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Ovals

Rogier Wolff

Thu, Sep 6, 2018 12:58 PM

On Thu, Sep 06, 2018 at 11:22:37AM +0100, nop head wrote:

Yes but brim adds just more outlines that can be removed easily. If you add
it to the model it will be fully incorporated, how do you remove it from
the print?

IF it is easy to remove, because adjoining lines do not adhere
perfectly to eachother, the brim doesn't serve the purpose we have for
it to help adhering the object to the platform. So IMHO, IF the brim
works, it is also plastic-wise "incorporated into the object" as you
say.

In practise, that is one of the problems: On the first layer the
adhesion between adjacent lines is not perfect. Then the print fails.

"tri" is the object I want,
print_tri () is how I print it.

The half cones snap off by hand. The "cube" to stabilize the whole
thing while printing can be snipped of with side-cutting pliers.

Printing this-side-up worked better for me. I don't remember if it was
surface finish or something else that prompted me to print it this
way.

Roger.

$fs = 0.2;

module hcone (d, h)
{
difference () {
cylinder (d1=d, d2=0, h= h);
translate ([0,-d/2-1,-1]) cube ([d/2+1, d+2,h+2]);
}
}

module tri (l=100)
{
hull ()
for (i=[0:120:240])
rotate (i) translate ([10,0,0]) cylinder (d=3, h=l);
}

module print_tri ()
{
cy = 16;
cz = 12;
cx = 0.8;
len = 80;
translate ([0,0,11.5]) rotate ([0,90,0]) tri (l=len);

translate ([0,-cy/2,0]) cube ( [cx, cy,cz]);
hcone (20,1);

translate ([len,cy/2,0]) rotate (180) cube ( [cx,cy,cz]);
translate ([len,0,0]) rotate (180) hcone (20,1);
}

print_tri ();

On 6 September 2018 at 11:09, Rogier Wolff R.E.Wolff@bitwizard.nl wrote:

On Wed, Sep 05, 2018 at 04:47:07PM +0100, nop head wrote:

I have never had much success with other people's STLs for 3D
printing. Even if they are manifold they are often not correct for
3D printing on my machines. I mostly design everything I print from
scratch in OpenSCAD.

For SOME stuff I import "their" STL and add the things I need for
printing on my printer. I think "brim" is overrated. It adds material
where the object doesn't need it and not enough where it does.

For stuff that is high and long, and tends to pull the ends off the
bed, I now add a half cone of a few layers high to the ends. Works
great. Except when there end up being STL errors.

     Roger.

--
** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 **
** Delftechpark 26 2628 XH Delft, The Netherlands. KVK: 27239233 **
-- BitWizard writes Linux device drivers for any device you may have! --
The plan was simple, like my brother-in-law Phil. But unlike
Phil, this plan just might work.

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On Thu, Sep 06, 2018 at 11:22:37AM +0100, nop head wrote: > Yes but brim adds just more outlines that can be removed easily. If you add > it to the model it will be fully incorporated, how do you remove it from > the print? IF it is easy to remove, because adjoining lines do not adhere perfectly to eachother, the brim doesn't serve the purpose we have for it to help adhering the object to the platform. So IMHO, IF the brim works, it is also plastic-wise "incorporated into the object" as you say. In practise, that is one of the problems: On the first layer the adhesion between adjacent lines is not perfect. Then the print fails. "tri" is the object I want, print_tri () is how I print it. The half cones snap off by hand. The "cube" to stabilize the whole thing while printing can be snipped of with side-cutting pliers. Printing this-side-up worked better for me. I don't remember if it was surface finish or something else that prompted me to print it this way. Roger. $fs = 0.2; module hcone (d, h) { difference () { cylinder (d1=d, d2=0, h= h); translate ([0,-d/2-1,-1]) cube ([d/2+1, d+2,h+2]); } } module tri (l=100) { hull () for (i=[0:120:240]) rotate (i) translate ([10,0,0]) cylinder (d=3, h=l); } module print_tri () { cy = 16; cz = 12; cx = 0.8; len = 80; translate ([0,0,11.5]) rotate ([0,90,0]) tri (l=len); translate ([0,-cy/2,0]) cube ( [cx, cy,cz]); hcone (20,1); translate ([len,cy/2,0]) rotate (180) cube ( [cx,cy,cz]); translate ([len,0,0]) rotate (180) hcone (20,1); } print_tri (); > > On 6 September 2018 at 11:09, Rogier Wolff <R.E.Wolff@bitwizard.nl> wrote: > > > On Wed, Sep 05, 2018 at 04:47:07PM +0100, nop head wrote: > > > > > I have never had much success with other people's STLs for 3D > > > printing. Even if they are manifold they are often not correct for > > > 3D printing on my machines. I mostly design everything I print from > > > scratch in OpenSCAD. > > > > For SOME stuff I import "their" STL and add the things I need for > > printing on my printer. I think "brim" is overrated. It adds material > > where the object doesn't need it and not enough where it does. > > > > For stuff that is high and long, and tends to pull the ends off the > > bed, I now add a half cone of a few layers high to the ends. Works > > great. Except when there end up being STL errors. > > > > Roger. > > > > -- > > ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 ** > > ** Delftechpark 26 2628 XH Delft, The Netherlands. KVK: 27239233 ** > > *-- BitWizard writes Linux device drivers for any device you may have! --* > > The plan was simple, like my brother-in-law Phil. But unlike > > Phil, this plan just might work. > > > > _______________________________________________ > > OpenSCAD mailing list > > Discuss@lists.openscad.org > > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org > > > _______________________________________________ > OpenSCAD mailing list > Discuss@lists.openscad.org > http://lists.openscad.org/mailman/listinfo/discuss_lists.openscad.org -- ** R.E.Wolff@BitWizard.nl ** http://www.BitWizard.nl/ ** +31-15-2600998 ** ** Delftechpark 26 2628 XH Delft, The Netherlands. KVK: 27239233 ** *-- BitWizard writes Linux device drivers for any device you may have! --* The plan was simple, like my brother-in-law Phil. But unlike Phil, this plan just might work.