Extrusion Widths

Can someone point me to some documentation about the rationale for the decisions that Slic3r makes about default extrusion widths? I'm using 0.9.10b, and with a 0.4mm nozzle and 0.1mm layers, it's defaulting to 0.68mm bead width for the perimeters, and 1.28mm for infill. Those both seem a bit excessive to me, but especially the infill one. Assuming that you've set the same linear speed for perimeters and infill, you're going to end up with huge volumetric extrusion rates for the infill. Most likely more than the extruder can handle if the speeds you chose were in any way based on an assumption that you'd be getting an extrusion width that's roughly equal to nozzle width.

I realize that I can override the bead width settings, but I'm puzzled that the defaults seem so aggressive.

This may be a good place to start...

[manual.slic3r.org]

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Waitaki 3D Printer

Thanks, but I don't see anything in the Manual that explains the rationale for the specific widths that Slic3r picks. Have I just overlooked it? I presume there's some sort of scaling factor applied based on nozzle width and/or layer height - but the defaults that I'm seeing just seem likely to break extruders.

I've discussed this in more detail here... I'm just hoping to understand why it works the way it does.

When the layer height is small compared to the nozzle then the width should be not much bigger than the nozzle. Otherwise you are trying to force plastic sideways through a 0.1mm slit, which will give a lot of back pressure.

Also one of the advantages of using a lower layer height is the bead has less opportunity to spread sideways so you can have a width close to the nozzle aperture and hence get better X Y resolution as well as Z.

Those defaults seem crazy.

Edited 1 time(s). Last edit at 11/07/2013 02:48PM by nophead.

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