Cleaning the hot end

Stupid me, I decided to start a print while I went away and did something else. I usually check to see if the nozzle is extruding nicely before walking away.

When I returned, I had a ball of hair mess of PLA and a very dirty looking hot end. It appears that the PLA pig tailed and melted PLA all over the hot end, hex head screw, etc. It appears to be isolated to the metal hot end.

What is the best way to clean off all this excess filament? Not only is it unsightly, but the excess on the tip seems to cause newly extruded material to pigtail as it exits the tip.

I was thinking of cooling the machine down and carefully brushing/wiping acetone on the tip to clean it back to new. Good or bad idea? Is there a better procedure that I’m missing?

Thanks in advance,
Peter

Acetone will not cut PLA. When I need to clean melted plastic off the hot end, I bring it to printing temperature and pick off the bulky parts with tweezers and a qtip. Then I fold a cotton washcloth and vigorously rub the tip of the nozzle to get it nice and clean.

If the plastic still exits the nozzle and curls, you have a partial clog in the nozzle. Sometimes, these types of clogs can be cleared by warming the nozzle beyond the temps used for printing. I usually set it to 240C and extrude plastic 10 mm at a time until the temp is reached. I continue to extrude 10 mm at a time until the plastic drops straight out of the nozzle with no curl. If the curl doesn’t go away, I set the temp to something low like 160 C and extrude plastic while it cools. Sometimes the more viscous, cooler plastic will push the blockage out.

If that doesn’t work, search cold pull on this forum and give that a try.

If that doesn’t work, you can remove the nozzle and soak it in Scigrip Number 4 overnight. That solvent will dissolve PLA.

Thanks for the response and tips. I’m going to give your suggestions a shot.

-Peter