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ENBIS9 Goteborg

20 – 24 September 2009 Abstract submission: 1 February – 31 May 2009

Analysis of variation transmission: a case study in multistage machining processes

23 September 2009, 11:35 – 11:55


Abstract

Submitted by
Biagio Palumbo
Authors
B. Palumbo (1), G. De Chiara (2), F. Sansone (1), R. Marrone (2)
Affiliation
(1)Dept of Aerospace Engineering, Univ. of Naples Federico II, Naples-Italy; (2)AVIO S.p.A., Manufacturing Technologies Dept, Pomigliano, Naples-Italy
Abstract
The study of variation transmission in multistage machining processes is a strategic task in order to understand how variation is added and transmitted across the process stages and, therefore, to identify opportunities to reduce variation in key characteristics.

In this paper an application of a data-driven technique, based on a first order autoregressive model (AR(1)), to a multistage machining process of an aero-engine component is proposed. Data on 15 key characteristics of 42 randomly selected and tracked components are taken in consideration at each of 8 sequential process stages. The statistical analysis of data relative to critical key characteristics allows to determine the quantity of variation that is added at each stage and the quantity that is transmitted from upstream. This differentiation between added and transmitted variation allows to discover which stages contribute most to key characteristics variation. The statistical and technological interpretation of results enables to identify three typical technological scenarios affecting multistage machining process. The knowledge of the variance transmission modalities related to each scenario is a winning factor in achieving quality improvement and cost reduction. It has a direct influence on the effectiveness of variation reduction efforts and may provide useful information to define manufacturing cycles or to select the machining tolerances.

The proposed case study has been developed in AVIO industry, an international aerospace company at the leading edge of propulsion technology.

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