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A kinematic approach for error modelling in drilling

Wilma Polini (Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy)
Andrea Corrado (Department of Civil and Mechanical Engineering, University of Cassino and Southern Lazio, Cassino, Italy)

Engineering Computations

ISSN: 0264-4401

Article publication date: 10 May 2019

Issue publication date: 5 June 2019

110

Abstract

Purpose

The purpose of this paper is to model how geometric errors of a machined surface (or manufacturing errors) are related to locators’ error, workpiece form error and machine tool volumetric error. A kinematic model is presented that puts into relationship the locator error, the workpiece form deviations and the machine tool volumetric error.

Design/methodology/approach

The paper presents a general and systematic approach for geometric error modelling in drilling because of the geometric errors of locators positioning, of workpiece datum surface and of machine tool. The model can be implemented in four steps: (1) calculation of the deviation in the workpiece reference frame because of deviations of locator positions; (2) evaluation of the deviation in the workpiece reference frame owing to form deviations in the datum surfaces of the workpiece; (3) formulation of the volumetric error of the machine tool; and (4) combination of those three models.

Findings

The advantage of this approach lies in that it enables the source errors affecting the drilling accuracy to be explicitly separated, thereby providing designers and/or field engineers with an informative guideline for accuracy improvement through suitable measures, i.e. component tolerancing in design, machining and so on. Two typical drilling operations are taken as examples to illustrate the generality and effectiveness of this approach.

Research limitations/implications

Some source errors, such as the dynamic behaviour of the machine tool, are not taken into consideration, which will be modelled in practical applications.

Practical implications

The proposed kinematic model may be set by means of experimental tests, concerning the industrial specific application, to identify the values of the model parameters, such as standard deviation of the machine tool axes positioning and rotational errors. Then, it may be easily used to foresee the location deviation of a single or a pattern of holes.

Originality/value

The approaches present in the literature aim to model only one or at most two sources of machining error, such as fixturing, machine tool or workpiece datum. This paper goes beyond the state of the art because it considers the locator errors together with the form deviation on the datum surface into contact with the locators and, then, the volumetric error of the machine tool.

Keywords

Acknowledgements

This research has been partially funded by the Italian Ministry of University and Research (MIUR).

Citation

Polini, W. and Corrado, A. (2019), "A kinematic approach for error modelling in drilling", Engineering Computations, Vol. 36 No. 4, pp. 1364-1383. https://doi.org/10.1108/EC-11-2018-0511

Publisher

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Emerald Publishing Limited

Copyright © 2019, Emerald Publishing Limited

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