Production simulation as a management tool

Abstract: This thesis focuses on process simulation and modelling in the context of production engineering. The thesis is presented in the form of seven papers which range in content from the holistic analysis of the application of modelling (papers 1-5) to a detailed examination of some of the areas of weaknesses in commercially available software (papers 6 and 7). The papers can be summarised as follows; Paper 1, The Use of Virtual Reality Tools in Complex Work Cell Implementation - Experiences from Scandinavian Industry; The main contribution of this work is a demonstration of the ability of process modelling tools to predict risks and disturbances during the implementation of robotic based manufacturing cells. Paper 2: The Virtual Arena; experiences from the first industrial application of a new AMT implementation methodology; The main contribution here is a preliminary outline of a methodological approach for the application of process modelling tools in the development and implementation of AMT (advanced manufacturing systems). Paper 3: A new Modelling Approach to Support Identification and Development of Secondary Processes in an Industrial AMT Implementation; The main contribution of this paper is a demonstration of extended process mapping and a modelling approach involving both main and supporting processes and the importance of staff competence. Paper 4: Competence requirements and their impact on manufacturing system performance; This paper explains how staff competence can be implemented into process models to obtain a more representative simulation of overall system performance. Paper 5: Modelling the impact of supporting processes on manufacturing system performance - experiences from an industrial case study. This paper demonstrates the use of the method introduced in paper 5 and its applicability in small cell configurations and SMEs. Paper 6: The effect of process interruption and scrap on production simulation models; This paper investigates an area of weakness in commercially available simulation software; the treatment of breakdown related scrapping events. The paper explains the different types of breakdown/scrapping dynamic possible for any given machine and demonstrates the effect of these scrapping dynamics on the Overall Equipment Effectiveness. The paper demonstrates (for the first time) the need for careful analysis and the correct choice of breakdown/scrapping dynamics in simulation models. Paper 7: Simulation of production lines involving unreliable machines: the importance of machine position and breakdown statistics; This paper the importance of choosing the correct values and statistical distributions for breakdown frequency and duration when simulating production line productivity. The pitfalls of making the wrong choices from those offered in commercially available software are pointed out. The paper also demonstrates that the common technique of reducing the standard deviation of variables to obtain a more deterministic model can lead to inaccurate results. Also, it is demonstrated that the productivity of a production line can be improved by simply re-arranging the order of unreliable machines in the line.