High temperature PLA?

I've just finished building my Kossel Mini and have the calibration process well underway. The design is mature enough that the few problems I had during the build were answered with by searching the forums and other's build blogs.

I received my first roll of 1.75mm PLA from eBay last week, calibrated the G/W extruder and started trying to print a 20mm square shell. To keep things simple I have an unheated bed with masking tape and the MkIV J-Head set to 180 degrees.

Well, no matter how hard the extruder pushed, the maximim speed I could print at is 3mm/s. Pushing by hand was no better, in fact I couldn't exert as much force as the stepper.

After twice disassembling the hotend, and finding no faults, I took a punt and pushed the temperature up to 220 degrees. Well, did that make a difference! Still a few skips, so I went to 230. Everything just worked, the print came out at 30mm/s with no skips or blobs. Of course, this is a mostly uncalibrated printer so it's not perfect, but I can see perfect in the distance.

The crux of this post, of course, is why does my PLA need ABS temperatures to flow?

I've tested the thermocouple as best I can, my IR thermometer only goes to 100 degrees, but the lower temperatures are correct as far as I can see. When bent across my fingernail, the filament goes white across the diameter, then parts slowly and messily in a rough break, leaving a "hinge" still attached. It burns with a faint pale orange flame and drips to the floor, with a slight bit of pale smoke. There is no odor when printing, but the burning gives an extremely faint almost-sweet smell - nothing compared to the PLA I've smelt before.

I also left some printed scraps and unused filament in acetone overnight. The acetone was exaporated by this morning and the plastic was still whole and holding it's shape, but the blue was leached out and deposited on the base of the dish.

So that's my braindump. Can anyone suggest what kind of franken-plastic I have here? I don't dislike it, now I have some parameters to work it with, but it appers to have the diagnostic properties of PLA and the extrusion properties of ABS. I know that various manufactuers put all sorts of things in their hoppers, and I'll be trying to find out more about where this came from, but the tracking down the supply chain may be difficult.

Regards, glen.

Each manufacturer and hotend is different. Placement of heater, thermistor, extrusion point, and the materials used all make a difference hotend by hotend. On my Solidoodle hotend I printed perfect PLA at 162C, on my E3D v5 I print PLA at 235C, or if I'm using my pro filament I print at 245C. I'll be amazed the day all hotends extrude the same at the same temps, very truly amazed. You don't even know how much that would blow my mind to see them all the same, hotend and filaments alike.

Chinese suppliers typically have more fillers, and if you get the right ones [like I get from MatterHacker's non-pro PLA] it actually makes it a lot easier to extruder, and less jamming. It seems the better the filament, typically, the higher the temp you'll need, but my experience is very limited to three different manufacturers and two hotends.

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Realizer- One who realizes dreams by making them a reality either by possibility or by completion. Also creating or renewing hopes of dreams.
"keep in mind, even the best printer can not print with the best filament if the user is the problem." -Ohmarinus

I print PLA at 220C on an E3D. I'm using 3mm PLA from [www.ecoreprap.com] which is inexpensive and very good quality. ($10/kg + shipping).