Making a laser lumia/aura effects disk - with a slight silicone disaster

The Lumia or Aura effect is created by shining a laser through rippled glass, but it can be difficult to find the right glass, and someone who can cut a circle from it for you. This was an experiment to use a standard filament based 3D printer to create a silicone mould for optically clear resin.

This was my first attempt at creating a mould with liquid silicone. Apparently platinum-cured silicone is very fussy about what it's used with, and my master shape was fine on its own, but when pre-textured with UV cured resin it prevented the silicone from curing in that area and caused an outgassing effect. Even with ordinary two-part resin the silicone still stayed slightly sticky where it was in contact.

In the end the answer was to use the 3D printed PLA mould on its own and add the effects onto the cast resin disks afterwards.

When using UV curing resin I strongly recommend wearing gloves to protect your hands from contact with it. The chemicals used to make it light sensitive can also make your skin sensitive to sunlight.

This is an experimental device. I don't know how the resin will hold up to specific wavelengths of laser energy. It's also probably limited to low power lasers for safety. The disk can also be used with various styles of LEDs for an aurora borealis effect.

For laser use the disk should rotate very slowly to get the best optical warping effects.

Here's the OpenSCAD script that creates your custom mould for this project.
There are two adjustable variables - one for the outer diameter of the disk and one for the central hub where it attaches to a suitable motor. The script will automatically place a small central indent for aligning a drill if needed.

OpenSCAD can be downloaded for Windows, Linux and Mac (plus others) from the official site:-
https://openscad.org/

To use the script, copy and paste it into the left hand "editor" window in openscad. You can either adjust the two variables directly in the script or you can enable the customizer that will open a window to do it.
If you want to use the customizer then you can open it from the "window" drop down menu.

To see the results of any changes quickly, press the cube-button with two arrows on it. To do the full build press the cube-button with the hourglass on it, and when it is complete, save the file by pressing the STL button.
That will save a design file that can be used in your choice of slicer for 3D printing.

The script is below:-


//Ripple disk mould maker
//Diameter of disk in mm
dia=75;
//Diameter of central hub in mm
hub=20;
difference(){
cylinder(h=12,d=dia+12);
translate([0,0,1])
cylinder(h=12,d=dia+10);
}
difference(){
union(){
cylinder(h=5,d=dia);
cylinder(h=7,d=hub);
}
//Central drilling indent
translate([0,0,5.5])
cylinder(h=2,d1=0,d2=3);
}
$fn=100;