The Modern Numerical Control (NC) concept, the precursor to today’s Computer Numerical Control (CNC), was originally conceived around 1947 by John T. Parsons (1913-2007) and Frank L. Stulen (1921-2010) at the Rotary Wing Branch of the Propeller Lab at Wright-Patterson Air Force Base, Dayton, Ohio, as a result of the US Air Force’s (USAF) quest for a system to design and manufacture more precise aircraft parts and complex (Source: History of CNC Machining: How the CNC Concept Was Born”, CMS North America, Inc.). Early on, Parsons and Stulen developed a helicopter blade jig manufacturing system using an IBM 602A multiplier to calculate the aerodynamic coordinates and feed data points directly into a Swiss template punch, which impressed their USAF research colleagues Shortly thereafter, Parsons and Stulen developed a unique computerized punch card program to represent complex three-dimensional shapes, which led Parsons to start his own company, Parson Corp., which operates out of Traverse City. , Michigan.
In 1948, representatives of the United States Air Force (USAF) visited Parsons Corp. headquarters and Parsons received a contract to make new and innovative wing designs for military applications. This, in turn, led to a series of USAF research projects at the Massachusetts Institute of Technology (MIT) Servomechanisms Laboratory, culminating in the construction of the first numerically controlled prototype machine, albeit an awkward one. To accomplish this, Parsons purchased a Cincinnati DK-series Hydro-tel 28-inch vertical spindle contour milling machine consisting of a table and a spindle that moves along the X, Y, and Z axes. Over the next two years, the Cincinnati was stripped down, significantly modified, reconditioned, and reassembled. As application studies progressed, the prototype was expanded to produce a movement of the head, table, or cross slide with an accuracy of 0.0005″ for each electrical pulse fed by the director. To ensure that the prototype worked according to the instructions, a feedback system was added.In response to movement, synchronous motors adapted to each movement produced voltage.
By 1953, enough data had been collected to suggest practical aeronautical applications, and the Cincinnati prototype, employing a Friden Flexowriter with its 8-column paper tape, tape reader, and vacuum tube control system, became the de facto prototype for all successive developments. To this day, all CNC controlled machines, even the most sophisticated ones, still require three basic systems to operate: a command function system, a drive/motion system, and a feedback system.
Although CNC gained slow acceptance throughout the 1950s, in 1958 the MIT Servomechanisms Laboratory developed g-code, which has become the most universally used operating language for CNC devices.
In the early 1960s, standardized G-code and Electronic Industry Alliance (EIA) computer-aided design (CAD) became a fledgling technology that provided a firmer technological foundation. As a result, CNC took off and began to steadily replace older technologies.
In the 1970s, minicomputers like the DEC PDP-8 and the Data General Nova made CNC machines more powerful and cost-effective. American companies responsible for the CNC revolution, focused on high-end equipment. German and Japanese companies felt the need and began producing smaller, less expensive CNCs, and since 1979 they have outsold the United States.
Finally, PCs have now made CNC controls even cheaper, giving way to the use of CNC controlled machines for the hobby and general purpose markets. The CNC control language now known as LinuxCNC (formerly known as Enhanced Machine Controller or EMC2) continues to thrive, as do many other CNC technologies.
Work cited:
“History of CNC Machining: How the CNC Concept Was Born”, CMS North America, Inc., http://www.cmsna.com/blog/2013/01/history-of-cnc-machining-how-the-cnc – concept-nation/