Moderators: Dave Moll, Andrew Davie, Steve Anderson
$fn=128;
RADIUS = 150;
HOLESIZE = .75;
SPACING = HOLESIZE*0.75;
POSITION = RADIUS - 32*SPACING - 5;
SYNC = POSITION - 10;
SYNCHOLE = 1;
THICK=3;
SCREWHOLE = 1;
SCREWR = 25;
module holes(){
for (i=[0:31]) {
rotate([0,0,(i%4)*360/32+360/64])
translate([POSITION+(i*SPACING),0,THICK-1])
cylinder(r=HOLESIZE,h=THICK+4);
}
for (i=[0:3]){
rotate([0,0,i*360/32-360/64])
translate([SYNC,0,THICK-1])
cylinder(r=SYNCHOLE,h=THICK+4);
}
// The screw hole(s)
for (i=[0:0]) {
rotate([0,0,i*90+22.5])
translate([SCREWR,0,THICK-1])
cylinder(r=SCREWHOLE,h=THICK+4);
}
}
module pie_slice(r, start_angle, end_angle) {
R = r * sqrt(2) + 1;
a0 = (4 * start_angle + 0 * end_angle) / 4;
a1 = (3 * start_angle + 1 * end_angle) / 4;
a2 = (2 * start_angle + 2 * end_angle) / 4;
a3 = (1 * start_angle + 3 * end_angle) / 4;
a4 = (0 * start_angle + 4 * end_angle) / 4;
if(end_angle > start_angle)
intersection() {
circle(r);
polygon([
[0,0],
[R * cos(a0), R * sin(a0)],
[R * cos(a1), R * sin(a1)],
[R * cos(a2), R * sin(a2)],
[R * cos(a3), R * sin(a3)],
[R * cos(a4), R * sin(a4)],
[0,0]
]);
}
}
module jigslice(){
pie_slice(RADIUS, 0, 45);
for (i=[1:3])
translate([RADIUS*(i-0)/4,-15,0]) {
translate([-5,5])
square([10,10]);
circle(10);
}
}
module finalslide(){
linear_extrude(3)
difference(){
jigslice();
rotate([0,0,45])
offset(0.5)
jigslice();
}
}
difference(){
finalslide();
holes();
}
Andrew Davie wrote:Two more parts printed. It takes about 3 hours/pair to print. Next step is (yes) to glue them together. After that I'll test the rigidity perhaps by drlling holes and mounting - for now I'm really just testing the ability of the disk to be flat and have the hole positions marked accurately.
Harry Dalek wrote:OH i didn't see the mounting holes for your motor mount that might be enough to keep it all rigid .
Are you going to paint it matte Black ?
Andrew Davie wrote:Harry Dalek wrote:OH i didn't see the mounting holes for your motor mount that might be enough to keep it all rigid .
Are you going to paint it matte Black ?
No, this is just a test-print to see if it's rigid. I believe it will be just fine, but I can always glue a plate to the back as you suggest.
The final version will be printed in a black material. I won't paint this, as it's just a prototype. I'll finish printing this one and drill the holes and mount it to see just what sort of picture it produces - I will then know if it's accurate enough to trust the hole positions. I think it will be OK, not great. But we shall see!
Harry Dalek wrote:i do see theres light gaps between the pie shapes you will have to fill those make light proof...can you over lap the pie shape edges connections so this doesn't need filling ?
Tongue and groove would be good but hard to make so small ..
Klaas Robers wrote:Realise that the holes, you look at each moment through only ONE hole, have a over all transparency of only 0.1%. So the disc itself should have a light damping (darkness) of 99.9% and then you get a contrast of only a factor of 2. You wat to have a contrast of at least a factor of 50, so the disc should have an untransparency of at least 99.999%. This is also the reason that photographic discs are far too transparent.
So I don't believe in the blackness of black PMA. On top of that 3D-printing routines print only thin walls and fill up the empty space with a thin structure.
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