More reading for you about some basic fundamentals of CNC milling, drilling, etc.
https://en.wikipedia.org/wiki/Speeds_and_feeds
PCB Machining...Carbide Tools is your friend for longer tool life
https://en.wikipedia.org/wiki/Printe..._board_milling
https://en.wikipedia.org/wiki/Printe...board#Drilling
Good Luck on the your Adventure,
DJ