Related Experiment Video
Updated: Dec 16, 2025

Automatic Laser-based Geometry Capture for Finite Element Analysis of Weld Beads
Published on: July 25, 2025
An accurate inner diameter measurement
Sanjid Arif Mahammad1, K P Chaudhary2, Sanjay Yadav3
1Length, Dimension, and Nanometrology, CSIR- National Physical Laboratory, New Delhi 110012, India.
Abstract:
The inaccurate deflection behavior of the probing system degrades the performance of the diameter-measuring machines. In this experiment, the probing is improved, applying an autocollimator and an angular positioning datum. We have devised this datum using a liquid wedge. A ring gauge is chosen as a workpiece to evaluate the deflection behavior of the probing system. The improved uncertainty of the probing is found as low as 40 nm. Subsequently, the inner diameter of the ring gauge is measured on this experimental setup. By employing a simulation, we aligned the workpiece. The deflections of the stylus are optimized to achieve zero deflection error at the zenith points. Consequently, the swing of the probe at the zenith points is combined with the rectilinear displacement of the workpiece to estimate the inner diameter. The uncertainty of the measurement of the ring gauge is improved up to 140 nm.
Related Concept Videos
Uncertainty in Measurement: Reading Instruments
Distance Corrections
Accuracy and Precision
Accuracy, limits, and approximation
Accuracy is defined as the closeness of the measured value to the true or actual value. In engineering mechanics, repeated measurements are taken during theoretical or experimental analyses to ensure that the result is precise and accurate.
The accuracy of any solution is based on the...
Adjusting a Traverse
Uncertainty in Measurement: Accuracy and Precision

