Showing papers on "Production engineering published in 1987"

Automation, Production Systems, and Computer-Integrated Manufacturing

Abstract: This book provides the most advanced, comprehensive, and balanced coverage on the market of the technical and engineering aspects of automated production systems. It covers all the major cutting-edge technologies of production automation and material handling, and how these technologies are used to construct modern manufacturing systems. Manufacturing Operations; Industrial Control Systems; Sensors, Actuators, and Other Control System Components; Numerical Control; Industrial Robotics; Discrete Control Using Programmable Logic Controllers and Personal Computers; Material Transport Systems; Storage Systems; Automatic Data Capture; Single Station Manufacturing Cells; Group Technology and Cellular Manufacturing; Flexible Manufacturing Systems; Manual Assembly Lines; Transfer Lines and Similar Automated Manufacturing Systems; Automated Assembly Systems; Statistical Process Control; Inspection Principles and Practices; Inspection Technologies; Product Design and CAD/CAM in the Production System; Process Planning and Concurrent Engineering; Production Planning and Control Systems; and Lean Production and Agile Manufacturing. For anyone interested in Automation, Production Systems, and Computer-Integrated Manufacturing.

Production Management Techniques in UK Manufacturing Industry: Usage and Barriers to Acceptance

Abstract: The work described in this paper is part of a large study of the barriers to acceptance of production management techniques in UK manufacturing industry. The first part of this study is described, it:(i) establishes the use being made of proven traditional techniques of production management and operational research/statistical techiques by British production managers; and (ii) begins to investigate the barriers to acceptance of the techniques. The results reveal that in industry in the UK there is low usage of many of the techniques, particularly the highly quantitative techniques. The major barrier preventing usage of the techniques is lack of knowledge; training in production management has been found to be an extremely important factor in the usage of all the techniques examined.

An expert system for process planning

Abstract: Fully integrated manufacturing systems, the ultimate goal of today's production engineering research, cannot be realized without automated process planning systems. A knowledge-based expert system incorporating heuristic algorithms as well as analytical and empirical models and which can thus provide a partial replacement for human expertise is the only key to automated process planning. This paper presents an attempt to develop an expert system for automatic process planning using artificial intelligence. In this system, a structural database was incorporated with a knowledgebase for the execution of rules. The programs developed are user-friendly and highly interactive. They allow dialog between the system and the user and require only that the operator answer questions in a familiar workshop language.

Retrofit design of processes

Abstract: Retrofit design precludes the decomposition usually adopted in grassroots design where process decisions are made first to be followed by equipment decisions. The lack of this decomposition forces a potentially explosive growth in the search space. Retrofit design also requires models that can rate existing equipment for proper analysis; these models are much more complex. This paper reviews the as yet sparsely populated process retrofit literature where most work is for redesigning heat recovery systems. We see evolutionary strategies that reflect ones inability to explore all alternatives. It concludes with an assessment of where we are and ideas for future developments. Introduction A major portion of the chemical industry has matured. Most chemical plants were built at a time when profit margins could be kept large and thus were not typically designed to be the most efficient from an energy and raw material perspective. However, competitive pressures from Japan and European countries, as well as from developing countries, have greatly increased the need for more efficient processes. Consequently, process industries feel an increasing need to redesign and modernize existing facilities. Over the last five years, it has been estimated that 70-80% of all process design projects have dealt with the redesign, i.e., retrofit design, of existing facilities. One can expect that optimal plant redesign will play an increasingly important role in the future in response to uncertainties in the availability and prices of feedstocks and energy, as well as the market for commodity chemicals. Also, the successful commercialization of specialty chemicals will require the ability to redesign processes quickly to respond to changes in new technology and to the short life cycle of new products. Thus retrofit design constitutes a very important problem in the area of process operations. Only in the last few years has any significant design research taken place to deal with the retrofit problem in a systematic way. Clearly the motivation for this problem is provided by the industrial environment, but development of retrofit design strategies is also an interesting and difficult problem for academic research. In this paper we will define the retrofit problem and review recent research that addresses it. Moreover, we will stress why this problem is more difficult than the design of new processes (its grassroots counterpart). Specifically, we highlight some problem features that are currently very difficult to address simply by applying grassroots design strategies. Finally, we will present a framework for addressing general classes of retrofit problems in a systematic way. The paper is organized to deal with a number of retrofit issues. First, it will be shown by example that retrofit problems require a far greater number of alternatives than the grassroots problem. This is due to the need to evaluate and use existing equipment. Next, we show that straightforward applications of grassroots strategies will usually lead to suboptimal retrofit designs. This leads us to consider in detail the following factors for developing strategies: • search strategies that deal with the combinatorial retrofit problem • accurate evaluation of existing equipment • consideration of different and, often, multiple objectives for performing the retrofit problem As part of this discussion specialized strategies for retrofits, i.e. to improve economics, to conserve energy and to improve flexibility will be reviewed. This annotated review will provide the basis for a general framework for dealing with a wide class of retrofit problems. Finally, some guidelines and concepts that relate to a practical realization of this framework will be discussed. Nature of the Retrofit Problem The decision to redesign a process can arise for any of several reasons, such as the following. • To increase the throughput of the current process by debottlenecking it • To process a new feedstock. • To improve the quality of the product • To improve the economics by the use of less energy per unit of production • To increase the conversion of feedstocks. • To improve operability of the process (flexibility, controllability). • To improve process safety. • To reduce the environmental impact of an existing process. In order of increasing cost generally, the following indicate the types of modifications which can be used in retrofit design. • Alter the operating conditions of the process. Here no process equipment changes are implemented so this form of change is obviously the least costly in terms on investment • Keep the same equipment but alter the piping which connects it The equipment may be used for a new purpose. For example, relative to the cost of purchasing a new column, repiping typically incurs very modest costs. • Keep the process flowsheet intact but change the equipment sizing, sometimes in ways that the external physical dimensions of the equipment are not altered. Such changes could include putting new tube bundles inside of existing heat exchanger shells, closer packed trays or even packing inside of columns. Packing could be very expensive but cost effective if it is the only change needed. • Add new equipment. While the above operations indicate the changes one can consider, each process offers it own limitations on what really can be done. Building codes can be a problem. In some states if over 60% of the equipment on a rack of equipment is changed, then the rack has to conform to the latest building code regulations whereas, if the changes are less, the old regulations can be used. The cost of strengthening the equipment rack obviously changes the economics of some of the possible changes. In other cases what should have been a simple repiping is virtually impossible as the pipe rack can hold no more runs. Changes could also increase the physical size of the equipment which the current space cannot tolerate if the equipment is to be installed or maintained. Comparison of Grassroot and Retrofit Design Currently, redesign problems are tackled only on an ad hoc basis using tools that were developed specifically for "grassroots" designs, i.e., the design of new processes. However, as we shall now expose, there is a fundamental difference between these two design paradigms. Grassroots designs have many more degrees of freedom in the preliminary phase, and thus allows for a useful decomposition of effort; i.e, first the basic structure of the process is established and sizing and selection of suitable equipment follows. In retrofit design, modification of structure and equipment occurs simultaneously, as the economics of retrofit design dictate the reuse of much of the existing equipment The models required for analyzing a design are also fundamentally different In grassroots design, one can use models that characterize nominal behavior of the equipment types, whereas in retrofit design the models must indicate the performance of existing pieces of equipment which might be run far from the nominal conditions for which they were designed. These "rating" models are much more complex models. The Size of Retrofit Problems Before reviewing strategies for retrofit design it would first be useful to appreciate the number of alternatives for retrofit problems on a type of class of problems already well studied in grassroots design. Here we consider one of the most frequently considered problems in separation system design. A single mixture of N components is to be separated into N essentially pure component products using a sequence of distillation columns. Each column in the sequence has only two products (a distillate and a bottoms) which are the result of sharply splitting the column feed between two adjacent key components. Thus the light key and all species lighter than it exit in the distillate and the heavy key and all species heavier than it exit in the bottoms. No components distribute between the top and bottom products. Thompson and King (1972) showed that the number of alternative sequences, S(N), possible for this problem is given by the formula: (1) M (AM)! Each sequence is made up of N-l columns. Each column accomplishes a different task such as splitting A from BCD or splitting B from CD or splitting C from D. The number of different separation tasks, T(N), grows according to the formula: The first three columns of Table give the growth of these numbers versus N. As N gets large, the number of sequences grows factorially in N and thus much more rapidly than the number of tasks which is growing as the cube ofN. Table 1: Growth of Tasks and Sequences with Number of Components N T(N) S(N) TR(N,0) SR(N,0) TR(N,1) SR(N,1) 2 3 4 5 6 7 1 4 10 20 35 56 1 2 5 14 42 132 1 8 30 80 165 336 1 4 30 336 5,040 95,040 4 36 160 500 1,260 2,744 4 36 480 8,400 60,480 4,656,960 If we generate the number of alternatives possible when considering retrofit design, we begin to see clearly why it is a much harder problem than grassroots design. Here we follow the line of thinking of Neil Carlberg, a PhD student working with Westerberg on retrofit design at Carnegie Mellon University. Suppose that we wish to run the process with an increased throughput that exceeds the capacity of the current sequence. We might first look for an alternative sequence which uses the existing columns and which will accommodate the larger throughput An approach would be to test each of the N-l existing columns against the T(N) alternative separation tasks possible for the problem. This test will search over the allowable operating ranges set by weeping, flooding and materials constraints for the column pressures, reflux ratios and possibly number of stages (if we allow the column internals to be replaced) to discover if the task can be accomplished in the column. The number of tasks considered is N-l times that for the grassroots design. The effort to analyze each task is also much larger as it involves

Education and training in manufacturing systems engineering

Abstract: The educational processes in Britain, unlike those of our major industrial competitors, are biased towards the production of specialists. The ratio of scientists to engineers is out of balance with contemporary needs. Industry requires a new balance in the output of specialists and engineering generalists to ensure that the two key functions of product engineering research and development and manufacturing systems engineering research and development are adequately supplied. Also, engineering generalists capable of progressing to senior leadership positions are in short supply. To design, develop and operate the new types of factory required to meet the competitive market requirements of the 1 980s and 90s, we need a very large increase in the supply of manufacturing systems engineers. Traditional production engineering has not coped with the new challenges offered by Japan. The paper discusses the detailed manufacturing systems engineering curriculum requirements of courses for undergraduates and technicians, and also indicates the efforts being made in industry via continuing education to make up for past deficiencies in the higher education system.

Finite Element Methods in CAD

Abstract: This practical text concentrates on FEM as an integral part of the computer-aided design (CAD) process, and offers students of production engineering an in-depth look at the mathematical procedures behind the integration of FEM into CAD software. Intended primarily as a textbook for students of mathematics, computer science and production engineering, this comprehensive and useful reference will also be of interest to professional users of CAD in industry. This book should be of interest to undergraduate students of mathematics, computer science and production engineering.

General arrangement design computer system and methodology

Abstract: The ever increasing complexity of ships coupled with cost, schedule, and resource constraints require innovative methods by the Naval Sea Systems Command's ship design community to meet this challenge. This paper describes the effort by the NavSea Ship Arrangement Design Division to dramatically improve its ship design capability by the use of a system of computer-based design tools called the General Arrangement Design System. The General Arrangement Design System (GADS) is based on the engineering requirements of the ship arrangement design process. GADS is currently being used as a production engineering tool. This paper is organized into two parts. Part I describes the General Arrangement Design System, and Part II describes the general arrangement design methodology.

An IKBS for integrating component design to tool engineering

Abstract: Component design and tool engineering functions are two sequentially related activities. Many additional benefits may arise if these activities can be effectively integrated together within a central environment. The principal aim of the research described in this paper is to develop a component design and tool engineering Intelligent Knowledge Based System (IKBS), called Holdex to demonstrate such a concept. It is an implementation designed to deduce the planning, design, tooling, procurement and scheduling information at the component design stage. It also assists the component designers in the operation of a Computer Aided Design (Cad) system and leads them towards the rationalisation of resources by encouraging standardisation of designs. A major benefit to arise from the provision of such assistance is to facilitate the tasks of executing the production engineering functions. The range of functions performed by Holdex includes the specification of a set of cutting tools; planning a set of pre-machining requirements; recommendation of the appropriate machine tool and manning level; and the automated design of fixtures. Towards this end, this research aims to provide a foundation for enabling industry to manufacture with the least amount of manual interpretation.

EXMAS—Knowledge based system for maintenance of complex mechanical systems

Abstract: EXMAS is a Knowledge Based System for Integrated System Maintenance Complex Mechanical System (EXMAS being an abbreviation for: Expert Maintenance System) It is part of a complex DESIGNER expert system, which is currently under development at the Department for Production Engineering Department of the Faculty of Mechanical Engineering in Belgrade The theoretical approach for the DESIGNER expert system is the theory of automata applying artificial intelligence tools The knowledge block is introduced as a structure of the man-machine cybernetic entity Basic engineering activities in the integrated system of maintenance are: computer aided design for maintenance, computer aided maintenance technology design, and computer aided maintenance planning and control This paper gives several parts of this expert system

Availability analysis of flexible manufacturing system

Abstract: Availability analysis of flexible manufacturing system " (1987). Retrospective Theses and Dissertations. Paper 8504. In ail cases this material has been filmed in the best possible way from the available cooy. Problems encountered w/ith this document have been identified here with a check mark V .

Problems in the Production Management System of the Steel Industry

Abstract: The production structure of the steel industry is liable to be regarded as a typical case of “non-order production of a few items in large quantities” because of the large products and the large production scale. Actually, however, it is “100-percent production to order of many items in small lots” to meet the highly complicated requirements of individual customers.

Design of a Generic Manufacturing Cell Control System.

Abstract: The feasibility of design and demonstration of a cell control system to function in the fully integrated manufacturing environment independent of the parts produced or the manufacturing processes involved was investigated. A hierarchical control structure was used. Free standing implementations of a cell controller, a workstation controller, and programmable device interfaces were designed. The system is data driven, and was designed to use the manufacturing databases that exist in the computer integrated manufacturing environment. Operation of the cell controller and its interaction with the rest of the system was demonstrated in real-time by simulating the computer integrated manufacturing environment on microcomputers connected to each other via communication links. CHAPTER

The US Air Force R&M 2000 Initiative Special Introduction

Abstract: IEEE Transactions on Reliability dedicated to the US Air are incorporated into a system from inception to producFo Transactionseon Reliability anddedilicted tM te UIition and deployment. The future operational effectiveness Force Reliability and Maintainability (R&M) 2000 Iniof our systems will be determined by how well we integrate tiative. For several years we have focused intense attention reliability and maintainability into the design process. To on improved combat readiness. At the very top of our list focus defense contractors on this goal, we have drastically of ways to accomplish this is improved reliability and altered acquisition priorities. Reliability, maintainability, maintainability. The rationale is compelling: broken and producibility now stand as the first items in the highest equipment and unusable systems don't deter war or prevail ranked areas for source selection. on the battle field. R&M improvements will translate hardIn the Air Force, R&M factors have come of age with ware on the ramp into improved sortie rates, increased priority equal to or greater than such traditional factors as mobility, decreased manpower and lower costs. All that performance, cost, and schedule. This R&M attention is adds up to more warfighting capability and, hence, more clear recognition that logistics is not just in the \"nice to deterrence. have\" category. Logistics is the essential prerequisite for deterrence. ~~~~~~~~and supporter of warfighting capability. Reliability and For the R&M initiative to be fully effective, it must be ain a ina modernlitic takdable. I understood and applied by all those involved in design, challenge all of you in the engineering and academic comresearch, development, acquisition, and management of munities to join me in this important initiative to build Air Force systems. R&M 2000 cuts across academic, insupportable Air Force capabilities. dustrial, and governmental lines to redefine system capability not only in terms of performance, but also in Manuscript TR8711 received 1986 December 15; revised 1987 April 21. terms of reliability, maintainability, and producibility. The IEEE Log Number 15946 4 TR >

An Optical Cam Program For Automatic Production-Engineering Of A Lens

Abstract: The program automatically designs and draws all parts and tools that are needed for manufacturing spherical lenses. The input is the lens production drawing; the output consists of production drawings of all the tools. Two blocking methods (pitch bonding and recessing) are available, each defining a complete set of tools. The program is integrated with the Euclid CAD system, and can be operated either in an interactive mode (on a graphic CAD screen), or in a batch mode.

Recovering schemes integrated in the production planning and control of flexible manufacturing systems

Abstract: The guidelines of the design of an Integrated Production Planning and Control System for FMS are sketched, with special emphasis on the capability of managing transients due to unplanned events by means of on-line control policies which can be selected in accordance with the specific requirements of particular production conditions.