Irregular Blobbing Artifacts

JadonM

Good evening!
I've encountered another perplexing issue with my custom cartestian, and I don't have the foggiest idea what could be causing it!

I'm getting a blobbing as shown in the pictures below, but it doesn't align with my layer seam, and happens in the middle of a print move segment. It started happening when I converted my printer to a BMG extruder, but it's not repeating like I imagine a drive gear would cause.

I tried increasing my drive gear tension as far as the screw would go, and that made it change into these stringing-like artifacts Reducing the tension does nothing.

I contacted Matterhackers, who made the ABS I'm using, and they first suggested that my extruder was improperly tuned, but when I tuned it my results were quite similar to Bondtech's and my top surfaces are nearly perfect. (You are seeing the bottom surface in my pictures.)

They next suggested filament diameter - it's an amazingly consistent 1.70mm. They then thought it was moist filament, but using a brand new spool didn't alleviate the issue.

I'm printing at .15mm layer heights with a .3mm nozzle. My temps are 280 on the hotend and 110 on the bed with a 70C chamber. I've tried varying the temperatures, including printing at the normal 235C, to no avail.

Matterhackers seems to be unable to give any more help, and I'm most certainly stumped so all help is appreciated!
Thanks!

Phaedrux

What slicer?
What does the Gcode preview look like in those areas?
Direct drive or bowden?
Have you tuned retraction?
Are you using pressure advance?

JadonM

Sorry for the lack of details - I have a habit of doing that!

@Phaedrux said in Irregular Blobbing Artifacts:

What slicer?
What does the Gcode preview look like in those areas?
Direct drive or bowden?
Have you tuned retraction?
Are you using pressure advance?

Simplify3D V4.1.0
Boring!
Direct
Yes. The same settings worked great with the new extruder. (1mm @ 25mms on an e3d v6)
Yes, but turning it off makes absolutely no difference to the artifacts.

Thanks very much for your time, @Phaedrux!

Phaedrux

@JadonM said in Irregular Blobbing Artifacts:

Boring!

Yes, from the outside, but what does it look like on the inside? Are there any features that occur in those sections internally? Is the path of the travel move through there?

What is your extrusion width? Have you tried a higher layer height?

JadonM

@Phaedrux
Today I tried a higher layer height, but that didn't do anything, and about that time Matterhackers finally got back with me and thought it could be a partial nozzle clog. I wouldn't have guessed that one because extrusion seemed consistent, but I changed my nozzle and that vastly improved the print quality.

Thanks very much for your time and help!
Jadon