reprap

PLA and Z motors

PLA plastic
I read up on PLA a bit today and this evening tried something mentioned on the Wiki.

You can print this stuff at room temperature on blue tape. No heating of the print bed required, no warping occurs.

I can flip the printer on, slap down some blue tape and start printing in about 3 minutes.  With ABS it took at least 15 minutes for the glass to warm to 110 on the top surface (the heater hits 110 in about 2 minutes, but the glass is thick and heavy). Then 10 to 15 minutes before the thing cooled enough to pop the print off. Then 10 minutes to heat back up again.

Because I was using PLA on blue tape tonight, I was able to print, test, modify and reprint and get through four prototype versions tonight, even with time out to go to a halloween event.

PLA is also very strong. The layers seem to bond extremely well, probably because it prints at a lower temp so it loses degrees more slowly and the previous layer is closer to melting point when the next layer goes on.

I was prejudiced against it but I think I'm a PLA convert except when ABS is required for heat resistance. This stuff rocks.

Z motors:
I have been bugged that the Z axis has needed adjusting before every print for a while; this time I was watching at the end of a print and noticed that the right Z motor just skipped steps on the end-of-print retract, which means it went out of level and became lower than the side with the endstop sensor. I was running with the old motors. I put the new ones on, wired them in series, and now even at the fastest speed that the firmware will allow I actually can't stop the motors by hand.

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