Printing the Clock Parts
The Word Clock Pieces can be printed from the STL's below:
I printed them in Black PLA on a Bambu Labs A1 and this worked fine. The clock does get a little warm during operation as the LED matrix generates quite a bit of heat. This heat is enough to warp the Light Grid a little bit but I have not found this to be an issue.
If this is a concern then you could print it (or just the grid) out of PETG.
The outside of the could be printed in other colors, however it is recommended that the grid be printed in black otherwise light bleeds between the letters.