Computer numerical control (CNC) is defined as a method for automating control of machine tools through the use of software embedded in a microcomputer attached to the tool. A CNC machine produces a product using coded instructions, without manual operation of the machine. These machines can be varied in size, function and design, and include lathes, milling machines and multi-axis machines.

The total cost of poor quality is often depicted as an iceberg with some of the costs visible above the water, but most of the costs hidden beneath the surface. This image is an excellent way to illustrate how poor quality management issues in manufacturing likely cost more than you realize. Although many costs are directly attributable to the quality issue itself, many other costs are incidental or secondary and may be hidden and unrecognized.