What Is CNC Machining

CNC is short for Computer Numerical Control. It's a method used in modern machining to perform a wide range of associated tasks. In this article, we are going to take a look at CNC machining and how it is used in both large metalworking fabrication applications and by thousands of home hobby enthusiasts.


History

• Before the invention of CNC machining, metalworking fabrication was performed by NC (numerical controlled) machines. These machines were designed and developed in the late 1940s and early 1950s by John T. Parsons, who worked in collaboration with MIT. The work being conducted by Parsons and MIT was commissioned by the U.S. Air Force as a means to develop a more cost-effective way to manufacture aircraft parts featuring complex curved geometries. Over the course of the decade, NC machining became the industry standard.

  In 1967, the concept of computer-controlled machining began to circulate. In 1972, major developments in the evolution of CNC machining began to take place, with the implementation of CAD (Computer Aided Design) and CAM (Computer Aided Machining). In 1976, the first 3D CAD/CAM systems were introduced and by 1989, the CNC machines became recognized as the industry standard.

Significance

• The original NC machines were controlled by paper punch cards that featured a series of codes--called G-Codes--that gave the machine its positioning instructions. These machines were all hard-wired and as such, they were not capable of changing their pre-set parameters.

  With the development of CNC machines like milling machines and lathes, G-Codes are still used as a means of control but are now designed, controlled and conducted through computers. In some of the more recent variations of CNC machines, G-Codes and logical commands are combined to form a new programming language called parametric programs. Machines that feature parametric programs allow the operator to make adjustments on-demand and makes it easier to access important system parameters.

  The primary advantage of CNC machining is that it allows for greatly improved accuracy, efficiency, productivity and safety over other forms of metalworking equipment. With CNC machining equipment, the operator is placed less at risk and human interaction is significantly decreased. In many applications, CNC equipment can continue to operate unmanned over the weekend. If an error or a problem occurs, the CNC software automatically ceases operation and calls or pages the off-site operator.