The first CNC (CNC is the short form for Computer Numerical control) 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 now obsolete as the data required quickly transitioned to analog and then digital computer processing in the 1950s and 1960s.
The CNC machine comprises a mini computer or microcomputer that acts as the controller unit of the machine, in CNC machines the program of instructions is fed directly into the computer via a small board similar to the traditional keyboard. All the cutting processes and final dimensions are fed into the computer via the program. The computer thus knows exactly what is to be done and carries out all the cutting processes. CNC machines work like a Robot, which has to be fed with the program and it follows all your instructions.
The way coordinates are plotted are via the X, Y and Z axis which controls the movement of the cutter on a 3D CNC machine. This allows materials to be machined in three directions (3D manufacture).
Machine tools that can run on CNC programmes are: Lathes, Milling Machines, Drilling Machines etc. The main purpose of these machines is to remove some of the metal to give it proper shape. In traditional methods these machines are operated by the operators who are experts in these machines. Most parts need to be machined accurately. In manufacturing with CNC machines the role of the operator is minimized. The operator has to merely feed the program of instructions into the computer, load the required tools into the machine, and rest of the work is done automatically by the computer. The computer directs the machine tool to perform various machining operations as per the program of instructions fed into it by the operator.
Types of CNC Machines: CNC machines typically fall into one two general categories: conventional machining technologies and novel machining technology.
CNC Machine Lathes:
Some view Lathes as the only universal CNC Machine tool because a lathe can make all of the parts needed for another lathe. A lathe spins the workpiece in a spindle while a fixed cutting tool approaches the workpiece to slice chips off of it. Because of this geometry, lathes are ideal for parts that have symmetry around some axis that could be chucked up in the spindle.
CNC Milling Machines:
CNC Mills have at the very least the ability to drive cut in 3 dimensions (some older machines may be limited to 2 or 2 1/2 if there are limitations on when that 3rd dimension may be used) which are referred to as the X, Y, and Z axes.
A CNC Router is actually a type of CNC Mill, typically one that uses what's called a "gantry" configuration. Typically they're called CNC Routers instead of CNC Gantry Mills when they're used to cut wood, but this need not exclusively be the case.
Many think of CNC machines as being focused on cutting metal, but there is also a market for CNC woodworking machines of which the CNC Router is the principle example.