Analysis of a Flowshop with Finite Capacity Buffers through Heuristic Rules

The production facilities of some factories can be considered as a flowshops. Flowshops are composed of resources arranged serially in r sections or stages where a set of n parts is processed. There are buffers between two consecutive stages. Each part has at most r operations (one per stage) and the flow of the jobs is oneway from stage 1 to stage r. In some companies of this type, the input sequence of items has a very important incidence in the capacity dimension of buffers between stages. Though the capacity dimension problem must have been tackled during the productive and logistic system design phase, it can appear again during the different life-cycle phases of the designed system and due to different circumstances: increasing of customised products, reduction of life-cycle of products, acquisition of new equipment, redesign of the lay-out, changes in processing times and tools, etc. The aim of this study is to analyse the impact of the different sequence heuristic rules on the capacity dimension of the buffers between some of the stages belonging to a shoe factory. The company section under study can be considered as a flowshop. The analysis need arises due to a productive process modification of one of the three stages that affects the processing times of items considerably. Given a set of heuristic rules the company objective is to determine the heuristic that, satisfying the capacity buffers restrictions and considering the new productive data, provides the best results for the company’s criteria.