Recent issue printing detailed holes

Hi all -
I have a Mendel90/Sanguinololu/Sprinter using a Wades extruder/ 0.5 mm nozzle, a fan (always on) & heated bed with 3mm PLA. I use Repetier/Slic3r.

I have dialed in some pretty decent prints, but have been having trouble recently with some more detailed prints, notably printing holes with not very large sides, and am not sure why. Attached is an example. I am not sure what changed. I did switch PLA spools recently, but the PLA is the same type/color/vendor as before, so my temp settings should be fine. In any case, most of the print is great, it's in some of the finer detail areas that the print kind of falls apart.

Any ideas on what is going on here? Too warm? Too fast? Thanks in advance for your help!

Rob

It's always the simple things.

After making this post, I went back to remove the fan assembly for one print. What I found was subtle - the extruder carriage assembly, mounted on three bearings, had a loose zip tie on the rear bearing. The zip tie was so loose that the whole assembly could tip a bit. Not noticeable to the naked eye, but I bet with rapid turns, the assembly had some vibration.

I tightened up the zip tie and am retrying the print to see if this solves the issue.

Stay tuned!

Rob

Alas, correcting the zip tie issue did not resolve the printing problem. I also opened up the extruder assembly to make sure the hobbed bolt was functioning properly. To simplify the problem, I went back to printing the 5mm cube calibration model. It is also showing signs of print difficulty now.

My current working theory is that the filament temp (195 C) for this spool of filament is set too high (the new filament spool is one of the variables that has changed, even though the filament is the same type/color/vendor - you never know). I will try some lower temps and see if that helps.

Rob

Have you checked out possibly things like retraction settings?

No, but one item that I discovered was that my extruder motor was significantly over-extruding filament (~30-40%). I recalibrated the extruder, and printed another 5mm cube step model. Significant improvement! Still have a corner issue, might be unrelated. I will continue to investigate.
Rob