scad/strain_relief.scad

   1 //-- Stepper mounted extruder cable harness strain relief
   2 //-- with nylon ties
   3 //-- by AndrewBCN - Barcelona, Spain - December 2014
   4 //-- GPLV3
   5
   6 //-- I designed this for use with Marty Rice's awesome
   7 //-- Direct Drive Extruder which I have installed on my
   8 //-- P3Steel, but it can probably be used for many other
   9 //-- extruder setups. Simple fact is,  there is a thick
  10 //-- bunch of electrical wires that comes out of the extruder, go
  11 //-- around the top of the printer and then down to the
  12 //-- RAMPS electronics. All this moves left and right together
  13 //-- with the X-carriage and common sense dictates that a strain
  14 //-- relief is required to avoid wire breakage and the usual
  15 //-- disastrous consequences.
  16 //-- I have designed this strain relief so that it is very easy
  17 //-- to install even after everything is in place. It requires
  18 //-- one long and two short nylon ties, the long one goes around
  19 //-- the stepper and the two shorter ones are tightened around the
  20 //-- cable harness.
  21
  22 //-- Some tweaks by MRice - I made the bit around the cables
  23 //-- curved so that it would grab a little better, and
  24 //-- parameterized the larger ziptie cut and then made it a
  25 //-- little wider than the original.
  26
  27 //-- Parameters
  28 large_ziptie_w = 6;
  29 small_ziptie_w = 3;
  30 mount_w = 4 + large_ziptie_w;
  31
  32
  33 //-- Modules
  34 module ziptie_groove() {
  35   rotate([90,0,0]) difference() {
  36         cylinder(r=12,h=small_ziptie_w);
  37         translate([0,0,-1]) cylinder(r=10,h=small_ziptie_w+2);
  38   }
  39 }
  40
  41 module strf() {
  42   // stepper mount
  43   difference() {
  44     union() {
  45       union() {
  46             cube([17.2,6,mount_w]);
  47        translate([17.2,0,0]) rotate([0,0,45]) cube([6,6,mount_w]);
  48       }
  49       mirror([1,0,0]) union() {
  50          cube([17.2,6,mount_w]);
  51             translate([17.2,0,0]) rotate([0,0,45]) cube([6,6,mount_w]);
  52       }
  53     }
  54     // tunnel for nylon tie
  55     translate([-25,2.2,mount_w/2-large_ziptie_w/2]) cube([50,large_ziptie_w/3,large_ziptie_w]);
  56     // delete some useless material
  57     translate([-30.4,-1,-.5]) cube([10,10,mount_w+1]);
  58     mirror([1,0,0]) translate([-30.4,-1,-.5]) cube([10,10,mount_w+1]);
  59   }
  60   // arm
  61   difference() {
  62     union() {
  63       translate([7,0,7]) cube([6,6,28]);
  64       translate([7,6,25]) cube([6,6,10]);
  65       translate([7,0,33]) rotate([0,45,0]) cube([6,12,10]);
  66       translate([13,0,33]) mirror([1,0,0]) rotate([0,45,0]) cube([6,12,10]);
  67       translate([7,0,33]) cube([6,12,10]);
  68     }
  69     // cup to hold harness
  70     translate([10,16,49.5]) rotate([90,0,0]) scale([1,1.4,1]) #cylinder(r=9, h=18,$fn=40);
  71     // save some material
  72     translate([4,13.08,17.9]) rotate([45,0,0]) cube([10,10,10]);
  73     // tunnels for nylon ties
  74     translate([10,4,46]) #ziptie_groove();
  75     translate([10,11,46]) #ziptie_groove();
  76   }
  77 }
  78
  79 //-- Print the part
  80 rotate([90,0,0]) strf();