Numerically controlled machine tools in Japan

• Autores: Masao Sugimoto
• Localización: Actas, 1961, págs. 239-244
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • During the last few years the research and manufacture on numerically controlled machine tools has been carried out in the Government Mechanical Laboratory, Tokyo University, Tokyo Institute of Technology and some builder companies. In this paper the description on the research results and design features of jig borers with automatic positioning systems and vertical milling machines with numerical control, and some other experimental works on numerical control systems will be reported.

    1. Jig Borers with numerically controlled positioning system. The table travel of this machine is 800 mm in X and 600 mm in Y. Programming resolution is to be 0.001 mm and the expected overall accuracy is 0.002 mm. The logic and counter data handling circuitry consists of parametron network. The parametron was originated and developed in Japan. Coarse positioning is accomplished by incrementally counting the graduation on a main scale, fine positioning by counting Moire fringes generated by diffraction gratings. Digital compensation of the main scale is also included. Coarse positioning is accomplished by a hydraulic servo and an induction motor, but final fine positioning uses D.C. shunt motor.

    2. Milling Machines with punched tape control system.

    The numerical control systems of milling machines has been under development in the Government Mechanical Laboratory Tokyo. In March this year two milling machines which were reformed for this purpose, were operated with one kind of control system. This is a complete three-axis control and the overall accuracy is +- 0.03 mm. The pulse distributor was originally set up in our laboratory using parametron circuitry, and it consist of shift register, checking circuit, control circuit, gate circuit, binary counter and so on. The digital servo which converts the command pulse to shaft position contains decatron reversible counter, digital-analogue converter, servo-amplifier and servo-motor and feedback pulse generator. The other decoding system is now under development. The two system of synchro coupled power servomechanics which produces the movement of the table and saddle of the machines were completed. One is electro-hydraulic, and the other is overall electric.