By Cruz Lena
CNC stands for Computer Numerical Control. It is a technology that converts designs produced in computer aided design software (CAD) into numeral form. The numerals are sent from the computer to the carving machine in the form of graph coordinates and control how the cutter moves. The machines used are controlled by a computer to carve items from a base material such as metal or wood. This way, model-making becomes easier and more accurate.
CNC technology started in the 18th century, whereas the idea of turning a machine with a metal frame began in 1751. This was in an aim to increase accuracy and produce more accurate products compared to those crafted by hands. The development of automation in CNC machines began during the cold war. John T. Parsons helped in the motorization of the mechanisms used in making helicopter blades for the U.S Navy. He figured out how to calculate airfoil coordinates using the IBM 602, a multiplier. After keying in the data points in the Swiss jig borer, he made the first numerically controlled machine. This was the first machine that manufactured goods from information fed to it. He increased productivity tremendously. Parsons further studied how to manage the production machines using a computer, which led to the development of the CNC machining method.
Parsons received considerable help from Frank L. Stulen, who headed the Propeller Lab Rotary. Stulen started working with Parsons alongside three other engineers. He adopted the use of punched card calculators from his brother Curtis. This helped in running the stress calculations on helicopter rotors. Through this technology, they were able to generate an outline with more points. They increased the points from 17 to 200. Thus, they came up with a pair of numbers, the X and Y-axis. Using this, they moved the cutter to the points indicated, then lower the tool for an excellent cut. At first, this method was the by-the-numbers method. What they produced was similar to the current 2.5 axis machining, but required more labor. With time, Parson developed a less labor-intensive machine.
For further research, Parsons started working with MIT, which was at the forefront of mechanical computing. After some analysis, the MIT team led by William Pease found a way to improve Parsons’ machine. They suggested that, instead of the machine cutting at exact pint A and B, it could cut smoothly between the two points. This would increase accuracy and reduce the number of points required. In 1949, Parsons, the Air force, and MIT struck an agreement to run the project. However, Parsons was soon thrown out of the deal as MIT bought a Hydro Tell mill and hit a contract directly with the airport. Parsons went on to file for a patent and received rights on Motor Controlled Apparatus. MIT continued with further advancements and was successful in creating a highly accurate machine. However, it was very costly and complex to operate, which made production unreliable.
The development of computer Numerical controlled technology continues to date. With the development of other technologies such as computers, it is much easier to create machines. It is even possible for someone to design their CNC machine at the comfort of their home or purchase desktop CNC machines.
