Virtual groups - a new strategy for functional layouts

The research presented in this thesis identifies the need to develop a strategy specially designed to improve the operational performance of functional layouts. The traditional approach has been to replace functional layouts with product-oriented layouts such as cellular manufacturing or flow lines. However, conditions exist in some functionally organised factories that prevent changes to the factory layout being made. In such cases, a number of tactics, operational strategies and concepts were identified which are capable of addressing the operational weaknesses of functional layouts. These include lean, agile and virtual cellular manufacturing. It was these concepts, which influenced the development of a new manufacturing strategy for functional layouts called virtual groups. Virtual groups are groups of machines with the potential to form physical manufacturing cells. This potential is limited by the difficulty of moving machines and shortages in the number of machines available to populate manufacturing cells. Virtual groups are virtual° because although they are considered as manufacturing cells, the constituent machines are physically dispersed throughout the factory. There are two key aspects of virtual groups. The first is the opportunity to replace the focus on °processes° with a focus on products'. This is achieved by replacing process managers withgroup managers who are responsible for the production of products rather than the management of processes, to whom all the production resources required to produce a family of parts/products are assigned. The second aspect is the assignment of the most appropriate production strategy to each virtual group. This presents the opportunity to target the production capabilities and management policies that will best address the market conditions in which the products will compete. Other benefits of virtual groups are expected to include lower WIP, improved quality, on-time delivery and reduced throughput times. Also presented in this thesis is the development of a new methodology for the formation of virtual groups called enhanced production flow analysis. Enhanced production flow analysis has been developed to identify virtual groups of machines and families of parts, which each virtual group is responsible for producing. Initially it was believed that elements of J.L Burbidge's production flow analysis could be used to form virtual groups however the first trial of the methodology showed that to identify the most appropriate virtual groups some enhancements were required, particularly to the method for forming modules. The ability of enhanced production flow analysis to form virtual groups was successfully tested through the use of two data sets collected from two different Pirelli factories. In both cases, opportunities were identified to form lean process-oriented virtual groups and agile product-oriented virtual groups. The formation of process-oriented virtual groups is not ideal, as some of the machines will continue to be managed in a functionally organised group. However, their existence signals the relevance of virtual groups over cellular manufacturing.