Correctly Placing a 3d Image Inside a Crystal

At work, we've now got a new laser. It creates 3d images in crystal by, rapidly, firing a single laser. The crystal shatters at the focal point to create a permanent white dot. The laser has a working Z focal range of about 80mm. Because some crystals are of awkward dimensions the laser has an adjustable table. When the table is adjusted, I have to manually adjust the Z centre of engraving. This calculation has to take into account the refractive index of air. Sometimes I also want a greater margin below the image, so that it looks 'right'.

Formula = Height of crystal / 2 - H * 1.52
H is the distance that the table has been lowered

To reduce human error I've been working on a program that calculates the "True Z" and show me where the engraving will be. It's written in Mono using Visual Studio to design the GUI and MonoDevelop to do the coding. It is functional if the engraving centre is half of the crystal block size. It crashes if any of the textboxes are empty.

Future plans include

  • Handling empty textbox crashes
  • Checking that my calculations are correct
  • Showing a point cloud instead of representing the object with a rectangle
  • Saving the settings along with notes to make repeat jobs quicker to setup


gassrini's picture

Got a new laser at work. With better software. I don't need to use this any more. :)


Hi John,             I am working on similar problem. I have to drill hole into glass of thickness 10mm. drilling should be bottom to top. As we know glass has different refractive index. how to find accurate point( correct the error).RegardsNagesh

gassrini's picture

I'm presuming you using a drill which doesn't have a method for setting depth? Perhaps a hand operated drill? Get a ruler, measure 10mm from the tip and put some coloured tape around the bit.

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