CNC machines have been around for decades but have just recently moved into the consumer/hobby market. CNC stands for Computer Numerical Control and is a general term used to describe any machine that has its moves and cuts controlled by a computer. In our context, a CNC machine is a cutting tool mounted on a machine capable of moving the tool along the X, Y and Z axis.
When coming from a 3D printing background it's often easy to think of a CNC machine as the exact opposite of a 3D printer. A 3D printer starts with nothing and adds material layer upon layer until the entire item is constructed. A CNC machine starts with all the material in place and removes material layer by layer until the final result is achieved.
The number of Desktop CNC machines on the market today is relatively low. The Shapeoko has one or two serious competitors but there are only a few CNC machines that can be purchased for under $5,000. On top of that, the initial learning curve on a CNC machine is relatively high. While a failed 3D print might only result in a few grams of plastic being lost, a failed CNC job normally ruins your entire block of material (stock). A single, small, sheet of aluminum can cost more than an entire roll of 3D filament.
The Shapeko XL, aside from being one of the only affordable machines on the market, is now in it's third (3rd) revision. Many issues with version 1 and 2 of the machine were resolved in version 3. The Shapeko XL also offers a large cutting area of 33" x 17". You can even upgrade to the Shapeoko XL to an XXL which provides a full 33" x 33" cutting area.
Here is a quick video of our CNC machine cutting out some aluminum computer-case parts. The material being cut in this video is 1.6mm aluminum plate. It is being cut with a 1/8 inch carbide bit.