I’ve only recently started printing in PLA, and I was wondering if anyone else has this issue. When a print finishes, a very small amount of oozed PLA dries beneath the nozzle as the extruder is cooling down. As a result, when the printer homes on the z axis for the next print, that tiny amount of dried plastic is just enough to stop the z endstop from being triggered. I’m thinking maybe I should just add a line to retract a bit after a print finishes, or having it home the z axis next to the build plate so that the z will home uninterrupted, the nozzle will heat, then the molten PLA will rub off when it moves back over the print surface.
PLA is very runny when hot, so it’s nearly impossible to prevent some oozing when the head is still. A bit of retraction can’t hurt, but the plastic in the hot end is liquid, and will drip down, even if the filament is retracted.
That is, unless you unload completely. But that’s a hassle to reload…
Been printing PLA for some time now. Preheat your hot end before homing and ensure it’s clear of plastic. As long as the hot end is to temp even a ooze string of PLA will bend up if it hit the printbed when homing. You can also preheat on the cooler side, something like 190ish. That should be enough to clear the plastic but not hot enough to cause more oozing. Then home and run you print at the desired temp.
It took me a while to realize why I never ran into this issue - the Replicator has springs on the print bed (so it isn’t a hard stop), and it Z-homes to a switch on the platform, not the print bed.
I have a rep2 as well. The spring definitely help.
I’ve actually got some springs under my bed I think they might just be to strong relative to the fairly light aluminum x axis bridge.