There are still a few hand engravers, and lots of machine engravers.
(think about trophy companies) The machines fall into 2 basic types,
diamond drag which is very shallow but can be very small and usually
done on finished pieces (buffing tends to erase). The other uses a
rotating cutter, will go much deeper but the minimum size is limited
by the cutter size… small cutters are fragile and expensive.
A cnc mill can be used for either and while cheaper than a "real"
fancy dedicated engraving machine still a big investment of $$$ and
learning. A very powerful and fun tool but if you only want a few
plates find a local guy who makes bowling trophies. Talk to them
(the guy/gal running the machine), often an unusual job request will
get better service and price. Makes up for the more routine and
Analog/Digital Modelling & Goldsmithing