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OK, before we get into the meat of the problem, I will admit that I have sinned. I am guilty of not writing down my settings. There. I've said it. I am an evil bad person who strives for consistency without taking the necessary steps to get there. I have learned my lesson at the school of hard knocks and I have seen the light and the error of my ways. Henceforth I will record my settings so as not to be lost in the wasteland of guesswork again.



I printed some of the OpenForge walls from Thingiverse in Hatchbox white PLA. It came out beautifully. No "boogers" on the print, layers nice and even, great bed adhesion, etc. I switched materials to ABS to build some other stuff, then back to the white PLA with different settings for another project, then decided to go back to printing more of the OpenForge walls. I *thought* I had my settings all the same, but apparently not.

Here's the result. The first (smaller) one is on the right. Nice and smooth. The second one is on the left. Note all the little globs on the print.

[img]http://i.imgur.com/9jpsVee.jpg[/img]

I kicked off another print, lowering the temp by 5 degrees to see if it would make a difference, but I'm still getting the globs. In this particular print, a bit of roughness to the "stone" is no big deal, these are supposed to be dungeon walls after all, but those globs would ruin other prints.

Here's my settings:

Filament: Hatchbox White PLA 1.75mm (measured at 1.78mm and entered as such)
Extruder temp: 205 C (tried 200C as well)
Bed temp: 70C
Infill speed: 45mms
perimeter speed: 40mms
Outside perimeter speed: 40mms
Layer height .2mm
infill 20%, hex.
Retract speed: 2mms
Retract length on move: 5mm
ZLift on move: .3mm

Edited to add: I am using MatterControl, with MatterSlicer set as my slicer.

Any suggestions on what to change to get rid of the bumps?

Follow up: I set extrusion to 90% and did a few small prints. That seems to have taken care of the problem. I'll do another wall now to see if it's truly fixed.

Edit: nope. The larger print I just ran had the same issue. I expect that I actually got my settings back to what I had before, it's just the larger print that is having issues. I think I read somewhere that buffering large amounts of data can be an issue that leads to this kind of thing. I will try printing from the SD card next to see if that works.

The first thing that I would look at here is "coast", not all slicer support it. Coast sets the distance before the end point where the extruder is stopped preventing a "blob" of filament sputum being left at the retract launch point.

Mattercontrol doesn't have a coast setting.

ooops

That's ok. It looks like running off the SD card is working fine. I did another large wall print, and the bumps are gone. No changes other than running the Gcode off the card instead of over the USB cable.

TMIB wrote:That's ok. It looks like running off the SD card is working fine. I did another large wall print, and the bumps are gone. No changes other than running the Gcode off the card instead of over the USB cable.

Could be something is using up processor cycles on your desktop. I've got a pretty beefy desktop, octa core processor, 16Gb of ram, but it will still cause printing issues when I try to run Meshmixer at the same time. Oddly enough, I can play Fallout 4 with no problems...

I'm running it off of an old ASUS slate. Only 4 Gig of ram, only dual-core 1.33. Not a beefy setup at all.

Should be plenty for the job