What could be causing this inconsistency?

[nailcannon 0]

https://drive.google.com/file/d/0B0NkngkTIDmYR3VKanZhS3J4bjg/view?usp=sharing

 

I've been trying to print but it keeps extruding very unpredictably. It's Gizmo Dorks white PLA printing at 220 and 30mm/s. It's not skipping, at least i dont hear the sound of the feeder skipping. I'm really hoping it's not the filament being an inconsistent diameter. Any advice is much appreciated.

 

 

[nallath 577]

White fillament is known for not printing well. So it could always be that.

But juding from the picture, it can be two things; The glass plate not being flat or an inconsistent diameter.

 

[gr5 1,020]

I don't think it's the diameter as it would have to vary by about 2X to get that kind of 50% underextrusion.

Either the filament is slipping in the feeder or the feeder is skipping backwards. The first layer is the hardest to get perfect because it's easy to be a little too close to the glass such that it's over extruding and pressure builds for a long time and suddenly skips. Or it could be too far from the glass such that you aren't extruding enough - but it should be more consistent. I'd be very curious to see if the problem goes away on second layer. If so it's a leveling issue.

I suspect it's neither issue and that you just have slippery filament. Maybe tighten the feeder tension screw so it holds the filament tighter? How deep are the holes in the filement created by the feeder? You want them pretty deep like image on right:

 

 

[nailcannon 0]

I suspect it's neither issue and that you just have slippery filament. Maybe tighten the feeder tension screw so it holds the filament tighter? How deep are the holes in the filement created by the feeder? You want them pretty deep like image on right:

 

It would seem that may be the issue. the holes are rather shallow. I'll tighten it and test tonight when i get back home. A follow up question. I make a lot of models so naturally my prints require quite a bit of retraction. But the constant retraction is making the feeder grind the filament down and stop extruding. what settings would you recommend to best counteract this while still retaining good quality?

 

[yellowshark 133]

Wow those are deep holes. I do not have a UM, which may well explain it, but my holes are like the filament on the left.