Design of a Period Batch Control planning system for cellular manufacturing

Period Batch Control is a production planning system that decomposes the cellular manufacturing system into N stages and gives each stage the same amount of time P to complete the required operations. Applying the PBC system in combination with cellular manufacturing is said to result in short and reliable throughput times, and low inventory costs. However, the design of the PBC system, i.e. the size of N and P, does not follow directly from the cellular organization. We show that varying the values of both the number of stages N and the period length P greatly influences the performance of PBC. Furthermore, if both N and P have been determined, system performance is still very sensitive for different allocations of operations to the stages. We present a mathematical programming model that determines an optimal allocation of operations to stages, using a longest path orientation accompanied by a bottleneck orientation. INTRODUCTION Period Batch Control (PBC) is a production planning system that has been proposed for application within cellular manufacturing.[Burbidge,1996; Hyer and Wemmerl`v, 1982] The PBC system supports the transparency needed to effectively exploit the advantages of the cellular organised manufacturing system. Reported advantages are reliable throughput times that facilitate a reduction of the lead times, smaller work in progress, and increased autonomy within cells. Figure 1 shows the structure of the PBC planning system. The PBC system uses the same manufacturing throughput time T for all products. The period before the orders are released to the production floor is the ordering period O. This period is used for ordering raw material and required parts, controlling designs and required tools, etcetera. The products for which these activities are performed have entered the system during the order acceptance period AC. A program meeting at the end of this period determines if specific actions (such as hiring extra capacity) have to be undertaken in order to complete these orders within the total throughput time. Work orders for products are released to the production system at the end of the ordering period O. The operations that are allocated to the first stage are being performed during the next period. At the end of the period, all finished work is positioned in the decoupling stock. Bought parts that are required in the next stage will also be available at the start of the next period. The new period allows production activities on operations of the products that entered the system at time 0 and were allocated to stage 2. Note that these PBC: N=3 stages Sales Ordering