摘要:

We present a family of rolling horizon heuristics to minimize maximum lateness on a single machine in the presence of sequence-dependent setup times. This problem occurs as a subproblem in a decomposition procedure for more complicated job shop scheduling problems. The procedures solve a sequence of subproblems to optimality with a branch and bound algorithm and implements only part of the solution obtained. The size and number of the subproblems are controlled by algorithm parameters. Extensive computational experiments show that these procedures outperform myopic dispatching rules by an order of magnitude, both on average and in the worst case, in very reasonable computation times.

ISSN:0020-7543    

DOI:10.1080/00207549408956998

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Process planning is the systematic determination of the detailed methods by which parts can be manufactured from raw material to finished product. In a real manufacturing environment, usually several different parts need to be manufactured in a single facility sharing constrained resources. The existence of alternative process plans for each part makes the selection of process plan a very important issue in manufacturing. The objectives in process plan selection might be imprecise and conflicting. In this paper, a fuzzy approach is used to deal quantitatively with the imprecision of the process plan selection problem. Each process plan is evaluated and its contribution to shopfloor performance is calculated using fuzzy set theory. A progressive refinement approach is used to first identify the set of process plans that maximize the contributions, and then consolidate the set to reduce the manufacturing resources needed.

ISSN:0020-7543    

DOI:10.1080/00207549408956999

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Flexible manufacturing systems (FMSs) are usually composed of general purpose machines with automatic tool changing and integrated material handling. FMSs offer the advantages of high utilization levels and simultaneous production of a variety of part types with minimal changeover time. Although the trend in FMS operation appears to be towards unmanned production, there is much diversity in the policies under which FMSs can be operated. These policies are governed to some extent by the available technological resources. In this paper several policies are described. Tool loading and production assignment models for setting production plans over a short term planning horizon when using these policies are then formulated. Heuristics for the solution of these models are detailed and computational results are presented.

ISSN:0020-7543    

DOI:10.1080/00207549408957000

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Tool wear monitoring and estimation are essential for improved productivity of manufacturing systems. Multi-sensory approaches based on force, vibration and Acoustic Emission (AE) signals have been recognized as potential methods for tool wear monitoring. In the present work, steady-state components of force, dynamics of the main cutting force and vibration in the direction of the main cutting force have been used for on-line tool wear estimation in a turning process. The group method of data handling (GMDH), a heuristic self-organizing method of modelling, has been used to integrate information from different sensors and the cutting conditions to obtain estimates of tool wear. Different methods of preprocessing the forces have been attempted to determine the best method to suit the data. Various heuristics of GMDH have been analysed to obtain the appropriate models for tool wear estimation. The results show that GMDH can be effectively used to integrate sensor information and obtain reliable estimates of tool wear.

ISSN:0020-7543    

DOI:10.1080/00207549408957001

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

To achieve high productivity in today's plants and warehouses, an efficient, orderly, and flexible flow of materials is essential. It is increasingly being realized that material handling and warehousing activities cannot be separated from plant layout and design activities. The interface between plant layout, material handling, and warehousing systems represents a crucial step toward an integrated and systematic facilities design. The manufacturing entities who design for the total operating system by a well-defined set of objectives and constraints tend to increase their chance of improving or increasing throughput, space utilization, operating flexibility, employee morale/working conditions, and overall productivity. These also tend to reduce capital expenditure and operating costs. Once an integrated facilities system is envisioned and contemplated, the emphasis shifts to models and optimizing the system. Quick and Dirty Methods, Simulation Methods, and Clustering Analysis Methods have been proposed as viable options for modelling and optimization. A detailed procedure for analysis and application of Cluster Identification (CI) Algorithm is presented. At the conclusion, advantages and practical implications of CI algorithm is presented and analysed and a comparison with simulation models is provided.

ISSN:0020-7543    

DOI:10.1080/00207549408957002

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This study describes the development of a PC-based production scheduling system for a plastic manufacturing company. The complexity associated with the company's scheduling problem arises from the need to address three major scheduling issues simultaneously, namely, lot sizing, machine loading and meeting target due-dates. The resulting system acts as a quantitative planning tool capable of generating short-term production schedules that minimize cost, also a decision-support tool assisting the scheduler in analysing and evaluating user-proposed schedules, provides useful information for short-term planning purposes and uses a user-friendly menu-driven environment allowing the user to specify parameters and to access information on interests.

ISSN:0020-7543    

DOI:10.1080/00207549408957003

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

The architecture and design of process planning systems should follow the architecture and design of the manufacturing systems they are intended to serve. This article describes a process planning system specifically intended for a workshop orientated factory, a factory which is specialized for the production of a limited number of group technological product lines. The goal of the system is to generate automatically and rapidly reliable part programs from order information. With the system, a process plan can be generated by workshop personnel on the basis of process plan specifications stored in part family models. A part program generation algorithm can then create a part program automatically by pasting together segments of program code stored in the process models of the system. The part program generator can be tailored by new parametric part program definitions related to features. The tool paths of the generated code can be visualised. The system described forms the operative process planner part of the MCOES (BE-3528) process planning system.

ISSN:0020-7543    

DOI:10.1080/00207549408957004

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Proper management of maintenance offers many companies significant potential for improving productivity and profitability. Traditional management thinking regards maintenance costs as accidental, rather than planned and controllable. Additionally, research in maintenance management has focused on preventive maintenance and has ignored corrective maintenance even though the latter is also considered to be a critical activity in industry. This study proposes a decision model that could assist in a comparative evaluation of alternative corrective maintenance policies. This decision model consists of a simulation model and economic analysis. The simulation model predicts inventory costs and delivery performance of a corrective maintenance policy in various production systems. Based on simulation results, an economic analysis, consisting of a net present value model and breakeven models, determines the economic value of alternative maintenance policies. A detailed example is offered to evaluate two particular correciive maintenance policies (machine redundancy and worker flexibility) although the decision model can be applied to other options. The results of the example demonstrate the decision model's capability to assist managers in selecting the best corrective maintenance policy.

ISSN:0020-7543    

DOI:10.1080/00207549408957005

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We investigated the relationship between flexibility and performance of manufacturing systems. In particular, the effect of varying flexibility in either part production requirements or the machines capabilities is examined. Conditions under which a positive correlation between flexibility and performance exists are identified and the characteristics of this correlation are described. System management and control mechanisms necessary for realizing the benefits of flexibility are outlined. The results are first illustrated through a series of models of specific manufacturing situations. A unifying and generic framework for flexibility modelling and analysis is then introduced. The framework is used to re-interpret and generalize the result of the previous models. It is also used to argue for the existence of a number of fundamental relationships between flexibility and manufacturing performance.

ISSN:0020-7543    

DOI:10.1080/00207549408957006

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

We consider a production system consisting of several fabrication lines feeding an assembly station. The machines in the fabrication lines and at assembly are assumed to have general processing time distributions. Releases to the system are governed by the CONWIP protocol. We model this system as an assembly-like queue and develop approximations for the throughput of the system. Comparisons with simulations show that this approximation is robust over a wide range of conditions. Finally, we observe that throughput tends to be higher when machines with higher mean processing times and/or higher variances are in fabrication rather than assembly.

ISSN:0020-7543    

DOI:10.1080/00207549408957007

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor