Taz 6 messing up layers

Hey guys

I recently got my first lulzbot and have been fiddling with the gcode perfecting every setting (i have previous experience with the Prusa i3 and makerbot Replicator 2x). Now there is something i can’t explain. For the first 6 layers, the Tax prints flawlessly. Like absolutely perfect and then the first layer after its done with the bottom layer of the box i am printing, the quality drops dramatically and the sides and insides start to get clumpy. Ive slowed down the print, made the outer walls thicker, decreased infill density and overlap and it continues to print the same. I fixed it originally by decreasing the infill but then it started doing it again even though i didn’t adjust the settings at all. Ive cleaned the nozzle, disassembled the extruder and cleaned off every thing, sanded the bed with 1500grit to prevent warp thinking that might be a reason and nothing has fixed it. Any suggestions? is it a code problem or a printer problem? Thanks in advance

Picture would be useful, what type of filament and what infil settings also useful. Could be a fan issue if this is PLA, could be nozzle temperature, could be over or under extrusion, etc.

Infill is at 20% with a 7.5% infill overlap (lower from 15% to see if that was the problem), I’m using 2.97mm abs filament off eBay (i know sometimes its crap but I’m not gonna blame the filament as its always the same layers that get messed up, not the entire print), nozzle is at 230 degrees, and the box is printing at 105% extrusion for the entire box except for layer no. 1 where it is increased to 110% for better bonding and a clean bottom print.

Both attached pictures are the same settings, same filament (different light so they look different), and printed one after the other, the nicer one has been sanded but it didn’t print with those ridges, it was a clean even print. They also both warped in the same spots so i can’t imagine that would be the reason either

When I see this type of anomaly, I usually slow down my infill speed and set the infill overlap to 1%.
I also try if possible to print with thicker outer shells.

The only time I really see this is if I’m printing with an overhang.
The small infill overlap seems to cure that problem for me.

#1. Your nozzle is too close to the bed. Measure your skirt thickness and compare it to what you have your initial layer set to. It’s probably going to be a lot thinner on your print than what you have it set for. You’ll need to adjust your Z offset.

  1. If that doesn’t fix it 100% then you’ll need to back off on your flow rate % a bit.

Definitely looks like #1 though. Print some calibration cubes with a skirt and report back what the actual skirt thickness you measure is.

Definitely too close at start, plus you are getting some lifting later. Bump your bed temperature up 5 to 10 degrees. You also are getting inconsistent extrusion. While this can be temperature based, it’s often idler arm tension. Make sure you have about 7mm between the washers on either side of the idler arm springs. Also clean yhe hotbed bolt hobs.

Crap fillament will definitely impact printing. It would be a good idea to buy one roll of good stuff to learn with. Lulzbot villiage plastic or push plastic 3.00mm abs works very well.

You are getting the phenomenon known as elephants foot in addition to being too close to the bed. Lulzbot stock profiles deliberately over extrude on the first layer to promote better bed adhesion. Once you get everything else except that first 2 layers dialed in, you can experiment with dropping the initial layer extrusion percentage too.

Thanks a lot guys, ill try it all and report back