unable to print threads that slic3r has no problem with

[jspiro]

Now that Josef Prusa released his own tuned settings for the i3 (http://shop.prusa3d.com/forum/print-tip ... t337.html), I'm giving S3D another try. I hate that I can't find a way to use S3D and always end up going back to Slic3r when I need something done right and don't have time to tinker.

Surprisingly, I couldn't find anyone talking about the finer points of printing threads.

Here's the problem. No threads on the printed model.



I have an OpenSCAD generated STL with two parts that connect with generated threads. Slic3r had no problem slicing this at 0.2mm and I got a beautiful print from it (below). Slicing the same file with S3D, no matter what settings I tried, produced either really bad threads or none at all (the higher the resolution of the STL, the fewer threads printed).

S3D on the left, Slic3r on the right, mostly identical settings (except for concentric fill on the left, and ignore the missing column on the right, I broke it):


There's other fit and finish issues with the left print. It's shiny and it lacks a nicely finished top layer. Every print I've done in S3D has a poorly finished top layer.

I tried enabling support and found S3D trying to build random supports for the threads. I suspect there's an overhang settings I haven't found that might help.

------------

Green part (no threads printed)
OpenSCAD: https://dl.dropboxusercontent.com/u/331 ... older.scad ('res' was 360 for the green part)
Original: https://dl.dropboxusercontent.com/u/331 ... d/test.stl
Netfabbed: https://dl.dropboxusercontent.com/u/331 ... _fixed.stl

Purple part (many short threaded segments printed)
OpenSCAD: https://dl.dropboxusercontent.com/u/331 ... older.scad ('res' was 30 for the purple part)
Slic3r: https://dl.dropboxusercontent.com/u/3311552/s3d/top.stl
S3D: https://dl.dropboxusercontent.com/u/331 ... d/top2.stl

S3D settings
0.2 NORMAL from Josef Prusa: http://shop.prusa3d.com/forum/download/file.php?id=533
Factory: https://dl.dropboxusercontent.com/u/331 ... ds.factory

[CompoundCarl]

Ok, so it sounds like there's 2 issues. One of your STL files isn't printing the outer threads, and you're trying to get better top surfaces.

1) post your factory file for the missing threads problem (go to File > Save Factory File). That should make it really easy for us to give you advice.

2) For the top surfaces, it looks like your under-extruding a bit. If you under-extrude, there's going to be more gaps between the top surfaces and they won't be fully sealed (or fully smooth!). So try extruding a bit more. You may also want to print a few more top solid layers, as that can also help the layers turn out better.

[dkightley]

Your thread not printing issue is explained thoroughly in this thread in the Feature Request forum section:
viewtopic.php?f=23&t=3471

If you use a 0.2mm nozzle, S3D will print the threads....but not with a nozzle of 0.4mm or larger.

Perhaps you may wish to add your thoughts to it...so it regains some focus.

Posting your factory file as requested above will allow some advice to be given on the surface quality issue....