پیکربندی انعطاف پذیری: تجزیه و تحلیل تجربی از انعطاف پذیری حجم و ترکیب محصول

In this paper we address flexibility and investigate the relationship between volume and product mix flexibility. One view of flexibility is that of being a capability in itself; another view is that of flexibility as an enabler, providing the manufacturing system with properties on which other competitive capabilities are built. In this research, the latter view of flexibility is used, where flexibility acts as a second order competitive criterion. The aim is to differentiate between two dimensions of flexibility important to the manufacturing value chain, i.e., volume and product mix flexibility, and to investigate how different flexibility configurations are related to various manufacturing practices. A clustering research approach is used to identify groups of companies based on flexibility configurations. The groups are then analyzed with respect to characteristics and impact on operational performance. For the empirical investigation, we use empirical data from the high performance manufacturing (HPM) study, including three industries and seven countries—a total of 211 plants. We find that flexibility configurations based on high or low levels of volume and mix flexibility combinations show significant differences both in terms of operational performance, and in terms of emphasis put into different flexibility source factors.

Increased competition, global markets, and more challenging customers are all ingredients of today's business environment and contributors to higher uncertainty and variability. Manufacturing flexibility has been proposed to handle or mitigate the effects of these challenges [1] and [2]. Manufacturing flexibility is an important element of a firm's operations strategy, as being one of the main competitive priorities commonly used [3]. This view makes flexibility a goal in itself. Another view of flexibility is as an enabler; a means for providing the capability to respond quickly to shifts in the market [4]. In this study we take the latter perspective, with manufacturing flexibility as an enabler that provides the manufacturing system with properties on which other capabilities are built. Although manufacturing flexibility is recognized as important, the value of flexibility has been difficult to establish empirically. However, there are case studies concerned with the evaluation of flexibility using mathematical modeling, see [2], [5] and [6]. Still, Dreyer and Grønhaug [7] claim that empirical research on manufacturing flexibility is still lagging. Then again, performance metrics such as overall profitability and return on assets are related to the company as a whole and thus distorted by other functions within the company. To better assess the actual impact from manufacturing flexibility on the performance of the manufacturing function, the use of operational performance have been proposed [8] and [9]. While past research informs about how manufacturing firms can successfully achieve a certain type of flexibility, there are few insights for understanding how different types of flexibility can be simultaneously achieved within a manufacturing plant and its supply chain [10]. In a recent case study, Salvador et al. [10] found that a few approaches used to increase volume flexibility actually negatively affected mix flexibility and vice versa. They also observed that, to some extent, volume and mix flexibility may be achieved synergistically. They identified a need for large-scale empirical research. This paper fills this gap by providing an empirical study of the interrelationships among volume and product mix flexibility. The purpose of this empirical study is threefold: (i) we aim to investigate how volume flexibility and product mix flexibility are interrelated. For flexibility configurations based on high or low levels of volume and product mix flexibility, we aim to (ii) analyze the impact on operational performance, and (iii) analyze the source factors that firms use to establish high levels of volume and/or mix flexibility. We link the flexibility source factors to the strategic flexibility approaches by Gerwin [1] for how to cope with uncertainty, i.e., proactive and adaptive approach. In doing so, we answer Gerwin's [1] call for applied flexibility research aimed at managerial application and problem-solving that makes academic operations management research more relevant and accessible to managers. The paper is organized as follows. We first review the literature on manufacturing flexibility related to our purpose, before presenting our conceptual model. We then describe the research methodology and the empirical study. Finally, we present the results and discuss managerial and research implications.

In this paper, we have used flexibility configurations to show the operational value of manufacturing flexibility. We also analyzed the effects of various practices, both proactive and adaptive, on the development of flexibility. We find that the flexibility configurations based on high or low levels of volume and mix flexibility combinations show significant differences both in terms of operational performance and in terms of emphasis put into different flexibility source factors. Since there are some significant differences between the firms focusing on volume flexibility versus those that focus on mix flexibility, we can conclude that there are indeed differences between mix and volume flexibility, and it is not only a question of high versus low levels of flexibility. We find that plants exhibiting high levels of flexibility generally perform better than those showing low levels of flexibility, on all four operational performance measures: cost, conformance quality, on-time delivery, and delivery speed. The volume flexible plants generally perform better than mix flexible plants, but the difference is only significant for on-time delivery. Volume flexibility seems to be the key ingredient in high flexibility plants, but for delivery speed it seems to be more important to be both volume and mix flexible, since the high flexibility plants perform significantly better than the plants that are only volume flexible. The findings have implications for both practitioners and researchers. To gain managerial insights we have targeted manufacturing practices that are hands on and broadly applicable in order to provide practical guidelines for flexibility development for manufacturing value chain operations. In this paper, we have answered Gerwin's [1] call for flexibility research aimed at providing managerial guidelines for developing manufacturing flexibility, as well as the call by Salvador et al. [10] for large-scale empirical testing of mix flexibility, volume flexibility and their interaction. We also addressed Upton's [21] observation that one of the major causes for unsuccessful flexibility development efforts is the inability to identify “which factors most affect it (flexibility)”. In general, Table 5 indicates the relative importance of practices for volume and mix flexibility. The top three practices for both volume and mix flexibility are design for manufacturing, multi-trained employees, and advanced manufacturing technology, referring to flexibility competencies related to the product, the process, and the personnel. This indicates that flexibility is not achieved through a single factor; rather it is created through a mix of flexibility source factors. When comparing volume and mix flexibility, the volume flexible plants show higher levels of practices of TPM, SPC, STR, AMT, SLC, and MTE, while mix flexible plants show higher levels of DFM and modular product design, both related to the product–process interface. Thus, all adaptive approaches are utilized to a higher extent for volume flexibility. The result for STR is interesting, since the empirical study shows that this practice is significantly higher for volume flexible plants than for mix flexible plants. The results support the finding in the case study by Salvador et al. [10] that slack capacity and worker training improve volume flexibility. The results also support the finding in the case study by Yang et al. [44] that DFM is more related to mix flexibility (but not significantly compared to volume flexibility). For researchers, this study adds detail to the analysis of the relationships between flexibility source factors, output flexibility types, and the impact on operational performance. The results of the study show that specific flexibility configurations have distinctly different effects on operational performance of the manufacturing value chain.