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Printed screw_knob() is now fully customisable by passing a parameter

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list, constructed by screw_knob(), in place of the screw.

Screws can still be passed for backwards compaibility.
This commit is contained in:
Chris Palmer
2022-04-01 16:31:45 +01:00
parent b9f676a753
commit d46913ce4f
6 changed files with 116 additions and 41 deletions
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96
printed/screw_knob.scad
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@@ -23,49 +23,93 @@
include <../core.scad>
use <../utils/hanging_hole.scad>
knob_wall = 2;
function screw_knob_screw(type) = type[0]; //! The hex screw
function screw_knob_wall(type) = type[1]; //! Wall thickness
function screw_knob_stem_h(type) = type[2]; //! The stem height below the flange
function screw_knob_flange_t(type) = type[3]; //! The thickness of the flange
function screw_knob_flange_r(type) = type[4]; //! The flange outside radius
function screw_knob_solid(type) = type[5]; //! Is the flange solid or just a wall
function screw_knob_waves(type) = type[6]; //! Number of waves around the flange edge
function screw_knob_wave_amp(type) = type[7]; //! Wave amplitude
function screw_knob_fluted(type) = type[8]; //! Fluted instead of sine wave
function screw_knob(screw, wall = 2, stem_h = 6, flange_t = 4, flange_r = 9, solid = true, waves = 5, wave_amp = 2, fluted = false) = //! Constructor
[screw, wall, stem_h, flange_t, flange_r, solid, waves, wave_amp, fluted];
function knob_nut_trap_depth(screw) = round_to_layer(screw_head_height(screw));
knob_stem_h = 6;
knob_thickness = 4;
knob_r = 8;
knob_wave = 1;
knob_waves = 5;
knob_height = knob_stem_h + knob_thickness;
function knob_height() = knob_height;
function knob_height(type) = screw_knob_stem_h(type) + screw_knob_flange_t(type); //! Total height of the knob
module screw_knob(screw) { //! Generate the STL for a knob to fit the specified hex screw
knob_stem_r = nut_trap_radius(screw_nut(screw)) + knob_wall;
module screw_knob(type) { //! Generate the STL for a knob to fit the specified hex screw
type = !is_list(type[0]) ? screw_knob(type) : type; // Allow just the screw to be specified for backwards compatability
screw = screw_knob_screw(type);
wall = screw_knob_wall(type);
trap_r = nut_trap_radius(screw_nut(screw));
stem_r = trap_r + wall;
amp = screw_knob_wave_amp(type);
flange_r = max(screw_knob_flange_r(type), stem_r + amp);
flange_t = screw_knob_flange_t(type);
knob_h = knob_height(type);
waves = screw_knob_waves(type);
function wave(a) = knob_r + sin(a * knob_waves) * knob_wave;
function wave(a) = flange_r - amp / 2 + sin(a * waves) * amp / 2;
points = [for(a = [0 : 359]) wave(a) * [sin(a), cos(a)]];
solid = screw_knob_solid(type);
module shape()
if(screw_knob_fluted(type))
difference() {
circle(flange_r, $fn = 360);
c = flange_r * sin(90 / waves); // Flute half chord
d = flange_r - flange_r * cos(90 / waves); // Distance from chord to perimeter
b = amp - d; // Distance from chord to flute bottom
flute_r = (b^2 + c^2) / b / 2;
for(i = [0 : waves - 1])
rotate(360 * i / waves)
translate([0, flange_r - amp + flute_r])
circle(flute_r, $fn = 360);
}
else
polygon(points);
stl(str("screw_knob_M", screw_radius(screw) * 20))
union() {
render() difference() {
cylinder(r = knob_stem_r, h = knob_thickness + knob_stem_h);
cylinder(r = stem_r, h = knob_h);
hanging_hole(knob_nut_trap_depth(screw), screw_clearance_radius(screw))
rotate(45)
circle(r = nut_trap_radius(screw_nut(screw)), $fn = 6);
circle(r = trap_r, $fn = 6);
}
linear_extrude(knob_thickness, convexity = 3)
difference() {
polygon(points = [for(a = [0 : 359]) [wave(a) * sin(a), wave(a) * cos(a)]]);
for(i = [0 : 1])
linear_extrude(i ? flange_t : round_to_layer(wall), convexity = 3)
difference() {
shape();
circle(knob_stem_r - eps);
}
if(i && ! solid)
offset(-wall)
shape();
circle(stem_r - eps);
}
}
}
//! Place the screw through the printed part
module screw_knob_assembly(screw, length) //! Assembly with the screw in place
assembly(str("screw_knob_M", 20 * screw_radius(screw), "_", length), ngb = true) {
translate_z(knob_height)
vflip()
stl_colour(pp1_colour) screw_knob(screw);
module screw_knob_assembly(type, length) { //! Assembly with the screw in place
type = !is_list(type[0]) ? screw_knob(type) : type;
screw = screw_knob_screw(type);
knob_h = knob_height(type);
translate_z(knob_height - knob_nut_trap_depth(screw))
rotate(-45)
screw(screw, length);
assembly(str("screw_knob_M", 20 * screw_radius(screw), "_", length), ngb = true) {
translate_z(knob_h)
vflip()
stl_colour(pp1_colour) screw_knob(type);
translate_z(knob_h - knob_nut_trap_depth(screw))
rotate(-45)
screw(screw, length);
}
}
module screw_knob_M30_stl() screw_knob(M3_hex_screw);