09515240(95)ooo38-0 ELSEVIER Framework to analyse flexibility and unplanned change in manufacturing zyxwvutsrqponmlkjihg (hmpu”r lnr qr ar ed Manuf ~ cf ur r n~ Sysvmr Vol. 9. No I. pp. 57-M. 1996 Copyright @ 1996 Published hy Elsevier Science Ltd Printed in Great Rntam. All nghts reserved 09.51.S?4OM! $15.00 + 0 00 systems Henrique L Corr&a* and Nigel Slack+ zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONM *University of S6o Pa&o, Brazil ‘University of W arwick Business School, W arw ick, UK This paper reports on the results of case-based research carried out in four organizations at the level of the ‘total manufacturing system’, two in UK and two in Brazil. The objective was to develop a conceptual framework which can be used to help analyse (and therefore manage) the ‘unplanned changes’ which affect the performance of any manufacturing system. A typology of ‘unplanned changes’ is proposed from which a new approach to the management of unplanned change in manufacturing systems is developed. This uses two complementary concepts: systems f]exibjIjty and unplanned change systems control. Unplanned change control is related to actions which avoid having to deal with the changes, whereas flexGHty is related with the decisions and actions which aim at dealing with the effects of those unplanned changes which remain uncontrolled. Copyright @ 1996 Published by Elsevier Science Ltd. Keywords: flexibility. control, uncertainty, variability Manufacturing systems flexibility Central to the effectiveness of any computer integrated manufacturing system is generally accepted as being its ability to cope with changes in the nature, mix, volume or timing of its activities. This ability is usually compressed into the team ‘flexibility’. Much of the research on computer integrated manufacturing systems flexibility has suggested that two particular factors, ‘environmental uncertainty’ and the ‘variability of outputs’, which are required from the system, are the underlying reasons for manufacturing flexibility. How- ever, there is relatively little empirically supported work which explores the mechanisms behind these influences on systems flexibility. The overall objective of this research is to fill this gap by trying to understand and explore the relationships between ‘variability of outputs’, ‘environmental uncertainty’, and ‘flexibility’ in manufacturing systems. The nature of the relationship between uncertainty and flexibility may be treated at the level of a firm’s total manufacturing operation. For example, Swamidass and Newell’ develop a model which includes the variables ‘environmental uncertainty’ and ‘manufactur- ing flexibility’, test it empirically and conclude that an organization may find some help in coping with the high uncertainties imposed by the environment by increasing its manufacturing flexibility. Gerwin2 argues that social systems facing uncertainty utilize flexibility as an adaptive response, and that since there are several kinds of uncertainty, there should be several kinds of corresponding flexibilities. Gupta and Goyal” and Slack4 suggest that manufacturing systems can utilize flexibility as an adaptive response to unpredict- able situations in both the short and long term. Gerwin and Tarondeau’ go further by suggesting links between particular types of flexibility and different types of uncertainty. Similarly, at the more micro level of the individual manufacturing cell or system, Carter6 sees manufacturing flexibility as providing an ‘insurance’ against process-related short-term uncertainty. And while techniques such as system simulation can outline the consequences of short-term uncertainty on performance, there is still a need for a priori structuring of flexibility relationships’. The literature concerning the effects of required variability at the total manufacturing systems level is relatively sparse, although it is generally seen by most authors as forming the theoretical rationale for manu- facturing system’s interest in flexibility. According to Gupta and Goya13 flexibility would allow the organiza- tion to change its competitive strategy from economies of scale to economies of scope, the thesis originally proposed by Goldhar and Jelineks. Flexible systems are also important, according to Muramatsu et aL9, to adapt the system’s output levels and variety of products to match changes in the market. Gerwin2, Kumar”, Chambers”, Frazelle12 and Stecke and Ramal also argue that the need for increased variety, and therefore flexibility, is increasing due to the changing nature of competition, which is increasingly based on the degree of responsiveness which manufacturing systems can 57