[(somewhat) Solved] How to get one filament thin walls ?

I'm in the process of doing first settings on my Huxley.

I'm trying to print a single hollow cube that would need only one pass to make each wall, but I cannot get it with skeinforge : however thin I make the walls in the STL, skeinforge still makes each wall with 2 widths of extruded plastic.

Is there a setting I'm missing that I could disable to get the expected result ? I know I could just handcraft the gcode for that simple goal (or hack the gcode output of skeinforge), but I rather learn something in the process if possible

Using SF41 btw.

Thanks !

Edited 2 time(s). Last edit at 08/24/2011 02:47AM by DeuxVis.

Did you try changing the three Extra Shells settings in Fill to 0?

Yes I did, without result.
Actually I even try disabling the fill plugin, but same result, so I suppose it's not the cullprit.


Oh wait I found why. My STL cube wall was not thin enough, it was 0.2 mm, lowering to .02mm worked.

Strange that a 0.2 mm wall needs more than 1 pass with a 0.5mm nozzle doing 0.4mm layer height.
Oh well.

Thanks for your help.

Nozzle size doesn't really come into it as much as you'd think.. Also, the perimeter w/t setting in carve is what controls the width of perimeter threads - multiply that by the layer height to get thread width.

Either way, glad you got it sorted.

It still does not works sometimes.

Of those 2 attempts, only the 2cm get one pass walls from sf41 for me. Although the 4cm is way thinner. Go figure...

# 2 cm thin walled box
difference() {
cube( [20, 20, 5], true);
cube( [19.09, 19.09, 5.1], true);
}

# 4 cm thin walled box
difference() {
cube( [40, 40, 10], true);
cube( [39.9999, 39.9999, 10.1], true);
}

Attaching the STL if anyone without openscad want to give it go through his sf setup.

SF Fill tab:

solid surface thickness: 1
extra layers (3 settings): all zero
infill: zero

Edit:
Shouldn't this work with random stl object? Except some will have inside planes that are surfaces and might get some layers in the middle where that happends, but other than that for a solid cube should work. But if you take a random solid cube and run sf like that, i think this should give you just 1 wall and nothing else.

Edited 1 time(s). Last edit at 09/29/2011 10:55AM by NoobMan.

DeuxVis

I've had the same problem as you (though I didn't recognise it at the time).
See my thread about infill problems here: [forums.reprap.org]

I printed the 2 cuboids you provided (thanks for that – very useful) and had precisely the same results. The 2 cm cuboid printed with a single thickness wall, the 4cm cuboid with double thickness.

Very odd

Interestingly (possibly) when I printed with this 2cm cuboid (http://www.thingiverse.com/thing:5573 ), it also printed with double thickness walls. (I think but may be wrong) the only difference with your 2cm cuboid is that it has curved corners.

Perhaps Skeinforge is doing something clever about corner construction (e.g. the Stretch Plug-in?) that is causing it to decide it should build a double wall????
Why that would then happen again for your 4cm cuboid but not the 2 cm one I have no idea. These are just my random thoughts........

Fingers crossed we find a solution

Cheers

Pete