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Topic: Switching between ABS and PLA and vs Versa

Yesterday I got my first rolls of PLA (Blue).  I removed my Orange ABS from the printer, put the blue in, heated it to ABS temp and extruded, clearing as much of the ABS as I could, i know there can be quiet a bit hiding in the extruder.   

Lowered the temperature to PLA (175c).  Well I started printing an object, it was doing fairly well, for being uncalibrated for the new filament, I went a way for a bit and came back to find the printer not extruding for many layers.  clogged.

I bumped up the heat to ABS levels to try and clear it, nope.  Took it all apart, used a small torch to melt out all the crud, Brown, Orange + Blue goo....

Now, I think I didn't do something right, how are you supposed to clear the ABS?  Is there a procedure that prevents the above from happening?

Thanks
  Andrew

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Re: Switching between ABS and PLA and vs Versa

I mostly do the same thing:
1. Heat to ABS temp.
2. Extract remaining ABS filament.
3. Switch to PLA.
4. Keep at ABS temp and extrude at least 300 mm of the new PLA (more if the PLA is a much lighter color than the ABS) - I set the speed to 200 for this, thinking that the PLA runs fast enough that it won't clog up.
5. Lower the temp to PLA and try to start the print job without sitting too long.

I've had some PLA that needs to print around 180, and I got one spool of translucent purple that seemed to need 190 (so it was basically running at ABS temp).   Right now, I have a yellow ABS that needs 210.

Cheers,
Fred
Fredrick C. Hagemeister
http://blog.richmond.edu/ti3d

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Re: Switching between ABS and PLA and vs Versa

Thanks, your post I think will help a lot.  I had cleaned out everything and reassembled, plugged up again when using transparent blue pla.  Again at 175c.  It didn't occur that I should use a higher temperature, which, when I get brave enough to try again I will do.  I had to rip apart the head again and because the last rebuild leaked pla from the heatbreak, I used some Teflon tape to seal it, so far so good, but only printing with ABS right now.

Thanks again
  Andrew