PLA Oozing out and Messing with the Z Endstop?

[radicalrealign]

I'm what I would consider a newbie. Is it normal for PLA to ooze out and dry under the nozzle when the extruder cools down? It seems as though that the dried PLA I'm referring to then stops the Z Endstop from starting up. Any suggestions? Is this normal?

[DrLuigi]

Well ye its pretty normal when you have printed something, that gravity will pull on your filament a little bit during its cooling down, after a while it will be cold enough so it simple isnt molten anymore and can't extrude anymore.
This can also happen when printing, thats why we have retraction, and even that doesnt solve it for some hotends its worse than others, depends on how large your hot/melting zone is.

[3dkarma]

If your slicing software allows (let us know which it is and we can help you further), you could add some custom g-code at the end of the print to retract before the hotend cools down and prevent the oozing. You'll also need to add some g-code at the start of the print after the hot-end heats up to extrude the same amount.

To retract:
G92 E0; // Set extruder to 0.
G1 E-1 F200; // Retract 1mm - play with this length to your satisfaction.

To extrude:
G92 E0;
G1 E1 F200;