What settings for ABS

I have had good success printing in PLA for the past week since I put the Mendle90 Dibond kit together. I would like to try printing with ABS. It does not appear that there is a customized SF profile for ABS in the files that shipped with the kit. The default ABS settings don't look right. For example they have raft turned on and use the SF temperature tab. This is not how Nophead setup the PLA settings so I assume these are not his.

I tried printing the android man using the G code produced for PLA and just changing the temperatures to 240 and 130. However, the surface finish during the first part of the print looks granular, like mashed potatoes, with some scorched plastic. It could be that I didn't get all of the PLA out of the nozzle when I switched over since the quality cleared up with higher layers.

Can someone suggest appropriate SF settings for ABS on the Mendel90 to get me started or confirm that they are the same as for PLA just with different temperatures in the start code.

Thanks

Overall, I think it turned out well and the initial layer issues were from contamination by PLA. Since that worked o.k. I copied the PLA0.3 profile to a new profile ABS0.3 and then changed only the start file to start_ABS.gcode. Does that sound about right?

I am still interested in any further suggestions to tweak the settings.

Edit:
Oh, and I also printed without the extruder fan as I thought I recalled Nophead mentioning that before. Thoughts?

Edited 2 time(s). Last edit at 09/27/2013 05:29PM by neuport.

Yes the main difference between plastics are the temperatures. The filament diameter may be different of course and you have to set that on the dimension tab. Also I don't use a fan with ABS on a heated bed.

A subtle difference is the E steps per mm will be a little larger for ABS because it is softer so sinks further into the teeth and hence sees a smaller pinch wheel diameter. This can be compensated for by changing the filament packing density also on the Dimension tab.

ABS has more die swell than PLA so you can use higher layer heights. For example a 0.35mm layer will probably work but probably not for PLA Conversly low layer heights will stretch ABS more so bigger W/T values work better..

To get all the PLA out before switching filaments heat it to 80C and then rewind it for about 200mm. It will completely empty the barrel.

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