PLA Oozing

[dsnettleton]

First off, let me say how much I like using PLA. The only problem I seem to have with it is that it oozes like none other. I've done everything I could with the retraction and can't seem to get it to stop. Either I get chunky little tendrils or long, thin cobwebs. I'm using Repetier Firmware, and I've noticed it has some anti-ooze settings that I still haven't played around with, but I expect these to be very similar to my slicer's retraction behaviours. Has anyone found settings that work really well for minimizing (or completely removing) these issues?

[Polygonhell]

You probably need to print a little cooler, unlike ABS PLA get's less and less viscous as the temperature increases until it's almost the consistency of water.
This lets you print faster, but means you have issues with ooze.
KisSlicers wipe is about the best anti ooze setting IME, but in general, you want to print PLA as cold as you reliably can.

[dsnettleton]

You probably need to print a little cooler, unlike ABS PLA get's less and less viscous as the temperature increases until it's almost the consistency of water.
This lets you print faster, but means you have issues with ooze.
KisSlicers wipe is about the best anti ooze setting IME, but in general, you want to print PLA as cold as you reliably can.

That was it. I was printing at 190 C, so I did several test prints in five degree increments, using the simple bridge test from thingiverse (http://www.thingiverse.com/thing:113160). It has two separate columns far apart, and it's easy to see stringing or oozing between them. The edges of the towers didn't get clean until I got down to 175, but 170 looked better still. I haven't tried a lower temperature than that, but I don't think I'll need to now.

[geneb]

I'd REALLY check that thermistor against a thermocouple just to make sure that it's not greatly under-reporting.

g.

[dsnettleton]

I don't have a thermocouple, unfortunately, but I purchased my PLA from Ultimachine, and the documentation on their website seems to indicate that anywhere from 160-220 might be an acceptable range. https://ultimachine.com/pla. My hot end starts oozing around 165 or so. It could be that my thermistor isn't actually reporting accurately, either because it's not making good contact with the aluminum on the hot end, or because I'm using the wrong thermistor table in my firmware. Or because it's faulty. But where a fix can't be found, a workaround must.
Any ideas on how I could check the thermistor without a thermocouple to compare it to? I do know that it's reporting accurately at room temperature.

[Tinyhead]

Instead of posting a new thread, I thought I'd try to add to this one! I've got the exact same problems that were mentioned at the beginning of this thread. I get PLA oozing and little blobs and strings all over my print. I'm using PLA and was running it at 195 degrees. I'm using the settings provided by geneb in the manual (all 30mm/s and 80% on external perimeters). I've been experimenting with those speeds a bit too to try and get better results, but they always seem to come out the same. I'm using Slic3r right now (might give Cura a try when I gather up my courage to try something different). I'm printing at 195 and if I go much lower, I end up with skipping on the extruder so I haven't wanted to go too low to avoid a jam. I've also tried different retract settings and wipe with success on smaller prints, but if I have a few things on the build plate or a larger object, I end up with this mess:

I've printed the hollow pyramid (http://www.thingiverse.com/thing:8757) and it turns out great. As well as many other smaller items. The SeeMeCNC hot end fan shroud came out looking like it was bought in a store (very minor little strings). But then I'll try printing a few chess pieces and I'll spend hours trying to clean them up poking my fingers on all the little bumps just to toss them in the trash afterwards because they looked like hell. I'm sure some of you guys might be able to suggest something right away, but I'm just at a bit of a loss.