COMPUTER-INTEGRATED MANUFACTURING: A TAXONOMY OF INTEGRATION AND RESEARCH ISSUES

The past decade has seen an upsurgence in the number of manufacturing companies that are attempting to transform into computer-integrated enterprises. However, much of the computer-based integration efforts in these manufacturing organizations have been limited in scope and localized within certain areas of the organization (particularly, technology-intensive areas such as the shop floor). Such compartmentalized and myopic approaches to the development of computer-integrated manufacturing (CIM) systems undermine the ability of these systems to reach their fullest potential. CIM is much larger in scope and can impact an organization along various dimensions and at various levels. The fact that no completely integrated manufacturing enterprise has been developed to date can be attributed, in part, to a lack of understanding of the scope and implications of CIM. The purpose of this paper is, therefore, twofold. First, the paper presents a meta-schema (called TRIAD) for multidimensional and multilevel integration of a manufacturing system. Second, on the basis of the proposed meta-schema, the paper develops a taxonomical framework for defining key integration issues in CIM system design and discusses critical research needs that exist in this area. It is hoped that this paper will serve as a road map for research efforts that will enable the emergence of comprehensive CIM systems.     

Computer integrated manufacturing applications in an automotive factory

Abstract

System integration is critical to development and implementation of CIM (computer integrated manufacture). This paper outlines the elements of the CIM system implementation strategy and deals with the representation of CIM implementation stages in TO FAS; which is a car manufacturing factory. In TOFA?, a pilot CIM project has been completed with success and other projects are in the development phase.     

Economic view of CIM system architecture

The synergistic advantage of systems integration for Computer Integrated Manufacturing (CIM) has been a powerful thrust behind the productivity advancement in recent decades. However, the dependency among components, the intangible benefits and complexity of the system have been a barrier for system developers and the business community. This paper reports a systematic approach to assess economic merits of the CIM system. It projects CIM system designs on a multiple layer architecture with consideration of project life cycle. It introduces a modelling formalism to present a structured view of the economic aspect of the CIM system. The multiple criteria's aspect of CIM justification was treated with the AHP (Analytical Hierarchy Process) method. The complexity of various cost factors is reduced through application of the ABC (Activity Based Costing) method. The benefits of low level activities, both tangible and intangible, are then hierarchically aggregated into higher level system objectives. It also provides the necessary linkages between the economic and other views. A simple example was used to illustrate the approach.     

A MINIMUM-COST AUDIT SAMPLING METHODOLOGY UNDER CONDITIONS OF PREDETERMINED BETA RISK

This paper presents a minimum-cost methodology for determining a statistical sampling plan in substantive audit tests. In this model, the auditor specifies β, the risk of accepting an account balance as correct when it is not, according to audit evidence requirements. Using β as a constraint, the auditor then selects a sampling plan to optimize the trade-off between sampling costs and the costs of follow-up audit procedures. Tables to aid in this process and an illustration are provided.     

THE IMPACT OF POLLUTION CONTROL ON CONSUMER INCOME A METHODOLOGICAL STUDY

This paper develops a methodology for assessing the impact of a comprehensive pollution control program on income distribution. A regional input-output table is employed to determine the overall effect of pollution control costs on prices. These price changes, are then translated into changes in consumption expenditures by income groups, which serve as a measure of the impact on consumers. The validity of this methodology is tested on the metropolitan Philadelphia region. It was found that the EPA air quality standards would raise the spending of middle income groups by about 3 percent as compared to about 2 percent increase for the highest and the lowest income groups. The paper concludes with an examination of the advantages and limitations of the proposed methodology.     

QUANTIFYING THE IMPACT OF INVENTORY HOLDING COST AND REACTIVE CAPACITY ON AN APPAREL MANUFACTURER'S PROFITABILITY

This paper was motivated by the operational problems faced by Northco, a school uniform manufacturer in the Northeastern United States. Northco was facing high working capital costs while also incurring high stockout and markdown costs. This paper models the impact of inventory holding cost and reactive capacity on Northco's targeted understocking and overstocking cost and offers a solution methodology for such problems. We quantify the impact of varying inventory carrying costs (and hence, high working capital costs) on stockout costs and the value of additional capacity. Our results illustrate that apparel manufacturers with high working capital costs, and hence high inventory carrying costs, should target higher stockout costs and achieve lower capacity utilization. The results presented have application beyond Northco because high working capital cost is endemic to many supply chains.     

Improving throughput for an electronic assembly line using a constraint analysis methodology

Electronic assembly operations are vital to industries such as telecommunications, computers and consumer electronics. This paper presents a constraint analysis methodology for planning and improving electronic assembly operations that draws on concepts from queueing theory, simulation and production planning. The proposed methodology identifies the operational bottleneck and predicts the utilization, throughput and lead time of the assembly line. It also quantifies the relationship between yields and utilization for the assembly operations. A case study is presented that applies the methodology at an Ericsson, Inc., telecommunications equipment assembly facility. The constraint analysis methodology provided valuable decision support as the managers of Ericsson evaluated the costs and benefits of additional production capacity. Although the focus of this paper is electronic assembly operations, the methodology can be applied to general flow line assembly systems with feedback loops for test and rework under dedicated high-volume production.     

EVALUATING THE TRADE-OFFS BETWEEN IDLING AND SHUTTING DOWN PRODUCTION LINES IN PROCESS INDUSTRIES

The costs of starting-up and shutting down production lines (and plants) in a process industry are often quite high. Therefore, when a plant's capacity significantly exceeds its forecast demand over an annual planning horizon, a manufacturer must either plan temporary production line shutdowns during the year, or plan to temporarily idle production lines without formally shutting line(s) down. The trade-offs between these two strategies can be complex. In this paper, we propose a methodology to evaluate the impact of both strategies on a plant's production costs by developing an analytical model based on the authors' experience with several process industries.     

The use of life cycle costing in acquiring physical assets

This paper examines the concept of life cycle costing and explains what is involved in the use of the technique. It relates the subject to asset management and particularly to the costs of physical asset ownership. It emphasises the life cycle aspect of physical asset management and underlines the values of trade offs between initial running, operating and disposal costs. It outlines a methodology for the introduction of the technique, though allowing that the technique may be applied piecemeal. The paper includes a cast study illustrating the significance of life cycle costing.     

Linear programming and financial cost models for industrial enterprises

Linear programming models of complex interrelated manufacturing enterprises have improved production planning decisions. With a linear programming formulation, the planning engineer concerned with specifying levels of production activity need not be concerned with cost accounting formulations of product costs to make his production decisions. He is only concerned with examining alternative production activities in terms of the added production costs the activity incurs, and the amount of product that is fed or consumed. The financial analyst, however, is concerned with development of budgetted average product costs. He must roll the costs of feed and intermediate products down to the final stage products. This paper bridges these two interests by demonstrating a methodology for the direct translation of the solution of the linear programming model to the development of rolled product standard costs.     

Total production control

The new requirements for enterprise flexibility, quality improvement, costs and throughput limes reduction cannot be achieved by using traditional approaches. While US and European industry developed the grand CIM, FMS, CAD/CAM and MRP II projects, Japan introduced just-in-time and lean production, not to demonstrate the possibilities of the new technology but to expose operational inefficiencies and waste in the manufacturing process. The main CIM effort was in the flexibility and productivity improvement, bin its implementation stressed above all the technical aspects of the factory integration and the most flexible production factor, people, remained in the background. The new technology must be implemented into the organizational framework that uses and develops the skills, knowledge and creativity of the human resources. People in the production process need a new kind of decision support in the rapidly changing business environment. A new concept, total production control (TPC), that is a reaction to the present manufacturing problems will be presented. TPC integrates many methods and tools for production system analysis and improvement, production system design and production planning and control. This concept emphasizes a preventive aspect of the problem solution in the production process and supports a production manager at the three time views: past (archive and statistical database); present (shopfloor data capture and production progress monitoring); and future (simulation and modelling tools).     

Assessing the Benefits and Costs of Homeland Security Research: A Risk-Informed Methodology with Applications for the U.S. Coast Guard

This article describes a methodology for risk-informed benefit–cost analyses of homeland security research products. The methodology is field-tested with 10 research products developed for the U.S. Coast Guard. Risk-informed benefit–cost analysis is a tool for risk management that integrates elements of risk analysis, decision analysis, and benefit–cost analysis. The cost analysis methodology includes a full-cost accounting of research projects, starting with initial fundamental research costs and extending to the costs of implementation of the research products and, where applicable, training, maintenance, and upgrade costs. The benefits analysis methodology is driven by changes in costs and risks leading to five alternative models: cost savings at the same level of security, increased security at the same cost, signal detection improvements, risk reduction by deterrence, and value of information. The U.S. Coast Guard staff selected 10 research projects to test and generalize the methodology. Examples include tools to improve the detection of explosives, reduce the costs of harbor patrols, and provide better predictions of hurricane wind speeds and floods. Benefits models and estimates varied by research project and many input parameters of the benefit estimates were highly uncertain, so risk analysis for sensitivity testing and simulation was important. Aggregating across the 10 research products, we found an overall median net present value of about $385 million, with a range from $54 million (5th percentile) to $877 million (95th percentile). Lessons learned are provided for future applications.     

A methodology for the design of manufacturing systems using group technology

The primary objectives in implementing computer integrated manufacturing systems (CIMS) are to improve quality, enhance flexibility, and increase productivity. One of the approaches used to achieve these objectives is to organize and group the production machines into manufacturing cells using group technology concepts. Cellular manufacturing allows small batch production to gain economic advantages similar to mass production while maintaining the flexibility of job shop production. This paper presents a methodology which uses design and manufacturing attributes to form manufacturing cells in a computer integrated manufacturing setting. The methodology is implemented in two phases. In phase I, parts are grouped into part families based on their design and manufacturing attributes. In phase II of the methodology, the machines are grouped into manufacturing cells based on relevant operational costs, and the various cells are assigned part families using an optimization technique. The optimization technique employs integer programming to minimize the total operational costs.     

Redesigning a Cellular Manufacturing System to Handle Long-Term Demand Changes: A Methodology and Investigation*

Cellular manufacturing systems have been proposed as an alternative to the job shop since they provide some of the operational benefits of a flow line production process, while retaining to some extent the flexibility of job shops. However, this must be balanced against the possibility of additional initial investments in equipment to form the cells and a certain loss in manufacturing flexibility, particularly in terms of the ability to deal with long-term demand changes. This paper presents a model-based heuristic cell system redesign methodology to deal with such demand changes. The methodology is validated and applied to system designs generated from several data sets published in the literature. Results show that different kinds of demand changes incur distinct kinds of costs. Further, characteristics of cell designs that can handle long-term demand changes at least cost are identified.     

Production control for just-in-time tool-and-die manufacturing

The strategy to implement production control varies in different types of manufacturing systems. We address the issue of production control in unit-based manufacturing systems where the production batch size of the final product is one or two, the product is custom designed and is made up of numerous individual components with similar process routeings lor special machine tools, turbines, boilers, tool-and-die, injection moulding equipment, custom fabrication, etc. We have developed algorithms to generate master production schedules in this particular domain of manufacturing systems using the concept of workgroups. We show how a Kanban-based JIT shopfloor control and purchasing system can be implemented in such systems in tandem with an inventory management system by utilizing the concept of demand lists. We also propose a model for practical implementation of production control in this domain. The methodology is illustrated at a tool-and-die plant where a CIM software is used to apply the JIT-based production control. Preliminary results show a significant reduction in lead times. We try to show the relationship between research and industrial applications of productions of production control and how to bridge the gap between them.     

Decision support tool for lean product and process development

Lean and concurrent engineering (CE) are widely acknowledged business process improvement strategies. These strategies can improve processes, reduce costs, and cut waste enabling organisations to remain competitive. Lean manufacturing offers an enterprise-wide methodology that improves reliability and flexibility while reducing lead-times and inventory carrying costs. Companies in manufacturing and service sectors are focusing on integrating lean manufacturing methodology with other applications, so that, all their systems and processes are aligned. This article proposes a CE framework based on application of information technology and object-oriented methodology for lean manufacturing. This approach expected to give manufacturing companies an extra edge in today's competitive market. A case study is presented in this article to demonstrate the effectiveness of CE framework in a machine tool manufacturing company. CE practice was adopted for new products, to align the systems and processes of the company. Product development lead-time was found to decrease by more than 50% compared to similar development projects carried out by the company. The need for rework was found to be negligible and the development cost was reduced considerably.     

An empirical excursion into the quicksand of vehicle replacement

The rapid increase of physical distribution costs relative to other categories has resulted in a renewed interest in the analysis of transport operations. One of the most common problems is that of vehicle replacement, and in this paper we present an analysis of real data. The methodology is developed paying due regard to the role of quantitative analysis in the decision-making process, and the sort of data which is readily available in most transport departments. A traditional discounted cost model is presented and this is followed by a productivity-based analysis, which is shown to be an improvement. The latter generates optimal solutions and is flexible enough to carry out considerable sensitivity analysis.     

An optimal design for process quality improvement: modelling and application

Existing research works on process quality improvement focus largely on the linkages between quality improvement cost and production economics such as set-up cost and defect rate reduction. This paper deals with the optimal design problem for process improvement by balancing the sunk investment cost and revenue increments due to the process improvement. We develop an optimal model based on Taguchi cost functions. The model is validated through a real case study in automotive industry where the 6-sigma DMAIC methodology has been applied. According to this research, the management can adjust the investment on prevention and appraisal costs on quality improvement that enhances process capability, reduces product defect rate and, as a result, generates remarkable financial return.     

Production planning and control within a CIM environment: some current developments and requirements for the future

Abstract. This paper considers the integration problems associated with incorporating production planning and control (PP&C) systems within CIM; these problems are typically not differentiated from functionally related problems, and have in the past received relatively little attention. The on-going emergence of a number of standards relevant to manufacturing software systems provides an opportunity to assess the current situation with regard to proprietary PP&C systems and to suggest ways forward towards ‘seamless’ integration of PP&C within the CIM environment. The problems arising from conventional integration approaches are briefly described, and the concept of a simplifying ‘integration platform’ is introduced; the three-schema information architecture is presented as part of this ‘integration simplification’ approach. Current and developing PP&C systems are assessed against a number of information system integration criteria, and the results of a small survey of proprietary packages are presented. The paper concludes that information must be regarded as an enterprise-wide asset, rather than belonging to individual software applications, and that the adoption of relevant standards will enable seamless integration within a three-schema architecture. An increasing number of proprietary packages are adopting standards and methodologies which ease the integration problem significantly.