The Assessment of the suitability of reconfigurable design through simulation and decision trees

Abstract

Positioning of the equipment of a manufacturing company is done foreseeing that it will remain fixed for a long time. This is because changes in the plant layout are thought to be costly, as they involve redesigning equipment support services, developing new foundations, using heavy machinery to move equipment, and causing non-productive time at the plant. However, the increased competition due to globalization, lead us to consider the alternative of making modifications to the layout more frequently to improve productivity. Changing the position of the equipment can be facilitated by specifying smaller mobile process equipment or by anticipating the availability of services at different points in the workshop and the existence of cranes or other means of transportation [2]. These forecasts, result in a greater investment in elements that, at least initially, do not generate any profit. This work shows the evaluation of the feasibility of modifying the positions of the equipment when there are variations in the probability distribution in production speeds. This evaluation is carried out using decision trees and process simulation. The case study addressed consists of a generic production line with serial workstations. Jobs arrive at the first computer and join their product on hold if space is available, otherwise the job is lost. In the same way, the product on hold of the other teams are limited in size, and when a product on hold is full, the team behind stops until there is space available. Due to the use, the speeds of the equipment are changing with respect to the ones they had when new: the process times are increasing and / or becoming more variable. To improve productivity under the new process speeds, the space between the equipment can be modified, however, during this change, production must be suspended. This work shows how, by simulating processes and decision trees, it is possible to determine the ranges of values of the suspension time and the cost of transport for which it is convenient to make changes in the spacing of the equipment.