The world's first successfully developed CNC machine tool was a three coordinate CNC milling machine, which was completed in 1952 in collaboration with Parsons and MIT in the United States. As early as 1948, the United States proposed the initial idea of developing a CNC machine tool when developing a prototype for machining helicopter blade contour inspection. In 1949, with the support of the US Air Force, Parsons Corporation officially accepted a commission to collaborate with the Massachusetts Institute of Technology Servo Mechanism Laboratory and began developing CNC machine tools. After three years of research, the world's first CNC machine tool experimental prototype was successfully developed in 1952. This is a true line interpolation three coordinate continuous control milling machine using the principle of pulse multiplier. Its control device consists of over 2000 electronic tubes, which occupies the size of an ordinary laboratory. The birth of this CNC milling machine marks the beginning of the digital control era in mechanical manufacturing.