Methods of Roundness Measurement: An Experimental Comparative Study


F.A. Elerian†, Wasim M. K. Helal*‡, M.A. AbouEleaz†


† Production Engineering and Mechanical Design Department, Faculty of Engineering, Mansoura University, Mansoura 35516, Egypt
‡ Department of Mechanical Engineering, Faculty of Engineering, Kafrelsheikh University, Kafrelsheikh, 33156, Egypt

Corresponding Author Email: dr_waseemhelal@eng.kfs.edu.eg

This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Roundness is one of the important parameters of a machined workpiece. This parameter value greatly affects the performance and lifetime of the mechanical parts. It is considered as one of the most used parameters in the control of the workpiece’s complex form. Increasing requirements to the workpiece’s form accuracy determine the relevance of improving methods and instruments for the control of form surfaces. There are many methods used to evaluate error of roundness. The most important and famous of these methods are; least square circle (LSC), maximum inscribed circle (MIC), minimum zone circle (MZC) and minimum circumscribed circle (MCC). The current study presents an experimental investigation and comparison among the methods of estimating error values of roundness by these methods. Our experimental work is based on using calibrated Ra-120 instrument. Round test RA-120 instrument was used to measure the roundness error value by the four methods (LSC, MZC, MIC, MCC) on cylindrical mild steel specimens. The main findings of the proposed experimental investigation show that the use of (MZC) method gives the lowest value for the error in measuring the roundness which justifies the mathematical and theoretical results in the literature.