From COTS simulation software to an open-source platform: a use case in the medical device industry

The implementation of Discrete Event Simulation (DES) - based decision support tools in complex manufacturing environments could prove of invaluable help to industrial practitioners involved in cross-functional decision processes at multiple hierarchical levels. The increasing number of decision variables, their stochastic nature and the non-linearity of their mutual relationships theoretically make simulation a preferred modelling approach for a great variety of manufacturing systems as strict simplifying assumptions are not necessarily required and the models' detail level can be tuned according to the analysis purposes. However, recourse to Commercial Off-The-Shelf (COTS) simulation packages to develop and implement simulation-based solutions in real manufacturing environments usually presents significant cost-of-ownership (COO). Along with license costs, modelling flexibility and sustainability represent fundamental issues raised by industrial engineers that adopt COTS simulation packages. In order to promote the use of DES in production related decision making processes and reduce the associated COO for manufacturing companies, an open-source simulation platform, ManPy, has been developed. ManPy consists of a library of DES objects implemented in SimPy. ManPy's scope is to provide modellers with generic, highly customizable open-source simulation objects that can be connected to form a model in the same fashion of COTS simulation packages. ManPy's on-going development is based on guidelines provided by the analysis of real industrial use cases. Specific pilot models developed in SimPy are used to identify new objects and relevant features to be incorporated in ManPy in order to make it a highly flexible simulation tool. In this article, a use case based on a labour intensive serial production line operating in a medical device manufacturing plant is described. Insights for the transition from a COTS simulation model to a specific SimPy model and finally to generic ManPy objects are presented. (C) 2014 The Authrs. Published by Elsevier B.V.