Simulation Modeling in Manufacturing Cell Design

The interwoven phases of the manufacturing process in Computer Integrated Manufacturing (CIM) require a carefully designed facility. Simulation modeling can be combined with other techniques to provide a rigorous methodology for CIM system design. This paper describes CIM, simulation ana their relationship. A case study demonstrates the described methodology in the design of a flexible manufacturing cell

A Methodology for Continuous Quality Assurance of Production Data

High quality input data is a necessity for successful Discrete Event Simulation (DES) applications, and there are available methodologies for data collection in DES projects. However, in contrast to standalone projects, using DES as a day-to-day engineering tool requires high quality production data to be constantly available. Unfortunately, there are no detailed guidelines that describes how to achieve this. Therefore, this paper presents such a methodology, based on three concurrent engineering projects within the automotive industry. The methodology explains the necessary roles, responsibilities, meetings, and documents to achieve a continuous quality assurance of production data. It also specifies an approach to input data management for DES using the Generic Data Management Tool (GDM-Tool). The expected effects are increased availability of high quality production data and reduced lead time of input data management, especially valuable in manufacturing companies having advanced automated data collection methods and using DES on a daily basis

Development of a regionalized implementation strategy for smart automation within assembly systems in China

Companies struggle to overcome the difficulties stemming from the dynamic environment of global production due to the specific conditions in different regions. Particularly, insufficient know-how about a regionalized implementation strategy of smart automation (SmAu) technologies is one significant difficulty for enterprises. Thus, developing a key performance indicator (KPI) oriented, regionalized implementation strategy for smart automation technologies is increasingly important. In this context, a new approach is exposed to systematically investigate and identify the interdependencies among location factors, smart automation technologies, and KPIs. Firstly, the environment consisting of location-related factors, KPIs and smart automation technologies is defined in detail. Further, a Catalog quantifies the influence of different regions in China. Secondly, important aspects to model the qualitative and quantitative interdependencies in a multimethod simulation are introduced. Subsequently, an approach to analyze suitable implementation strategies is presented. A case study based on a production line for digitalized production technology is used to validate the proposed approach

Assessing Excel VBA Suitability for Monte Carlo Simulation

Monte Carlo (MC) simulation includes a wide range of stochastic techniques used to quantitatively evaluate the behavior of complex systems or processes. Microsoft Excel spreadsheets with Visual Basic for Applications (VBA) software is, arguably, the most commonly employed general purpose tool for MC simulation. Despite the popularity of the Excel in many industries and educational institutions, it has been repeatedly criticized for its flaws and often described as questionable, if not completely unsuitable, for statistical problems. The purpose of this study is to assess suitability of the Excel (specifically its 2010 and 2013 versions) with VBA programming as a tool for MC simulation. The results of the study indicate that Microsoft Excel (versions 2010 and 2013) is a strong Monte Carlo simulation application offering a solid framework of core simulation components including spreadsheets for data input and output, VBA development environment and summary statistics functions. This framework should be complemented with an external high-quality pseudo-random number generator added as a VBA module. A large and diverse category of Excel’s incidental simulation components that includes statistical distributions, linear and non-linear regression and other statistical, engineering and business functions require execution of due diligence to determine their suitability for a specific MC project. Editorial note Although the present article is not directly concerned with “spreadsheets in education”, the decision to publish it was made on more general grounds. Microsoft Excel has received plenty of bad press concerning its statistical functions over a period of many years, and Microsoft has been slow to address many of these issues. However, the situation appears to have improved significantly since the early publications of McCullough & Wilson in the journal Computational Statistics & Data Analysis (references [72] and [73] herein), in which problems with Excel’s statistical functions were highlighted. We have chosen to publish the present article so readers have some more up-to-date information on which to base their decisions. As a final comment, readers should also be aware of the existence of RExcel, a port of the statistical package R to Excel as an add-in. It is a free download and is the work of one of our own editorial board members, Emeritus Professor Erich Neuwirth, University of Vienna. Thus, one may have one’s cake and eat it too: the acknowledged accuracy and respectability of R, along with the friendly, well-known interface of Excel

A Robust Aggregation Approach To Simplification Of Manufacturing Flow Line Models

One of the more difficult tasks facing a modeler in developing a simulation model of a discrete part manufacturing system is deciding at what level of abstraction to represent the resources of the system. For example, questions about plant capacity can be modeled with a simple model, whereas questions regarding the efficiency of different part scheduling rules can only be answered with a more detailed model. In developing a simulation model, most of the actual features of the system under study must be ignored and an abstraction must be developed. If done correctly, this idealization provides a useful approximation of the real system. Unfortunately, many individuals claim that the process of building a simulation model is an “intuitive art.” The objective of this research is to introduce aspects of “science” to model development by defining quantitative techniques for developing an aggregate simulation model for estimating part cycle time of a manufacturing flow line. The methodology integrates aspects of queueing theory, a recursive algorithm, and simulation to develop the specifications necessary for combining resources of a flow line into a reduced set of aggregation resources. Experimentation shows that developing a simulation model with the aggregation resources results in accurate interval estimates of the average part cycle time

Integrated knowledge-based hierarchical modelling of manufacturing organizations

The objective of this thesis is to research into an integrated knowledge-based simulation method, which combines the capability of knowledge based simulation and a structured analysis method, for the design and analysis of complex and hierarchical manufacturing organizations. This means manufacturing organizations analysed according to this methodology can manage the tactical and operational planning as well as the direct operation of shop floor. [Continues.

A framework for the provision of online discrete event simulation for operational decision support in complex manufacturing environments

The engineering body of knowledge contains an array of methodologies and techniques to address the effectiveness and efficiency of operational activities within a manufacturing environment. One such example is simulation modelling, a powerful analytical tool that can potentially be valuable in assisting decision makers, managers and engineers to gauge improvement opportunities and achieve process advancements. However, the cost of ownership for simulation models is not insignificant even for large multinationals, this stems from the requirements for specialist skills in simulation software, model development, data mining and statistical analysis. Simulation projects typically require a large investment to develop and usually are used-once-and-thrown-away. To reuse the model, it would require repeating a large portion of the development cycle. In order for simulation modelling to achieve wider recognition as a decision support tool there is a necessity to reduce the cost of model maintainability, promote reusability, increase flexibility and improve user friendliness. The research proposed framework intends to achieve four goals. i.) Improve and advance the deployment and maintenance requirements of simulation projects in comparison to traditional methods. ii.) Integrate automation into model deployment phase of a simulation projects. Thus, allowing unique user-specified simulation models to be generated by automatically extracting and manipulating data from factory databases. iii.) Enforce a strong documentation technique to achieve interoperability and re-traceability of project progress, therefore permitting programme code or even entire models to be reused and utilised in future projects. iv.) Advance user friendliness and acceptance towards simulation modelling. Reducing the expertise required to conduct simulation studies will improve the programming exercise image associated with typical simulation studies. This framework assists in developing customised simulation modules. These modules facilitate automated online rapid development of reconfigurable, flexible, self-maintaining simulation models, aiming to deliver tailored analysis to support real-time operational decision making

Procurement policy and allocation policy of common component in a two-echelon assembled-to-stock system

Ph.DDOCTOR OF PHILOSOPH

Análise e melhoria de um processo produtivo recorrendo a ferramentas Lean numa empresa de componentes eletrónicos

Dissertação de mestrado em Engenharia e Gestão IndustrialO presente documento insere-se no projeto de dissertação no âmbito do Mestrado Integrado em Engenharia e Gestão Industrial, realizado na empresa Aptiv. O principal objetivo deste projeto foi a análise do sistema produtivo atual e a implementação de alterações e melhorias com vista à produção de um novo produto, designado nesta dissertação de produto A, através da utilização de ferramentas Lean e outras ferramentas. Contudo, este projeto ocorre num contexto específico. De facto, este foca-se num novo produto, o produto A, constituído pelas placas eletrónicas 1 e 2, que se encontra na fase de pré séries, ou seja, em fase de testes. Assim, o projeto ocorre numa fase de planeamento estando a análise apoiada no standard para o dimensionamento de buffers, 8 horas entre Surface Mount Technology (SMT) e Circuit Board Assembly (CBA) e 4 horas entre CBA e Final Assembly (FA), e nos princípios que estarão por detrás do funcionamento do sistema. De seguida, procedeu-se à análise crítica da situação atual onde foi analisado o sistema produtivo, recolhidas todas as informações acerca deste e realizado um Value Stream Mapping (VSM) de modo a identificar a cadeia de valor e assinalar os seus principais desperdícios. A partir desta análise constatou-se que o Work-In-Process (WIP) terá um impacto elevado no sistema produtivo, devido ao facto do standard existente originar um sobredimensionamento dos buffers e, também, dos princípios de funcionamento deste serem propícios à existência de WIP. Adicionalmente, também se verificaram ineficiências ao nível do standard work. Identificadas as oportunidades de melhoria, foram realizadas diversas propostas para melhorar a performance do sistema produtivo. Estas passaram pela realização de uma simulação, com vista à obtenção de uma representação das necessidades de WIP mais ajustada à realidade, de uma nova proposta para o funcionamento do sistema baseada em FIFO LANES, e pela atualização/criação de diversas instruções de trabalho. Estimou-se que as propostas apresentadas poderiam ter um impacto bastante significativo na empresa, podendo-se traduzir num ganho anual de 28310.94€ ao nível do capital parado, numa poupança de 3545.00€ anuais resultado da redução de espaço, num aumento do rácio de valor acrescentado em 5.71% para a placa 1 e 9.7% para a placa 2 e, por fim, numa diminuição do Lead Time de 54.63% e de 57.83% para a placa 1 e para a placa 2, respetivamente.The present document describes the dissertation project carried out under the Master in Industrial Engineering and Management, developed at the company Aptiv. The main goal of the project was the analysis of the current productive system and the implementation of changes and improvements in order to produce a new product, through the utilization of Lean tools and other tools. Firstly, it is necessary to explain the context in which the project is inserted. In fact, the focus will be on a new product, product A, constituted by board 1 and board 2, currently in the pre-series stage. This way, the project occurs at a planning stage, being the analysis supported by the buffers dimensioning standard, 8 hours between SMT and CBA and 4 hours between CBA and FA, and by the principles that will be behind the functioning of the production system once regular production begins. Having this in consideration, the critical analysis of the current situation has been initiated. Here, the production system was analysed, all of its details were scrutinized and a VSM was performed in order to identify the value chain and to identify the main wastes associated with the system. In result of this analysis, it was verified that the WIP would have a major impact on the system, not only due to the fact that the standard for buffers dimensioning represents its over dimensioning, but also due to the systems functioning principles, that foster the existence of WIP. Additionally, some inefficiencies regarding the standard work were also verified. Once this analysis was finalized and the improvement opportunities were clear, several proposals towards a better efficiency of the system were developed. In the end, they can be summed up as a simulation of the functioning of the production system, a new systems design based on FIFO LANES, and the creation/actualization of work instructions. In conclusion, it was estimated that the proposal can have a very significant impact in the organization. In fact, they can be translated in an annual gain of 28310.94€ in terms of idle capital, in a reduction of the warehousing space, resulting in a saving of 3545€/year, in an increase of the value added ratio of 5.71% for board 1 and 9.7% for board 2 and, finally, in a decrease of the Lead Time in 54.63% for board 1 and 57.83% for board 2