Modular Assembly Systems Simulation for Lead Time Reduction

The industrial environment and competition today is hard, all companies need to strive forward to survive, not only in the aspects of buying and selling, but also in the research aspects. Increased global competitiveness is only one important issue mentioned in Visionary Manufacturing Challenges for 2020 (NRC 1988), Swedish technology foresight panel 4 (IVA 2000) and Made in Holland (Deloitte 2003). These roadmaps are addressing the importance of flexibility, reusability, competitiveness, competence and customer value of the future manufacturing systems. If nothing is done within a few years to improve the situation, it is predicted that 20% of the production facilities will be lost to low cost countries with labour flexibility as the main tool for production planning and control. Some of the other issues in these roadmaps for the future are: Functional sales, flexibility, reconfigure ability, individualised products, and short lead times. These statements make modular assembly systems to one of the future key enablers for successful and profitable production. However, there is a need for technology enabling minimisation of modular assembly systems resetting lead-time. In order to reconfigure the assembly system with a minimum of lost production caused by time consumption in the reconfiguration process, rework, and ramp-up of new products or product variants, there is a need for “offline” reconfiguration, without disturbing the ongoing product assembly. This can be done by using an approach where the modules in the assembly system are available in digital form, where discrete event simulation software can be used to analyse the reconfiguration process as well as the assembly process effectiveness. Johansson and Kaiser (2002) discusses the use of Discrete Event Simulation software in the reconfiguration process of assembly systems, however this approach did not consider the modular aspects of the assembly system, which is even more powerful. In this paper an extensive review is made in order to find the right discrete event simulation software approach to use with reconfigurable modular assembly systems, in order to handle “offline” experiments and reconfiguration of the systems. The aim is to sort out the effects and various important factors for successful use of Discrete Event Simulation software applied on reconfigurable modular assembly systems. The results indicates that no such “perfect” software is available on the market, however development in certain software platforms are aiding the demand and in the near future some software packages will provide solutions for this technology. Twelve potential softwares were chosen out of over 50 to be included in a deeper study, where each software was analysed more in detail, the functionality was tested, the interface was evaluated etc