摘要:

This paper extends previous work on implementation problems associated with a flexible system that produces flat sheet-metal parts with interior holes. The paper makes four main contributions. First, we formulate the problem of selecting tooling and design standards to minimize the cost of producing parts as an optimization model. Second, we develop a projected subgradient algorithm for the Lagrangian relaxation of the problem by using the model's special structure to develop relationships between the Lagrangian multipliers. Third, we demonstrate that the algorithm produces close to optimal solutions (duality gap less than 2%) very quickly on a number of problems derived using a substantial data set obtained from a Chicago area firm. Fourth, an important variant of the traditional repair kit problem is shown to be a special case of the tool selection problem.

ISSN:0740-817X    

DOI:10.1080/07408179508936758

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In manufacturing parts, multiple processes are frequently used in sequence to produce the designed feature. The sequence of processes can easily be identified from previous experience. But no work has been done to determine whether any of the processes in the sequence are really necessary. A mixed integer mathematical programming model has been set up to determine the optimal set of processes and the amount of material to be removed by each process to minimize either the total process time or the total production cost.

ISSN:0740-817X    

DOI:10.1080/07408179508936759

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

A structured systems methodology was developed to analyse the problems of production interruptions occurring at random intervals in continuous process type manufacturing systems. At a macro level the methodology focuses on identifying suitable investment policies to reduce interruptions of a total manufacturing system that is a combination of several process plants. An interruption-tree-based simulation model was developed for macroanalysis. At a micro level the methodologyfocuses on finding the effectsof alternative configurations of individual processplants on the overallsystemperformance.A Markov simulationmodel was developed for microlevel analysis. The methodology was tested with an industry-specific application.

ISSN:0740-817X    

DOI:10.1080/07408179508936760

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In a stopped arrival queue the arrival process is switched off as soon as the available queue space is full and not switched on again until there is space in the queue. A simple approximation forGI/GI/1/Nstopped arrival queues is developed and shown to be remarkably accurate in predicting throughput. Becausea two-stageflowline is equivalent to a stopped arrival queue, theGI/GI/1/Nstopped arrival queue can be usedas the building block for approximating the performance of multistage flowlineswhere the service times at the stages have general distributions. Numerical tests of the throughput approximation show that it gives accurate throughput predictions, in spite of its simplicity and minimal computation requirements.

ISSN:0740-817X    

DOI:10.1080/07408179508936761

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Automated process planning has been recognized as an interface between computer-aideddesignand computer-aided manufacturing. To achieve true computer integrated manufacturing (Cllvl), process planning should be integrated with scheduling. One approach to this integration problem is to merge process planning and scheduling into a single optimization task. However, the scheduling problemalone belongs to the classofnondeterministic polynomial complete(NP-complete) problemsand whencombined with processplanning, the resulting problemis evenmore difficult. One solution to this is to adopt a progressive approach, in which the interaction between process planning and scheduling starts from a more global level and ends at a more detailed level. The progressive approach described in thispaper greatlyreduces the computational complexity of the integration problemand hence can be realized in a real manufacturing environment where time is critical.

ISSN:0740-817X    

DOI:10.1080/07408179508936762

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper applies genetic optimization with an adaptive penalty function to the shape-constrained unequal-area facility layout problem. We implement a genetic search for unequal-area facility layout, and show how optimal solutions are affected by constraints on permitted department shapes, as specified by a maximum allowable aspect ratio for each department. We show how an adaptive penalty function can be used to find good feasible solutions to even the most highly constrained problems. We describe our genetic encoding, reproduction and mutation operators, and penalty evolution strategy. We provide results from several test problems that demonstrate the robustness of this approach across different problems and parameter settings.

ISSN:0740-817X    

DOI:10.1080/07408179508936763

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper, a lead-to-pad alignment technique for surface mount component placement on printed circuit boards is developed. The problem is expressed as a nonlinear optimization problem with a linear objective function and quadratic constraints. A solution procedure is developed and compared with a known nonlinear optimization solution technique. Results show substantial improvements in execution time of the optimization and yield of the placement operation when implemented in a robotic cell.

ISSN:0740-817X    

DOI:10.1080/07408179508936764

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper presents an evaluation of four different sequential approaches to solving the one-dimensional cutting-stock problem in an industrial setting where trim loss and pattern changes costs are of importance. The evaluation is made with sample problems generated from data of a manufacturing company as well as with real problems. Triangular distributions, which are representative of many practical environments, are introduced as proxies to the distribution of the lengths required. Conclusions are drawn based on the various problem sizes and distributions tested.

ISSN:0740-817X    

DOI:10.1080/07408179508936765

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

This paper presents a model for allocating storage space to inventory in a way that minimizes the cost of material handling. The space allocation problem is modeled as a generalized transportation problem; however, transporting material within the facility is the focus. The basic formulation of the model considers material type, material flow transitions, and distance transported. The model is extended to determine production levels for multiple products such that additional material handling costs (i.e., load/ unload times) are minimized. Applications of the just-in-time (JIT) concept and material handling in the job shop environment are discussed. Finally, an industrial case study is presented.

ISSN:0740-817X    

DOI:10.1080/07408179508936766

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We consider a production system consisting of several fabrication lines feeding an assembly machine. The machines in the fabrication lines and at assembly are assumed to have general processing time distributions. Releases to the system are governed by thekanbanrelease mechanism. We first derive a heuristic for the throughput of this system by replacing the assembly system under kanban release by an equivalent system under CONWIP release and by making use of an approximation for the throughput of a CONWIP assembly system (Duenyas, 1992). Comparisons with simulation show that this heuristic is robust over a wide range of conditions.

ISSN:0740-817X    

DOI:10.1080/07408179508936767

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor