The Americans with Disabilities Act has changed our industry quite a bit. Lots and lots of our customers have Braille and raised letters on all their signs. First we cut and paint the blank signs. Then we apply a thin plastic for the letters and route them out quickly before the adhesive gets to aggressive. Last we pull off the excess plastic leaving the raised letters. Our CNC router is invaluable for this type of sign as it cuts the letters and drills the holes for the rasters. Lastly we press the rasters into the holes and clean up the sign.
Here's a stack that I helped with the other day. We have a little tool that sucks the rasters up and holds them until you press them into the holes. It takes quite a bit of pressure to seat them, so my arm was sore by the end of the day, but we got them done. And now Kaiser Permanente is happy, happy, happy with their signs.