Swee K. Leong

Framework and indicators for a sustainable manufacturing mapping methodology

Increasing numbers of companies in the manufacturing industry have identified market potential for implementing sustainable and green manufacturing. Yet, current sustainability assessment tools for companies are complicated, requiring vast amounts of data and technical expertise to use them. Value Stream Mapping (VSM) is founded on lean practices, and it uses a simple method to analyze various types of material, energy, and information flow needed to bring products and services to the end-customer. The objective of this paper is to introduce and illustrate the application of a VSM-based assessment, termed as Sustainable Manufacturing Mapping (SMM). SMM takes chosen sustainability indicators into consideration and is based on VSM, Life Cycle Assessment (LCA), and Discrete Event Simulation (DES). The main phases of SMM include goal definition, identification of the sustainability indicators, and modeling the current and future state process maps. In this paper, some example indicators were identified and an SMM process map was generated for illustrative purposes.

The expanding role of simulation in future manufacturing

Simulation technology holds tremendous promise for reducing costs, improving quality, and shortening the time-to-market for manufactured goods. Unfortunately, this technology still remains largely underutilized by industry today. This paper suggests benefits to industry resulting from the widespread, pervasive implementation of manufacturing simulation technology. Potential simulation impact areas are closely intertwined with strategic manufacturing. Yet, a number of factors currently inhibit the deployment of simulation technology in industry today. The development of new simulation interface standards could help increase the deployment of simulation technology. Interface standards could improve the accessibility of this technology by helping to reduce the expenses associated with acquisition and deployment, minimize model development time and costs, and provide new types of simulation functionality that are not available today.

A test implementation of the core manufacturing simulation data specification

This paper describes an effort of testing the Core Manufacturing Simulation Data (CMSD) information model as a neutral data interface for a discrete event simulation model developed using Enterprise Dynamics. The implementation is based upon a model of a paint shop at a Volvo Car Corporation plant in Sweden. The model is built for a Swedish research project (FACTS), which focuses on the work procedure of developing new and modified production systems. FACTS has found standardized simulation data structures to be of high interest to achieve efficient data collection in conceptual stages of production development programs. For the CMSD-development team, implementations serve as an approach to validate the structures in CMSD and to gather requirements for future enhancements. CMSD was originally developed to support job shops, but the results of this implementation indicate a good possibility to extend CMSD to also support flow shops.

Discrete event simulation to generate requirements specification for sustainable manufacturing systems design

A sustainable manufacturing systems design using processes, methodologies, and technologies that are energy efficient and environmental friendly is desirable and essential for sustainable development of products and services. Efforts must be made to create and maintain such sustainable manufacturing systems. Discrete Event Simulation (DES) in combination with Life Cycle Assessment (LCA) system can be utilized to evaluate a manufacturing system performance taking into account environmental measures before actual construction or use of the manufacturing system. In this paper, we present a case study to show how DES can be utilized to generate requirements specification for manufacturing systems in the early stages of the design phase. Requirement specification denotes the description of the behavior of the system to be developed. The case study incorporates use of LCA data in combination with DES. Data for the model in the case study is partly provided through the format supported by the Core Manufacturing Simulation Data (CMSD) standardization effort. The case study develops a prototype paint shop model, and incorporates alternate decisions on energy use, choice of machines, and environmental bottleneck detection. The study results indicate the potential use of utilizing DES in combination with LCA data to generate requirements specification for designing sustainable manufacturing systems.

Input data management methodology for discrete event simulation

Input Data Management (IDM) is a time consuming and costly process for Discrete Event Simulation (DES) projects. In this paper, a methodology for IDM in DES projects is described. The approach is to use a methodology to identify and collect data, then use an IDM software to extract and process the data. The IDM software will structure and present the data in Core Manufacturing Simulation Data (CMSD) format, which is aimed to be a standard data format for any DES software. The IDM methodology was previously developed and tested by Chalmers University of Technology in a case study in the automotive industry. This paper presents a second test implementation in a project at the National Institute of Standards and Technology (NIST) in collaboration with an aerospace industry partner.

Stress testing a supply chain using simulation

Simulation provides the capability to evaluate performance of a system operating under current or proposed configurations, policies and procedures. It is very applicable to evaluation of strategic and operational level plans for supply chains. It is especially useful for exploring the viability of a supply chain before beginning production. This paper describes the use of simulation for determining the readiness of a supply chain designed by a small company for providing sub-systems to a defense contractor. The supply chain had to be stress tested at surge and mobilization volume levels to meet the requirements. Simulation provided the ideal methodology to identify and demonstrate the behavior of the supply chain under stress and evaluate strategies to meet the defined volumes. It was used to prove the readiness of the supply chain reducing perceived risks in using the virtual operation.

A framework for standard modular simulation

The primary reason for building manufacturing simulations is to provide support tools that aid the manufacturing decision-making process. Simulations are typically a part of a case study commissioned by manufacturing management to address a particular set of problems. The objectives of the case study determine the types of simulation models, input data, and output data that are required. Neutral model libraries and interface data standards could simplify the simulation analysts job and significantly improve the simulation case study process. This paper describes a proposed framework for simulation standards development. The framework is comprised of four major component elements: (1) industry sector, (2) hierarchical level of the manufacturing organization, system, or process, (3) simulation case study area, and (4) manufacturing model and data types.

Enabling flexible manufacturing systems by using level of automation as design parameter

Handling flexibility in an ever changing manufacturing environment is one of the key challenges for a successful industry. By using tools for virtual manufacturing, industries can analyze and predict outcomes of changes before taking action to change the real manufacturing systems. This paper describes a simulation tool that can be used to study the effect of level of automation issues on the design of manufacturing systems, including their effect on the overall system performance, ergonomics, environment, and economic measures. Determining a suitable level of automation can provide a manufacturing system with the flexibility needed to respond to the unpredictable events that occur in factory systems such as machine failures, lack of quality, lack of materials, lack of resources, etc. In addition, this tool is designed to use emerging simulation standards, allowing it to provide a neutral interface for both upstream and downstream data sources.

Energy efficiency analysis for a casting production system

A growing number of manufacturing industries are initiating efforts to address sustainability issues. A study by the National Association of Manufacturers indicated that the manufacturing sector currently accounts for over a third of all energy consumed in the United States. There are many areas and opportunities to reduce energy costs and pollution emissions within a manufacturing facility. One way to achieve an energy efficient manufacturing system is to measure and evaluate the combined impact of process energy from manufacturing operations, their resources (e.g., plant floor equipment), and facility energy from building services (e.g., ventilation, lighting). In this paper, issues associated with integrating production system, process energy, and facility energy to improve manufacturing sustainability are explored. A modeling and simulation case study of analyzing energy consumption in a precision casting operation is discussed.

Impact of Energy Measurements in Machining Operations

Over the past years, institutions in general are increasingly interested and involved in sustainability and social responsibility. In addition, social and political pressures have lead to the creation of new regulations and policies that support new business opportunities around global sustainability. Considering sustainable manufacturing, a number of indicators have been proposed and currently being researched. The aim of this paper is to explore and discuss the impact of energy measurements as an indicator for sustainable manufacturing. The main question to be asked is that can energy measurement be used for process optimization in machining level. Based on energy monitoring during two Computer Numerical Control (NC) machining case studies, the significance of energy cost based on different CNC machining strategies and parameter settings is examined and discussed. The preliminary results from the energy measurements on the case studies indicate that potential cost savings in energy will be minimal in CNC operations. Based on the case studies, the potential energy savings in monetary value do not necessarily justify a companys investment in implementing real time energy tracking technologies the results were limited in scope with regards measuring energy as indicator for evaluating other performance outcomes.