41 lines
1.6 KiB
OpenSCAD
41 lines
1.6 KiB
OpenSCAD
//
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// NopSCADlib Copyright Chris Palmer 2018
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// nop.head@gmail.com
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// hydraraptor.blogspot.com
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//
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// This file is part of NopSCADlib.
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//
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// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
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// GNU General Public License as published by the Free Software Foundation, either version 3 of
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// the License, or (at your option) any later version.
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//
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// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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// See the GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License along with NopSCADlib.
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// If not, see <https://www.gnu.org/licenses/>.
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//
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//
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//! Nitrile rubber O-rings.
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//!
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//! Just a black torus specified by internal diameter, ```id``` and ```minor_d``` plus a BOM entry.
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//! Can be shown stretched by specifying the ```actual_id```.
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//
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include <../core.scad>
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module O_ring(id, minor_d, actual_id = 0) { //! Draw O-ring with specified internal diameter and minor diameter. ```actual_id``` can be used to stretch it around something.
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vitamin(str("O_ring(", id, ", ", minor_d, "): O-ring nitrile ", id, "mm x ", minor_d, "mm"));
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D = actual_id > id ? actual_id : id; // allow it to be stretched
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//
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// assume volume conserved when stretched. It is proportional to major diameter and square of minor diameter
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//
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r = (minor_d / 2) * sqrt(id / D);
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R = D / 2 + r / 2;
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color([0.2, 0.2, 0.2]) rotate_extrude()
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translate([R, 0])
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circle(r = r);
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}
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