The letters "CNC" on a woodworking router stands for computer numerical control. It means that a computer controls the router. In older machines, the operator puts in the axis coordinates. If it only cuts for length and width, the router has x/y axis. Many CNC woodworking routers now offer a lot more than the earlier models with a multitude of uses and dimensions.
Expect to pay a lot when you buy a CNC woodworking router. These bad boys are highly sophisticated, and the CNC woodworking router can work all night without much help from you. Many of the larger CNC routers are for commercial woodsmiths as opposed to the casual hobbyist, but there are some out there for the hobbyist that range between $600 and $1000. The CNC woodworking router also routes materials like plastic, composites, acrylic, MDF, aluminum and brass.
You can use most newer CNC routing systems for three-dimensional cuts. They also are perfect for engraving materials. The CNC routers come in various sizes. There's a size that's perfect for your production. The biggest advantage of a CNC router over hand routing is that the results are repeatable and the machine does most of the work. The accuracy is important, particularly if you create a mortise or other fitted joints.
Make your own CNC router from wood or metal or buy one. There are kits to make the CNC woodworking routers for the home shop hobbyist. They include all the boards necessary for assembly and run about $1100, but they don't come with the electronics that make it run. The electronics set you back another $500 and require a computer and the programs. For additional stability, you can also incorporate a drive system with two motors. If you like to keep the shop area clean, add the price of a vacuum attachment for debris.
Use several different programs to run the CNC woodworking router. EasyCAD takes pictures of items you want to produce and then turns them into g-code. The Vetric Company offers a variety of programs for CNC machining. They have one that converts 2 dimensional drawings into 3D relief. There are also volumes of programs that allow you to design items and then convert them to CNC toolpaths. Mach3 is also great PC-based software for CNC. If you have limited experience, Meshcam lets you quickly create toolpaths without any prior know-how.
When you set up your CNC woodworking router, you have many different areas to explore. One process is learning the different feeds and cutting speeds that are right for your jobs and comfort level. If you purchased the machine, then you'll have a set of instructions to follow. After a while, you'll get a feel for the right settings and adjust them accordingly for your desired results.
Purchase a used CNC woodworking router. Often small manufacturers upgrade or the hobbyist finds that he never uses the one he built and wants to sell it. These are often great buys. If part of your passion isn't building your own, this is an alternative and cheap route to go. Be aware that the prices of CNC routers dropped so make sure you're getting a good deal. Older models may have been more expensive but not necessarily better.
Whether you build the CNC router yourself or purchase one, you need one that fits your needs. You need to decide whether you'll have a mobile gantry or mobile bed, the amount of cutting area you need for your projects, the size of the machine, the tolerance levels required and what you can afford. Listing all these factors narrows the playing field and points you in the direction of the right machine.