33 lines
1.3 KiB
OpenSCAD
33 lines
1.3 KiB
OpenSCAD
screw_gear(8, 4, 2, 8, 18, 32);
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module screw_gear(outer_radius, inner_radius, thickness, thread_length, precision, total_length)
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{
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linear_extrude(height=total_length, twist=360*total_length/thread_length, slices=360)
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polygon(
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points = screw_crosssection(outer_radius, inner_radius, thickness, thread_length, precision),
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paths = [ range((precision+8)*2) ]
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);
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}
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function screw_crosssection(outer_radius, inner_radius, thickness, thread_length, precision) =
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concat(
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[ for (x=[1 : 8]) polar(outer_radius, thickness*360/thread_length*x/8) ],
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[ for (x=[1 : precision])
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polar(
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outer_radius-(outer_radius-inner_radius)*x/precision,
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thickness*360/thread_length + x/precision*(180-(thickness*360/thread_length))
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)
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],
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[ for (x=[1 : 8]) polar(inner_radius, 180 + thickness*360/thread_length*x/8) ],
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[ for (x=[1 : precision])
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polar(
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inner_radius+(outer_radius-inner_radius)*x/precision,
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180 + thickness*360/thread_length + x/precision*(180-(thickness*360/thread_length))
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)
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]
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);
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function polar(r,theta) = r*[sin(theta), cos(theta)]; // convert polar to cartesian coordinates
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function range(n) = [ for(x = [0 : n-1]) x ];
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