工作機械の温度制御に関する研究(第3報)

減衰槽を用いた超精密油温制御

抄録

Super precision control of oil temperature is essential to obtain thermal stability required in super precision machining. For this purpose, two types of temperature control have been used ; PID control and multi-stages ON-OFF control. The former requires a preliminary temperature control of ±0.1°C prior to the main control, and frequency of temperature fluctuation must be over 1 h. The latter requires at least two system of ON-OFF control, and flow rate of controlled element must be set large, causing increase in the size of set-up and its total cost. In this study ON-OFF control is combined with an absorber which damps the temperature fluctuation from ON-OFF control. This system requires only a single step of ON-OFF control, and far more inexpensive than PID control system ; moreover huge tanks are not needed. Based upon theoretical analyses, super precision control system of oil temperature has been constructed and its performances have been tested. As the results, the temperature fluctuation was kept less than 0.014°C and drift of temperature during continued operation was only about 0.006°C/h. Key words : machine tools;super precision temperature control;temperature fluctuation absorption