摘要:

While carrying out a study of the collection and use of quality-related costs in manufacturing industry the authors found in the literature many notional models purporting to indicate the relationships between the major categories of quality costs and a few sets of real data. Despite being based on common principles, there are wide differences between some of the models and between the models and real data. The paper categorizes and discusses the models in the light of the research experience. It is concluded that many of the models are inaccurate and misleading and serious doubts are cast on the concept of an optimum quality level corresponding to a minimum point on the total quality-cost curve.

ISSN:0020-7543    

DOI:10.1080/00207548808947986

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Multi-aisle S/R machine system (MASS) can substantially reduce high initial investment cost which is a major reason for the low popularity of AS/RS in manufacturing companies. The objective of this study is mainly related to the design aspects of MASS. With a travel time model developed, average travel time of S/R machine is determined. We propose rack-class-based storage assignment procedure and class selection procedure to find the minimum number of S/R machines required and identify the number of aisles each S/R machine serves. Example problems are solved to illustrate the procedures. The results show that MASS is effective in reducing initial installation cost, provided that the pallet demands are relatively low.

ISSN:0020-7543    

DOI:10.1080/00207548808947987

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Flexibly automated facilities permit a wider variety of products as well as objectives for making those products—thus requiring manufacturing control strategies to face an environment of ever present change. To operate in this environment, a system composed of hard automation, flexible automation and humans, which can be responsive to product and process requirements, machine breakdowns and delays, engineering changes and improvement opportunities, is needed. Such a system does not fall into the realm of any current manufacturing solution techniques. Something more than exact optimization, heuristic algorithms or stochastic estimates must be utilized. The research discussed herein describes a dynamic solution strategy to operate in this changing environment with adaptive self-improving characteristics. The proposed methodology for optimizing the control of an automated manufacturing facility is an integrated approach utilizing real-time feedback from the operating facility, direct feedback from a simulation of the facility and guidance from a historical knowledge base. This system is being implemented in a knowledge based environment called CAYENE. CAYENE is a hybrid artificial intelligence system, written in Lisp, based on the idea of using object oriented programming as a unifying principle for functional, frame and rule-based programming.

ISSN:0020-7543    

DOI:10.1080/00207548808947988

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This paper examines a just-in-time (JIT) system with kanbans with three subassembly lines feeding a final assembly station. Variability in operation times exists and variability effects are reduced by increasing work in process levels or by unbalancing the subassembly lines through assignment of work content at each station. Of the several unbalancing methods that were analysed in this study, only the high-medium-low showed a consistent improvement in the output rate of the JIT production system. The output rates with unbalanced stations were always superior to the output rate of the perfectly balanced configurations used as controls. The extent of improvement over the output rate of balanced systems increased directly with the variability in operation times in final assembly and subassembly stations and inversely with the interstage buffer capacity allowed in the system.

ISSN:0020-7543    

DOI:10.1080/00207548808947989

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The paper deals with the orthogonal machining characteristics of anisotropic and normal stress sensitive polymers. Tensile and compression tests were carried out to define the mechanical properties of the chosen polymers, nylon and polycarbonate. The deformation during cutting is assumed to occur under plain strain conditions and a suitable yield equation is chosen to describe the material yielding behaviour. For the cutting process, a single shear plane model is assumed and the minimum energy criterion applied to the appropriate yield criterion to develop a representative shear angle relationship, which depends on the mechanical state of the chosen polymer. Orthogonal cutting tests were carried out varying three main parameters; cutting speed, tool rake angle and depth of cut. Measured forces and shear angles are compared with the values predicted from the theoretical analysis and an excellent correlation is obtained. It is concluded that, for the assumed mode of deformation, the minimum energy criterion applied to a representative yield equation is justified in explaining polymer behaviour under orthogonal cutting conditions.

ISSN:0020-7543    

DOI:10.1080/00207548808947990

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

The ‘Linguistic Pattern’ approach to the facilities and panels layout is presented. This approach is based on Zadeh's possibility theory and the Lukasiewicz multivalued implication formula. The idea of the approach is presented on the basis of a simple exemplary problem of an automobile display arrangement. The general idea of a computer algorithm is presented and some potential benefits of the proposed approach are discussed.

ISSN:0020-7543    

DOI:10.1080/00207548808947991

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

It is suggested that a quantitative analysis of the risks inherent in a specific project can be easily carried out using spread-sheet models. This is to be preferred to the application of a blanket hurdle rate, which is the usual procedure when IRR is used to assess the viability of an investment in new technology. The methodology suggested is applied to the analysis of a projected investment where a conventional machine shop and flexible machining system are the alternatives.

ISSN:0020-7543    

DOI:10.1080/00207548808947992

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

This paper solves the machine interference problem in whichNdifferent machines are looked after by a team ofroperatives. The run time of each machine is assumed to have a general distribution, different for each machine and the repair times are assumed to have a negative exponential distribution with different means for the different machines. An explicit expression for the probability that a particular group of machines is found running in the steady state is derived. From this other useful measures for the system can be obtained. It is shown that these depend on the run time distributions only through the means of those distributions.

ISSN:0020-7543    

DOI:10.1080/00207548808947993

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Performance obstacles are factors in the work environment that restrict productivity by inhibiting employees in the execution of task responsibilities. In spite of their apparent importance, little research has been done to describe, categorize, or assess these obstacles. A research project carried out in 12 United States electronics firms demonstrates that employees in two groups (circuit board assemblers and manufacturing engineers) view performance obstacles as having a significant influence on their performance. Materials and information obstacles emerged as being the most important to the circuit board assemblers. For the engineers, information and control/authority were the most important obstacle categories. Managers tended to agree with circuit board assemblers about the importance of obstacles for that employee group. However, managers tended to disagree with the engineers, giving lower ratings of importance than the engineers did in several categories. The research provides a step toward a typology of performance obstacles, demonstrating similarities and differences between employee groups and it suggests that at least in some areas managers may not be as accurate as they could be in assessing the influence of performance obstacles on their employees. The findings indicate that the themes that have prevailed in the research on operations management (i.e. materials, quality, scheduling) are viewed by employees as being predominant factors in the productivity equation.

ISSN:0020-7543    

DOI:10.1080/00207548808947994

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor

摘要:

Some controversy exists about the advocacy of top-down versus bottom-up forecasting strategies. Top-down forecasting refers to the process of forecasting the demand for the aggregate of items in a class and then inferring individual demands according to a percentage of the total; bottom-up refers to separately forecasting the requirements for each individual item. This paper outlines the relative advantages of each strategy and indicates the situations in which each should be preferred.

ISSN:0020-7543    

DOI:10.1080/00207548808947995

出版商:Taylor & Francis Group    

年代:1988

数据来源: Taylor