getting rid of 'snot'

[frankpirz]

parts without snot

arm.body.all.rz0.factory

factory file

(342.45 KiB) Downloaded 211 times

parts with 'snot'

New to S3D, used Slic3r for over a year.
I've been told what I'm calling 'snot' (see the picture) is excess filament (not enough retract) that winds up
creating a 'bump' on the start of a new layer. [I've tried random layer start, that just distributes the snot
around, doesn't get rid of it!]
the parts with snot were printed at .2mm layer height for better definition on the slots.
for comparison, there are photos of different parts, without any snot, printed at .3mm layer height.
[so the printer can do it, it's a matter of settings....]
can anyone confirm that this is actually a retract problem?
if not, what else should I be looking at?
how many settings do I have to tinker with when I change layer height?

really lost in the woods..

Frank Pirz
Media Conversions LLC

[JoeJ]

Yes, it looks like your retraction settings could use a little work. What printer are you using?

[frankpirz]

JoeJ
thanks for the comment.
The printer is an 'orphan' - Trinity Labs A1.
I'm using a J-head, retract default was set to .8mm
it's already been increased to 1mm.
what you are implying is that retract is a function of layer height.
if that's true (and I'm not arguing it isn't) then the slicer ought to be adjusting it.
[and further, what do you do if you variable layer height during a print.?]

Frank Pirz

[jimc]

Retraction isnt really a factor if layer height. S3d has a ton of retraction setting. Coasting, restart distance, etc. the blobs are what oozes out during the travel moves then at the start of the next line you are left with a bump. There are many things beynd settings that affect this. Moisture content of your filament is the biggest, plastic formulation is also a factor. Speed, length if the travel move, temp and a bunch of others. What i see there isnt terrible but could be better. Keep in mind you will always have a seam or start and stop point on each layer which will make a line up the side of your print or scatter spots all over depending on how you have that set.