High precision work like making lenses of different focal lengths for custom experiments are now easier to make. A few examples are given below.
Lens making with a CNC – Part 1
Lens making with a CNC – Part 2
The internet has a lot to offer as there are several DIY ( Do It Yourself) innovators who share their work and sometimes even designs.
Just search and you are certain to get a few hits.
Here are a few resources to get you started with designing and cutting your own projects. Laser cutting projects can also be modified and used for CNC’s.
1) 3Axis.co (Free) – https://3axis.co/laser-cut/toys/
2) MakeCNC (Paid) – https://www.makecnc.com/browse-store/premium-patterns/
3) DesignsCNC (Free) – https://designscnc.com/category/animals/