Improve the productivity and accuracy of your calibration laboratory
Local variations in the air temperature are unavoidable. They affect the wavelength of light, causing errors in the length measurements made with laser interferometers. AcWaCo is the only system that compensates for these errors, offering unprecedented accuracy of real-time length measurements.
A common method of improving the measuring accuracy in a calibration laboratory is the use of an air conditioning system. In a typical calibration laboratory the long term air temperature is in the range 20.0 ± 0.5 °C, but short term variations are often twice as big. In some high-grade calibration laboratories the air-conditioning system is able to keep the air temperature within a much narrower range, so that the air temperature never exceed the range 20.0 ± 0.15 °C. This is an example from such high-grade calibration laboratory:
Please note, that AcWaCo only removes the environmental errors. All the other sources of errors still remain and can be seen in the blue line. The thermal movements in the measured object (a steel bar in this case) affect its length. They also affect the mounting of the interferometer and the retroreflector, causing Abbey error. Other sources of errors include the variations in the frequency of the laser head, etc.
It is also necessary to understand the difference between increasing accuracy by averaging long measurements and the instant accuracy of AcWaCo. For example, long term averaging can never expose the behavior of the measuring system and the measured object caused by unpredictable thermal expansions, because the small thermal movements are completely hidden in the environmental errors.
As one can see, AcWaCo achieves target accuracy immediately (in fact, AcWaCo achieves much better accuracy because in a laboratory environment the uncertainty is always < 0.02 ppm). This has some practical consequences:
- With AcWaCo the calibration procedure is very short because long term averaging is not needed. A calibration laboratory is a business enterprise, and decreased measurement time means increased productivity.
- With AcWaCo calibration laboratories achieve better measurement accuracy. This improves their competitiveness and may be converted to higher prices for service.
- With AcWaCo calibration laboratories can be built with cheaper air conditioning systems, without degradation of measurement accuracy. It is important to keep the average temperature steady, but the range of variations is not important at all. AcWaCo compensates all temperature variations, big or small, so there's no need to invest in minimizing them.
If you are interested in the AcWaCo technology, please send an e-mail to info@acwaco.com or fill the following contact form.