CORRECTING PROGRAMMES FOR MACHINING FREE-FORM SURFACES ON THE BASIS OF COORDINATE MEASUREMENT DATA

Malgorzata Poniatowska

Abstract

The paper presents a methodology of correcting systematic influence of machining processes on free-form surfaces. Such correction is performed off-line by introducing alterations compensating this influence to machining programmes. The effect of systematic influence of machining are deterministic deviations of surfaces. CAD models of these deviations, averaged for a number of surfaces machined under repeatable conditions, represent machining pattern models which serve as the basis for performing correction. The basis for developing such models, are surface deviations determined during coordinate measurements carried out along a regular grid of points. For estimating surface models of deterministic deviations, the author’s own methodology is proposed, in which the regression analysis, spatial statistics methods, an iterative procedure, and NURBS modelling are applied.<BR />A machining pattern model with the opposite sign was used for compensating systematic influence of the milling process through modifying the nominal geometry data and correcting the machining programme. Surfaces machined after the correction according to the proposed methodology has been introduced are characterised by a considerably greater accuracy than these produced after the correction performed on the basis of raw measurement data.

Keywords

coordinate measurement, free-form surface, deviation, machining pattern model, error correction

Download

IMEKO-TC14-2013-36.pdf

DOI

-

IMEKO TC

TC14 - Measurement of Geometrical Quantities

Back to the proceedings