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thingismith
Posts: 26
Joined: Sat Mar 11, 2017 3:18 pm

PLA Strange Layer Behaviour

See my two pics of PLA prints. The layers where the prints change I get extrusion issues. Maybe it's because it's the layer that goes from an infill to solid, or it's when there's a change in the amount of material for a layer. I'm not sure which settings apply.

It had happened on a previous print, but much worse, for the same type of layer changes. I had lowered the retraction settings a lot, which helped some, but not completely. Now they are as follows:

Multiplier 1.10, Width .40mm
Retr. Distance: .5mm, Speed: 50mm/s
No extra restart, no vertical lift, no coasting, no wiping,
Only retract when crossing spaces
No force retraction between layers,
minimum travel 10mm

Temp of Extruder: 230, bed 55, fan speed 60%
Infill 30%

Using my Prusa i3 MK2S, white Shaxon PLA 1.75mm(from Frys)

Let me know if there are any other settings you'd like to know. As always, thanks in advance.
Attachments
Bottom and top layers of 3rd tier
Bottom and top layers of 3rd tier
Layer between tabs and wall
Layer between tabs and wall
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DarthRevan
Posts: 480
Joined: Wed Feb 18, 2015 8:29 am

Re: PLA Strange Layer Behaviour

Looks like a retraction issue still. Moving from location to location and seeing under-extrusion like this most often stems from retraction settings. You may also need to look into increasing the number of perimeters or infill percentage, as some of the gaps look like they extend into the areas where solid fill should meet perimeters. https://www.simplify3d.com/support/prin ... or-corners
airscapes
Posts: 403
Joined: Tue Mar 06, 2018 10:35 am
Location: Philadelphia PA Area

Re: PLA Strange Layer Behaviour

inconsistent filament diameter can also cause similar
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thingismith
Posts: 26
Joined: Sat Mar 11, 2017 3:18 pm

Re: PLA Strange Layer Behaviour

DarthRevan wrote: Looks like a retraction issue still. Moving from location to location and seeing under-extrusion like this most often stems from retraction settings. You may also need to look into increasing the number of perimeters or infill percentage, as some of the gaps look like they extend into the areas where solid fill should meet perimeters. https://www.simplify3d.com/support/prin ... or-corners
airscapes wrote:inconsistent filament diameter can also cause similar
Thanks for the input guys, but the problem areas consistently occur for the entire layer for the layers where there is a solid infill. I think that if it was an issue with the perimeters or infill % it'd only occur in the top, solid parts of the layer...not for the entire layer. If it was an inconsistent filament diameter, it'd be occurring along the whole print, not just on those layers. Is there a retraction setting that is affected by the solid infills?

At first I thought it might be the "Speed Overrides" setting under the Speeds tab (Reduce speed was 90% for layers below 15 seconds), but how would that explain my tea light holder?

The only retraction setting is for .5mm at 50mm/s, with nothing checked in ooze control but a 10mm min travel for retraction.
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thingismith
Posts: 26
Joined: Sat Mar 11, 2017 3:18 pm

Re: PLA Strange Layer Behaviour

I just remembered I had a similar problem with another print where I would get extrusion problems printing in nylon for entire layers, for certain layers:

viewtopic.php?f=8&t=9485&p=39573#p39573

That was printed on my delta, the prints in this post were made on my prusa.

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