spiral in cylinder - not printing

Hi all

I've been trying to print the attached sketchup. I'm converting it to stl and then importing it into replicator g+skeinforge.

All I get for the internal spiral is some seemingly random lines.

Can anyone suggest drawing or skeinforge setting changes that will guarantee a good print?

Thanks

Mike

Basically your model is broken. I see a lot of zero-thickness triangles, intersecting triangles and missing triangles.

A basic rule of thumb is you need to make sure your model has at least 2x extrusion width thick walls, and 2x layer height thick floors. Thicker is often better, based on what you want to achieve.

Other than that, your model is quite complex, and not very straight forward to make in a mesh modeller. I have no clue how to build something like that in sketchup, so here's a fast hack I did in openscad. It slices fine in slic3r, so should be good for skeinforge. The stl is attached.

scale(4){
linear_extrude(height = 10, center = true, twist = 360,slices=20)
translate([1,-0.5,0]) square([2.6,1]);

cylinder(r=1.5,h=10,center=true,$fn=20);
difference(){
	cube([8,8,10],center=true);
	translate([0,0,-1]) cylinder(r=3.5,h=13,center=true,$fn=20);
}
}

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-Nudel
Blog with RepRap Comic

Hi Nudel

Interesting! That stl you sent was made by OpenSCAD! I repeated that exercise. Neat. Thanks for introducing me to OpenSCAD.

I'm confused about why the printer prints all outer walls of the cube and the cylinders, but not the spiral ramp?

I had guessed that was the problem, and had started on a more simplistic model to prove it to myself, but my computer stopped sending commands to the printer and it buried the entire print head in plastic. Once I de-glob it, I'll give these models a try. I'm really hoping for a single thickness of plastic.

Thanks very much for the input!!

Mike

Hi Nudel

OK. I finally got my printer up and going again yesterday. Your Openscad model printed reasonably well. Thanks very much for that!

How would you go about changing the ramp in openscad to make it one layer of plastic?

Mike

Not sure if a single layer is feasible, it will depend on the layer slicing height and such being perfect.

I don't have an idea right now on how to make it single layer, and I don't have openscad to experiment right now, but perhaps someone else has a solution.

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-Nudel
Blog with RepRap Comic