Glop in the corners (ABS)

My TAZ 4 is my first 3D printer. I’ve had it for about three months now, and kept it pretty busy the whole time.

I generally print with the ‘fine’ and ‘medium’ lulzbot profiles. I use both slic3r and cura, and update those to the latest development versions frequently.

I’m seeing ‘gloppy’ corners pretty frequently (both slic3r and cura, 220/80 to 230/85), and I’m hoping that someone’s experienced eye will just recognize the issue immediately.


Detail of the circled area:

There is a time-lapse movie and higher resolution images in this gallery. I can post more print settings/info if wanted. But with just this info, can anybody tell me what causes this? Much obliged for any help!


What type and brand of filament are you using here? Also, what are your acceleration settings at in you FW?


Hi 3dprintdaddy,

Thanks so much for your reply! I use ABS from two suppliers: Lulzbot and an american ebay vendor that sells filament from china. I was very skeptical of the chinese filament at first. But I took the entire roll off the spool and measured its diameter and eccentricity at about 30 points throughout the length. It is a very consistent 2.89 +/- 0.015 mm. I did the same for the Lulzbot, which just barely bests it at 2.85 +/- a fat 0.01 mm. I also noticed that the Lulzbot filament pops and snaps more than the chinese one (I keep all my open filament in a sealed tub with dry rite). I set the filament diameter in the slicing software every time.

I just double checked my extruder steps/mm setting and found that it’s _under_extruding by about 2%. I think I just let that go when I first got the printer. But from now on I’ll make sure I’ve got that right.

I haven’t changed the acceleration: Accel: 500, Amax x: 9000, Amax y: 9000

The example prints in my first message were with the chinese filament (all the blue examples). Here are some more examples from the same filament (much higher res images are available in this gallery).

The Make overhang test:

The same parts, just flipped over (70 degrees is at the bottom):

Now compare them to the Lulzbot filament:

And the same parts flipped:

Aside from the overall increase in gloppiness, you can still see that the corners present a special problem. I see it the 3rd and 4th pieces, near the top (30 and 45 degrees).

Clearly I do not have the hang of this yet, and that’s why I’m here asking for help. I’m hoping someone can just say something like “You dope! You’ve got the _____ set too ____!” :slight_smile:

Any and all advice is greatly appreciated!

I personally keep my printer right around 1000 for acceleration to allow it to take corners better. Something you might also consider is playing with temperatures for the different filaments. Different colored filaments print differently, and sometimes need little different temperature settings. My experience is that usually black filaments especially need 5-10 degrees higher, and other manufacturers’ filaments are all different as well.

I’m by no means an expert of any Kind, having started only recently with my TAZ4.

However, I did have the glops especially in circular organic objects after some printing and traced it down the the X-axis toolhead having too much Play (the IGUS bearings Holding the print head to the X axis)

check this thread

Or maybe I’m wrong and you have a different issue. However I would surely check your X (and also Y axis) for Slop since These IGUS bearings seem to be notorious for this.

If you hold your toolhead and shake it around a bit, it should only have minimal Play. Mine started having huge Play after only around 50-100 hours of printing so I replaced them recently (see thread)

Edit: do you mind sharing your ebay Filament seller? sounds interesting

Hi zhd,

If you look at that thread, you’ll see I posted several times in it. So, yes, I’m aware.

I’m no expert either, but I’m not so convinced that the IGUS bearings are a problem, or at least my problem. Yes, my stock X and Y axes were both very sloppy, exactly as erv described. So I printed out a bunch of tests, and then I replaced both axes bearings with LMuu10’s (or whatever the right part number is) and replaced the rods too. By the way, if you do it, I would recommend printing out new bearing holders (link to singleand double) so that you can easily reverse the change. You’re supposed hot-insert threaded parts into the Y-axis ones, but you can use longer screws and regular nuts. [Edit: the other advantage to printing new bearing holders is that you can insert the bearings immediately after printing, while the holder is still warm and more elastic.]

Both my axes are rock solid now, no lash or wobble. Then I reprinted my tests, and found no difference in print quality.

It’s very easy to improve things like rigidity. But it’s important to be sure that the things we fix actually caused problems in the first place. I’m not scolding anyone. I’m just saying that in my case, it didn’t improve my prints. erv said his prints improved. I’m very interested in everyone else’s experience.

Thanks very much for taking the time to reply! I really appreciate it!

oops didn’t notice you had already posted in there. Thanks for the hints concerning installation of the LMU10 bearings and hardened rods, I will go ahead anyway and replace them since I don’t like that the IGUS bearings wear out so quick.

Thing is, in my case at least, something must have degraded compared to the initial state of the printers. I had brilliant prints or at least as brilliant as they can get considering I was using the stock slic3r profiles and just learning how to run the printer.

Print quality definately degraded over time for me, so I assumed it must be the bearings.

But you are right, I boldly assumed that must be the reason, even though the printer has a bit of slop even out of the box and that didn’t seem to reduce the quality of the results.

So far when I had layer bonding problems like that I just recalibrated until the results improved. But I’m sure you did a lot of that so it must be a different problem… really wondering if someone has an idea

If you could post pictures of before and after IGUS --> LMU010, showing how the print quality changed, that would be incredibly useful.

Well, I did a first test print yesterday after replacing just the X axis IGUS bearings.

Unfortunately , print Quality has not improved, but maybe i Need some more time calibrating the bed. (tho i took 30 min for calibration alone) … I’m sure the IGUS needed replacement since the X axis Slop was extreme. But as you suspected that was not the cause of the Problems.

I seem to get ABS glops on Corners or also on straights whenever the print head changes direction.

Maybe i Need to check my Y axis bearings as well but I don’t think thats the reason (and there’s not much Play either)
Howevr I noticed that the printed part on the upper left Corner of the TAZ (the upper left Chassis brace? no idea what to call it… Where the Z-axis smooth rod and the machined threaded rod joins in) is broken, like cracked. So maybe that’s why the TAZ was out of alignment and also prints worse than before.

I can post pics later tonight I hope.

Luckily I printed the spare part in advance so I’ll replace that and try again.

Edit: I should revise the Statement that Quality did not improve: I only printed a straight part, not a organic one which came out the worst normally. So maybe it has improved a bit but I haven’t noticed yet. However the Problem is clearly still there, not fully solved.

Edit again: I should also state that my “glops” look different that the ones you posted initially in this thread. Maybe it’s different issues or really just a calibration problem. will come back with pics.

ok since i’m not yet convinced how much difference the IGUS fix made since it was a different kind of print, I decided to print the same object i’ve done with sloppy bearings once more, with the same settings.

Will be back with results


very little time right now, just checked the print briefly and it looks like my quality issues are NOT solved either. Came out just as shitty with the fresh IGUS bearings.

however as stated my issues might be of a different nature than yours, and may be solved with optimized retraction settings or something…

will post pics of both models hopefully tonight.

ok , the first 2 pics are before I replaced the X-axis IGUS bushings

second 2 pics are after replacing them, eliminating most of the slop I had on the toolhead

As you can see, there wasn’t really any noticeable difference so the reason for these crappy prints must be a different one :frowning: i would’ve replaced the IGUS anyway since the slop in the toolhead was quite alot

Before replacing X-axis IGUS bearings
Brown ABS @ 230c / 90c
0,2 layer height, 65% infill, 70mm/s speed
Slicer: Simplify3d
not my hands. :laughing:

After replacing X-axis IGUS bearings, same settings

Wow! I think those glops are at the start of each layer, after a retraction and a move to the radomized layer start. I don’t know about Simplify3D, but in slic3r there is a rarely used parameter “extra length on restart.” It’s usually zero. Maybe the equivalent parameter in Simplify3D is set to something non-zero … maybe? [Reminder: I not an expert by any stretch of the imagination.]

I bet if you send a message pointing to your post, they will have some good suggestions.

I’m pretty sure you’re printing this model (thingiverse link). I will try printing it too. But I don’t have Simplify3D. I’ll use slic3r, and if you like, you can try my gcode file (dropbox link). It’s based on the lulzbot ABS fine profile. So it has lulzbot’s stock suggested speeds and acceleration. It has my calibrated steps/mm for my extruder, which you’ll want to change to match yours (or just delete that line if you haven’t calibrated it yet).

Is it Lulzbot Brown ABS filament? Because I have some of that and will use it to try and match your situation as much as possible.

I’ve started the print.

Finished. Pictures are in the reply to your next message.

wow thanks so much for taking the time to look at this.

i attached the retraction settings I have (default simplify3d).

I think the setting you mention is called “tool change extra restart distance” and is set to -0,5 mm.

Should I try a zero here?

The idea with using slic3r again crossed my mind as well, I used to use only the default slic3r settings by Lulzbot

Yeah the model is off thingiverse, and yes I was using the brown Lulzbot ABS for this print.

Looking forward to your print :slight_smile:

I don’t get nearly the glops you do. Maybe your extruder is overextruding. Do you know the steps/mm? In the firmware (CONTROL --> MOTION --> ESteps/mm), but it can also be overridden in the gcode generated by the slicing software.

One for general scale:
The flower pot.
I have similar little blips at the places where the layers start. But mine are hardly noticeable.
The overhang brings out the badness.
And my TAZ could not even finish printing it. By the time it got to this level, it ripped off Groot’s right arm, and even gentle overhangs are horrible.
bed time (I’m UTC-8). I’ll be back in the morning. I would definitely recommend getting lulzbot involved… and checking extruder steps/mm, [EDIT] and check filament diameter in the slicer [/EDIT]. cheers.

Wow you rock, thanks for taking the time to do this print. Sorry for taking over the thread as well, initially we were talking about your glop problems :wink: have you contacted lulzbot concerning your issues?

Overextrusion could actually be an issue now that you mention it, the steps/mm setting i will have to check when im at the printer. Is that setting to determine the steps of the stepper motors per mm?

I will also contact support in that case, I can reference this thread and maybe they have an idea. However before all that, I will check the filament diameter and other extrusion related settings and also check the steps / mm settings and report back.

Thanks again, cheers

edit: i can also post the actual GCODE I used for my prints, will check

Hey, If you decide to go ahead and upload your gcode, I’ll try printing it. Cheers.

thanks man, super busy with work so i couldn’t test differnet settings but here’s what i ran: (5.03 MB)

I started printing your gcode a while ago. It hasn’t even finished the flower pot yet. But I think it looks very similar to how it looks in your pictures. I see big huge globs at the retract/restart sites. I think this is good news for you.

Either 1) there is some problem common to both our TAZes, and your Simplify3D gcode provokes it and Slic3r’s doesn’t. Or, more likely I think, 2) you either have a parameter out of whack, or it’s a bug in Simplify3D.

I did look through your gcode, but my untrained eye couldn’t find anything odd.

I’ll post pictures when it’s done (in about 3 hours).

[Edit:] Ok. It’s done. But before I post the pictures, I have a very important question: Is this gcode file the same as the one that you used to print the model shown in your pictures? Or, did you reslice the stl file with the identical parameters and send me that gcode? Thanks!