DETERMINATION OF THE GEOMETRICAL PARAMETERS OF ROCKWELL DIAMOND INDENTERS BY ITERATIVE REGRESSION METHOD

Satoshi Takagi

Abstract

For the verification of Rockwell diamond indenter exactly following the international definition, an iterative method with the least square circle fitting was introduced. This method was applied to the analysis of verification data obtained with a laser probe 3D profile measurement instrument. It was demonstrated that the technique can be used to express the geometrical parameters properly with analytical results as an example. In addition, this technique can be applicable to determine equivalent geometrical parameters obtained with the optical measurement system currently used at NMIJ to establish the national standard indenters. It is shown that the proposed method can describe the geometry of indenter better than currently used method. These results suggest that the uncertainty of the national standard indenter could be improved through this high resolution geometry measurement and the multiple regression analysis NMIJ has been using.

Keywords

Rockwell diamond indenter, tip radius, cone angle, laser probe 3D profile measurement instrument, least square circle fitting

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IMEKO-WC-2012-TC5-O4.pdf

DOI

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IMEKO TC

TC5 - Hardness Measurement

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