3dprint/screw_gear.scad

48 lines
2.0 KiB
OpenSCAD

translate([-40, 0, 0]) mirror() rotate([0, 0, 180]) screw_gear(8, 4, 2, 2, 8, 18, 32);
difference() {
union() {
for (i=[1:10]) rotate([0, 0, 360*i/10]) screw_gear(8, 6, 2, 60, 64, 18, 64);
}
// translate([-50, 0, 0]) cube(size=[100,100,100]);
}
#difference() {
translate([-15, 0, 0]) mirror() rotate([0, 0, 360/2/10]) {
union() {
for (i=[1:10]) rotate([0, 0, 360*i/10]) screw_gear(8, 6, 2, 60, 64, 18, 64);
}
}
// translate([-50, 0, 0]) cube(size=[100,100,100]);
}
module screw_gear(outer_radius, inner_radius, outer_thickness, inner_thickness, thread_length, precision, total_length)
{
linear_extrude(height=total_length, twist=360*total_length/thread_length, slices=360)
polygon(
points = screw_crosssection(outer_radius, inner_radius, outer_thickness, inner_thickness, thread_length, precision),
paths = [ range((precision+precision)*2) ]
);
}
function screw_crosssection(outer_radius, inner_radius, outer_thickness, inner_thickness, thread_length, precision) =
concat(
[ for (x=[1 : precision]) polar(outer_radius, 360*outer_thickness/thread_length*x/precision - outer_thickness/2/thread_length*360) ],
[ for (x=[1 : precision])
polar(
outer_radius-(outer_radius-inner_radius)*x/precision,
outer_thickness/2/thread_length*360 + 360*(1-outer_thickness/thread_length-inner_thickness/thread_length)/2*x/precision
)
],
[ for (x=[1 : precision]) polar(inner_radius, 180 + 360*inner_thickness/thread_length*x/precision - inner_thickness/2/thread_length*360) ],
[ for (x=[1 : precision])
polar(
inner_radius+(outer_radius-inner_radius)*x/precision,
180 + inner_thickness/2/thread_length*360 + 360*(1-outer_thickness/thread_length-inner_thickness/thread_length)/2*x/precision
)
]
);
function polar(r,theta) = r*[sin(theta), cos(theta)]; // convert polar to cartesian coordinates
function range(n) = [ for(x = [0 : n-1]) x ];