overextrusion?

I have been having an issue with an ABS print that I think is overextrusion, but could be something else. I end up with these raised ridges, any ideas? I am printing at 240C with a 0.4 nozzle 30mm/s solid infill, 0.2 layer height, 0.4 extrusion width. let me know if you need any other info.

The problem area:


And the other end:


Edited 1 time(s). Last edit at 03/28/2016 04:25PM by TbirdMan.

It's hard to see what's going on in the pictures because of the lighting and the dark filament color, but in general, you want line widths to be a bit wider than the nozzle diameter. The Slic3r developers suggest at least 5% increase in width up to a maximum of 70% greater. I typically use 0.5mm line widths with a 0.4 mm nozzle.

You're not running a print cooling fan, are you? It's usually a bad idea for ABS...

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I was getting exactly the same occurring.
Dialed the extruder factor right back and bingo it went away.

Printed a LOT of cubes and staircases getting it dialled in.

I tried setting the factor to 0.8 i think (might have been 0.9) and this was a bit better, but i was under-extruding on the bottom layers causing gaps and pinholes.

If you're setting line width to 0.4 mm with a 0.4 mm nozzle and you're dialing the extrusion multiplier down to prevent over extrusion, you need to calibrate the extruder. With a 0.4 mm line width and 0.8 extrusion multiplier it should be badly under extruding.

Yes, you can tweak it and get it to work, but do you want to have to do that all the time? You only have to calibrate once, then your results will be predictable.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]