Cura Lulzbot Edition - The Good, the Bad, and the Ugly

I've been using the "Lulzbot" version of Cura for the whole time I've been printing. It uses a different number versioning system than the original Ultimaker Cura. (I'll refer to it as Cura LE.)

I have an ancient desktop OSX machine that is still functioning. Apple maxed out its upgrades at 10.9.5 which has caused some small headaches that will only get worse. For now, it works. It handles Blender with ease. It's stable. There's old software that I don't have replacements for. And it is maxed out in Cura "Developer edition" through Lulzbot - a test build from August 2017...every upgrade I've tried to install has failed.

The Must-Solve Issue

Lately though, the 2017 Cura LE has been problematic. The amazing Micro .25 SL toolhead prints fine objects with an uneven top relatively well. Sometimes on the bottom, the walls don't meet up with the infill, but it's been mostly minor. But give Cura LE a flat top, and...it gets bad.

You can see the bottom dino meeples have what appears to be support showing through - it's actually the top printing layer...and does not get any better than that.

Dinosaurs on the top, showing the "best results" for the side on the printer bed.
Dinosaurs on the bottom showing bad cross-hatching/spiraling for their top layer.

On this T(eal) Rex, you can also see the wall not meeting up with infill. Photo is a little blurry, not the dinosaur's fault...it wasn't moving THAT fast.

T-Rex from the printer bed side - walls and infill separating

The older Cura LE is fine for printing with the .5mm nozzle, and the Micro *could* print okay on non-flat surfaces, but why make bad prints if you can solve it? Incidentally, the upcoming experience has been summarized. I probably burned about 6-8 hours this weekend troubleshooting the logs, then trying various solutions.

The Good (eventually) - Ubuntu 18.04

Let's start with the Good — this morning I managed to get my laptop running Ubuntu 18.04 to run "one-step behind current", i.e. Cura LE 3.2.32. I finally have access to ironing, in case that was necessary for the fix (it wasn't necessary to resolve the surface issues, but it's nice). The best stories are one with an element of hope.

The Bad - OSX 10.9.5

Don't bother, it's not going to work. (I tried the various OSX installs on the Lulzbot site.) Some versions would just crash and terminate, not generating a log. The best case scenario, was when it generated a log as it failed to launch. You can poke around Console>Applications>cura (stderr.log) and learn some troubleshooting.

The "useful" error log:

  File "cura/CrashHandler.pyc", line 17, in <module>
ImportError: dlopen(/Applications/cura-lulzbot.app/Contents/Resources/lib/python3.5/lib-dynload/PyQt5/QtCore.so, 2): Symbol not found: _LSCopyDefaultApplicationURLForURL
  Referenced from: /Applications/cura-lulzbot.app/Contents/MacOS/../Frameworks/libQt5Core.5.9.1.dylib
 in /Applications/cura-lulzbot.app/Contents/MacOS/../Frameworks/libQt5Core.5.9.1.dylib
  File "/Applications/cura-lulzbot.app/Contents/Resources/__boot__.py", line 81, in <module>
  File "/Applications/cura-lulzbot.app/Contents/Resources/__boot__.py", line 66, in _run
  File "/Applications/cura-lulzbot.app/Contents/Resources/cura_app.py", line 86, in <module>
    import cura.CuraApplication
  File "cura/CuraApplication.pyc", line 4, in <module>
ImportError: dlopen(/Applications/cura-lulzbot.app/Contents/Resources/lib/python3.5/lib-dynload/PyQt5/QtNetwork.so, 2): Symbol not found: _LSCopyDefaultApplicationURLForURL
  Referenced from: /Applications/cura-lulzbot.app/Contents/MacOS/../Frameworks/libQt5Core.5.9.1.dylib
 in /Applications/cura-lulzbot.app/Contents/MacOS/../Frameworks/libQt5Core.5.9.1.dylib

It turns out that the modern libraries of PyQt5 (Qt 5.10+?) aren't compatible with 10.9.5. This won't stop someone from publishing software that "works" with 10.9.5...their code is fine. It's just PyQt5 that will reject you. There's a suggestion of this problem here: https://github.com/Ultimaker/Cura/issues/4466

The Ugly - Back to Ubuntu 18.04

How can it be both Good and Ugly? Because it is. I'm pretty sure that the Lulzbot developers are Debian folks. The Ubuntu instructions...*should* work. "Jessie" is Debian 8, "Stretch" is Debian 9, and "Buster" is Debian 10...what is Ubuntu 18.04? (You can check /etc/debian_version and find out.) Buster! So...it should be easy enough. But if it's ugly, clearly there is something up.

It turns out that their most recent (3.6.3) Buster build doesn't work with 18.04. (If you want to skip ahead to the solution, go to the Lulzbot site here and grab the older 3.2.32. Afterward, go to the directory you downloaded it to, and enter this command - "sudo dpkg -i cura-lulzbot_3.2.32_amd64.deb") The current Cura LE 3.6.3 is looking for a file (GLIBC_2.28), and Ubuntu 18.04 uses GLIBC_2.27. (The event viewer for Ubuntu 18.04 is called Gnome Logging, and you can find it as an application installed on the general build.) The problem is called out in the Cura backlog, but I don't expect it to be fixed again (although it had been previously fixed the 3.2.32 version) Someone else mentioned the same solution here: Ultimaker Cura github page. (Basically, use 3.2.32, install command is done differently.)

You might be able to install 3.6.3 by using "sudo apt-get install glib2.0", to get GLIBC_2.28. I'm not an expert on Linux, and don't know what it could break. (For the most part, I use my laptop for internet, and for portable Blender/Cura...easily refreshed if I needed to do a clean reinstall.) If I hadn't spent the time setting up preferences and printers in 3.2.32, I would go back and try it.

So...what does this mean?

If you're not running straight Debian, you might be stuck with 3.2.32. I wouldn't get too hung up...3.2.32 and ironing seems to work just fine. At least the ironed T-Rex on the left thinks so...

Ironed T-Rex on the left, regular 3.2.32 T-Rex on the right

Credits:

The T-Rex meeple was remixed (thickened) from here: https://www.thingiverse.com/thing:2749410
The Teal PETG is Polymaker's PolyLite.
The Stegosaurus meeple was taken from here: https://www.thingiverse.com/thing:2749406
The Silver PETG is Filastruder.
The Triceratops meeple was remixed (thickened) from here: https://www.thingiverse.com/thing:2749413
The Orange PETG is leftover from MakerGeeks. Sadly, I can't recommend shopping with them anymore...6+ months of not fulfilling an order, I'm still unhappy about that. Used to be so great.