Extensive discussion at: Origin/consistency of chipload recommendations and https://shapeokoenthusiasts.gitbook.io/shapeoko-cnc-a-to-z/feeds-and-speeds-basics with a spreadsheet for this at: Speeds, Feeds, Power, and Force (SFPF) Calculator
and see https://www.youtube.com/watch?v=S9bceJxpqG0 for concepts on this and see the series #MaterialMonday: #MaterialMonday on YouTube for specifics.