Slic3r retration tweak - any ideas?

Okay so here's the issue - I've noticed this on many different printers, so its not machine specific. If I get my retraction tuned really nicely so that I get no blobs or strings, I notice that the first bit of filament after a retraction is a little bit thin i.e. it under extrudes for a small distance.

So is it the case that my retraction settings are too aggressive? Or is it that the optimum between not retracting enough (or fast enough) and retracting too much is just a very fine point between the two? I say this as I feel fairly confident that if I back the retraction off even a small amount I'll go back to getting the blobs and strings.

I'm using slic3r and intend to do so for the time being, is there a setting or a trick to slightly boost the extrusion multiplier just after a retract? I say this as the retraction is fine its just a little low on filament pressure when it recommences printing.

Any advice gratefully received.

If it makes a difference I'm using a T3P3 kossel mini, ramps/mega/ e3d v5 genuine hotend, 1.75 mm filament and Rich Cattel's marlin master branch, slic3r 1.29a.

Sure, that's the "extra length on restart" field in printer settings -> extruder

Cheers James good spot.

What setting do you use fr this field? What are your typical retraction settings?

I haven't tried the extra length setting out - retraction tuning is still on my very long todo list! I've been using pretty fierce retraction for nylon and still not really controlling stringing;6mm @ 160mm/s (direct drive mk8 and 1.75mm filament). For petg I used 4mm @ 30mm/s, and at the other end of the scale I've been using 1mm @20mm/s for 3mm pla with a geared extruder. In other words, I'm all over the map trying out too many different things. Once I get this build more stable I'll come back and have a more methodical look at it.

Okay well Im going to give it a try now so I'll report back I use 2.2mm @ 150mm/s on my kossel for abs, so Ill start with +1mm extra length and see how it goes.

I'm getting a similar problem with pla on travel moves that don't use retraction - shame there isn't (as far as I know) a setting for a little extra extrusion after travel. Perhaps I should try and force retraction on all moves and then use the existing extra length setting.

Look forward to seeing/hearing the results of your testing

Hi,
In my case Slic3er is set to 1mm retraction.
After the skirt is done, just at the very start of the part, the extruder produces a large blob on the glassplate and then continues to work on the perimeter. Then when the well made perimeter is finished, at the start of the infill it seems that there is not enough material to make a correct fill. Only for a few mm the infill is to thin. After that it's ok, I get a perfect correctly filled first layer, except for these few first millimeters.
This is occurring only when I use a .5 mm nozzle, not when using a .35 mm nozzle. And what's strange it's not always happening.
I never have strings btw.
I use a set of (selfmade - [www.thingiverse.com]) fast removable extruder and do switch frequently between them.

Edited 1 time(s). Last edit at 03/04/2016 03:32AM by chriske.

Well so far, I haven't had much time to try too many settings but 1mm extra length is too much and results in over extrusion around small delicate areas. So I've got back to 0 for now but will definitely try a few more times when I get chance. I get the feeling for my setup something around 0.2mm might be more acceptable.