The CNC controller History
Past to Present

CNC controller History

Numerically Controlled (NC) machines were introduced in the late 1940’s and early 1950’s and were used for all machine control and data processing before the advent of microprocessors or computers. Computerized Numerically Controlled (CNC) controllers are sometimes still refereed to as NC controllers.

An NC controller receives a set of sequenced instructions, the program, consisting of alphanumeric characters. The controller then uses this set of instructions to direct the motions of a machine tool such as a milling machine, lathe, plasma cutter and of course router, much like the controllers today.

In the past the program was edited and programmed with the very basic computers of the time. The program would then be transported to the controller via a tape.

This permitted the program instructions to be read by the controller's tape reader only once and then stored in the controller's memory. Magnetic tape recorders and floppy disk drives were also being used for program recording and storage. There were no direct links between the computer and controller on early systems.

In the past the program was edited and programmed with the very basic computers of the time. The program would then be transported to the controller via a tape.

This permitted the program instructions to be read by the controller's tape reader only once and then stored in the controller's memory. Magnetic tape recorders and floppy disk drives were also being used for program recording and storage. There were no direct links between the computer and controller on early systems.

Debugging an N/C program before the advent of the computerized NC required making a new tape, trying out the new tape, finding the next error, making another tape, and so on.

The process of debugging a new program could require making a dozen or more punched tapes until an error free program was achieved. Engineering changes required a new tape to be made and debugged.

Modern Controllers

Today, with the use of powerful microprocessors and computer systems, the NC controller now communicated directly to a computer system with a real time link. This is the CNC controller that is standard today.

The controllers today do far more than drive motors. Some controller systems have the capabilities to control spindle speeds, coolant flow, and other peripherals.

Modern controllers still require operators to create a program for the controller to follow. Operators today receive help from Software such as Computer-Aided Design (CAD) packages and Computer-Aided Manufacturing (CAM) software along with the controller software to create the necessary numerical code such as G-code.

The CNC controllers’ today range from professional standalone systems, with their own keyboard and user interface, to hobby CNC controllers that require a personal computer.

In the next section, CNC Controller Components, the breakdown of the CNC controller components and their function will be discussed.


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