In the beginning there was no NC, nor were there any computers. The beginning referred to here is manufacturing prior to 1945 when machine tools were all manually controlled. Between 1945 and 1958 two major events occurred that are credited with starting a second industrial revolution. The first event was the creation of a practical digital electronic computer in 1945 called ENIAC (Electrical Numerical Integrator And Calculator). The second was John T. Parsons' invention of numerical control. On Sept. 10, 1998, a dinner was held in Chicago honoring John Parsons for his contribution to industry on the 50th anniversary of NC. This very special "once in a life-time" event was organized by MDSI, in cooperation with EDS and Microsoft. I was among the 200 who were invited to attend. It was a thrill to be present, to talk to John again and hear his account of how NC got started.
Mr. Parsons is now 85 years old and aside from poor eyesight, he is in good health for his age and unusually sharp. In his address he talked about the events leading up to the development of numerical control and subsequently being granted patent No. 2,820,187 in 1958 for Motor Controlled Apparatus for Positioning Machine Tool (later called numerical control).
The story of numerical control starts with Mr. Parsons and his chief engineer, Frank Stulen, becoming aware of the use of accounting machines for solving engineering problems and employing this technique to check helicopter rotor blade airfoil patterns. Utilizing early model punched card tabulating equipment, his company, Parsons Corp., generated two-axis coordinate tables of the contours for checking the airfoil patterns with which they had been furnished. Once they were able to define the pattern numerically, Mr. Parsons then had the idea to use the same data to direct the machine and thus define the part numerically. Mr. Parsons and Mr. Stulen proceeded to generate a two-axis airfoil machining path set of data with a factor entered for cutter diameter offset. The XY machining coordinate tables were taken to a plain Bridgeport milling machine where the X points were called out to one operator who ran the X-axis handwheel and the Y-axis to a second operator who controlled the Y-axis. At that time the machine motions were merely known as table and saddle controls. This started the process that led to Mr. Parsons being granted the patent for numerical control.
Mr. Parsons addressed the group with humility, relating at one point that he does not have a college degree. (He does however, hold an honorary Doctor of Engineering degree from the University of Michigan.) He also gave a lot of credit to his lifelong friend, associate, and chief engineer Mr. Stulen, the one who has turned many of Mr. Parsons' ideas into reality. He did not even say that the concept of numerical control has changed the control of machines and industrial processes from an imprecise craft to an exact science, spawning a second industrial revolution—these are the words used by the National Inventors Hall of Fame to describe him. Mr. Parsons was inducted into the National Inventors Hall of Fame in 1993 for inventing numerical control. There are currently 135 other inventors in the National Inventors Hall of Fame, many who you would easily recognize, such as Alexander Graham Bell, Thomas Edison, Eli Whitney and the Wright brothers.
Mr. Parsons is also well known in the Aerospace Industry. The U.S. Repository for the National Air and Space museum has some 200 cubic feet of Mr. Parsons' papers, memoranda, financial records, engineering drawings, specifications and so on. In the Repository listing, they refer to Mr. Parsons as manufacturer, inventor, and father of "numerical control." In addition to conceiving a machine tool for automatically producing aircraft structural shapes, he originated a manufacturing operation that became the world's largest designer, producer and overhauler of helicopter rotor blades. He also built the first all composite airplane for the Office of Navy Research.
Mr. Parsons, we in the industry salute you for your contribution of NC. To MDSI's CEO, Chuck Hutchins, who conceived the program to celebrate 50 years of NC and to MDSI's president, Larry Schultz, who hosted the evening, and to all the other industry leaders who participated in the program, thank you for the opportunity to honor a great man while he is still alive and able to participate in the program.blog comments powered by Disqus