I call this "stringing". I can remove it altogether 100% if I lower the temp enough but only for certain colors of PLA. For example I found "printbl White" to be impossible to stop it completely. Here's an experiment I did with it:
http://umforum.ultimaker.com/index.php?/topic/1872-some-calibration-photographs/
Recommended Posts
illuminarti 18
The general problem here is that retraction isn't working, so that you are stretching out strings of filament as the head moves from one place to another. There are small imperfections in the height/density of the string, and then as the head moves over it again and again, you get more plastic pulled out of the head as it crosses the thicker part, and the structure gradually grows and evolves. You can probably prevent it happening (at least to this extent) by enabling/tweaking your retraction settings.
But you're right, there's a related issue that I've seen sometimes where just a single column grows away from the base of a surface. I think it's mostly still retraction related - that while retraction is working well enough to prevent threading, there is still a slight ooze from the head during a longish move. The ooze gets wiped on the base of the print at the end of the move, providing a seed that wipes the ooze on the next layer, and so on up, such that the 'growth' grows away from the solid print, but opposite to the direction of head travel at that point.
Another example of this is not related to retraction. It happens when printing the low-density grid infill in the latest Cura builds, especially at high speeds. This was a 150mm/s test print:
The head prints a full grid on each layer, but traveling in opposite direction from one layer to the next. It prints continuously, but seems to stutter as it crosses over the perpendicular lines that have already been printed. This causes a gap, and a blob, which then grows in much the same fashion you showed above.
Link to post
Share on other sites