226 lines
9.0 KiB
OpenSCAD
226 lines
9.0 KiB
OpenSCAD
// ====================================================================
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// Two-part self-watering flower pot, designed for PETG
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// ====================================================================
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// OUTER pot : watertight reservoir cup. Spiral ridges on the outside, smooth tapered inside, with a conical seat at the rim.
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// INNER pot : planter with drainage holes. Its conical underside rests on the seat, which leaves a water reservoir underneath. It lifts straight out (tapered fit, no snap that can jam).
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// ====================================================================
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/* [What to render] */
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part = "print"; // [print:Both parts laid out for printing, outer:Outer pot only, inner:Inner pot only, assembly:Assembled preview, section:Assembled cut-away preview]
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/* [Main dimensions (mm)] */
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// Outer diameter at the top, measured over the ridge crests
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pot_diameter = 100;
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// Height of the outer pot (rim included)
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pot_height = 100;
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// Bottom diameter / top diameter (1 = straight sides, lower = more taper)
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bottom_ratio = 0.8;
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/* [Reservoir, walls and fit] */
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// Water space between the outer floor and the underside of the inner pot
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reservoir_depth = 25;
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// Wall thickness (6 x 0.4 mm lines)
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wall = 2.4;
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// Floor thickness of both parts
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base_thickness = 2.4;
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// Gap between the inner pot and the outer pot (raise for a looser fit)
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clearance = 0.4;
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// Height of the collar that stands above the outer rim (also your finger grip)
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collar_height = 1;
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// Horizontal width of the conical seat at the top of the outer pot
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seat = 1.4;
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// Steepness of the seat, measured from vertical (smaller = steeper = easier to print; max 50)
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seat_angle = 40;
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/* [Spiral pattern] */
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// Number of ridges around the pot
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ridge_count = 12;
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// Peak-to-valley depth of the ridges
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ridge_depth = 2.4;
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// Total twist from bottom to top in degrees (negative = other direction)
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twist = 180;
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/* [Drainage holes in the inner pot] */
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hole_diameter = 5;
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// Centre-to-centre distance between holes
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hole_spacing = 12;
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// Keep-out distance between holes and the wall
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hole_margin = 3;
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/* [Hidden] */
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$fn = 1024;
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bottom_chamfer = 1.2; // height of the elephant-foot chamfer on the outer pot
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bottom_chamfer_run = 0.8; // its horizontal width (less than the height = under 45 degrees)
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inner_chamfer = 0.6; // horizontal width of the 1 mm high elephant-foot chamfer on the inner pot
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// ---------------------------------------------------------------------
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// Derived geometry
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// ---------------------------------------------------------------------
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Rt = pot_diameter / 2; // crest radius at the top
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Rb = Rt * bottom_ratio; // crest radius at the bottom
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s_top = Rt / Rb; // scale applied by the twisted extrusion
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Rv = Rt * (1 - ridge_depth / Rb); // valley radius at the top
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Cb = Rb - ridge_depth - wall; // cavity radius at z = 0
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Ct = Rv - wall; // cavity radius at z = pot_height
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zb = base_thickness + reservoir_depth; // z of the inner pot's underside
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m = (Ct - Cb) / pot_height; // slope of the cavity radius (taper)
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k = tan(seat_angle); // slope of the seat cone (radius per mm of height)
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seat_dz = seat / k; // vertical height of the seat
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z_seat = pot_height - seat_dz; // where the seat starts
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function lerp_z(a, b, z) = a + (b - a) * z / pot_height;
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function cav(z) = lerp_z(Cb, Ct, z); // outer pot: inner (cavity) radius
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function rb(z) = cav(z) - clearance; // inner pot: outer radius
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function env(z) = lerp_z(Rb, Rt, z); // crest radius
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r_seat_top = cav(z_seat) + seat; // seat radius at the rim height where the inner pot's wall meets the seat cone
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z1 = z_seat - clearance / (k - m);
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// ---------------------------------------------------------------------
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// Sanity checks
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// ---------------------------------------------------------------------
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rim_flat = Rv - r_seat_top;
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overhang = atan((ridge_depth / 2) * ridge_count * (abs(twist) * PI / 180 / pot_height) * s_top
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+ (Rt - Rb) / pot_height);
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assert(bottom_ratio > 0.4 && bottom_ratio <= 1, "bottom_ratio must be between 0.4 and 1");
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assert(pot_height > reservoir_depth + 2 * base_thickness + 30,
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"pot_height is too small for this reservoir_depth");
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assert(seat_angle > atan(m) + 5 && seat_angle <= 50,
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"seat_angle must be between about 10 and 50 degrees");
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assert(rim_flat >= 0.8,
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"Rim too thin: increase wall, or reduce seat / ridge_depth");
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assert(z1 > zb + 2,
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"Seat is too low for this reservoir_depth: reduce seat or increase pot_height");
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assert(Ct > hole_diameter, "pot_diameter is too small for these settings");
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echo(str("Outer pot, steepest outward overhang: about ", round(overhang), " deg (PETG prints well up to ~40-45)"));
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echo(str("Inner pot, steepest overhang: ", seat_angle, " deg (seat cone); no flat underside"));
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if (overhang > 45)
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echo("WARNING: ridges too steep. Reduce twist, ridge_depth or ridge_count.");
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echo(str("Flat rim width: ", rim_flat, " mm"));
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echo(str("Reservoir volume: about ", round(PI * pow(cav(zb / 2), 2) * reservoir_depth / 1000), " ml"));
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// ---------------------------------------------------------------------
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// OUTER pot
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// ---------------------------------------------------------------------
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module wavy_profile() {
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n = ridge_count * 16;
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polygon([for (i = [0 : n - 1])
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let (a = 360 * i / n,
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r = Rb - ridge_depth / 2 + (ridge_depth / 2) * cos(ridge_count * a))
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[r * cos(a), r * sin(a)]]);
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}
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module spiral_body() {
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linear_extrude(height = pot_height, twist = twist, scale = s_top,
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slices = max(ceil(pot_height / 2), ceil(abs(twist) / 2)),
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convexity = 10)
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wavy_profile();
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}
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// Chamfers the bottom edge only; follows the crest line elsewhere.
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module envelope() {
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rotate_extrude()
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polygon([[0, 0],
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[env(bottom_chamfer) - bottom_chamfer_run + 0.05, 0],
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[env(bottom_chamfer) + 0.05, bottom_chamfer],
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[Rt + 0.05, pot_height],
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[0, pot_height]]);
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}
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module outer_cavity() {
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rotate_extrude()
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polygon([[0, base_thickness],
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[cav(base_thickness), base_thickness],
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[cav(z_seat), z_seat],
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[r_seat_top + k, pot_height + 1], // conical seat, continued past the rim
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[0, pot_height + 1]]);
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}
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module outer_part() {
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difference() {
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intersection() {
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spiral_body();
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envelope();
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}
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outer_cavity();
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}
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}
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// ---------------------------------------------------------------------
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// INNER pot
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// ---------------------------------------------------------------------
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// The outside widens along the seat cone from the wall (z1) up to the rim, then rises as a vertical collar. Nothing hangs out horizontally.
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module inner_profile() {
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polygon([[0, zb],
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[rb(zb + 1) - inner_chamfer, zb], // bottom chamfer, under 45 degrees
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[rb(zb + 1), zb + 1],
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[rb(z1), z1],
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[r_seat_top, pot_height], // rests on the outer pot's seat
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[r_seat_top, pot_height + collar_height],
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[0, pot_height + collar_height]]);
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}
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module inner_cavity() {
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z0 = zb + base_thickness;
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rotate_extrude()
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polygon([[0, z0],
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[rb(z0) - wall, z0],
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[rb(pot_height) - wall, pot_height],
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[rb(pot_height) - wall, pot_height + collar_height + 1],
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[0, pot_height + collar_height + 1]]);
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}
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module drain_holes() {
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fr = rb(zb) - wall - hole_margin;
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rings = floor((fr - hole_diameter / 2) / hole_spacing);
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translate([0, 0, zb - 1])
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linear_extrude(height = base_thickness + 2)
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union() {
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circle(d = hole_diameter, $fn = 24);
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if (rings >= 1)
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for (k = [1 : rings]) {
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r = k * hole_spacing;
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n = floor(2 * PI * r / hole_spacing);
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for (i = [0 : n - 1])
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rotate(i * 360 / n + (k % 2) * 180 / n)
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translate([r, 0])
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circle(d = hole_diameter, $fn = 24);
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}
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}
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}
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module inner_part() {
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difference() {
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rotate_extrude() inner_profile();
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inner_cavity();
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drain_holes();
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}
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}
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// ---------------------------------------------------------------------
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// Output
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// ---------------------------------------------------------------------
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module assembled() {
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color("sienna") outer_part();
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color("seagreen") inner_part();
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}
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if (part == "outer")
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outer_part();
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else if (part == "inner")
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translate([0, 0, -zb]) inner_part(); // sits on the bed
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else if (part == "assembly")
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assembled();
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else if (part == "section")
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difference() {
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assembled();
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translate([-400, -400, -10]) cube([800, 400, pot_height + 100]);
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}
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else { // "print"
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outer_part();
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translate([pot_diameter + 10, 0, -zb]) inner_part();
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}
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