Slic3r Retraction Settings

Does slic3r extrude extra filament equal to the amount retracted? I'm currently adjusting my retraction settings and have found that less is better, even though I don't know why. If slic3r doesn't account for the retraction done, I believe this would be the reason less retraction is better. Thanks!

yes - slicer extrudes the exact amount it retracts. You CAN tell it to extrude extra, but it is not a good idea because your are basically losing track of filament when you do that.

Incidentally, this can be easily verified by looking at the G Code. You will see an extrusion number exactly equal to the retraction numbers. The exact numbers may be different because there could be an axis reset in between, but the filament amounts should be equal.

What retraction does is buy you a bit of time while you are making a long travel so that if there is oozing, it is within the hot end and does not foul the print.

Hi jbernardis,
Thanks! I haven't learned G code too much yet... is the extrusion/retraction command written with an "E?" I have thought about this some and believe that a slower retraction speed is best, but not too slow as to not create enough pressure to prevent oozing. What are your thoughts?

As fast as possible. Depending on your extruder-setup.
You want to have zero pressure in your nozzle when you retract. That's the goal. I have a direct-drive bowden setup and can run 120mm/s retract-speed.

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okay, thanks! ill adjust my retraction speeds. What about the amount of retraction? I assume a smaller number is best. I have had good success at 2mm with some stringing at 1mm. im wary of going too high.

This depends also on your setup (extruder and hotend).

If you don't have a bowden-setup between 0.5mm and 2mm should be enough. Bowden normally needs more retract.
For my E3D V6 with a bowden-extruder I need 3.5mm retract.

This is trial and error.

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Triffid Hunter's Calibration Guide

--> X <-- Drill for new Monitor

Most important Gcode.

Hello I have a little problem while retracting. When every layer is printed my printer puts some points of plastic. I think that the points are randomly placed. Is there any retraction setting to get rid of those nasty points?

Thaks in advice !

If they occur at the start of travel moves, the cure is more retraction. Increase it gradually until the problem is fixed. I find that about 0.9% of the Bowden tube length plus about 1mm works well.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

If it is important to minimise the size of the bumps, then slowing the perimeter print speed by a lot can help a lot. The slower the print speed, the better the extrusion rate matches the nozzle position. Not only is there less movement per unit time, but also the nozzle pressure is lower so there is less extrusion lag. Obviously that increases the print time - but in general the slower the printing, the better the quality.

On the other hand it is usually pretty quick to file off the bumps after printing - a Dremmel with a sanding cylinder is great for doing that.

Dave