Save Time! Save labour! Save Material! Produce goods when you're someplace else, make money at home when you're at work. R&D, and concepts, prove your idea in hours not weeks or months, save on material by having less error.
The following are some of the advantages:
CNC machines do the dirtywork,
If a CNC machine is working properly there's no real need for an operator, the machine can load new parts even package finished ones, just keep providing enough raw materials for the machine to keep running, if the needs of the machine are taken care of it could run uninterrupted for days, even weeks, that way the operator can attend to other important things, since the machine is automated and computer controlled the accuracy of produced parts are of a very high level.
Since the machine is driven by software the operator doesn't have to be a skilled craftsman, even if a CNC workshop has several machines, having just one supervisor is enough to manage high production levels, saving on labour.
When you use a CNC machine you have the option of making a wide range of different products without any problems, it's as easy as changing the program, often this program is a simple text file that can be used time and time again to produce the exact same part, time after time.
Since CNC machines could be adjusted to manufacture different products in short times it's not necessary to have a big inventory, but not a big deal if you do either, machine set up is usually pretty simple, jigs help with complex setups, production runs for new product can be started in limited time, often a new part can be planned, programmed, and produced in one day.
machines are developed so well that they never need an operator to work, they
can be controlled over the web, in cases where raw material has run out, the
machine runs out of oil, or in case of a break down, the machine will send an
alert to the operators mobile phone for attendance.
DISADVANTAGES OF CNC MACHINES
CNC machines are generally more expensive than manually operated machines, however costs are offset by production levels and quality, prices are also coming down, do it yourself builds are inexpensive but still result in high quality production.
Software is expensive for the most part, MasterCAM and others can cost into the thousands of dollars, Solidworks for example could cost as much as ten thousand dollars, machine software often comes with proprietary machines but may not, some Machine software can be found free online (EMC), however Windows versions cost money (Mach3).
Because CNC machines need fewer operators (one operator could look after a number of machines) it contributes to unemployment and deflation of goods, however maintenance people still need to be employed to keep these machines working, and replacement parts still need to be built by someone.
The form of education has changed, with CNC's the present day school curriculum may not include training on manually operated machines, this limits new grads to Computer controlled machines, they may not have the same skill as past graduates, the computer does all the manual work for them.
When you weigh advantages against disadvantages of the CNC machine however, it appears to me that the advantages may outweigh the disadvantages, therefore, the CNC machine is not only going to stay but also develop further in the future.
After the 1970s when computers made their appearance, Conventional and Numerical Control systems were modified for Computer Control, instead of running off a special punched Tape, today Machines are controlled from a file generated from a Computer mathematically.
Today, an Operator has to sit near the machine to monitor the progress and interrupt the process in case anything goes wrong, and the Operator loads the raw material, opposed to physically producing the first example, setting up the machine, loading the raw material, and monitoring/ controlling the machine.
Before CNC it was NC (1940s and 1950s) which stands for numerical control, different from today mainly because of the invention and evolution of IC's (Integrated Circuits).
Arduino/ PLC/ AVR/ ARM:
The Arduino is one very good example of a Micro-Controller with some very interesting IC's, it has an Atmel chip that functions as a processor and it can store code, the Arduino board also has an FTDI integrated circuit for USB connection.