Cutting corners?

[Captain Starfish]

Hi, trying to print the attached STL using SeeMe green ABS.

First, now that I've dropped my bed down to 50º the smaller parts are very happy with Elmer's glue so that's nice.

But I'm seeing this where I should be seeing a neat internal thread. The part that will screw into it has printed just fine. Understandably, given that there's no void for the filament to cut across on the male thread.

Bumping temp up to 235º and resetting my filament's extruder ratio setting back to 1.0 from where it was at 0.89 based on probably incorrect measurements back when I was REALLY starting out has helped a bit, but this is the best I've got so far.

Printing 0.25mm layers with no supports.

Any ideas what I can try to make this a little neater?

Cheers!

tubeskt.stl

(1.21 MiB) Downloaded 198 times

[img]http://www.simonlockwood.net/linky/3dp/ ... orners.jpg[/img]

[bubbasnow]

so i sliced that file in kiss and it has errors in the tool path

in your slicer step through the layers and see if your paths are messed up also

[bubbasnow]

just ran in netfabb and it made it worse i think...

[Captain Starfish]

Interesting, looks fine in slic3r and came out of a clean solid. Support artefacts?

:edit: thank you for looking into this!

[bubbasnow]

i had support disabled, do you have the free netfabb? once you load it inside the object there are tons of red lines which i think means un-closed triangles. it should be solid green. maybe try a different cad>stl setting like increasing resolution or decreasing the degree for the triangle.

[Captain Starfish]

Interesting. I'll grab netfabb and have a look. Also interesting that I had slic3r whine about non-manifold part for the PEEK fan shroud but not for this.

[Captain Starfish]

Wow, it looks horrible in netfabb. But it doesn't look anything like that if you go layer by layer in slic3r, the offset ring of the thread just worms its way up like it should. Same watching the hot end during the print - it's tracking correctly, but looks like the filament isn't quite sticking in place at those spots. So I'm going to call shenanigans on netfabb, ignore its whining as a red herring, and hope someone can come up with a settingsy kind of cause/solution for a filament not sticking kind of problem which could be just a function of the 60º thread angle. Seeing as I'm doing both sides I can drop it to 50º and see if that gives a little more overlap for support-free printing.

Another note - anyone else printing this kind of thing, is there a standard sort of clearance you build into slide-fitting parts so they do slide fit? 0.1mm? 0.25mm?

Ta!

[Captain Starfish]

For anyone else who gets caught by this, I suspect it was caused by me being simply too aggressive with the overhang angle and no support on a tight circle.

I opened up the pitch from 1.0mm to 1.5mm and changed the thread angle from 60º to 80º and it's now printing perfectly.

0.5mm is working well on a 10mm diameter part to allow clearance for the male and female threads to mate cleanly.