Here is an interesting project. Milling PCBs though may not get the fine pitch required for some SMD parts.

https://www.youtube.com/watch?v=O7gI6XYmP2o&t=0s https://bitbucket.org/compactpcbmaker/cpcbm/src/master/

This works great for single and potentially two later boards, the problem is when scale up to 4 layer and beyond boards. For quick turn production level boards I have used https://www.allpcb.com, JLPCB takes a day or so longer than ALLPCB in my experience.