New TAZ 6 (week old) ABS printing degrading over time

Hi,

I’m printing a somewhat complex part and having issues with the IC3D ABS frequently not sticking to the plate on the first layer. Small circles are the worst. In my last print some of the support material was found elsewhere like a small tumbleweed. Strangely it didn’t effect that part of the design. My guess is that it got stuck to the nozzle and the nozzle moved it until it broke off? I need to get a video setup for this rig.

Lastly, and most disturbingly, I cannot use this part because one corner is 2mm higher that is should be relative to the base plane. There is a gentle curve up. That I cannot explain.

My prints seem to be more problematic over time.

Using latest cura (2.6.63), firmware, High Quality profile, 100% infill (not that it is required (all thin parts)), Skirt, Generate Support.

Thoughts?

Thanks.

I encountered similar issues with my Lulzbot Mini with ABS. (Oddly enough, the white ABS was far worse than the black or silver ABS from the same manufacturer.)

The problems pretty much went away after adding an enclosure and adjusting the first layer settings.

The enclosure solved the problem of the corners of large parts lifting off the bed, the problem being that ABS shrinks as it cools, and enclosing it keeps the part warmer and away from drafts and other nasties. I started by trying a simple hacked-up enclosure made from cardboard boxes and masking tape. The results were dramatic enough that I investing in the “Printed Solid” enclosure (it’s nice to be able to see the entire printer and print bed, and worth a few dollars more to me).

Adjusting the first layer was largely trial-and-error, and seemed to impact small parts more than the larger ones – which makes sense, since the large ones have more contact with the bed to begin with. In a nutshell, over-extruding that first layer is the key. With the original (aka “legacy”) Cura, which I still use since I find Cura2 to be far, far too buggy at present, the first layer width needs to be 125%, and the first layer height I usually set to 0.30 or 0.35 – the idea I’m working with is that the head needs to be close enough to “squash” that over-extruded first layer onto the PEI surface, but not so close that it impedes the flow. As mentioned, the white ABS was just difficult – so using a raft has been necessary for some of the really small parts. And raising the print temperature by 5C for the white ABS was helpful not just for the first layer, but also in making the layers adhere better in general.

I should have mentioned I do have the printed solid enclosure.

Thanks for all the tips. I’ll try to find a good fast benchmark to test multiple settings. Right now my parts take 9-12 hours to print.

Definitely find a good quick calibration print to check the bed level and adhesion. I like the “target” style print that lets you check the entire bed. The attached covers the entire bed… I usually stop it after the first few rings. If the autolevel isn’t working, check that your frame is square, clean the discs and wiper pad… manually clean the nozzles at extrusion temp with a paper towel.

For your adhesion issues:

  • Clean the bed with isopropyl alcohol with a scotch brite pad to remove any oil and helps to abrade the surface a little more. I like using a crosshatch pattern.
  • Turn off the extrusion fan for ABS.
  • Increase extrusion temps for the first few layers
  • Use the Z-offset to help with initial layer adhesion. A “-.1” should help.

If the nozzle is hitting the print, it may be a sign of overextrusion. Try reducing the multiplier / flow rate percentage to .95 - .97. If that helps, then go through the motions to check the extrusion e-steps. Different filament brands / colors will require some tweaking.



Hope those help.

Attached? Thanks.

Trying one thing at a time. This failed the first time, but worked the 2nd. The 2nd time I was more aggressive with the scotch brite pad.

Thanks again. Please reattach that attachment when you get a chance. Thanks.

Sorry. Here’s the bed level / initial nozzle height STL.

Like I mentioned, I usually let a few rings print and check for a uniform extrusion width all the way around. I’ll stop the print if its not uniform or not sticking enough. Then I’ll let it print the center disc to check the bottom surface. It’s .6mm or something like that to help with removal.

The modular bed’s PEI needed a lot of work to get a good surface for sticking. I stuck with the green scotch bright pad which seemed fairly abrasive.

Good luck with dialing in your settings.
-Calib Circles.BIG.stl (731 KB)

I replaced the stock PEI with a much thicker one that I got from Amazon or Matterhackers. It is insane how much better a thicker piece works and how long it remains workable as opposed to the constant air bubbles in the thin Lulzbot-supplied stuff. Replacing the PEI was pretty easy using the freezer method.