History Of NC Machine

As mentioned in the previous section, the NC is the system that enables machine

tools to machine parts with various shapes rapidly and precisely. In NC, the servo

motor is used for controlling the machine tool according to the operation of a user

and a servo motor drivemechanismfor activating the servo motor. That is, NC means

a control device thatmachines a target part by activating the servo motor according to

commands. The NC combined with computer technology is called computerized NC

or CNC (Computer Numerical Control). An NC machine which consists of vacuum

tubes, transistors, circuits, logic elements such as large-scale integrated circuits (LSI)

is called “Hardwired NC”, and performs NC functions through connecting elements

by electrical wiring. Instead of elements and circuits, NC functions are implemented

based on software in CNC. That is, this change from hardwired NC to CNC was driven by the advance in capacity and availability of microprocessors and memory.

Such CNC is called “Softwired NC”.

Through observing the advancement of NC, the fact that NC has the same development

history as its components can be seen. In the beginning, the pulse division

circuit was made from the computer with tens of thousands of vacuum tubes and

the machine tool was controlled by activating an oil-pressure motor and controlling

a relay according to the result of logical processing. However, as semiconductors

appeared and were applied to NC during the 1960s, electrical motors and power elements

during the 1970s and PC components during the 1980s, so Hardwired NC

evolved into a Softwired NC machine based on micro processors, electric power and

electronic technology, and software technology.

Now, NC and CNC mean Numerical Controller and there is no difference between

them. Therefore, NC machine means a machine tool with a CNC system.

It is known that the general-purposemanualmachine tool was introduced after the

steam engine was developed in the late 18th century. Thereafter, Jacquard invented

the method of automatic control of the weaving of fabrics with a loom machine by

using punch cards and this method was the beginning of the concept of NC. The

concept of NC was actually applied to machine tools afterWorldWar II and in 1947,

the United States Air force and the Parsons company developed the method almost

simultaneously for moving two axes by using punch cards including coordinate data

to machine aircraft parts. Since then, this technology was transferred to the servo laboratory in MIT and in March 1952, a 3-axis milling machine, being the first NC

machine tool, was developed. In this era, because there was not the circuitry such as

transistors and ICs, a vacuum tube was used and the size of NC was bigger than that

of the machine tools.

Since then, with the research effort, the use of NC became practical and in the

USA, an NC milling machine was put on sale by Giddings & Lewis, Kearney &

Tracker, and Pratt &Whitney. The concept of NC, which was introduced in scientific

journals from the United States, was also introduced into Japan and, in 1957, an NC

turning machine was developed.

Opi Sumardi.2017