It is a relatively new process in the world of machining which allows for increased efficiency through higher levels of automation and by allowing the machine and it's computer controls to do all the work.
CNC machines can be left unattended for hours or even days if necessary, allowing operators to focus on other tasks.
CNC machines can also work much faster than human machinists, since they are faster, stronger, and do not need to take breaks.
They can also be run late at night, when most of the workers have gone home, since machines do not need to worry about being sleepy or getting paid overtime.The second big advantage to CNC machining is that it produces an exact result every single time.
Even the best human operator will have minor variations between finished results, whereas a CNC machine will produce exactly the same result each and every time it is run.
This is very important in the modern world of standardized and interchangeable parts, where a single defective cut can make an entire machine wholly unusable.