Optimizing cylindricity measurement accuracy: Error sources analysis and error compensation strategies in calibration labs

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Volume Title

Insinööritieteiden korkeakoulu | Master's thesis

Date

2024-06-10

Department

Major/Subject

Zero Defect Manufacture for a Circular Economy

Mcode

Degree programme

Master’s programme in Manufacturing

Language

en

Pages

55 + 16

Series

Abstract

Cylindricity, a critical parameter in mechanical engineering, ensures the quality of rotary components. The cylindricity measuring machine in a calibration laboratory is dedicated to accurately measuring the straightness and roundness of cylindrical objects. A traditional cylindricity measuring machine consists of a rotary table, a stylus, and a column and arm for guiding vertical and horizontal movement. This thesis aims to enhance the accuracy of cylindricity measurements in laboratory settings. Four key error sources were identified: rotary table error, probe precision, parallelism error, and straightness error. To quantify these error sources, five types of measurements were conducted according to the ISO 17025:2017 and ISO 9001:2015. The measured results were then compared with the manufacturer’s specification. Importantly, MATLAB scripts were also employed to analyse and compensate for these errors. Results show that while the rotary table error meet specifications and probe precision is acceptable, parallelism error and straightness error exceed them. However, compensation techniques can be applied for parallelism error and straightness error, significantly reducing instrument contribution to measured cylindricity error. Finally, measurement uncertainty was evaluated both with and without error compensation, demonstrating a notable reduction when compensation techniques were applied. The insights gained will be applied to future cylindricity measurements at VTT MIKES, with accompanying instructions recorded in the institute's instructional materials. The findings also offer practical solutions for improving cylindricity measurements in calibration laboratories, contributing to the field's ongoing refinement and development.

Description

Supervisor

Partanen, Jouni

Thesis advisor

Hemming, Björn
Ghadimi, Pezhman

Keywords

metrology, cylindricity error, error separation, measurement uncertainty, roundness, straightness

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Citation