I looked into the production of PCB (HA!). The two choices are machining or chemical. (I have purchased both options.)
Chemicals will be messy and potentially hazardous, but would be faster for larger productions. You can print on transparent vellum and expose your treated PCB with bright light, then the rest resembles home-photo lab process.
Machining you can get your results quicker for small runs/prototyping but like @BobJewell mentions, precision will be an issue. And remember, you are milling copper faced fiberglass board. That’s nothing to sneeze at. (…get it? sneeze from the dust.)
Alas, I have yet to crank out a PCB due to a lack of electronics project worthy of the effort, yet. I wanted to share what I did discover so far.