Switching from ABS to PLA

OK, so I have only printed with ABS and nylon (for a short time). I have a project coming up that I want to use PLA for and so I have some on order.

I have an AirWolf 3D printer (Based on Prusa Air I think) with a Budaschnozzle.

What is the recommended procedure for switching back and forth without gumming anything up or burning the PLA?

Also what is the best temp for PLA? I do ABS at 245c

Thanks!

PLA is a lot lower than ABS in temps the ballpark is normally 185-200 for PLA,

the best way to clean if for a switch i am not sure off hand,

I don't have an answer for you, but FYI you're awfully close to the max temp for a Buddaschnozzle when you print ABS at 245ºC. Lulzbot recommends 230º for ABS. The max the hot end can get is 250º, over that you can damage your hotend. The fact is, when it reaches its temperature it can overshoot by quite a few degrees before stabilizing to the set temp. At 230º you would be safer.

Since I got my Lulzbot printer I've been printing ABS at 230 with no problem, with 4 different colors (all from Lulzbot though).

As for PLA the temperature recommended by Lulzbot is 185ºC, but that is again with their own brand of PLA, it seems it can vary a lot.

I think my temp reads a bit off. At 240c I cave slight delamination issues but at 245 it's good

I can extrude at 230 but nothing sticks together well.

I do not have a Lutzbot but on my MendelMax 1.5, I regularly run ABS and PLA. I do not clean the nozzle before switching, I just extract enough material to make sure the material I am switching to is extruding properly. I leave the Pet tape on the bed for both types of material. For PLA I set the bed temp to 40c with a nozzle temp of 190c. I also use a coating of ABS juice on the bed when doing PLA. It seems to help with the sticking, but allows the finished print to 'pop' off the bed when done with very little effort. It works for me.

Milt

Coincedence, I just started a similar topic in Printing subforum.

However, putting it in General turns out to be (yet again) a better idea, since > replies.

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Edited 1 time(s). Last edit at 08/04/2013 03:22PM by Ohmarinus.

I open up the bearing off the extruder and heat the ABS up to 120C. As it's approaching 110+C start gently pulling at the filament... it should come away in one piece and leave a clean nozzle. The start running PLA at about 210C and extrude any possible left over bits of ABS out... you'll find that there's a comfortable overlap in temps with both plastic. Then print!

You can do the reverse with PLA ant heat up to around 90C to pull the filament.

Alright I think I have enough to go on. It's kind of what I expected but I just wanted to make sure before I screwed something up.

Thanks to everyone.