摘要:

In a production system using multi-purpose and flexible machines, reducing setup time is an important task for better shop performance. Numerous cases were reported about successful reduction of setup times by standardization of setup procedures. However, setup times have not been eliminated and remain an important element of real production problems for production systems such as commercial printing, plastics manufacturing, metal processing, etc. It is especially critical when the setup time is sequence dependent. In this situation, shop performance cannot be effectively improved without the aid of an appropriate scheduling procedure. Review of the past studies shows that there has not been a significant amount of research done on the scheduling procedure for a dynamic job shop with sequence dependent setup times. This paper investigates the job shop scheduling problems that are complicated by sequence-dependent setup times. The study classifies and tests scheduling rules by considering whether setup time and/or due date information is employed. These scheduling rules are evaluated in dynamic scheduling environments defined by due date tightness, setup times and cost structure. A simulation model of a nine machine job shop is used for the experiment. A hypothetical, asymmetric, setup time matrix is applied to the nine machines.

ISSN:0020-7543    

DOI:10.1080/00207549408957019

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We examine the role and potential application areas of machine vision inspection systems in the printed circuit board (PCB) manufacturing industry. Available automatic optical inspection (AOI) techniques are reviewed, this revealing limitations which stem mainly from the stand-alone operational nature of the present-generation AOI systems. As a result the authors argue that, fuelled by the need to achieve integration and information sharing between AOI systems and other components of computerized manufacturing systems, it is necessary to define architectural guidelines that structure the way in which next generation AOI systems should be organized in order to enable them to share information of a common interest and cooperate on an enterprise-wide basis. We also examine typical applications of AOI in PCB manufacture. Upon extracting common features of these applications, a model of AOI task decomposition is proposed, which characterizes the main features of the two major subtasks that an AOI system needs to perform; so that it can benefit from information sharing and improve its performance in terms of providing more valuable and reusable inspection information to other computerized systems and processes. These two subtasks are (1) an initial local inspection subtask, and (2) a global inspection, analysis and inspection information generation subtask. The importance of the second subtask relates to the general requirement for AOI systems not only simply to automate PCB inspection processes, but also to provide readily reusable inspection information that can be utilized to support other relevant manufacturing processes. Based on the AOI task decomposition model, we propose a hierarchical architecture which can structure the design, implementation and re-organisation of AOI software algorithms and routines, in such a way that typical AOI operations can be enhanced, this through making use of available global information, and that more widespread, efficient and timely use of AOI-generated inspection information can be made by other manufacturing processes. Finally; a proof-of-concept implementation of the AOI reference architecture is described.

ISSN:0020-7543    

DOI:10.1080/00207549408957020

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A fast heuristic for the facilities layout problem including aisle location is developed. The procedure utilizes the scatter diagram of Drezner to obtain a relative location between departments. A simple modification of the new algorithm produces a powerful technique for pure and near-pure flowshops.

ISSN:0020-7543    

DOI:10.1080/00207549408957021

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Geometric programming (GP) has been successfully used for the determination of cutting parameters considering minimum production cost or maximum production rate as objective functions. However, GP was found not to be useful for another important criterion of optimization, namely maximum profit rate, due to its signomial nature. In this paper it has been shown that, through modification of the constraint set, the problem of profit rate maximization can be converted to posynomial form, and thus can be solved by GP combined with linear programming (G P-LP). The problems of single and multipass turning are formulated and solved for profit rate maximization using the GP-LP approach. The resulting cutting conditions have been compared with the conditions obtained for minimum production cost and maximum production rate.

ISSN:0020-7543    

DOI:10.1080/00207549408957022

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This study deals with the development of a model for a production line in a corrugated box factory. The main feature of the study is to combine different problems in a single model. The problems considered in the model were; minimizing the waste resulting from cutting the paper rolls into carton boards for the products (cutting stock problem), utilizing the limited storage capacity to enable the corrugated board dry for a specified period of time (storage space problem), and utilizing the converting machines fully during a shift (machine loading problem). After a detailed analysis of the factory, a linear programming (LP) model was developed to obtain solutions to the above mentioned problems. A case example was selected based on the actual data from the factory records and solved using the LP model developed.

ISSN:0020-7543    

DOI:10.1080/00207549408957023

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Risk analysis is frequently carried out on projects in feasibility and project definition. However, in full development and initial production often the risk is not monitored and controlled, and many projects fail at this point. This paper describes some proposed methods making up an integrated risk management structure, based on project experience, particularly with the defence industry.

ISSN:0020-7543    

DOI:10.1080/00207549408957024

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A number of methods exist for determining fraction-defective sampling plans for single items. However, most methods currently exist for determining a set of optimal sampling plans for serial assembly processes. This paper develops a risk and cost-based model which explicitly considers the effect of the quality of lower level items on the quality of the final product. The model allows us to determine a minimum cost set of sampling plans for all items in a multi-level, non-serial product. We study the performance of the model with an algorithm for solving nonlinear, multiple-criteria formulations.

ISSN:0020-7543    

DOI:10.1080/00207549408957025

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The problem of scheduling jobs with non-identical capacity requirements or sizes on a single batch processing machine to minimize total completion time and makespan is studied. These problems are proven to be NP-hard and heuristics are developed for both, as well as a branch and bound algorithm for the total completion time problem. Computational experiments show that the heuristics are capable of rapidly obtaining near-optimal solutions.

ISSN:0020-7543    

DOI:10.1080/00207549408957026

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Closed queuing networks have been widely used in recent years to model manufacturing systems, especially modern flexible manufacturing systems. These models have tended to be descriptive. In this paper, we explore the application of optimization procedures to closed queuing network models for the purpose of selecting optimal parameter values for manufacturing system operation. Optimal levels of work-in-process inventory are determined jointly with workcentre processing rates. A simple procedure is developed for obtaining the optimal work-in-process levels and processing rates for balanced workload systems. The tradeoff between work-in-process levels and processing speeds is examined. In general, investigation of model results indicates the importance of jointly determining processing rates at all workcentres and shop loading. Small facilities are seen to have an advantage over large facilities.

ISSN:0020-7543    

DOI:10.1080/00207549408957027

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The design and analysis of complex machining fixtures is difficult. This paper describes software which aids the designer in this task. Using this system, a designer specifies the basic geometry of the fixture in a series of steps. After each step, the designer validates the design using the analysis facilities of the software. The output of this process is a design which satisfies kinematic restraint, total restraint, and tool path clearance requirements. In addition the lower bounds on required clamp actuator intensities are also determined.

ISSN:0020-7543    

DOI:10.1080/00207549408957028

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor