Don’t leave your extruder on and not running too long. It will drip, then the PLA will turn amber, and then it will clog.
That’s all I’ve learned about PLA first hand.
Oh, well, that and it’s a royal pain in the ass.
MakerBlock
And I, for one, welcome our new robotic overlords
If it drips and turns yellow it is too hot. 10C can make all the difference. I would reduce in 10C steps until it stops dripping and just oozes a little. I use 190C, which is not much above the melting point, so another 10 lower can cause a jam. It really is quite critical with PLA. YMMV as I may have a different type of PLA.
I’ll definitely try a much lower operating temperature. When the PLA jams with a lower temperature does raising the temperature help? Or is it time to disassemble the extruder?
BTW, thank you for posting all of your research – I read your blog all the time.
Which PLA are you using anyhow? Also, are you talking about 190 as the nozzle temperature?
I’ve got the Ingeo 4032D from MakerBot. Rick has suggested the 4032D melts at 160 and the 4042D melts at 150.
I don’t know what type my PLA is. It came from Vik Olliver in NZ.
Yes I am talking about the nozzle temperature. In my extruder designs the heater block and nozzle are the same part and made from aluminium so it is all about the same temperature.
There are two issues with PLA that make it jam. Its viscosity falls rapidly after the melt point so it is a fine line between being too hard to extrude and dripping out like syrup.
The other problem is it has a glass transition at 50C. Above that it becomes like rubber, so when you push it, it just expands sideways and grips the tube. You either need to keep the part of the filament path that is above 50 but below the melt point very short, as in my designs with heatsinks, or have it in something very slippery, preferably with an expanding taper.
The symptoms of the latter problem are that you can extrude fine while you keep it moving but once you stop for a while it can no longer go forward but can be pulled back easily.