From 25836f14f59bdeb216a6fb189b6c4720db518c0d Mon Sep 17 00:00:00 2001 From: Michael Krelin Date: Sat, 04 Feb 2017 18:00:01 +0000 Subject: Initial --- diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..c25a6bd --- a/dev/null +++ b/.gitignore @@ -0,0 +1,3 @@ +/Makefile.local +/*.stl +/*.gcode diff --git a/Makefile b/Makefile new file mode 100644 index 0000000..9444a03 --- a/dev/null +++ b/Makefile @@ -0,0 +1,22 @@ +-include Makefile.local + +OPENSCAD_APP?=/Applications/OpenSCAD.app +OPENSCAD_BIN?=${OPENSCAD_APP}/Contents/MacOS/OpenSCAD +OPENSCAD_FLAGS=-D draft=false + +default: + @echo "And?" + +clean: + rm -f *.stl *.gcode + +stl-another-%: + $(MAKE) another-$*-{body,lever}.stl + +another-%-body.stl: another-%.scad another.scad + $(OPENSCAD_BIN) $(OPENSCAD_FLAGS) -D 'what="body"' -o "$@" "$<" +another-%-lever.stl: another-%.scad another.scad + $(OPENSCAD_BIN) $(OPENSCAD_FLAGS) -D 'what="lever"' -o "$@" "$<" + +%.stl: %.scad + ${OPENSCAD_BIN} ${OPENSCAD_FLAGS} -o "$@" "$<" diff --git a/another-E0.scad b/another-E0.scad new file mode 100644 index 0000000..2f639b9 --- a/dev/null +++ b/another-E0.scad @@ -0,0 +1,13 @@ +use ; + +what="body"; +vitamins=false; + +rotate([180,0,0]) +the_extruder(what=what, vitamins=vitamins, + + left=true, + pulley_d=12.65, pulley_elevation=1, + teeth_elevation = 7.88, + bore_l = 20 +); diff --git a/another-E1.scad b/another-E1.scad new file mode 100644 index 0000000..bbd42f0 --- a/dev/null +++ b/another-E1.scad @@ -0,0 +1,13 @@ +use ; + +what="body"; +vitamins=false; + +rotate([180,0,0]) +the_extruder(what=what, vitamins=vitamins, + + left=false, + pulley_d=11.5, pulley_elevation=1, + teeth_elevation=7.5, + bore_l=17.6 +); diff --git a/another.scad b/another.scad new file mode 100644 index 0000000..f78d1b0 --- a/dev/null +++ b/another.scad @@ -0,0 +1,300 @@ +draft=true; +layer_height=0.2; extrusion_width=0.4; +epsilon=0.01; +$fs=0.0125; + +use ; +module pushfit_thread(h=10) { + thr = 3/8 + .5/25.4; + slit = 25.4*thr/2 + 0.4; + if(draft) cylinder(d=thr*25.4,h=h); + else english_thread(diameter=thr,threads_per_inch=28,length=h/25.4,internal=true); + translate([-2,-slit,0]) cube([4,2*slit,h]); +} + +module the_extruder( + // motor properties + gearbox_d = 36, + mount_d = 28, // the distance between opposite mounting holes + mounthole_depth = 5, + protrusion_d = 22, protrusion_h = 2.2, // the dimensions of the protrusion on top of gearbox + bore_d = 8, bore_l = 17.6, + // pulley properties + pulley_d = 11.5, pulley_h=10, + pulley_elevation = 1, // pulley elevation above the protrusion + teeth_elevation = 7.5, // distance from the bottom of the pulley to its teeth + // idler properties + idler_d = 9.5, idler_h = 4, idler_id = 3, // idler dimensions: outer and inner diameters and height + // spring properties + spring_d = 10, spring_lc = 9.6, // spring diameter and compressed length + // filament path properties + filament_d = 1.75, + filament_path_d = 2, + filament_guide_d = 4, // PTFE filament guide diameter + + // screw it + mount_screw_d = 3, mount_screw_l = 20, + mount_screwhead_d=6, mount_screwhead_h=3, + + // empty spaces + idler_travel = 3, // how far should idler travel when pressed + idler_clearance=1, + pulley_clearance=2, + lever_v_clearance=.7, // vertical clearance for the lever + spring_d_clearance=1, + protrusion_tolerance_h=.5, // horizontal tolerance for the motor protrusion + protrusion_tolerance_v=.5, // vertical tolerance for the motor protrusion + mount_screw_d_tolerance=.5, + idler_v_tolerance=.5, + + what="lever", + left=false, + vitamins = true +) { + lever_shell = mount_screwhead_h+0.5; + lever_thickness=max(spring_d+layer_height*8,idler_h+idler_v_tolerance+2*lever_shell); + lsd = idler_d-idler_clearance*2; + longwing=gearbox_d/2+spring_d/2+lsd/2; + h_ = (pulley_d+idler_d)/(2*sqrt(2)); + ri = sqrt( pow(h_,2) + pow(mount_d/2-h_,2) ); + spring_dl = idler_travel*longwing/ri; + + module mirrorleft() { + mirror([left?0:1,0,0]) children(); + } + module place_idler() { + rotate([0,0,45]) + translate([(pulley_d+idler_d)/2,0,0]) + children(); + } + module finger_indent(d=lever_thickness,depth/*=1*/,r/*=15*/) { + if(depth) { + hh = (-4*pow(depth,2)+pow(d,2))/(8*depth); + rr = depth+hh; + translate([0,0,hh]) sphere(r=rr,$fn=2*PI*rr); + }else if(r) { + hh=sqrt(pow(r,2)-pow(d,2)/4); + translate([0,0,hh]) sphere(r=r,$fn=2*PI*r); + } + } + + // vitamins + % if(vitamins) mirrorleft() { + translate([0,0,-epsilon]) mirror([0,0,1]) cylinder(d=gearbox_d,h=1,$fn=60); + for(zr=[0:90:359]) rotate([0,0,zr]) translate([mount_d/2,0,0]) + cylinder(d=mount_screw_d,h=20,$fn=30); + translate([0,0,-epsilon]) cylinder(d=protrusion_d,h=protrusion_h,$fn=30); + translate([0,0,protrusion_h]) { + cylinder(d=bore_d,h=bore_l,$fn=30); + translate([0,0,pulley_elevation]) { + cylinder(d=pulley_d,h=pulley_h,$fn=30); + translate([0,0,teeth_elevation]) { + place_idler() { + cylinder(d=idler_d,h=idler_h,center=true,$fn=30); + cylinder(d=idler_id,h=lever_thickness+2,center=true,$fn=30); + }//place idler + // filament path + rotate([0,0,45]) translate([(pulley_d-filament_path_d)/2,0,0]) { + rotate([90,0,0]) cylinder(d=filament_d,h=gearbox_d*2,center=true,$fn=15); + rotate([-90,0,0]) + translate([0,0,mount_d/sqrt(2)/2+mount_screw_d]) + pushfit_thread(); + } + }//translate teeth + }//translate pulley + }//translate protrusion + }// vitamins to let + + module lever() { + translate([0,0,protrusion_h+pulley_elevation+teeth_elevation]) { + difference() { + union() { + hull() { + place_idler() + cylinder(d=lsd,h=lever_thickness,center=true,$fn=60); + translate([mount_d/2,0,0]) + cylinder(d=lsd,h=lever_thickness,center=true,$fn=60); + }//hull + hull() { + translate([mount_d/2,0,0]) + cylinder(d=lsd,h=lever_thickness,center=true,$fn=60); + translate([mount_d/2,-longwing,0]) rotate([0,90,0]) + cylinder(d=lever_thickness,h=lsd,center=true,$fn=60); + }//hull + }//union + + // filament path + place_idler() translate([-(idler_d+filament_path_d)/2,0,0]) rotate([90,0,0]) { + cylinder(d=filament_path_d,h=3*gearbox_d,center=true,$fn=30); + translate([0,-filament_path_d/2/sqrt(2),0]) rotate([0,0,45]) + cube(size=[filament_path_d/2,filament_path_d/2,3*gearbox_d],center=true); + } + + // idler space and mounting hole + place_idler() { + difference() { + cylinder(d=idler_d+idler_clearance*2,h=idler_h+idler_v_tolerance,center=true,$fn=60); + // supports + for(y=[-lsd/2+extrusion_width:(lsd-2*extrusion_width)/3:lsd/2-extrusion_width]) + translate([-lsd/2-1,y-extrusion_width/2,-idler_h/2-idler_v_tolerance/2-1]) + cube(size=[lsd+2,extrusion_width,idler_h+idler_v_tolerance+2]); + } + cylinder(d=mount_screw_d+mount_screw_d_tolerance,h=lever_thickness+2,center=true,$fn=30); + translate([0,0,lever_thickness/2-mount_screwhead_h]) + cylinder(d=mount_screwhead_d,h=mount_screwhead_h+1,$fn=2*PI*mount_screwhead_d); + } + // mounting screw hole + translate([mount_d/2,0,0]) + cylinder(d=mount_screw_d+mount_screw_d_tolerance,h=lever_thickness+2,center=true,$fn=2*PI*mount_screw_d); + + // lever end + translate([mount_d/2,0,0]) rotate([0,90,0]) { + translate([0,-longwing,lsd/2]) finger_indent(d=lever_thickness-1,r=15); + translate([0,-longwing,0]) + mirror([0,0,1]) + difference() { + cylinder(d=spring_d+spring_d_clearance,h=lsd,$fn=2*PI*spring_d); + sphere(d=spring_d*3/4,$fn=PI*spring_d); + } + }//rotate-translate + }//difference + // bridging patch + place_idler() + translate([0,0,lever_thickness/2-mount_screwhead_h]) + mirror([0,0,1]) + cylinder(d=mount_screwhead_d,h=layer_height); + }//translate + }//lever module + + module body() { + filament_elevation=protrusion_h+pulley_elevation+teeth_elevation; + ls_z = filament_elevation; + body_h = max(protrusion_h+bore_l,mount_screw_l-mounthole_depth/2+mount_screwhead_h,ls_z*2); + ls_h = lever_thickness+lever_v_clearance; + difference() { + union() { + cylinder(d=gearbox_d,h=body_h,$fn=2*PI*gearbox_d); + // finger and spring support + fsw = gearbox_d/2+mount_screwhead_d/2; + translate([-gearbox_d/2,0,0]) difference() { + union() { + hull() { + translate([0,-longwing,ls_z]) + rotate([0,90,0]) + cylinder(d=lever_thickness,h=fsw,$fn=2*PI*lever_thickness); + hh=body_h-ls_z; + translate([0,0,ls_z-lever_thickness/2]) + mirror([0,1,0]) cube(size=[fsw,longwing-hh+lever_thickness/sqrt(2),hh+lever_thickness/2]); + hhh=ls_z; + translate([0,0,0]) + mirror([0,1,0]) cube(size=[fsw,longwing-hhh+lever_thickness/sqrt(2),hhh+lever_thickness/2]); + } + } + translate([0,-longwing,ls_z]) rotate([0,-90,0]) + finger_indent(d=lever_thickness-1,r=15); + } // translate + + // pushfit bracket + translate([0,0,filament_elevation]) + rotate([0,0,45]) translate([pulley_d/2,0,0]) + rotate([-90,0,0]) + translate([0,0,mount_d/sqrt(2)/2+mount_screw_d-gearbox_d/2/*TODO:*/]) + cylinder(r=min(body_h-filament_elevation,filament_elevation)/sin(60)-epsilon,h=10+gearbox_d/2/*TODO:*/,$fn=6); + }//union (first child of difference) + // protrusion + translate([0,0,-1]) + cylinder(d=protrusion_d+protrusion_tolerance_h,h=protrusion_h+protrusion_tolerance_v+1,$fn=2*PI*protrusion_d); + // mount screw holes + for(zr=[0:90:359]) rotate([0,0,zr]) translate([mount_d/2,0,0]) { + translate([0,0,mount_screw_l-mounthole_depth/2-layer_height-1]) + mirror([0,0,1]) + cylinder(d=mount_screw_d+mount_screw_d_tolerance, + h=mount_screw_l-mounthole_depth/2-layer_height+1, + $fn=2*PI*mount_screw_d); + translate([0,0,mount_screw_l-mounthole_depth/2]) + cylinder(d=mount_screwhead_d,h=body_h+1,$fn=2*PI*mount_screwhead_d); + }//for + // pushfit threads + translate([0,0,filament_elevation]) + rotate([0,0,45]) translate([pulley_d/2,0,0]) + rotate([-90,0,0]) + translate([0,0,mount_d/sqrt(2)/2+mount_screw_d+epsilon]) + rotate([0,0,180]) { + pushfit_thread(h=10); + cylinder(d=filament_guide_d,h=gearbox_d,center=true,$fn=2*PI*filament_guide_d); + translate([0,-filament_guide_d/2/sqrt(2),0]) + rotate([0,0,45]) + cube(size=[filament_guide_d/2,filament_guide_d/2,gearbox_d],center=true); + } + // pulley + cylinder(d=pulley_d+pulley_clearance,h=body_h+1,$fn=2*PI*(pulley_d+pulley_clearance)); + // leverspace + hull() for(x=[0,gearbox_d]) + rotate([0,0,45]) + translate([x,0,ls_z-ls_h/2]) + cylinder(d=idler_d+idler_clearance,h=ls_h,$fn=2*PI*idler_d); + + a=cos(45)*(pulley_d+idler_d)/2; + b=mount_d/2-a; + x=sqrt(pow(a,2)+pow(b,2)); + translate([mount_d/2,0,ls_z]) + intersection() { + r = x+idler_d/2+1;/* TODO: */ + cylinder(r=r,h=ls_h,center=true); + translate([-r-1,0,-1]) cube(size=[2*r+2,r+1,ls_h+2]); + } + + rotate([0,0,-45]) + translate([0,0,ls_z-ls_h/2]) + cube(size=[gearbox_d,gearbox_d,lever_thickness+lever_v_clearance]); + translate([0,0,ls_z-ls_h/2]) { + translate([mount_screwhead_d/2,0,0]) + mirror([0,1,0]) + cube(size=[gearbox_d,gearbox_d/2+1,lever_thickness+lever_v_clearance]); + } + //translate([-mount_d/2,-longwing,filament_elevation]) + translate([mount_d/2,-longwing,filament_elevation]) + rotate([0,-90,0]) difference() { + cylinder(d=spring_d+spring_d_clearance,h=spring_lc+spring_dl,$fn=PI*spring_d); + translate([0,0,spring_lc+spring_dl]) sphere(d=spring_d*3/4,$fn=PI*spring_d); + } + //sphere(d=spring_d*3/4,$fn=PI*spring_d); + *difference() { + // spring support + translate([0,-longwing,filament_elevation]) + sphere(d=spring_d*3/4,$fn=PI*spring_d); + } + + }//difference + + intersection() { + difference() { + translate([0,0,ls_z-ls_h/2-epsilon]) + cylinder(d=gearbox_d,h=ls_h+2*epsilon,$fn=2*PI*gearbox_d); + cylinder(d=pulley_d+pulley_clearance,h=body_h+1,$fn=2*PI*(pulley_d+pulley_clearance)); + } + // supports + // TODO: hardcoded stuff below… + if(false) { // parallel + for(y=[-gearbox_d:4:gearbox_d]) + translate([0,y-extrusion_width/2,0]) + cube(size=[gearbox_d,extrusion_width,body_h]); + }else{ // radial + for(zr=[-65:(65+50)/7:50]) + rotate([0,0,zr]) translate([0,-extrusion_width/2,0]) + cube(size=[gearbox_d,extrusion_width,body_h]); + } + } + + }//body module + + mirrorleft() + if(what=="lever") color("green",0.7) lever(); + else if(what=="body") color("yellow",0.7) body(); + else if(what=="both") { + color("green",0.7) lever(); + color("yellow",0.7) body(); + } +} + +the_extruder(what="both",left=false); diff --git a/threads.scad b/threads.scad new file mode 100644 index 0000000..8dd0b7b --- a/dev/null +++ b/threads.scad @@ -0,0 +1,332 @@ +/* + * ISO-standard metric threads, following this specification: + * http://en.wikipedia.org/wiki/ISO_metric_screw_thread + * + * Dan Kirshner - dan_kirshner@yahoo.com + * + * You are welcome to make free use of this software. Retention of my + * authorship credit would be appreciated. + * + * 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)); + + +// ---------------------------------------------------------------------------- +// 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) size 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/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). +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) +{ + // 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 * cos (angle); + + h_fac1 = (square || rectangle) ? 0.90 : 0.625; + + // External thread includes additional relief. + h_fac2 = (square || rectangle) ? 0.95 : 5.3/8; + + 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. + tapered_diameter = diameter - length*taper; + 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); + } + } +} + + +// ---------------------------------------------------------------------------- +// 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) +{ + // 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); +} + +// ---------------------------------------------------------------------------- +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 (current_diameter/2, pitch, internal, n_starts, + thread_size, groove, square, rectangle, angle); + } + } + } +} + + +// ---------------------------------------------------------------------------- +// z (see diagram) as function of current radius. +// (Only good for first half-pitch.) +function z_fct (current_radius, radius, pitch, angle) + = 0.5* (current_radius - (radius - 0.875*pitch*cos (angle))) + /cos (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 * cos (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 = z_fct (outer_r, radius, thread_size, 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 + ] + ); + } + } + } +} + + -- cgit v0.9.0.2