A machine tool is a used for shaping metal or other inflexible materials, normally by boring, cutting, grinding, shearing, or other types of bending. Machine tools utilize some kind of equipment that does cutting and shaping. All machine tools have some means of restraining the work piece and supply a guided movement of the parts of the machine. Thus the comparative movement between the cutting tool and work piece is controlled or guarded by the machine to at least some degree, rather than being entirely “offhand”.
Today machine tools are usually powered other than by human power (e.g. hydraulically or electrically) used to make manufactured parts in many ways that include cutting or some other kinds of buckling.
Machine tools can be operated manually, or under mechanical control. Early machines used flywheels to alleviate their movement and had compound systems of gears and levers to manage the machine and the piece being worked on.
After WWII, the numerical control (NC) machine was invented. These machines used a series of numbers punched on punched cards or paper tape to control their motion. In 1960s, computers were added to the machine give more flexibility to the course of action. Such machines are known as computerized numerical control (CNC) machines. NC and CNC machines could exactly repeat sequences time and again, and could produce much more intricate pieces than even the most expert tool operators.
Before long, the machines could involuntarily change the particular cutting and shaping equipment that were being used. For instance, a drill machine might contain an arsenal with many drill bits for producing holes of diverse sizes. Until that time, either machine operators would generally have to manually change the bit or move the work piece to another station to perform these dissimilar actions. The next rational step was to join different machine equipment together, all under computer control. These are known as machining centers, and have noticeably changed the method parts are made.
From the simplest to the most multifaceted, most machine equipment are competent of at least fractional self-replication, and produce machine parts as their key function. Some of the examples of machine tools are as follows:
Stewart platform mills