Jerry
82 lines
2.5 KiB
OpenSCAD
82 lines
2.5 KiB
OpenSCAD
include <BOSL2/std.scad>
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/* [Main Dimensions] */
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// Outer diameter of the impeller back-plate
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impeller_diameter = 90; // [50:1:150]
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// Diameter of the central bore hole
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bore_diameter = 12; // [4:0.5:30]
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// Thickness of the main back-plate
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backplate_thickness = 3; // [1:0.5:10]
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/* [Hub Dimensions] */
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// Outer diameter of the raised central hub
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hub_diameter = 26; // [15:1:50]
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// Total height of the hub from the bottom of the back-plate
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hub_height = 20; // [10:1:60]
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/* [Blade Parameters] */
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// Number of backward-curved blades
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blade_count = 7; // [3:1:15]
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// Height of the blades above the back-plate
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blade_height = 12; // [2:1:40]
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// Thickness of each blade
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blade_thickness = 3; // [1:0.5:8]
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// The angle (in degrees) that the blades sweep backwards
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sweep_angle = 75; // [10:1:180]
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/* [Appearance] */
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part_color = "#B0C4DE"; // LightSteelBlue
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$fn = 64;
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module centrifugal_impeller() {
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difference() {
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union() {
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// Back-plate
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cyl(d=impeller_diameter, l=backplate_thickness, chamfer1=1, anchor=BOTTOM);
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// Raised Hub
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cyl(d=hub_diameter, l=hub_height, chamfer2=1.5, anchor=BOTTOM);
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// Blades (logarithmic spiral for constant incidence angle)
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// Inner radius overlaps the hub slightly to ensure a solid union
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blade_inner_r = (hub_diameter / 2) - 0.5;
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// Outer radius stops slightly short of the rim so the round endcaps don't overhang
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blade_outer_r = (impeller_diameter / 2) - (blade_thickness / 2);
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steps = 48; // Curve resolution
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// Calculate the 2D path of the sweeping blade
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pts = [
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for(i = [0 : steps])
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let(
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t = i / steps,
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r = blade_inner_r * pow(blade_outer_r / blade_inner_r, t),
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a = -sweep_angle * t
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)
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[r * cos(a), r * sin(a)]
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];
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// Distribute and extrude the 7 blades
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for(i = [0 : blade_count - 1]) {
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zrot(i * 360 / blade_count)
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up(backplate_thickness)
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linear_extrude(height = blade_height)
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stroke(pts, width=blade_thickness, endcaps="round");
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}
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}
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// Central Bore (subtracted at the end to ensure a clean hole through hub and blades)
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down(1)
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cyl(d=bore_diameter, l=hub_height + 2, anchor=BOTTOM);
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}
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}
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color(part_color)
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centrifugal_impeller(); |