摘要:

A three-station production line with a Laplace transformable distribution of service time of the middle station and phase-type distribution of service times of the two outside stations is treated. A general formula for the throughput rate is derived. In this formula a system of linear equations with the number of equations equal to the number of stages of the service time of the last station needs to be solved. For some special cases, this formula reduces to simple expressions.

ISSN:0020-7543    

DOI:10.1080/00207548708919922

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Much has been written on the essential features and potential benefits of the Justin-Time production system. Using a simulation model, some salient parameters such as (a)scheduling rules, (6) the effects of pull demands level, (c) the effects of the production Kanban size and the minimum Kan ban level, and (d) the significance of the job mix are evaluated. The study shows that a common prevailing practice of assigning greater priorities to jobs with higher pull frequencies is not as efficient as a shortest process time based rule. Unlike the traditional ‘push’ method, raising the pull demand in a JIT system does not ensure a high process utilization level. Results also show that an increase in the production Kanban size and minimum output Kanban level improve the mean job tardiness but causes an escalation in the output Kanban inventory level. Contrary to common conjecture, an enlarged product mix would actually produce better process utilization and mean job tardiness.

ISSN:0020-7543    

DOI:10.1080/00207548708919923

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

This paper discusses various techniques for layout planning and outlines an application of fuzzy set techniques to the block layout design problem. In particular, a fuzzy linguistic heuristic for the location of the departments within a facility is proposed. This heuristic utilizes imprecise descriptors for two distinct design categories: closeness and importance, expressed in the form of fuzzy relations for every pair of departments. A numerical example is given to illustrate the proposed approach and directions for further research are discussed.

ISSN:0020-7543    

DOI:10.1080/00207548708919924

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The allocation of inspection effort problem for aerial systems is formulated as a 0-1 mixed integer linear programming problem. This formulation permits any combination of scrap, rework, or repair at each station and allows the problem to be solved using standard MILP software packages. Moreover electronic spread-sheets may be used to easily calculate the relevant coefficients. An additional advantage of this approach when compared with the traditional dynamic programming approach is the ease with which the basic model may be modified. For example, it is shown how the model may easily be modified to include both a material and a production constraint and to select between various material suppliers. Sensitivity analysis is also easily performed with this approach. This model is then used to show that the optimal inspection policy is dependent on whether a production or a material requirement is used.

ISSN:0020-7543    

DOI:10.1080/00207548708919925

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A prototype computer-aided process planning (CAPP) system, PWA_Planner (printed wiring assemblies planner), is presented. PWA_Planner is a rule based system for preparing assembly plans for the manufacture of PWAs via automatic component mounting machines, PWA_Planner uses a forward planning procedure, starts from a design blueprint and a bare printed wiring board (PWBrpar; components are mounted on the board until the completed PWA is reached. The final assembly plan includes a component assignment diagnostic file, a process plan, and automatic mounting machine program files. PWA_Planner utilizes a computer-aided design (CAD) representation of the PWA and automatic component mounting machine descriptions to prepare the assembly plans. The assembly plans eliminate interference between components and mounting heads, utilize preferred component mounting paths, and consider the order in which automatic mounting machines assemble the PWA. PWA_Planner is written in PROLOG. Board descriptions, parts information, blueprint description, and components specifications are represented as facts. The capabilities of automatic mounting machines, mounting sequence, and interference checking method are written as rules. A forward-chaining control logic is used. It can be used to provide feedback to PWA designers on the producibility of the design and to generate good assembly process plans. The current version of PWA_Planner does not have optimizing scheme built-in. This paper demonstrates a sound application of artificial intelligence in manufacturing.

ISSN:0020-7543    

DOI:10.1080/00207548708919926

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Numerous empirical studies have shown that, in unpaced lines, the stations' processing times have a variety of shapes (i.e., skewness and kurtosis))65. Thispaper investigates how the line's utilization factor is affected by these skewness and kurtosis measures. We found that positive skewness has a significant negative effect on utilization, and that the magnitude of this effect is greater if the line has more stations or less buffer capacity, or if the processing-times' cv is larger. Kurtosis also affects utilization significantly, but the effect may be negative or positive, depending upon the processing-times' skewness and the number of stations in the line. Our findings imply that when simulating long lines with small buffer capacities, it may be necessary to model more accurately the actual processing times. Also, the common practice of using normal distributions to approximate the typically positively-skewed processing times often leads to an overestimation of the actual utilization rate.

ISSN:0020-7543    

DOI:10.1080/00207548708919927

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Considerable attention has been given to the problems associated with acquiring and implementing many of the advanced manufacturing technologies currently available to firms. Much of the information being published, however, is based on individual experiences under conditions that are frequently not reported, as is common in the trade journals and public media. Fifteen such generally-accepted ‘postulates’ for managing factory automation are identified here and analysed in terms of five in-depth case studies involving advanced manufacturing systems. In a few cases, the postulates are rejected. In some cases they are qualified, and in many cases they are reinforced with substantially more detail.

ISSN:0020-7543    

DOI:10.1080/00207548708919928

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The purpose of this paper is to define conceptually and operationally, a measure of quality density in manufacturing. This is expressed in terms of a manufacturing process propensity to ‘output’ units which are defectives, as a function of the manufactured production output, the manufacturing deterioration process, maintenance, quality control, and generally the risks a manufacturing process is subjugated to. Particularly, we assume that the production process induces ‘shocks’ which lead to poorer manufactured quality, while maintenance efforts are continually being employed to restore the process propensity to produce units of better quality. Quality control is used then to monitor the output quality of units produced. Using a methodology of level crossing in stochastic point processes, the stationary probability distribution of a manufactured output quality is defined. Applications to production quality management, combined quality and maintenance management, as well as quality control are considered. Finally, an exponential shock model is resolved analytically.

ISSN:0020-7543    

DOI:10.1080/00207548708919929

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

The COVERT job shop dispatching rule was tested extensively twenty years ago with impressive results, however, since then it has been included in only one comparative analysis with other sequencing rules, and, reported instances of its application have been infrequent. In this paper, the COVERT rule is examined in detail relative to its applicability, its sensitivity to various operating parameters and performance measures, and its performance compared to several other sequencing rules including truncated SPT rules, dynamic slack rules and modified duedate rules. The performance of COVERT is examined for a variety of tardiness measures. The examination is conducted within the context of a simulation model of a machine-constrained job shop with serial jobs and random routings. The results indicate that COVERT performs well as a sequencing rule and in most instances was superior to the other sequencing rules tested both directly and across varying degrees of due-date tightness.

ISSN:0020-7543    

DOI:10.1080/00207548708919930

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0020-7543    

DOI:10.1080/00207548708919931

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor