm sure once I know the right terminology I could then find what causes this, and ultimately how to prevent it in future prints.

 

Thank you in advance for all feedback.

 

 

[GregValiant 1,252]

I'd call it "intermittent under-extrusion".  The bad ones at the top of your print look like extrusion quit completely.  That would make it "non-extrusion".

A clogged nozzle would do it (my experience is that clogged nozzles don't happen very often).

A clog at the bottom of the bowden tube is a definite possibility.  The tube rotates in the fitting and the little knife edges work their way into the plastic allowing it to shuffle in and out by a mm or so.  That allows a gap to form between the back end of the nozzle and the bottom of the tube.  Plastic pulled into the gap makes a little o-ring and the filament doesn't want to feed.

Heat creep will also cause blockage in the heat break tube.  Check that the main hot end fan is working and isn't full of strings and crud.

Is the extruder skipping steps?

If the end of the filament isn't stowed properly (in a hole in the side of the reel) then a loop can form and the filament doesn't want to come off the reel.

When you pull the filament out is the section that was in the bowden tube straight or accordioned?

 

It looks like it got worse as the retractions increased.  If I was a betting man I'd put my money on a hot end clog.

 

[gr5 2,173]

If this were an ultimaker I'd look first at the fan that controls the hot end.

 

1) This could be several things though - it's possible cura sliced the model like this on purpose and the model has faults.  If this is true you will see the exact same gaps in the PREVIEW mode in cura.

 

2) Z axis issues can cause this although it looks so damn perfect everywhere else.  Z axis issues would be where the bed suddenly slips down a few extra layers.  If your Z axis moves the head and not the bed then I would 98% discount Z axis issues based on how the print looks.

 

3) Most likely is what Greg said.  Temporary underextrusion.  So many possible causes from tangled filament to feeder to hot end issues.

[rkondakjian 1]

It's an Ender 5 Plus, the bed moves down.

 

I wasn't present at the time those layers were printed, but I don't have any shavings in the extruder....

 

I will run the extrusion test again, make sure I don't have any issues there.

 

Thanks for the feedback

[Slashee_the_Cow 267]

Also try moving the bed up and down (in the software, that thing must have a controller where you can manually adjust the position, right? I really only know the Ender-3 series) and see if it has any problems where it gets stuck for a bit or jumps a bit.

[rkondakjian 1]

I couldn't manually feed filament, nozzle was clogged. I was able to clear the clog and get filament to extrude through the nozzle,   but not without casualties 😁. Restarted printing and will observe behavior.