Numerical Control NC
Getting geometric information from the CAD model is of particular relevance to the manufacture of parts directly by machining (i.e. by material removal), and to the manufacture of tooling for forming and molding processes by machining. The use of numerical information for the control of such machining processes is predominantly through the numerical control NC of machines.
Fundamentals of numerical control
Today numerically controlled devices are used in all manner of industries. Milling machines manufacture the molds and dies for polymer products. Flame cutting and plasma arc machines cut shapes from large steel plates. Lasers are manipulated to cut tiny cooling holes in gas turbine parts. Electronic components are inserted into printed circuit boards by NC insertion machines.
Numerical Control NC is a form of programmable automation in which the mechanical actions of a machine tool or other equipment are controlled by a program containing coded alphanumerical data.
Numerical control NC is any machining process in which the operations are executed automatically in sequences as specified by the program that contains the information for the tool movements.
The alphanumerical data represent relative positions between a workhead and a workpart as well as other instructions needed to operate the machine.
The workhead is a cutting tool or other processing apparatus, and the workpart is the object being processed.
Basic Components of an NC System
The essential features of numerically controlled machines have been established for many years. They comprise a controller, known as the machine control unit MCU, capable of reading and interpreting a stored program and using the instructions in this to control a machine via actuation devices. This arrangement is shown in the following Figure.
An NC system consists of three basic components:
(1) Program of instructions
(2) Machine control unit MCU
(3) Processing equipment
In the most common example of NC, machining, the processing equipment consists of the worktable and spindle as well as the motors and controls to drive them.
