微纳米三坐标测量机的高精度恒温箱研制

Development of a High Precision Constant-temperature Chamber for Micro-nanometric CMM

针对恒温室控制精度低和分离式恒温箱因振动而无法满足微纳米三坐标测量机需要的问题，研制了一套自然对流式高精度恒温箱。用定制尺寸的中空亚克力板和轻便型超低导热系数真空绝热板制成绝热箱体。以仪器测量点温度作为温度控制反馈值，均匀位于恒温箱顶部的9个半导体制冷片对其周围空气进行制冷，箱内冷空气均匀向下流动，与向上流动的热空气进行热交换。采用Lab VIEW与MATLAB混合编写高精度温控程序。实验结果表明：设定值为20℃时的稳态误差为0．0032℃，稳态时温度波动小于0．03℃，优于一级恒温室。新型恒温箱具有成本低、能耗小和无振动干扰等优点。

The spacious constant-temperature room and the separated constant-temperature chambers can ＇ t meet the requirement of micro-nanometric CMM because of low precision and vibration seperately. A high precision constant- temperature chamber based on the natural convection principle is developed. The walls of the custom-designed chamber is made of hollow acrylic upon which a lightweight thin vacuum insulation plate with ultra-low thermal conductivity coefficient is adhered. The temperature value of the instrument measuring point is taken as the feedback signal. Nine thermoelectric coolers used to cool the air inside the chamber are arranged on the ceiling of the chamber uniformly. The down flowing cool air and the up flowing hot air forms natural convection. The program of the high accuracy temperature-controlXed system is developed using LabVIEW and MATLAB software. The experimental results show that the system steady-state error is 0. 0032 ℃ on average, and the variation range is less than 0. 03 ℃when the set temperature is 20 ~C. It is superior to a Class I standard room. The new type constant-temperature chamber has the advantages of low cost, low energy consumption and no vibration