A New Environmental Chamber for Nano-meter Position Measurement and control on Ultra-precision Machine Tools with Interferometry

激光干涉仪系统具有精度高、非接触测量、安装方便等特点，已被广泛应用于精密切割机、测量机、光刻机等制造设备中。激光测量系统的测量单位取决于激光光源的波长。大气中的波长受周围空气的折射率的影响，而折射率又取决于温度、相对湿度和气压。如果没有适当的环境控制，系统精度和重复性将会下降，并限制最终产品的质量。我们用激光干涉仪系统设计并生产了一种新的精密机床环境试验室。该房间由一台精密空调、一个正负压控制器和一个被隔热板包围的封闭工作空间组成。空调提供了温度变化0.2℃P-V(峰谷)和湿度变化4%P-V的受控环境。通过将内部压力相对于外部调整为负或正，负/正控制器可以将均匀压力保持在0.4hPaP-V的精度内。采用绝缘板制作室框，成本低，施工方便。为了验证环境控制的长期性能，测量了刀具相对于工件的相对位移的波动和光栅式飞切形成的表面轮廓。获得了109 nm的P-V位移波动和91 nm的P-V形状精度；这两个结果都证明了由于新的环境室的高度补偿的精度。

Since laser interferometer systems are high accuracy, non-contact measurement and easy installation, the systems have been incorporated into such manufacturing equipment as precision cutting machines, measuring machines and lithographic systems. The unit of measure for a laser measurement system is dependent on the wavelength of the laser source. The wavelength in atmosphere is affected by the refractive index of surrounding air, which depends on the temperature, relative humidity and air pressure. Without proper environmental control, degradation in system accuracy and repeatability will occur and limit the quality of final products. We have designed and produced a new environmental chamber for precision machine tools with laser interferometer system. The chamber consists of a precise air conditioner, a negative/positive pressure controller and a closed workspace surrounded with the insulating panels. The air conditioner provides the controlled environment within temperature change of 0.2℃ P-V (peak-to-valley) and humidity change of 4% P-V. The negative/positive controller can maintain an even pressure within an accuracy of 0.4hPa P-V by adjusting inside pressure to either negative or positive relative to outside. To utilize the insulating panels for making the chamber frame allows for low cost and easy construction. The fluctuation in the relative tool displacement to the workpiece and the surface profile formed by raster flycutting are measured to verify the environmental control performance for a long period. A fluctuation of 109nm P-V in the displacement and a form accuracy of 91nm P-V are obtained ; both the results demonstrate the highly compensated accuracy due to the new environmental chamber.