18,664 research outputs found

    Production planning systems for cellular manufacturing

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    New product development is one of the most powerful but difficult activities in business. It is also a very important factor affecting final product quality. There are many techniques available for new product development. Experimental design is now regarded as one of the most significant techniques. In this article, we will discuss how to use the technique of experimental design in developing a new product - an extrusion press. In order to provide a better understanding of this specific process, a brief description of the extrusion press is presented. To ensure the successful development of the extrusion press, customer requirements and expectations were obtained by detailed market research. The critical and non-critical factors affecting the performance of the extrusion press were identified in preliminary experiments. Through conducting single factorial experiments, the critical factorial levels were determined. The relationships between the performance indexes of the extrusion press and the four critical factors were determined on the basis of multi-factorial experiments. The mathematical models for the performance of the extrusion press were established according to a central composite rotatable design. The best combination of the four critical factors and the optimum performance indexes were determined by optimum design. The results were verified by conducting a confirmatory experiment. Finally, a number of conclusions became evident.

    The development of a methodology for the evaluation of installed CAPM system’s effectiveness and efficiency

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    The objective of this work was to design, develop and evaluate an audit for a Computer Aided Production Management (CAPM) system. Such systems, despite their costs of purchase and implementation, find wide application in industry but there is still considerable debate as to their contribution to the overall performance of a company. A variety of possible methodologies were explored. However, it was found that most of the existing analytical techniques tended to focus on a comparison of systems with respect to best practice or to require data that a company was unlikely to have. Best practice is not an absolute measure, nor does it take account of different company types and their individual requirements. A flexible methodology, 'the CAPM Audit', designed to establish the effectiveness and efficiency of any installed CAPM system, has been developed. The audit is a development of the Delphi approach and is designed to establish the contribution of the CAPM system to the company's overall competitive position. In its development, a generic model for any CAPM system was devised to facilitate analysis without reference to any particular technology, management mode, or manufacturing control system. The audit developed (in the form of a workbook) consists of four stages: stage one establishes the context; stage two determines the underlying architecture of the system; stage three quantifies the contribution to the company's competitive position; and stage four identifies the causes of any failure of the CAPM system. The design of the audit is such that: it enables a systematic investigation of the effectiveness and efficiency of an installed CAPM system to be completed; it enables the CAPM system's contribution to the company to be identified; and it also enables any inadequacies to be determined

    Review of research in feature-based design

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    Research in feature-based design is reviewed. Feature-based design is regarded as a key factor towards CAD/CAPP integration from a process planning point of view. From a design point of view, feature-based design offers possibilities for supporting the design process better than current CAD systems do. The evolution of feature definitions is briefly discussed. Features and their role in the design process and as representatives of design-objects and design-object knowledge are discussed. The main research issues related to feature-based design are outlined. These are: feature representation, features and tolerances, feature validation, multiple viewpoints towards features, features and standardization, and features and languages. An overview of some academic feature-based design systems is provided. Future research issues in feature-based design are outlined. The conclusion is that feature-based design is still in its infancy, and that more research is needed for a better support of the design process and better integration with manufacturing, although major advances have already been made

    Human Management of the Hierarchical System for the Control of Multiple Mobile Robots

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    In order to take advantage of autonomous robotic systems, and yet ensure successful completion of all feasible tasks, we propose a mediation hierarchy in which an operator can interact at all system levels. Robotic systems are not robust in handling un-modeled events. Reactive behaviors may be able to guide the robot back into a modeled state and to continue. Reasoning systems may simply fail. Once a system has failed it is difficult to re-start the task from the failed state. Rather, the rule base is revised, programs altered, and the task re-tried from the beginning

    Preparation and control of intelligent automation systems

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    In the automation systems of tomorrow, it is likely that the devices included have various degrees of autonomy, and include advanced algorithms for perception and control. Human operators will be expected to work together with collaborative robots as well as with roaming robots for material handling.The volatile nature of the environment of such intelligent automation systems lead to an enormous amount of possible situations that can arise and which need to be suitably handled. This complexity makes development of control systems for intelligent automation systems difficult using traditional methods.As an alternative, this thesis presents a model-based control framework, which uses a combination of formal specification and automated planning. The proposed framework allows for defining the intentions of the automation system on a high level, which enables decisions that influence when things should occur to be modeled using logical constraints, rather than programming. To achieve a modular framework, low level, reusable, resource models are composed by 1) formal specification to ensure safety and 2) applying an abstraction called an operation, which couples the reusable resources to the intentions of the system. By planning also the resources\u27 detailed actions, the operations can, when possible, be completed regardless of the resources\u27 current state. This eases error-recovery, as resources do not have to be reset when an error occurs.Additionally, the thesis proposes an iterative and interactive workflow for integrating the proposed model-based control framework into a virtual preparation process, using computer-based simulation as a tool for validating formal specifications. The control framework allows for adding new constraints to a running system, enabling an efficient and interactive preparation process.The framework has been applied to a use case from final assembly, which features human-robot collaboration. Experimental results on the ability to handle unforeseen errors and planning performance are presented

    Self-managed teams in the auto components industry: Construction of a theoretical model

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    The author would like to thank the human resource managers of the three manufacturing companies that were studied for their kind gestures and their supply of data concerning organizational structure and functioning.Purpose – The overall purpose of this paper is to explain theoretically the autonomy phenomenon of teams working within the auto manufacturing context and its implications for the technical and social aspects of group work. Design/methodology/approach – Three auto component companies were studied. The procedures of a qualitative methodology were followed, adopting naturalistic observation techniques of work teams, and unstructured and semi-structured interviews conducted with operators, supervisors and middle managers. To analyse and interpret the qualitative data obtained, the grounded theory technique was used. Findings – In this paper 33 concepts were obtained, which resulted from the constant comparative method applied to data. The relationships between those concepts allowed the construction of a theoretical model that is settled in the “bridge” concept. This “bridge” is a metaphor that translates the process which binds operational work group goals to the needs of external clients. This process is supported by social aspects – team decision making, participation, mutual helpfulness, and social and emotional relationships, and by technical aspects – operations and information. The bridge has four pillars that are critical to the effective functioning of self-directed teams: team facilitation, hierarchical relationships established within the teams, quality of manufactured components, and productivity achieved. Research limitations/implications – The present investigation was carried out in a specific industry, which does not allow for the generalization of the model to other industries. Furthermore, it may be questioned whether the same results be obtained if the operators of the teams observed were interviewed, not individually, but in a group situation. Other kinds of research design and other industries organized on the basis of autonomous work groups must be studied, applying the grounded theory technique, in order to compare diverse theoretical models. Practical implications – The organization of the industrial automotive production based on self-directed teams, which know the needs of external customers and to whom a high level of participation in operational decisions was given, can generate a substantial increase of working groups' efficiency and an increase in job satisfaction. Originality/value – The study of teams in the automotive components industry – in a southern country of Europe – and the consequent elaboration of a specific theoretical model draws attention to the need for social research that takes into account the fact that realities are constructed by the actors who interact in a certain context. No theoretical model can ever encompass the reality of all contexts

    Smart Technologies for Environmental Safety and Knowledge Enhancement in Intermodal Transport

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    International concerns about security in transport systems are leading to a new international regulation in this field. This introduces new requirements for operators and authorities as well as it opens new challenges, in particular when referred to seaports and maritime transport in the Mediterranean area, where many seaport terminals and infrastructures are affected by a noteworthy technological divide from North European contexts. In such contexts, the adoption of the new regulations can represent the right chance for upgrading the local operative standards, increasing latu sensu the quality of maritime transport performances, while conferring a greater level to security and safety checks. This paper explores the chances for increasing the level of Mediterranean seaport competitiveness allowed by technological innovations in transport systems, both in operations and organization of these infrastructures. The aim of the work is to study the effects of the adoption of technological solutions such as wireless communications and radiofrequency identification on the competitiveness of Mediterranean seaport infrastructures. Technological solutions designed to identify good items help operators in organizing activities in terminals and make maritime transport faster in delivering goods, by cutting the handling time and costs in seaport terminals. Seaports that adopt this kind of technologies, and the surrounding economic areas connected to seaports, have a greater attractiveness on shipping companies and operators, since they allow faster handling activities and easier checks on goods. Besides, the analysis of direct and indirect effects of the use of such technologies specifically focuses on the contribution that the use of these solutions gives in ensuring higher security levels, by increasing the level of information and knowledge associated to goods. The different types of security provided (e.g. for people, environment and goods) and the extreme flexibility of the technologies involved give the overall worth of the challenge. It seems to be a great chance of growth for the Mediterranean area, more than a mere compliance to the international security regulations.
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