Length Measurement of Long Gauge Blocks by Interferometer

Kanokporn Kohmun,Prathan Buranasiri,Pichet Limsuwan,Monludee Ranusawud

doi:10.3844/ajassp.2020.196.203

Length Measurement of Long Gauge Blocks by Interferometer

Kanokporn Kohmun, Prathan Buranasiri + Show 2 more

Open Access

https://doi.org/10.3844/ajassp.2020.196.203

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Abstract

A gauge block interferometer with a vacuum chamber was designed and constructed for the measurement of gauge block lengths between 10 to 1,000 mm. In the chamber, four gauge blocks under the length measurement can be mounted on the measuring table. Furthermore, the length of all four gauge blocks can be measured continuously in one measurement. In this study, four gauge blocks with the nominal length of 125, 200, 400 and 500 mm were used for the length measurement. The environment parameters in the vacuum chamber including temperature, pressure, relative humidity and CO2 concentration were measured. The refractive index of air which depends on environment parameters was determined by using updated Edlen equation. Then, the lengths of four gauge blocks were measured and found to be 125.00025, 200.00019, 400.00070 and 500.00064, respectively.

Highlights

Gauge blocks are generally used for accurate calibration of length measuring instruments that are widely used in industries
Even though a very high accuracy measuring methods using an interferometer, there are critical errors in interferometry caused by the environment parameters such as temperature, pressure, relative humidity and CO2 concentration (Birch et al, 1993; JongHan et al, 2007; Andrew et al, 2010; Diz-Bugarin et al, 2013)
Since the refractive index of air surrounding the interferometer depends on these parameters, the wavelength of the laser used for the length measurement of gauge blocks depends on these parameters

Summary

Introduction

Gauge blocks are generally used for accurate calibration of length measuring instruments that are widely used in industries. Since the refractive index of air surrounding the interferometer depends on these parameters, the wavelength of the laser used for the length measurement of gauge blocks depends on these parameters. Wengierow et al (2013) further developed the above automatic multiple-wavelength interferometer system with extended measurement range for calibration of long gauge block up to 1 m.

Results

Conclusion