commit e7c68ba5a7922fcf3f5b7da10c291f5a23d1c114 Author: mmcwilliams Date: Mon Dec 5 22:09:19 2022 -0500 Add initial libraries diff --git a/knurledFinishLib_v2.scad b/knurledFinishLib_v2.scad new file mode 100644 index 0000000..f4011fa --- /dev/null +++ b/knurledFinishLib_v2.scad @@ -0,0 +1,181 @@ +/* + * knurledFinishLib_v2.scad + * + * Written by aubenc @ Thingiverse + * + * This script is licensed under the Public Domain license. + * + * http://www.thingiverse.com/thing:31122 + * + * Derived from knurledFinishLib.scad (also Public Domain license) available at + * + * http://www.thingiverse.com/thing:9095 + * + * Usage: + * + * Drop this script somewhere where OpenSCAD can find it (your current project's + * working directory/folder or your OpenSCAD libraries directory/folder). + * + * Add the line: + * + * use + * + * in your OpenSCAD script and call either... + * + * knurled_cyl( Knurled cylinder height, + * Knurled cylinder outer diameter, + * Knurl polyhedron width, + * Knurl polyhedron height, + * Knurl polyhedron depth, + * Cylinder ends smoothed height, + * Knurled surface smoothing amount ); + * + * ...or... + * + * knurl(); + * + * If you use knurled_cyl() module, you need to specify the values for all and + * + * Call the module ' help(); ' for a little bit more of detail + * and/or take a look to the PDF available at http://www.thingiverse.com/thing:9095 + * for a in depth descrition of the knurl properties. + */ + + +module knurl( k_cyl_hg = 12, + k_cyl_od = 25, + knurl_wd = 3, + knurl_hg = 4, + knurl_dp = 1.5, + e_smooth = 2, + s_smooth = 0) +{ + knurled_cyl(k_cyl_hg, k_cyl_od, + knurl_wd, knurl_hg, knurl_dp, + e_smooth, s_smooth); +} + +module knurled_cyl(chg, cod, cwd, csh, cdp, fsh, smt) +{ + cord=(cod+cdp+cdp*smt/100)/2; + cird=cord-cdp; + cfn=round(2*cird*PI/cwd); + clf=360/cfn; + crn=ceil(chg/csh); + + echo("knurled cylinder max diameter: ", 2*cord); + echo("knurled cylinder min diameter: ", 2*cird); + + if( fsh < 0 ) + { + union() + { + shape(fsh, cird+cdp*smt/100, cord, cfn*4, chg); + + translate([0,0,-(crn*csh-chg)/2]) + knurled_finish(cord, cird, clf, csh, cfn, crn); + } + } + else if ( fsh == 0 ) + { + intersection() + { + cylinder(h=chg, r=cord-cdp*smt/100, $fn=2*cfn, center=false); + + translate([0,0,-(crn*csh-chg)/2]) + knurled_finish(cord, cird, clf, csh, cfn, crn); + } + } + else + { + intersection() + { + shape(fsh, cird, cord-cdp*smt/100, cfn*4, chg); + + translate([0,0,-(crn*csh-chg)/2]) + knurled_finish(cord, cird, clf, csh, cfn, crn); + } + } +} + +module shape(hsh, ird, ord, fn4, hg) +{ + x0= 0; x1 = hsh > 0 ? ird : ord; x2 = hsh > 0 ? ord : ird; + y0=-0.1; y1=0; y2=abs(hsh); y3=hg-abs(hsh); y4=hg; y5=hg+0.1; + + if ( hsh >= 0 ) + { + rotate_extrude(convexity=10, $fn=fn4) + polygon(points=[ [x0,y1],[x1,y1],[x2,y2],[x2,y3],[x1,y4],[x0,y4] ], + paths=[ [0,1,2,3,4,5] ]); + } + else + { + rotate_extrude(convexity=10, $fn=fn4) + polygon(points=[ [x0,y0],[x1,y0],[x1,y1],[x2,y2], + [x2,y3],[x1,y4],[x1,y5],[x0,y5] ], + paths=[ [0,1,2,3,4,5,6,7] ]); + } +} + +module knurled_finish(ord, ird, lf, sh, fn, rn) +{ + for(j=[0:rn-1]) + assign(h0=sh*j, h1=sh*(j+1/2), h2=sh*(j+1)) + { + for(i=[0:fn-1]) + assign(lf0=lf*i, lf1=lf*(i+1/2), lf2=lf*(i+1)) + { + polyhedron( + points=[ + [ 0,0,h0], + [ ord*cos(lf0), ord*sin(lf0), h0], + [ ird*cos(lf1), ird*sin(lf1), h0], + [ ord*cos(lf2), ord*sin(lf2), h0], + + [ ird*cos(lf0), ird*sin(lf0), h1], + [ ord*cos(lf1), ord*sin(lf1), h1], + [ ird*cos(lf2), ird*sin(lf2), h1], + + [ 0,0,h2], + [ ord*cos(lf0), ord*sin(lf0), h2], + [ ird*cos(lf1), ird*sin(lf1), h2], + [ ord*cos(lf2), ord*sin(lf2), h2] + ], + triangles=[ + [0,1,2],[2,3,0], + [1,0,4],[4,0,7],[7,8,4], + [8,7,9],[10,9,7], + [10,7,6],[6,7,0],[3,6,0], + [2,1,4],[3,2,6],[10,6,9],[8,9,4], + [4,5,2],[2,5,6],[6,5,9],[9,5,4] + ], + convexity=5); + } + } +} + +module knurl_help() +{ + echo(); + echo(" Knurled Surface Library v2 "); + echo(""); + echo(" Modules: "); + echo(""); + echo(" knurled_cyl(parameters... ); - Requires a value for each an every expected parameter (see bellow) "); + echo(""); + echo(" knurl(); - Call to the previous module with a set of default parameters, "); + echo(" values may be changed by adding 'parameter_name=value' i.e. knurl(s_smooth=40); "); + echo(""); + echo(" Parameters, all of them in mm but the last one. "); + echo(""); + echo(" k_cyl_hg - [ 12 ] ,, Height for the knurled cylinder "); + echo(" k_cyl_od - [ 25 ] ,, Cylinder's Outer Diameter before applying the knurled surfacefinishing. "); + echo(" knurl_wd - [ 3 ] ,, Knurl's Width. "); + echo(" knurl_hg - [ 4 ] ,, Knurl's Height. "); + echo(" knurl_dp - [ 1.5 ] ,, Knurl's Depth. "); + echo(" e_smooth - [ 2 ] ,, Bevel's Height at the bottom and the top of the cylinder "); + echo(" s_smooth - [ 0 ] ,, Knurl's Surface Smoothing : File donwn the top of the knurl this value, i.e. 40 will snooth it a 40%. "); + echo(""); +} + diff --git a/path_extrude.scad b/path_extrude.scad new file mode 100644 index 0000000..aa2b0da --- /dev/null +++ b/path_extrude.scad @@ -0,0 +1,195 @@ +// path_extrude.scad -- Extrude a path in 3D space +// usage: add "use ;" to the top of your OpenSCAD source code + +// Copyright (C) 2014-2019 David Eccles (gringer) + +// This program is free software: you can redistribute it and/or modify +// it under the terms of the GNU General Public License as published by +// the Free Software Foundation, either version 3 of the License, or +// (at your option) any later version. + +// This program is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. + +// You should have received a copy of the GNU General Public License +// along with this program. If not, see . + +// Determine the projection of a point on a plane centered at c1 with normal n1 +function project(p, c, n) = + p - (n * (p - c)) * n / (n * n); + +// determine angle between two points with a given normal orientation +// see https://stackoverflow.com/questions/14066933/ +// direct-way-of-computing-clockwise-angle-between-2-vectors +// dot = p1 * p2; +// det = (p1[0]*p2[1]*n1[2] + p2[0]*n1[1]*p1[2] + n1[0]*p1[1]*p2[2]) - +// (n1[0]*p2[1]*p1[2] + p1[0]*n1[1]*p2[2] + p2[0]*p1[1]*n1[2]); +// atan2(det, dot); +// determine angle between two planar points and a centre +// with a given normal orientation +function getPlanarAngle(p1, p2, c1, n1) = + let(p1 = p1-c1, n1=n1 / norm(n1), p2=p2-c1) + atan2((p1[0]*p2[1]*n1[2] + p2[0]*n1[1]*p1[2] + n1[0]*p1[1]*p2[2]) - + (n1[0]*p2[1]*p1[2] + p1[0]*n1[1]*p2[2] + p2[0]*p1[1]*n1[2]), p1 * p2); + +function c3D(tPoints) = + (len(tPoints[0]) == undef) ? // single point + c3D([tPoints])[0] : + (len(tPoints[0]) < 3) ? // collection of 2D points + tPoints * [[1,0,0],[0,1,0]] : + tPoints; // 3D points + +// translate a point (or points) +function myTranslate(ofs, points, acc = []) = + (len(points[0]) == undef) ? + myTranslate(ofs, [points])[0] : + [ for(i = [0:(len(points) - 1)]) + [ for(d = [0:(len(points[0])-1)]) (ofs[d] + points[i][d])]]; + +// rotate a point (or points) +function myRotate(rotVec, points) = + let(rotX = [[1, 0, 0], + [0, cos(rotVec[0]), -sin(rotVec[0])], + [0, sin(rotVec[0]), cos(rotVec[0])]], + rotY = [[ cos(rotVec[1]), 0,-sin(rotVec[1])], + [ 0, 1, 0], + [ sin(rotVec[1]), 0, cos(rotVec[1])]], + rotZ = [[ cos(rotVec[2]), sin(rotVec[2]), 0], + [ sin(rotVec[2]), -cos(rotVec[2]), 0], + [0, 0, 1]]) + (len(points[0]) == undef) ? + myRotate(rotVec, [points])[0] : + c3D(points) * rotX * rotY * rotZ; + +// Determine spherical rotation for cartesian coordinates +function rToS(pt) = + [-acos((pt[2]) / norm(pt)), + 0, + -atan2(pt[0],pt[1])]; + +function calcPreRot(p1, p2, p3) = + let(n1=p2-p1, // normal between the two points (i.e. the plane that the polygon sits on) + n2=p3-p2, + rt1=rToS(n1), + rt2=rToS(n2), + pj1=(p2 + myRotate(rt2, [[1e42,0,0]])[0]), + pj2=project(p=(p1 + myRotate(rt1, [[1e42,0,0]])[0]), c=p2, n=n2)) + getPlanarAngle(p1=pj1, p2=pj2, c1=p2, n1=n2); + +function cumSum(x, res=[]) = + (len(x) == len(res)) ? concat([0], res) : + (len(res) == 0) ? cumSum(x=x, res=[x[0]]) : + cumSum(x=x, res=concat(res, [x[len(res)] + res[len(res)-1]])); + +// Create extrusion side panels for one polygon segment as triangles. +// Note: panels are not necessarily be planar due to path twists +function makeSides(shs, pts, ofs=0) = + concat( + [for(i=[0:(shs-1)]) [i+ofs, ((i+1) % shs + ofs + shs) % (shs * pts), + (i+1) % shs + ofs]], + [for(i=[0:(shs-1)]) [((i+1) % shs + ofs + shs) % (shs * pts), + i+ofs, (i + ofs + shs) % (shs * pts)]]); + +// Concatenate the contents of the outermost list +function flatten(A, acc = [], aDone = 0) = + (aDone >= len(A)) ? acc : + flatten(A, acc=concat(acc, A[aDone]), aDone = aDone + 1); + +// Linearly interpolate between two shapes +function makeTween(shape1, shape2, t) = + (t == 0) ? shape1 : + (t == 1) ? shape2 : + [for (i=[0:(len(shape1)-1)]) + (shape1[i]*(1-t) + shape2[i % len(shape2)]*(t))]; + +// Extrude a 2D shape through a 3D path +// Note: merge has two effects: +// 1) Removes end caps +// 2) Adjusts the rotation of each path point +// so that the end and start match up +module path_extrude(exPath, exShape, exShape2=[], + exRots = [0], exScale = [1], merge=false, preRotate=true){ + exShapeTween = (len(exShape2) == 0) ? + exShape : exShape2; + shs = len(exShape); // shs: shape size + pts = len(exPath); // pts: path size + exPathX = (merge) ? concat(exPath, [exPath[0], exPath[1]]) : + concat(exPath, + [exPath[pts-1] + (exPath[pts-1] - exPath[pts-2]), + exPath[pts-1] + 2*(exPath[pts-1] - exPath[pts-2])]); + exScaleX = (len(exScale) == len(exPath)) ? exScale : + [for (i = [0:(pts-1)]) exScale[i % len(exScale)]]; + preRots = [for(i = [0:(pts-1)]) + preRotate ? + calcPreRot(p1=exPathX[i], // "current" point on the path + p2=exPathX[(i+1)], // "next" point on the path + p3=exPathX[(i+2)]) : + 0 ]; + cumPreRots = cumSum(preRots); + seDiff = cumPreRots[len(cumPreRots)-1]; // rotation difference (start - end) + // rotation adjustment to get start to look like end + seAdj = -seDiff / (len(cumPreRots)); + adjPreRots = (!merge) ? cumPreRots : + [for(i = [0:(pts-1)]) (cumPreRots[i] + seAdj * i)]; + adjExRots = (len(exRots) == 1) ? + [for(i = [0:(len(adjPreRots)-1)]) (adjPreRots[i] + exRots[0])] : + [for(i = [0:(len(adjPreRots)-1)]) (adjPreRots[i] + exRots[i % len(exRots)])]; + phPoints = flatten([ + for(i = [0:(pts-1)]) + let(p1=exPathX[i], + p2=exPathX[(i+1)], + n1=p2-p1, // normal between the two points + rt1=rToS(n1)) + myTranslate(p1, myRotate(rt1, myRotate([0,0,-adjExRots[i]], + c3D(makeTween(exShape, exShapeTween, i / (pts-1)) * + exScaleX[i])))) + ]); + if(merge){ // just the surface, no end caps + polyhedron(points=phPoints, + faces=flatten([ + for(i = [0:(pts-1)]) + makeSides(shs, pts, ofs=shs*i) + ]) + ); + } else { + polyhedron(points=phPoints, + faces=concat( + flatten([ + for(i = [0:(pts-2)]) + makeSides(shs, pts, ofs=shs*i) + ]), + concat( // add in start / end covers + [[for(i= [0:(shs-1)]) i]], + [[for(i= [(len(phPoints)-1):-1:(len(phPoints)-shs)]) i]] + ) + )); + } +} + +myPathTrefoil = [ for(t = [0:(360 / 101):359]) [ // trefoil knot + 5*(.41*cos(t) - .18*sin(t) - .83*cos(2*t) - .83*sin(2*t) - + .11*cos(3*t) + .27*sin(3*t)), + 5*(.36*cos(t) + .27*sin(t) - 1.13*cos(2*t) + .30*sin(2*t) + + .11*cos(3*t) - .27*sin(3*t)), + 5*(.45*sin(t) - .30*cos(2*t) +1.13*sin(2*t) - + .11*cos(3*t) + .27*sin(3*t))] ]; + +myPointsOctagon = + let(ofs1=15) + [ for(t = [0:(360/8):359]) + ((t==90)?1:2) * [cos(t+ofs1),sin(t+ofs1)]]; +myPointsChunkOctagon = + let(ofs1=15) + [ for(t = [0:(360/8):359]) + ((t==90)?0.4:1.9) * + [cos((t * 135/360 + 45)+ofs1+45)+0.5,sin((t * 135/360 + 45)+ofs1+45)]]; +//myPoints = [ for(t = [0:(360/8):359]) 2 * [cos(t+45),sin(t+45)]]; + +pts=[2,0,0.5]; + +/*translate([0,0,0]) { + path_extrude(exRots = [$t*360], exShape=myPointsOctagon, + exPath=myPathTrefoil, merge=true); +}*/ diff --git a/threads.scad b/threads.scad new file mode 100644 index 0000000..a254f06 --- /dev/null +++ b/threads.scad @@ -0,0 +1,372 @@ +/* + * ISO-standard metric threads, following this specification: + * http://en.wikipedia.org/wiki/ISO_metric_screw_thread + * + * Copyright 2017 Dan Kirshner - dan_kirshner@yahoo.com + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation, either version 3 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * See . + * + * Version 2.3. 2017-08-31 Default for leadin: 0 (best for internal threads). + * Version 2.2. 2017-01-01 Correction for angle; leadfac option. (Thanks to + * Andrew Allen .) + * Version 2.1. 2016-12-04 Chamfer bottom end (low-z); leadin option. + * Version 2.0. 2016-11-05 Backwards compatibility (earlier OpenSCAD) fixes. + * Version 1.9. 2016-07-03 Option: tapered. + * Version 1.8. 2016-01-08 Option: (non-standard) angle. + * Version 1.7. 2015-11-28 Larger x-increment - for small-diameters. + * Version 1.6. 2015-09-01 Options: square threads, rectangular threads. + * Version 1.5. 2015-06-12 Options: thread_size, groove. + * Version 1.4. 2014-10-17 Use "faces" instead of "triangles" for polyhedron + * Version 1.3. 2013-12-01 Correct loop over turns -- don't have early cut-off + * Version 1.2. 2012-09-09 Use discrete polyhedra rather than linear_extrude () + * Version 1.1. 2012-09-07 Corrected to right-hand threads! + */ + +// Examples. +// +// Standard M8 x 1. +// metric_thread (diameter=8, pitch=1, length=4); + +// Square thread. +// metric_thread (diameter=8, pitch=1, length=4, square=true); + +// Non-standard: long pitch, same thread size. +//metric_thread (diameter=8, pitch=4, length=4, thread_size=1, groove=true); + +// Non-standard: 20 mm diameter, long pitch, square "trough" width 3 mm, +// depth 1 mm. +//metric_thread (diameter=20, pitch=8, length=16, square=true, thread_size=6, +// groove=true, rectangle=0.333); + +// English: 1/4 x 20. +//english_thread (diameter=1/4, threads_per_inch=20, length=1); + +// Tapered. Example -- pipe size 3/4" -- per: +// http://www.engineeringtoolbox.com/npt-national-pipe-taper-threads-d_750.html +// english_thread (diameter=1.05, threads_per_inch=14, length=3/4, taper=1/16); + +// Thread for mounting on Rohloff hub. +//difference () { +// cylinder (r=20, h=10, $fn=100); +// +// metric_thread (diameter=34, pitch=1, length=10, internal=true, n_starts=6); +//} + + +// ---------------------------------------------------------------------------- +function segments (diameter) = min (50, ceil (diameter*6)); + + +// ---------------------------------------------------------------------------- +// diameter - outside diameter of threads in mm. Default: 8. +// pitch - thread axial "travel" per turn in mm. Default: 1. +// length - overall axial length of thread in mm. Default: 1. +// internal - true = clearances for internal thread (e.g., a nut). +// false = clearances for external thread (e.g., a bolt). +// (Internal threads should be "cut out" from a solid using +// difference ()). +// n_starts - Number of thread starts (e.g., DNA, a "double helix," has +// n_starts=2). See wikipedia Screw_thread. +// thread_size - (non-standard) axial width of a single thread "V" - independent +// of pitch. Default: same as pitch. +// groove - (non-standard) subtract inverted "V" from cylinder (rather than +// add protruding "V" to cylinder). +// square - Square threads (per +// https://en.wikipedia.org/wiki/Square_thread_form). +// rectangle - (non-standard) "Rectangular" thread - ratio depth/(axial) width +// Default: 1 (square). +// angle - (non-standard) angle (deg) of thread side from perpendicular to +// axis (default = standard = 30 degrees). +// taper - diameter change per length (National Pipe Thread/ANSI B1.20.1 +// is 1" diameter per 16" length). Taper decreases from 'diameter' +// as z increases. +// leadin - 0 (default): no chamfer; 1: chamfer (45 degree) at max-z end; +// 2: chamfer at both ends, 3: chamfer at z=0 end. +// leadfac - scale of leadin chamfer (default: 1.0 = 1/2 thread). +module metric_thread (diameter=8, pitch=1, length=1, internal=false, n_starts=1, + thread_size=-1, groove=false, square=false, rectangle=0, + angle=30, taper=0, leadin=0, leadfac=1.0) +{ + // thread_size: size of thread "V" different than travel per turn (pitch). + // Default: same as pitch. + local_thread_size = thread_size == -1 ? pitch : thread_size; + local_rectangle = rectangle ? rectangle : 1; + + n_segments = segments (diameter); + h = (square || rectangle) ? local_thread_size*local_rectangle/2 : local_thread_size / (2 * tan(angle)); + + h_fac1 = (square || rectangle) ? 0.90 : 0.625; + + // External thread includes additional relief. + h_fac2 = (square || rectangle) ? 0.95 : 5.3/8; + + tapered_diameter = diameter - length*taper; + + difference () { + union () { + if (! groove) { + metric_thread_turns (diameter, pitch, length, internal, n_starts, + local_thread_size, groove, square, rectangle, angle, + taper); + } + + difference () { + + // Solid center, including Dmin truncation. + if (groove) { + cylinder (r1=diameter/2, r2=tapered_diameter/2, + h=length, $fn=n_segments); + } else if (internal) { + cylinder (r1=diameter/2 - h*h_fac1, r2=tapered_diameter/2 - h*h_fac1, + h=length, $fn=n_segments); + } else { + + // External thread. + cylinder (r1=diameter/2 - h*h_fac2, r2=tapered_diameter/2 - h*h_fac2, + h=length, $fn=n_segments); + } + + if (groove) { + metric_thread_turns (diameter, pitch, length, internal, n_starts, + local_thread_size, groove, square, rectangle, + angle, taper); + } + } + } + + // chamfer z=0 end if leadin is 2 or 3 + if (leadin == 2 || leadin == 3) { + difference () { + cylinder (r=diameter/2 + 1, h=h*h_fac1*leadfac, $fn=n_segments); + + cylinder (r2=diameter/2, r1=diameter/2 - h*h_fac1*leadfac, h=h*h_fac1*leadfac, + $fn=n_segments); + } + } + + // chamfer z-max end if leadin is 1 or 2. + if (leadin == 1 || leadin == 2) { + translate ([0, 0, length + 0.05 - h*h_fac1*leadfac]) { + difference () { + cylinder (r=diameter/2 + 1, h=h*h_fac1*leadfac, $fn=n_segments); + cylinder (r1=tapered_diameter/2, r2=tapered_diameter/2 - h*h_fac1*leadfac, h=h*h_fac1*leadfac, + $fn=n_segments); + } + } + } + } +} + + +// ---------------------------------------------------------------------------- +// Input units in inches. +// Note: units of measure in drawing are mm! +module english_thread (diameter=0.25, threads_per_inch=20, length=1, + internal=false, n_starts=1, thread_size=-1, groove=false, + square=false, rectangle=0, angle=30, taper=0, leadin=0, + leadfac=1.0) +{ + // Convert to mm. + mm_diameter = diameter*25.4; + mm_pitch = (1.0/threads_per_inch)*25.4; + mm_length = length*25.4; + + echo (str ("mm_diameter: ", mm_diameter)); + echo (str ("mm_pitch: ", mm_pitch)); + echo (str ("mm_length: ", mm_length)); + metric_thread (mm_diameter, mm_pitch, mm_length, internal, n_starts, + thread_size, groove, square, rectangle, angle, taper, leadin, + leadfac); +} + +// ---------------------------------------------------------------------------- +module metric_thread_turns (diameter, pitch, length, internal, n_starts, + thread_size, groove, square, rectangle, angle, + taper) +{ + // Number of turns needed. + n_turns = floor (length/pitch); + + intersection () { + + // Start one below z = 0. Gives an extra turn at each end. + for (i=[-1*n_starts : n_turns+1]) { + translate ([0, 0, i*pitch]) { + metric_thread_turn (diameter, pitch, internal, n_starts, + thread_size, groove, square, rectangle, angle, + taper, i*pitch); + } + } + + // Cut to length. + translate ([0, 0, length/2]) { + cube ([diameter*3, diameter*3, length], center=true); + } + } +} + + +// ---------------------------------------------------------------------------- +module metric_thread_turn (diameter, pitch, internal, n_starts, thread_size, + groove, square, rectangle, angle, taper, z) +{ + n_segments = segments (diameter); + fraction_circle = 1.0/n_segments; + for (i=[0 : n_segments-1]) { + rotate ([0, 0, i*360*fraction_circle]) { + translate ([0, 0, i*n_starts*pitch*fraction_circle]) { + //current_diameter = diameter - taper*(z + i*n_starts*pitch*fraction_circle); + thread_polyhedron ((diameter - taper*(z + i*n_starts*pitch*fraction_circle))/2, + pitch, internal, n_starts, thread_size, groove, + square, rectangle, angle); + } + } + } +} + + +// ---------------------------------------------------------------------------- +module thread_polyhedron (radius, pitch, internal, n_starts, thread_size, + groove, square, rectangle, angle) +{ + n_segments = segments (radius*2); + fraction_circle = 1.0/n_segments; + + local_rectangle = rectangle ? rectangle : 1; + + h = (square || rectangle) ? thread_size*local_rectangle/2 : thread_size / (2 * tan(angle)); + outer_r = radius + (internal ? h/20 : 0); // Adds internal relief. + //echo (str ("outer_r: ", outer_r)); + + // A little extra on square thread -- make sure overlaps cylinder. + h_fac1 = (square || rectangle) ? 1.1 : 0.875; + inner_r = radius - h*h_fac1; // Does NOT do Dmin_truncation - do later with + // cylinder. + + translate_y = groove ? outer_r + inner_r : 0; + reflect_x = groove ? 1 : 0; + + // Make these just slightly bigger (keep in proportion) so polyhedra will + // overlap. + x_incr_outer = (! groove ? outer_r : inner_r) * fraction_circle * 2 * PI * 1.02; + x_incr_inner = (! groove ? inner_r : outer_r) * fraction_circle * 2 * PI * 1.02; + z_incr = n_starts * pitch * fraction_circle * 1.005; + + /* + (angles x0 and x3 inner are actually 60 deg) + + /\ (x2_inner, z2_inner) [2] + / \ + (x3_inner, z3_inner) / \ + [3] \ \ + |\ \ (x2_outer, z2_outer) [6] + | \ / + | \ /| + z |[7]\/ / (x1_outer, z1_outer) [5] + | | | / + | x | |/ + | / | / (x0_outer, z0_outer) [4] + | / | / (behind: (x1_inner, z1_inner) [1] + |/ | / + y________| |/ + (r) / (x0_inner, z0_inner) [0] + + */ + + x1_outer = outer_r * fraction_circle * 2 * PI; + + z0_outer = (outer_r - inner_r) * tan(angle); + //echo (str ("z0_outer: ", z0_outer)); + + //polygon ([[inner_r, 0], [outer_r, z0_outer], + // [outer_r, 0.5*pitch], [inner_r, 0.5*pitch]]); + z1_outer = z0_outer + z_incr; + + // Give internal square threads some clearance in the z direction, too. + bottom = internal ? 0.235 : 0.25; + top = internal ? 0.765 : 0.75; + + translate ([0, translate_y, 0]) { + mirror ([reflect_x, 0, 0]) { + + if (square || rectangle) { + + // Rule for face ordering: look at polyhedron from outside: points must + // be in clockwise order. + polyhedron ( + points = [ + [-x_incr_inner/2, -inner_r, bottom*thread_size], // [0] + [x_incr_inner/2, -inner_r, bottom*thread_size + z_incr], // [1] + [x_incr_inner/2, -inner_r, top*thread_size + z_incr], // [2] + [-x_incr_inner/2, -inner_r, top*thread_size], // [3] + + [-x_incr_outer/2, -outer_r, bottom*thread_size], // [4] + [x_incr_outer/2, -outer_r, bottom*thread_size + z_incr], // [5] + [x_incr_outer/2, -outer_r, top*thread_size + z_incr], // [6] + [-x_incr_outer/2, -outer_r, top*thread_size] // [7] + ], + + faces = [ + [0, 3, 7, 4], // This-side trapezoid + + [1, 5, 6, 2], // Back-side trapezoid + + [0, 1, 2, 3], // Inner rectangle + + [4, 7, 6, 5], // Outer rectangle + + // These are not planar, so do with separate triangles. + [7, 2, 6], // Upper rectangle, bottom + [7, 3, 2], // Upper rectangle, top + + [0, 5, 1], // Lower rectangle, bottom + [0, 4, 5] // Lower rectangle, top + ] + ); + } else { + + // Rule for face ordering: look at polyhedron from outside: points must + // be in clockwise order. + polyhedron ( + points = [ + [-x_incr_inner/2, -inner_r, 0], // [0] + [x_incr_inner/2, -inner_r, z_incr], // [1] + [x_incr_inner/2, -inner_r, thread_size + z_incr], // [2] + [-x_incr_inner/2, -inner_r, thread_size], // [3] + + [-x_incr_outer/2, -outer_r, z0_outer], // [4] + [x_incr_outer/2, -outer_r, z0_outer + z_incr], // [5] + [x_incr_outer/2, -outer_r, thread_size - z0_outer + z_incr], // [6] + [-x_incr_outer/2, -outer_r, thread_size - z0_outer] // [7] + ], + + faces = [ + [0, 3, 7, 4], // This-side trapezoid + + [1, 5, 6, 2], // Back-side trapezoid + + [0, 1, 2, 3], // Inner rectangle + + [4, 7, 6, 5], // Outer rectangle + + // These are not planar, so do with separate triangles. + [7, 2, 6], // Upper rectangle, bottom + [7, 3, 2], // Upper rectangle, top + + [0, 5, 1], // Lower rectangle, bottom + [0, 4, 5] // Lower rectangle, top + ] + ); + } + } + } +} diff --git a/trap_cube.scad b/trap_cube.scad new file mode 100644 index 0000000..9675b10 --- /dev/null +++ b/trap_cube.scad @@ -0,0 +1,31 @@ +/* +// Height of trapazoid +height = 19; + +// Width of top cube +top_x = 30; +// Length of top cube +top_y = 34; + +// Width of bottom cube +bottom_x = 45; +// Length of bottom cube +bottom_y = 65; + +wall_thickness = 2; +*/ +module trap_cube(height = 19, top_x = 30, top_y = 34, bottom_x = 45, bottom_y = 65, wall_thickness = 2) { + difference(){ + hull(){ + translate([0,0,height]) + cube([top_x, top_y, 0.1], center=true); + cube([bottom_x, bottom_y, 0.1], center=true); + } + + hull(){ + translate([0,0,height]) + cube([top_x - wall_thickness, top_y - wall_thickness, 0.1], center=true); + cube([bottom_x - wall_thickness, bottom_y - wall_thickness, 0.1], center=true); + } + } +} \ No newline at end of file