Odd defects on outer surface

[Iridium]

I have been 3D printing for years on a custom delta printer that I build, and I have recently built a CR-10 S4 for some large format prints. It is using a volcano hotend with a .8mm nozzle, and I have just finished getting the print quality to what I consider an acceptable level. I have not perfected my retraction in part because I plant to switch to direct extrusion soon.

These are printed with Rigid.ink's Black ASA at 250C hotend temperature, which is a bit on the hot side, but I need these parts to be extremely strong. They were printed in a heated enclosure as well.

My problem is that there are sporadic marks on the print surface and I cannot figure out what is causing them. I don't believe moisture in the filament is the problem, both because it was printed immediately upon opening the package, and because the humidity in the enclosure is quite low.



The marks do not correspond to start/stop points, or to retractions, and they are not uniform across the print surface.

This is new to me, has anyone run into this problem before?

Some Info:
Filament: Rigid.ink Black ASA
Hotend: 250C, Bed 80C, Heated Enclosure
Print Speed: ~50mm/sec
Nozzle Diameter: .8mm
Layer Height: .2mm
Total Print Time: ~2 days
Infill: 85% Rectilinear

Sorry for the image quality, I don't have a macro lens handy for closeup shots.
ftp://vpn.karsttech.com/PrintIssue/IMG_1004.jpg
ftp://vpn.karsttech.com/PrintIssue/IMG_1006.jpg
ftp://vpn.karsttech.com/PrintIssue/IMG_1007.jpg
ftp://vpn.karsttech.com/PrintIssue/IMG_1008.jpg
ftp://vpn.karsttech.com/PrintIssue/IMG_1009.jpg
ftp://vpn.karsttech.com/PrintIssue/IMG_10010.jpg

[jgwinner]

Did you figure out what it was?

I'm looking around for CR-10 Volcano settings. I'm about to do some large prints, and thought I'd check and see what works.

Simplify3D is already printing better than Cura, but I'm sure I can make it better.

Hope you got further with yours!

== John ==