I'm having one heck of a time printing with PLA on my UM2. I can print ABS all day long, no problem what so ever. Different settings, different object, stopping, starting, no issues at all. PLA on the other hand ... no can do.
Whenever I put in PLA material, select the PLA setting on the printer and start a print, it would start but within a few layers the nozzle will clog up and it'll stop extruding. I'll abort the print, heat up the nozzle to what would be the ABS temperature and push material through. I'll get this black crud coming out for a while before it finally starts flowing again. That tells me it's getting clogged and burning the material in the nozzle. So I can clean it all out and try again. It'll do a few layers again before quitting. Lather, rinse, repeat.
I can switch back to ABS, and voila, no problems what so ever. So I took a closer look when I tried again tonight and something caught my eye. The Bowden tube has bits and pieces of ABS in it. This then make me wonder if that's what is happening. It gets pulled in with the PLA, and since the nozzle is at a lower temperature (for PLA), the ABS won't melt and therefor clog up the nozzle. And when I raise the temperature it unclogs, pushes the melted ABS out and the now burned PLA as well.
I'm literally grabbing in the dark here, this is the only thing I can think of that's going on. And if that's the case, how do I clean out the Bowden tube whenever I want to switch to PLA?
If anyone else has other ideas of what may be going on, or why it's constantly failing, I'm listening.
