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swh/web/tests/resources/contents/code/extensions/acme_screw.scad
- This file was added.
| include <config.scad> | |||||
| use <GDMUtils.scad> | |||||
| // Constructs an acme threaded screw rod. This method makes much | |||||
| // smoother threads than the naive linear_extrude method. | |||||
| module acme_threaded_rod( | |||||
| d=10.5, | |||||
| l=100, | |||||
| pitch=3.175, | |||||
| thread_depth=1, | |||||
| thread_angle=14.5 | |||||
| ) { | |||||
| astep = 360/segs(d/2); | |||||
| asteps = ceil(360/astep); | |||||
| threads = ceil(l/pitch)+2; | |||||
| pa_delta = min(pitch/4.1,(thread_depth+0.05)*tan(thread_angle)/2); | |||||
| poly_points = [ | |||||
| for ( | |||||
| thread = [0 : threads-1], | |||||
| astep = [0 : asteps-1], | |||||
| i = [0 : 3] | |||||
| ) let ( | |||||
| r = max(0, d/2 - ((i==1||i==2)? 0 : (thread_depth+0.05))), | |||||
| a = astep / asteps, | |||||
| rx = r * cos(360 * a), | |||||
| ry = r * sin(360 * a), | |||||
| tz = (thread + a - threads/2 + (i<2? -0.25 : 0.25)) * pitch + (i%2==0? -pa_delta : pa_delta) | |||||
| ) [rx, ry, tz] | |||||
| ]; | |||||
| point_count = len(poly_points); | |||||
| poly_faces = concat( | |||||
| [ | |||||
| for ( | |||||
| thread = [0 : threads-1], | |||||
| astep = [0 : asteps-1], | |||||
| j = [0 : 3], | |||||
| i = [0 : 1] | |||||
| ) let( | |||||
| p0 = (thread*asteps + astep)*4 + j, | |||||
| p1 = p0 + 4, | |||||
| p2 = (thread*asteps + astep)*4 + ((j+1)%4), | |||||
| p3 = p2 + 4, | |||||
| tri = (i==0? [p0, p3, p1] : [p0, p2, p3]) | |||||
| ) | |||||
| if (p0 < point_count-4) tri | |||||
| ], | |||||
| [ | |||||
| [0, 3, 2], | |||||
| [0, 2, 1], | |||||
| [point_count-4, point_count-3, point_count-2], | |||||
| [point_count-4, point_count-2, point_count-1] | |||||
| ] | |||||
| ); | |||||
| intersection() { | |||||
| union() { | |||||
| polyhedron(points=poly_points, faces=poly_faces, convexity=10); | |||||
| cylinder(h=(threads+0.5)*pitch, d=d-2*thread_depth, center=true, $fn=asteps); | |||||
| } | |||||
| cube([d+1, d+1, l], center=true); | |||||
| } | |||||
| } | |||||
| //!acme_threaded_rod(d=3/8*25.4, l=20, pitch=1/8*25.4, thread_depth=1.3, thread_angle=29, $fn=32); | |||||
| //!acme_threaded_rod(d=60, l=16, pitch=8, thread_depth=3, thread_angle=45, $fa=2, $fs=2); | |||||
| module acme_threaded_nut( | |||||
| od=17.4, | |||||
| id=10.5, | |||||
| h=10, | |||||
| pitch=3.175, | |||||
| thread_depth=1, | |||||
| slop=printer_slop | |||||
| ) { | |||||
| difference() { | |||||
| cylinder(r=od/2/cos(30), h=h, center=true, $fn=6); | |||||
| zspread(slop) { | |||||
| acme_threaded_rod(d=id+2*slop, l=h+1, pitch=pitch, thread_depth=thread_depth); | |||||
| } | |||||
| } | |||||
| } | |||||
| // vim: noexpandtab tabstop=4 shiftwidth=4 softtabstop=4 nowrap | |||||