Layer skipping

[Kristen L (Kal318)]

Ok I'm at a lose. I keep getting layer skips on my prints. There number tends to vary from as little as one over the entire part to several. My extruder clicks when this happens especially on small fast moving areas. I'm currently using default setting in both Cura and Pursa slicer with only changes to temp "220 PLA" and initial layer height. Retraction "at default" 6.5. Lowering this has made the issue much worse. e-steps are spot on and properly set, and I have tried nudging that up ever so slightly as I thought it was under extruding. I have made no changes to speed "50 mm/s in cura and 100 mm/s in pursa, these are the defaults" I have cleared any debris from the hot end and nozzle. And replaced the nozzle. I just cleared the nozzle again and ran a 3dbenchy which printed fine until it got to the smoke stack the problem return as well as the clicking. I can normally get away with printing small simple parts, but the moment I have to start adding supports I can expect problems. I'm almost afraid to run larger prints as I'd probably just be wasting filament when it ultimately fails. And unfortunately it does every time. Please help I feel like I'm running on empty for solutions.

[Edward Simpson]

Okay, couple questions to start with: Are you running direct drive or Bowden? and what type of hot-end setup/cooling configuration? The issue you describe is ether excessive retraction in a direct drive setup or under-powered part cooling on a bowden system. As for quick fixes, the fastest solution is to increase 'minimum layer time', it's in the filament profile settings for Prusa Slicer, try cranking it to 30 seconds and see if that fixes things or not, then go up or down to find the best balance of speed vs quality.

[3D Printing Tips and Tricks]

Another possibility is you’re getting heat creep within your hotend. 220c is on the high side for pla which typically ranges from 190-210c.

How to tell? Next time you get stepper studder stop it and pull out the filament from the hotend. If there’s a bulge by the tip or above the tip it’s heat creep. IOWs the filament is going soft above the melt zone. As the filament goes up and down if soft it’ll bulge within the thermal tube and inhibit the movement. What to do? Set you temps properly, make sure the hotend cooling fan is working right ( make sure it’s blowing on to the thermal barrier, lower retraction settings.

What printer is this?..

[vr...@optonline.net]

The problem you describe as regards to the smoke stack on the Benchy - definitely sounds like your issue involves short paths. Typically - if the path is too short - the layer is not get enough time to cool down. And, the clicking noises you speak of - its like the extruder motor is having problems pushing the filament into the extruder. Maybe its heat creep going upwards into the cool zone of the extruder. Not sure. But, I think some of the reply from Edward in his response may get you going in the right direction.

-Kurt

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[Dan Flemming]

I ran into this problem before.

It was fixed by several adjustments.

1) Turned nozzle temp up.

     Filament wasn't melting fast enough for extrusion at the speed I was printing.

2) Lowered retract distance.

     In small areas that require many retracts, the Filament was clogging the nozzle because it seemed to "pull in" cooler Filament back into the heat chamber.

3) Slowed down speed.

     I found models that had lots of smaller areas worked best printing slow, compared to models that had larger areas that didn't require as many retracts.

Also dried Filament helped reduce failures.

Each of my 3 printers now have dryers on them.

I always dry for at least 30 minutes before I start prints, just to make sure they are dry & pliable.

To view this discussion on the web visit https://groups.google.com/d/msgid/3d-printing-tips--tricks/7fce42ea.320.189ad514e1c.Webtop.66%40optimum.net.

[LukeH]

There should be a setting in the slicer to set minimum layer times. This will effectively slow down the printer on small layers (like the chimney), while still allowing it to run at full speed on the bigger layers. The system will slow the print all the way down to the minimum speed you set. If that is still faster than your minimum layer time, it will pause between layers.

It is specifically designed for this problem.

[Kristen L (Kal318)]

I'm a idiot. My ender 3 Pro is probably more a ender 3 s1 pro after mods, including a sprite extruder. I setup Cura with the stock ender 3 pro setting and adjusted the e-steps for the extruder but no the retraction. It appears to be a combination of heat creep and excessive retraction. After correcting the these my prints have been coming out wwwwaaaaayyyyy better. Thank you very much.