The name "CNC" actually stands for Computer Numerical Control and it represents one of two common methods to generate prototypes from a digital software file. CNC machines are electro-mechanical devices that manipulate machine shop tools using computer programming inputs. The first CNC machines were developed in the 1940s and 50s and relied on a common telecommunication data storage technology known as "punched tape" or "perforated paper tape." Punched tape technology is long obsolete as the data medium quickly transitioned to analog and then digital computer processing in the 1950s and 1960s.
Machining, in general, is a way to transform a stock piece of material such as a block of plastic and arrive at a finished product (typically a prototype part) by means of a controlled material removal process. CNC machines commonly combine tools into common units or cells from which the machine can draw. Basic machines move in one or two axes while advanced machines move laterally in the x, y-axis, longitudinally in the z-axis, and oftentimes rotationally about one or more axis. Multi-axis machines are capable of flipping parts over automatically, allowing you to remove material that was previously "underneath." This eliminates the need for workers to flip the prototype stock material and allows you to cut all sides without the need for manual intervention.
Types of CNC Machines
CNC machines typically fall into one the two general categories: Conventional Machining Technologies and Novel Machining Technology.
Drills: Drills work by spinning a drill bit and moving the bit about and into contact with a stationary block of stock material.
Lathes: Lathes typically make contact with the material by laterally moving a cutting tool until it progressively touches the spinning material.
Milling Machines: Milling machines are probably the most common CNC machine in use today. They involve the use of rotary cutting tools to remove material from the stock unit.
Electrical and/or Chemical Machining: There are a number of novel technologies that use specialized techniques to cut material. Examples include Electron Beam Machining, Electrochemical machining, Electrical Discharge Machining (EDM), Photochemical machining, and Ultrasonic machining.
Other Cutting Mediums: There are a number of other novel technologies that use different mediums to cut material. Examples include laser cutting machines, oxy-fuel cutting machines, plasma cutting machines, and water-jet cutting technology.
Materials used in CNC Machines are:-
Almost any material can be used in a CNC machine. It really depends on the application. Common materials include metals such as aluminum, brass, copper, steel, and titanium, as well as wood, foam, fiberglass, and plastics such as polypropylene.