Combing, All, None - What does it all mean man!?

Hey guys,

So I feel like I have kind of settled in to my Mini at this point, but there are settings I still don’t totally understand and in the quest for the perfect print. This weeks topic for me to ask my betters here in the Mini Group is about Combing.

So in Cura, there are 3 options for this and thought the pop-up does an admirable job trying to explain it I have to admit, I don’t really know what the feature will do in practice and when I might want to use it if at all. The entire time I have used my Mini it has been set to off. My question to you guys is, can you explain to me what this feature is and when I would want to use it (or more importantly when I wouldn’t) and just your general tips and goodies about it?

from http://support.3dverkstan.se/article/30-getting-better-prints

Normally cura will attempt to move from one area to the next by moving the shortest distance possible. With combing disabled this means that it will move across voids in your prints and potentially cause stringing (unless retraction takes care of it). By enabling combing you tell cura to only take the shortest route if it means it will not cross an outer border. If it cannot do that it will route the print head over already printed areas to reach its destination. By doing this any oozing gets deposited inside the model where it is not seen.

If you’re printing a cube or a cube accessory, then you probably won’t notice the difference. Printing something like an octopus the difference would be really noticeable since there are lots of squiggly perimeters in each layer.

If you’ve ever used slic3r, its very similar to the “avoid crossing perimeters” feature. If you slice two files with and without and use gcode.ws you could preview the difference.

I read that first of course but what are the implications of having Combing on then? Is it generally considered a feature to use only for certain shapes? You mentioned I would notice a difference in the octopus but not a cube. Would that just be a difference in how the head moves? Would it be slower or faster? Would enabling combing improve the print quality on the octopus and if so why?

Implications are different gcode, possible print quality differences, depending.

Yes. If no squiggly perimeters, no combing, if squiggly, use combing.

The head does not cross perimeters on travels and instead stays in the infill.

combing is usually slower, because it usually uses travel paths that are not straight lines.

Maybe combing would, but the difference is likely negligible, since the defect combing is there to prevent is almost entirely prevented by retraction anyway.