Filament Issues -- PLA and nGen

Hi! I am new here, so I apologize if I’m making mistakes in my post. Anyway, I recently purchased a roll of PLA+ Kodak filament, and I am having spaghetti monsters and gaps in my prints (see photo). I have a Lulzbot Mini 2.

I tried increasing the first layer height and other layer height (just by .1 mm each, because I’m not sure if this is even a thing I should be trying), and that did not work. Any ideas as to what’s going on here? After I tried printing with the increased layer height, not only did the print fail, but the printer then ground down the filament so hard that it was totally stripped inside the extruder. I got it out, but I’m not sure what I’m doing wrong.

Until this point, I had always printed with ColorFabb nGen filament and never had a filament-related problem. Also, because I’ve had no problems, I haven’t explored basically any of my printer’s settings. Any help for this newbie would be greatly appreciated!!

Not exactly sure what you mean by this… If this means the hobbed bolt dug a notch into the filament rather than extruding, and if you’re having under-extrusion problems, my first guess is that you don’t have the nozzle temperature set high enough.

That is what I meant – sorry, I’m not familiar with all the terminology yet. Thank you for suggesting this: I now see that I used a temperature recommendation I found on amazon that is about 25 C lower than what the brand actually recommends. Thank you so much! I will test and let you know (if you care) whether this solves the issue! I’m excited to be headed toward a solution!

Whenever I switch to a new filament type that I have no experience printing, it can be helpful to print a test part called a “temperature tower”.

Go to and do a search for “temperature tower” (Thingiverse is getting sluggish these days… don’t be surprised if it seems un-responsive or times out and you have to re-try).

Here’s a sample:

This tower has sections numbered from 180° (at the top) through 225° (at the bottom) and each floor is 10mm high.

Once you open the part in Cura, pick your material and set the printing temp to whatever the print temp is on the bottom floor of the tower.

Navigate (in Cura) to “Extensions” -> “Post Processing” -> “Modify G-Code”

Pick “Add a script” and the script you want to add is called “Tweak at Z or Layer”

By default it will be based on height (in mm) but you can change it to be based on layer number. It’s your choice.

Determine either how many mm or what layer number gets you up to the next level of the tower and the action you want is to tweak the temperature. You’d change the temp to 220°C.

Repeat this… do another “Add a script” and add another “Tweak at Z or Layer” script… this time determine the height for the next floor and change the temp to 215°C.

Repeat again and add another one for 210, 205, 200, etc. until you’ve got a tweak-at-z for each “floor of the tower”.

Now slice and send it to the printer.

You want to watch it (these things don’t take a long time to print) to see how it behaves. Keep an eye on the temperature display on your printer’s LCD to make sure the script is changing temps as expected.

You are looking to see how it handles stringing (as it goes from one side of the tower to the opposite side – there’s almost always a nice gap). At the edge there is usually an overhang section where you can inspect how it deals with overhangs at each temp. At the top of each level it will “bridge” across and you can see how the filament handles building the bridge (does it sag excessively, etc.)

When it’s done, you compare all the levels of the tower to work out which temp works the best for your needs using that particular filament.

While this tower is meant to let you inspect how temperature affects quality, other factors can also affect quality such as print speed, layer heights, retraction amounts, etc.

These calibration parts are designed to help you dial in the settings to get the results closer to what you want without taking hours to build or using a lot of filament.

1 Like

Maybe some basics first. Are you using 3mm (2.85mm) filament or 1.75mm? If you have a standard extruder with your Lulzbot printer, you can only use 3mm filament. Using 1.75mm will result in ugly prints and possible print head jams.

I am using 2.85mm, but thank you for checking!

Thank you so much! This is extremely helpful. I am going to try this with the problematic blue filament. This printer is at a library, so I don’t get to use it all the time, or monitor it very easily. But when a time is available, I’m going to do this. Thank you! I’ll post an update when I figure out a workable temperature!