Standards and Calibration Laboratory (SCL) has developed a new system for line scale calibration. Line scales are generally made of glass and are accurately engraved with equidistant parallel lines on the surface. They are commonly used as reference standards to determine the distance and travel accuracy. Line scales are usually embedded in or equipped with measurement systems such as length comparators, microscopes and length measuring instruments.

The new system uses the displacement method and employs an air bearing stage driven by a piezoelectric motor. A single laser interferometer is used in this system to compensate the Abbe error in two lateral directions. As the SCL is located on the 35th floor of a high-rise building, the system might experience vibration due to wind and road traffic. To mitigate this problem, the major part of the system is placed on a floating table. The system can calibrate line scales of range 0.01 – 750mm with the best measurement uncertainty of 0.15 – 0.41μm. The design concept of the system is described in a paper "A Submicron Automated Precision Line Scale Calibration System Developed at the SCL" presented at the National Conference of Standards Laboratories International Workshop & Symposium in August 2017.