belt-slot-cut-jig.scad

   1 // -*- C -*-
   2
   3 // todo
   4 //  various registration marks
   5 //   protrustions at ends at strap width and middle
   6 //   grooves on top face at 1/4,1/2,3/4 length and 1/2 width
   7
   8 crewpunch_slop = 0.3;
   9
  10 holder_min_wall = 2;
  11 holder_attach_near_wall = 5;
  12
  13 holder_attach_xsz = 5;
  14 holder_ctie_width = 4.0 + 0.5;
  15 holder_ctie_thick = 3.0 + 0.5;
  16 holder_attach_walls = 3;
  17 holder_attach_roof = 2.5;
  18
  19 holder_corner_round = 2.0;
  20
  21 jig_interval = 25;
  22 strap_width = 26.75 + 0.7;
  23 strap_thick = 3;
  24 edgewall_width = 3;
  25
  26 punch_travel = 8;
  27
  28 main_slop = 0.25;
  29
  30 jig_max_len = 160; // print diagonally
  31 //jig_max_len = 30;
  32
  33 registrationgroove_width = 0.8;
  34 registrationgroove_depth = 1.2;
  35
  36 registrationprotrusion_poke = 3;
  37 registrationprotrusion_slope = 0.75;
  38
  39 jig_overlap = 1;
  40
  41 // from careful measurement
  42
  43 crewpunch_shape =
  44   [[  6, [0.6, 6.0], [1.6, 12.3] ],
  45    [  8, [1.1, 6.2], [1.9, 12.5] ],
  46    [ 10, [1.6, 6.5], [2.1, 12.8] ],
  47    [ 12, [1.8, 6.6], [2.3, 12.7] ],
  48    [ 14, [2.1, 6.8], [2.6, 13.0] ],
  49    [ 16, [2.4, 6.9], [2.7, 13.2] ],
  50    [ 18, [2.5, 7.0], [2.9, 13.3] ],
  51    [ 22, [3.1, 7.1], [3.2, 13.4] ],
  52    [ 26, [3.3, 7.2], [3.5, 13.6] ],
  53    ];
  54
  55 crewpunch_shaft_max_y = 7.5;
  56
  57 crewpunch_systematic_size_error = +0.36;
  58
  59 crewpunch_smallest_shape = crewpunch_shape[0];
  60 crewpunch_biggest_shape = crewpunch_shape[len(crewpunch_shape)-1];
  61
  62 crewpunch_skew_angle = 3.5; //degrees
  63 crewpunch_skew_yoff = +1.1; //mm
  64
  65 // computed
  66
  67 punch_dx = 0.5 * (-crewpunch_biggest_shape[2][0]
  68                   +crewpunch_biggest_shape[2][1]);
  69 punch_dy = 0.5 * (+crewpunch_biggest_shape[1][1]
  70                   -crewpunch_biggest_shape[1][0]) + crewpunch_skew_yoff;
  71
  72 attach_ysz = holder_attach_walls*2 + holder_ctie_width;
  73
  74 holder_block_zsz = crewpunch_biggest_shape[0] - crewpunch_smallest_shape[0];
  75 holder_xsz = crewpunch_biggest_shape[2][0] + crewpunch_biggest_shape[2][1] +
  76   holder_min_wall*2;
  77
  78 holder_skewangle_yextra = holder_xsz/2 * sin(abs(crewpunch_skew_angle));
  79
  80 holder_max_y = punch_dy + crewpunch_biggest_shape[1][0] + holder_min_wall
  81   + crewpunch_systematic_size_error + holder_skewangle_yextra;
  82
  83 holder_attach_max_y = punch_dy
  84   - max(crewpunch_biggest_shape[1][1], crewpunch_shaft_max_y)
  85   - crewpunch_systematic_size_error - holder_skewangle_yextra;
  86
  87 holder_block_min_y = punch_dy
  88   - crewpunch_biggest_shape[1][1] - holder_attach_near_wall +
  89   - crewpunch_systematic_size_error - holder_skewangle_yextra;
  90
  91 holder_all_min_y = holder_attach_max_y - attach_ysz;
  92
  93 jig_max_y = max(holder_max_y + main_slop, strap_width/2) + edgewall_width;
  94 jig_min_y = min(holder_all_min_y - main_slop, -strap_width/2) - edgewall_width;
  95
  96 jig_main_zsz = holder_block_zsz + punch_travel;
  97
  98 jig_ends_extra = 2;
  99
 100 jig_iters = floor((jig_max_len - jig_ends_extra) / jig_interval);
 101 //jig_iters=2;
 102 echo(jig_iters);
 103
 104 // objects
 105
 106 module CrewPunch(){
 107   ourslop = crewpunch_slop - crewpunch_systematic_size_error;
 108   hull(){
 109     for(layer=crewpunch_shape){
 110       translate([0,0, layer[0]]){
 111         for(xind=[0,1]) //translate([xind?0:1,0,0])
 112           for(yind=[0,1]) //translate([0,yind?0.5:0,0])
 113             mirror([xind?1:0,0,0]) mirror([0,yind?0:1,0]){
 114               translate([-0.1,-0.1,-0.1])
 115                 cube([0.1 + layer[2][xind] + ourslop,
 116                       0.1 + layer[1][1-yind] + ourslop,
 117                       0.2]);
 118             }
 119       }
 120     }
 121   }
 122 }
 123
 124 module MaybeRoundedCube(sizes, roundedness){
 125   if (roundedness > 0) {
 126     translate([roundedness, roundedness, 0]){
 127       minkowski(){
 128         cube([sizes[0] - roundedness*2,
 129               sizes[1] - roundedness*2,
 130               sizes[2]]);
 131         cylinder(h=0.05, r=roundedness, $fn=20);
 132       }
 133     }
 134   } else {
 135     cube(sizes);
 136   }
 137 }
 138
 139 module PunchHolder(cutouts=true){
 140   roundedness = cutouts ? holder_corner_round : 0;
 141     difference(){
 142       translate([-holder_xsz/2, holder_block_min_y, 0])
 143         MaybeRoundedCube([holder_xsz,
 144                           holder_max_y - holder_block_min_y,
 145                           holder_block_zsz],
 146                          roundedness);
 147       if (cutouts)
 148         rotate([0,0,-crewpunch_skew_angle])
 149         translate([punch_dx,
 150                    punch_dy,
 151                    -crewpunch_smallest_shape[0]])
 152           CrewPunch();
 153     }
 154     difference(){
 155       translate([-holder_attach_xsz/2, holder_all_min_y, 0])
 156         MaybeRoundedCube([holder_attach_xsz,
 157                           attach_ysz,
 158                           holder_block_zsz + punch_travel
 159                           + holder_ctie_thick + holder_attach_roof + 1],
 160                          roundedness);
 161       if (cutouts)
 162         translate([-30,
 163                    holder_all_min_y + holder_attach_walls,
 164                    holder_block_zsz + punch_travel])
 165           cube([60, holder_ctie_width, holder_ctie_thick]);
 166     }
 167 }
 168
 169 module RegistrationGroove(l){
 170   // runs along the +ve X axis for length l but at correct z pos
 171   translate([0, 0, jig_main_zsz + 0.1]) {
 172     rotate([90,0,90])
 173       linear_extrude(height=l)
 174       polygon([[-registrationgroove_width/2, 0],
 175                [ +registrationgroove_width/2, 0],
 176                [ 0, -registrationgroove_depth ]]);
 177   }
 178 }
 179
 180 module OneJig(){
 181   difference(){
 182     translate([-(jig_interval/2 + jig_overlap),
 183                jig_min_y,
 184                -strap_thick])
 185       cube([jig_interval + 2,
 186             jig_max_y - jig_min_y,
 187             jig_main_zsz + strap_thick]);
 188     minkowski(){
 189       cube([main_slop*2, main_slop*2, 50], center=true);
 190       PunchHolder(false);
 191     }
 192     translate([-100, -strap_width/2, -10])
 193       cube([200, strap_width, 10]);
 194    translate([-100,0,0])
 195      RegistrationGroove(200);
 196    for (xfrac=[-1/4,0,+1/4])
 197      translate([jig_interval * xfrac, -100, 0])
 198        rotate([0,0,90])
 199        RegistrationGroove(200);
 200   }
 201 }
 202
 203 module RegistrationProtrusion(){
 204   // points towards the positive x axis
 205   xsz = registrationprotrusion_poke;
 206   ysz = registrationprotrusion_poke;
 207   diag_sz = xsz * sqrt(2);
 208   zsz = diag_sz / registrationprotrusion_slope;
 209   hull(){
 210     translate([0, 0, 0.1]){
 211       linear_extrude(height=0.1)
 212         polygon([[   0, -ysz ],
 213                  [ xsz,    0 ],
 214                  [   0,  ysz ]]);
 215       translate([-0.1, 0, zsz ])
 216         rotate([0,0,45])
 217         cube(0.1);
 218     }
 219   }
 220 }
 221
 222 module Jig(){
 223   for(end=[0,1]){
 224     for(yfrac=[-1/2, 0, 1/2]){
 225       translate([ end
 226                   ? jig_interval * (jig_iters - 0.5)
 227                   : -jig_interval/2,
 228                  yfrac * strap_width,
 229                  0])
 230         rotate([0,0, end ? 0 : 180])
 231         translate([ jig_overlap, 0, 0 ])
 232         RegistrationProtrusion();
 233     }
 234   }
 235   for (i=[0:jig_iters-1]) {
 236     translate([jig_interval * i, 0, 0])
 237       OneJig();
 238   }
 239 }
 240
 241 module JigT(){ ////toplevel
 242   rotate([0,0,-45])
 243     translate([0,0,jig_main_zsz])
 244     rotate([180,0,0])
 245     Jig();
 246 }
 247
 248 module PunchHolderT(){ ////toplevel
 249   PunchHolder(true);
 250 }
 251
 252 module Demo(){ ////toplevel
 253   %PunchHolder();
 254   Jig();
 255 }
 256
 257 module Kit(){ ////toplevel
 258   JigT();
 259   rotate([0,0,-45]){
 260     translate([(jig_iters-1)*jig_interval/2,
 261                jig_min_y - holder_max_y - 5,
 262                0])
 263       PunchHolder();
 264   }
 265 }
 266
 267 //CrewPunch();
 268 //PunchHolder();
 269 //PunchHolder(false);
 270 //OneJig();
 271 //Jig();
 272 //Demo();
 273 //JigT();
 274 //RegistrationProtrusion();
 275 //PunchHolderT();
 276 //Kit();