145 lines
3.5 KiB
OpenSCAD
145 lines
3.5 KiB
OpenSCAD
include <MCAD/math.scad>;
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include <lib.scad>;
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stock_color = "#aaa4";
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bushing_od = 12;
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bushing_id = 8;
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bushing_len = 8;
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nema17_face = 42.3;
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module colorize(colorname) {
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if (use_colors) {
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color(colorname) union() { children(); }
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} else {
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children();
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}
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}
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module bushing() {
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bom_item(printable=false, label="Bushing");
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colorize(stock_color) render() {
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difference() {
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cylinder(d = bushing_od, h = bushing_len);
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translate([0,0,-1])
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cylinder(d = bushing_id, h = bushing_len + 2);
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}
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}
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}
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// located with the shaft in +z, face on the XY plane
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module nema17(depth = 23.5) {
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bom_item(printable=false, label="NEMA-17 stepper motor");
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face = 42.3;
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screw_pitch = 31 / 2;
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color(stock_color)
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render()
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difference() {
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union() {
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translate([-face/2, -face/2, -depth])
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cube([face, face, depth]);
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translate([0,0,-1]) {
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cylinder(d=22, h=2+1);
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cylinder(d=5, h=22+1);
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}
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}
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translate([1.25, -5, 4])
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cube([10, 10, 20]);
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// screw holes
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for (x = [-screw_pitch, screw_pitch],
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y = [-screw_pitch, screw_pitch]) {
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translate([x,y,-10])
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cylinder(d=5,h=20);
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}
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}
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}
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// belts and pulleys
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belt_pitch = 2; // 2mm tooth width for GT2 = 2mm pitch
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belt_width = 6;
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belt_thickness = 1.38;
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belt_pld = 0.254; // distance between line of fixed length and tips of gear teeth
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belt_backing = 0.63 - belt_pld;
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tooth_height = 0.75;
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pulley_od = 13;
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pulley_clearance_rad = pulley_od / 2 + 2.5;
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module pulley(teeth, lrim, urim, belt_width, shaft=5, toothed=true, od = 0) {
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bom_item(printable=false, label=str(
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toothed ? "pulley(" : "idler(",
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"teeth=", teeth, ", ",
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"flange1=", min(lrim, urim), "mm, ",
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"flange2=", max(lrim, urim), "mm, ",
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"channel=", belt_width, "mm, ",
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"shaft=", shaft, "mm",
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")"
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));
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nominal_rad = belt_pitch * teeth / TAU;
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inner_rad = nominal_rad - belt_pld;
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outer_rad = (od > 0) ? od / 2 : nominal_rad + belt_backing;
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minor_rad = inner_rad - tooth_height;
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mid_rad = inner_rad - tooth_height / 2;
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idler_rad = nominal_rad - belt_backing;
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dtheta = 180 / teeth;
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tooth_points = [
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for (i = [1:1:teeth])
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let (theta = i * 360 / teeth)
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each [
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[sin(theta) * minor_rad, cos(theta) * minor_rad],
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[sin(theta) * inner_rad, cos(theta) * inner_rad],
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[sin(theta + dtheta) * inner_rad, cos(theta + dtheta) * inner_rad],
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[sin(theta + dtheta) * minor_rad, cos(theta + dtheta) * minor_rad]
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]
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];
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//echo([each [0:1:teeth]]);
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//echo(tooth_points);
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colorize(stock_color)
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render()
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difference() {
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union() {
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cylinder(r=outer_rad, h=lrim);
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translate([0,0,lrim])
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if (toothed) {
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linear_extrude(belt_width)
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polygon(tooth_points, convexity = teeth * 2 + 4);
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} else {
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cylinder(r = idler_rad, h = belt_width);
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}
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translate([0,0,lrim + belt_width])
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cylinder(r=outer_rad, h=urim);
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}
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translate([0,0,-1])
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cylinder(d=shaft, h=belt_width + lrim + urim + 2);
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}
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}
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idler_zmargin = [ 6.4 / 2 + 1.05, 6.4 / 2 + 1.05 ];
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module idler(height=0, toothed=false) {
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// pulley(20, 1.05, 1.05, 6.4, toothed=toothed, od=18);
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translate([0,0, height-idler_zmargin[0]])
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pulley(16, 1.05, 1.05, 6.4, shaft=3, toothed=toothed, od=13);
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}
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active_pulley_zmargin = [ 9.5, 4.5 ];
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module active_pulley(height=0) {
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translate([0,0,-active_pulley_zmargin[0] + height])
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pulley(16,6,1,7, od=13);
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}
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// required distance between centers of pulley and idler for an S-bend with right angles.
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pulley_sbend_offset = (9.5 + 9.7) / 2 + 0.63;
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//!pulley(12, 6, 2, toothed=false); |