-rw-r--r-- | .gitignore | 3 | ||||
-rw-r--r-- | Makefile | 22 | ||||
-rw-r--r-- | another-E0.scad | 13 | ||||
-rw-r--r-- | another-E1.scad | 13 | ||||
-rw-r--r-- | another.scad | 300 | ||||
-rw-r--r-- | threads.scad | 332 |
6 files changed, 683 insertions, 0 deletions
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} ${OPENSCAD_FLAGS} -o "$@" "$<" diff --git a/another-E0.scad b/another-E0.scad new file mode 100644 index 0000000..2f639b9 --- a/dev/null +++ b/another-E0.scad @@ -0,0 +1,13 @@ +use <another.scad>; + +what="body"; +vitamins=false; + +rotate([180,0,0]) +the_extruder(what=what, vitamins=vitamins, + + left=true, + pulley_d=12.65, pulley_elevation=1, + teeth_elevation = 7.88, + bore_l = 20 +); diff --git a/another-E1.scad b/another-E1.scad new file mode 100644 index 0000000..bbd42f0 --- a/dev/null +++ b/another-E1.scad @@ -0,0 +1,13 @@ +use <another.scad>; + +what="body"; +vitamins=false; + +rotate([180,0,0]) +the_extruder(what=what, vitamins=vitamins, + + left=false, + pulley_d=11.5, pulley_elevation=1, + teeth_elevation=7.5, + bore_l=17.6 +); diff --git a/another.scad b/another.scad new file mode 100644 index 0000000..f78d1b0 --- a/dev/null +++ b/another.scad @@ -0,0 +1,300 @@ +draft=true; +layer_height=0.2; extrusion_width=0.4; +epsilon=0.01; +$fs=0.0125; + +use <threads.scad>; +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
+ ]
+ );
+ }
+ }
+ }
+}
+
+
|