The outside ring of the clock will be made of plexiglass. This will act as a diffuser for the leds. The plexiglass was milled using a CNC. It was milled at 18k rpm with a 3mm endmill. The dept per pass was set to 1mm.
To try milling plexiglass I got a scrap piece of plexiglass, 200*100*10 mm. I setup the CNC for milling the entire circle and placed the scrap part some where along the cutting path.
By the looks of it, it would allow it to deeper. But the circle will be milled in 10 minutes so attempting a bigger depth would not gain much.
This is the end result, a real clean cut. Only the top part has some little dings but this could have been solved by glueing some thin triplex on top.