Machine automation is nothing new. The 1800s saw the development of cam-driven, automatic lathes and screw machines. The first half of the 1900s gave rise to numeric control of manufacturing equipment by way of punched cards and punch tape that controlled where the machine drilled or cut. The development of more affordable computer technology in the late 1960’s and early 1970’s led to computer numeric control or CNC machinery. Rather than feeding a punched card or tape into the machine to direct the operation, the commands are programmed directly into computer.
Virtually all CNC machinery operates using the same 3-axis system or a variation on it. There is a table designed to move along the X-axis, forward and back, and the Y-axis, left and right. The tool arm moves on the Z-axis, up and down. The table moves the workpiece to specified points along either the X- or Y-axis and the tool arm applies the drill, for example, to a specific depth. More complex machines sometimes call for the use of an A-axis, B-axis, or C-axis, which refer to rotational movements around the X-axis, Y-axis, and Z-axis, respectively.
Like any computer driven system, CNC machinery requires a program in order to function. In essence, these programs are little more than a series of commands that tell the machine when and where to move the table, apply the tool arm, or both. These programs can be developed manually, but contemporary CNC machinery is usually designed to work with computer-aided manufacturing (CAM) programs that generate CNC programs the machinery can interpret. Ideally, transfer of the program happens over a distributive numerical control or DNC system, which is a network of CNC machinery and a computer. In the absence of a DNC system, the program can be input manually or via a flash drive.
A wide variety of industries employ CNC machinery as a basic element in their manufacturing. The metal milling and metal fabrication industries rely on CNC for parts production. Electronics manufacturers employ it to solder circuit boards. Wood furniture manufacturers use CNC lathes for drilling and the production of identical components, such as table legs. Even some types of engraving work are performed using CNC.
CNC machinery offers a number of benefits. It enhances the accuracy of the work, which can be critical in industries where tolerances are measured in ten-thousandths of an inch. It limits worker exposure to particularly dangerous manufacturing processes. It reduces waste by limiting the number of flawed workpieces and it enhances efficiency. With regular maintenance and barring a mechanical failure, CNC machinery will continue to produce at the same pace indefinitely.
Interesting article. We are looking into a cnc machine purchase, they are not cheap however.