make sure corner rounding radius is big enough

[ozzloy@gmail.com/3d-printables] / 3030-dampener-feet.scad

/* GNU AGPLv3 (or later at your option)
   see bottom for more license info.
   please do not remove this notice. */

/* measurements from misumi's 3030 aluminum extrusion data sheet
   https://us.misumi-ec.com/pdf/fa/2012/p2_0545.pdf */

//$fn = 30; // use this while editing
$fn = 100; // use this for generating STL

foot_height = 18;
foot_length = 20;
wall_width = 2;
nub_depth = 4;
desired_corner_rounding_radius = 2/2.1;

// rounding radius needs to be just under half the size of the wall_width
maximum_corner_rounding_radius = wall_width / 2 - 0.1;
corner_rounding_radius =
  (desired_corner_rounding_radius < maximum_corner_rounding_radius)
  ?
  desired_corner_rounding_radius
  :
  maximum_corner_rounding_radius;

fudge = 0.1;
//fudge = 0.0;

// 3030 dimensions
x = 30; // adding a little because printers aren't perfect
y = 30; // adding a little because printers aren't perfect
opening_width = 8;

outer_block = (30 - 16.5) / 2;
wall = 2;

module ring(outer_radius, wall_width) {
  difference() {
    circle(outer_radius);
    circle(outer_radius - wall_width); } }

module fillet(r) {
   offset(-r) {
     offset(r) {
       children(); } } }

module round_corners(r) {
  fillet(r) { fillet(-r) { children(); } } }

module half_foot_2d() {
  // outer ring
  difference() {
    ring(foot_height + wall_width, wall_width);
    square(foot_height + wall_width);
    rotate(-45) {
      square(foot_height + wall_width); } }
  // upper connector, vertical 3030 holder
  translate([-wall_width, -wall_width]) {
    square([wall_width, foot_height + wall_width]); }
  // upper connecter, horizontal 3030 holder
  translate([-wall_width, -wall_width]) {
    square([wall_width + x / 2, wall_width]); }
  // bottom connector
  translate([cos(45) * foot_height,
             -(sin(45) * foot_height + wall_width)]) {
    square([x / 2 - cos(45) * foot_height, wall_width]); }
  // bottom nub, goes into bottom 3030 opening
  translate([(x - opening_width) / 2, 0]) {
    square([opening_width / 2, nub_depth]); }
  // side nub, goes into side 3030 openings
  a = opening_width;
  b = foot_height + wall_width - (y - opening_width) / 2;
  side_nub_length = (a < b) ? a : b;
  translate([0, (y - opening_width) / 2 + fudge]) {
    square([nub_depth, side_nub_length - fudge]); } }

module foot_2d() {
  round_corners(corner_rounding_radius) {
    translate([-x / 2, 0, 0]) {
      half_foot_2d(); }
    translate([x / 2, 0, 0]) {
      mirror() {
        half_foot_2d(); } } } }

module foot() {
  rotate(a = 0, v = [1, 0, 0]) {
    linear_extrude(height = foot_length) {
      foot_2d(); } } }

// half_foot_2d();
// foot_2d();
foot();

/*
  This file is part of 3d-printables.

  3d-printables is free software: you can redistribute it and/or modify
  it under the terms of the GNU Affero General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.

  3d-printables is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU Affero General Public License for more details.

  You should have received a copy of the GNU Affero General Public License
  along with challenge-bot.  If not, see <http://www.gnu.org/licenses/>.
*/