I know that there are several opensource printers, i.e. RepRap. Are there any similar projects for robotic woodworking saw or other instruments?
I don't believe there are many common computer controlled saws except for custom-built, highly specific machines.
However, there are three common machines that are more general purpose that can probably do the job you need:
- Computer controlled routers
- Computer controlled laser cutters
- Computer controlled high-pressure waterjet cutters.
There are many open source and custom built, as well as commercial CNC routers. As for the other two, I think those remain mostly commercially built.
There are also many companies that operate these machines that will cut things for you, for a fee.