Computer numerical control (CNC) is an advanced form of computerized production and manufacturing. However, CNC was not the first form of producing parts based on programming techniques. It was actually preceded by NC, or numerical control.
The concept of numerical control (NC) started when the automation of machine tools originally incorporated specific concepts of programmable logic in motors. The first NC machines were built in the 1940s. More advanced NC machines came along in the 1950s. These manufacturing machines were constructed based on existing tools that were modified with motors intended to move the controls of the machine. These controls followed specific points that were fed directly into the machine on punched tape. These early mechanisms were later improved with both analog and digital computers. The introduction of computer technology into the concept of numerical control led to what we now know as computer numerical control (CNC).
Computer numerical control, commonly abbreviated as CNC, is the concept of how machine parts operate based on how the parts – and any corresponding tools – are programmed to function. Precisely coded instructions are send to what is known as an internal microprocessor within the control system of a machine tool. This microprocessor basically functions as a small computer that is able to receive coded information. This internal processor accepts the informational instructions it receives, interprets how they are specifically meant to be implemented from a production standpoint, and then physically performs a desired function for a CNC machine. The primary benefit of CNC is that these pre-coded functions can be much more specific – and performed far more precisely – than what someone can manually do with a machine tool. This precision is far superior to traditional numerical control as well.
CNC is intended to help automate processes, making them more efficient and reducing – or even eliminating – the amount of manual labor involved in performing them. As such, CNC machines are often utilized with computer-aided design (CAD) and computer-aided manufacturing (CAM) software. Popular CNC machines include lathes, mills, routers, plasma cutters, water jet cutters, and grinders.
Modern CNC machines combine multiple tools into one area – or cell. In some cases, multiple machines are utilized in conjunction with an external controller, along with a human assistant or robot that moves the component from one machine to another. Either way, the sequence of computer-coded instructions needed to produce a part is highly automated, and this process produces a part that closely resembles the initial computer-aided design.
Like any form of technology, there are primitive and less efficient versions of machines that are improved significantly over time. This rule-of-thumb can be applied to NC and CNC machines. In essence, adding the “C” to “NC” simply means that a CNC machine is far more efficient than an NC machine due to advances in computer programming. But, as noted above, the two have many similarities. They are simply rooted in different eras of technology.