Material Handling System Design Research Articles

Marginal analysis guided design justification: a material handling example

The design and justification of an integrated manufacturing system and all of the supporting sub-systems (e.g. material handling system) is a difficult task. One of the most difficult aspects in the design process is determining how and where to proceed. This paper proposes the use of a marginal analysis-directed branch and bound approach as the basis for directing the design process so that a combined economic and performance justification path results. The background and rationale for a marginal analysis guided design approach is given and an example of a material handling system design is presented to illustrate the development of a design justification decision path.

An Analytic Model for Design and Analysis of Single-Vehicle Asynchronous Material Handling Systems

Most research to date on asynchronous material handling systems such as automated guided vehicle systems (AGVSs) has involved simulation studies. In this paper we develop an optimal design model for a single-vehicle AGVS that analytically accounts for the stochastic nature of real manufacturing systems. The model determines which stations and routes to include in the network to maximize the benefit of the network subject to a constraint that the average waiting time in the system not exceed a prescribed limit. In the absence of an analytical model, one would have to simulate all possible combinations of stations and routes in order to find the configuration that maximizes the benefit of the AGVS. Our contribution is to solve the problem analytically. We develop analytic expressions for key performance measures such as the full and empty trip distribution, vehicle utilization, and expected waiting time in the network. The model is formulated as a linear binary integer program with one nonlinear constraint. To solve the problem we develop bounds on the expected waiting time, which we use as part of an exact implicit enumeration solution procedure. We illustrate the model with an example of an AGVS design problem at Hewlett-Packard and we present computational experience for other representative problems.

A hybrid modelling approach to the design of an AGV-based material handling system for an FMS

Abstract The problem of organizing and controlling the material handling activity in an AGV-based material handling system for a flexible manufacturing system involves several decisions such as the number of vehicles required for the system, the layout of the tracks, the dispatching rules for the vehicles and the provision of control zones and buffers. This paper demonstrates the use of a two-stage approach for solving the problem. The required number of vehicles is estimated using an analytical model in the first stage. In the next stage, the effects of AGV failures and AGV dispatching rules on the system performance are observed through simulation studies based on which the AGV dispatching rule can be chosen.

Performance analysis of a LIM-based high-speed tool delivery system for machining

Material handling provides a major opportunity for productivity improvement in manufacturing systems. The poor performance of the conventional material handling systems, such as conveyors or automated guided vehicles, has led most researchers to focus on opitmal utilization of the material handling system through the design of new scheduling algorithms or control strategies. The low speed of currently available material handling systems is one of the major factors that lead to long process delays and correspondingly large work-in-process inventories common in many manufacturing systems. In this paper, we suggest a new design of material handling systems, driven by a high performance linear induction motor (LIM). The high speed of this LIM-based material handling system distinguishes it from the conventional material handling systems. To evaluate its performance, we have constructed a simulation model where the LIM-based vehicles serve as a tool delivery system in a flexible manufacturing system (FMS). We ...

The design of flexible manufacturing systems

Flexible manufacturing systems (FMS) have promised many benefits but there is evidence that the implementation of FMS is often fraught with difficulty. One result is that the implementation rate of FMS is much lower than has been expected. The aim of this paper is to review the approaches that can be used to design an FMS. A review is given of the work done to date on the design an FMS in the areas of facilities design, material handling system design, control system design, and scheduling. In each instance, the major research and development issues are given. Through examining the tools and approaches that are used to design these four phases it is apparent that no integrated design methodology exists for FMS. The tools available are not specifically tailored for FMS and their unique integrated form. Because of the lack of integration, an FMS must be designed by examining the four phases independently even though the design decisions from each area affect the efficiency of the other areas.

A framework for material handling system design justification

Abstract The integrating nature of material handling systems renders their design and economic justification critical to the performance of a manufacturing system. This paper describes a framework for the concurrent design and economic justification of a material handling system (MHS). An approach to concurrent design and economic justification termed design justification is presented, followed by a discussion of the nature of the MHS selection and specification problems The design justification framework utilizes a modified branch and bound concept which is guided by a marginal-analysis-based modification strategy. The prototype implementation of the design procedure involves automatic generation of discrete optimization, capacity, queueing network and simulation models. Illustrative examples are given of the design logic and information used within the framework. The application of the design justification framework enables system designers to develop material handling systems that are justifiable from ...

Development of an object-oriented simulator for material handling system design

Simulation is perhaps the best way to study any nontrivial real world material handling system. But approaches offered in most conventional simulation languages, discrete event simulation, network simulation and continuous simulation lack a natural way of simulation modeling. It is believed that object-oriented simulation may overcome the intrinsic limitations of conventional simulation languages. Object-oriented Simulation (OOS) provides a more natural way of modeling complex phenomenon and a higher productivity during the incremental phase of development but it is not a panacea. In this paper, the authors relate their experiment with SmallTalk-80, an object-oriented language which gained popularity in the last few years. More specifically, the article begins with a few historical developments that lead to object-oriented programming. We will also present some characteristics of an object-oriented simulation product specialized in material handling system design that is currently under development. The product called CAD/MHS (Computed Aided Design for Material Handling Systems) is in its early phase of development but it is already very promising. CAD/MHS is being written in SmallTalk-80 on a Sun SparkStation, it features windowing capabilities, integrated graphics an code portability, three fundamental aspects that are considered essential in todays very fast changing market. We will also discuss the ergonomically designed interface and some of its components. The modeling aspects of certain material handling devices, the potential of such an environment and future developments to be included will also be discussed.

A systematic procedure for the selection of bulk material handling equipment

Many companies use materials shipped in bulk and must solve material handling problems associated with these materials. This paper concentrates on the selection of relevant factors that need to be considered in the design of a bulk material handling system and on the selection of equipment once these factors have been considered. A model is presented which takes into account economics, characteristics of the equipment, environmental characteristics, and compatibilities between equipment types.

EXCITE: Expert consultant for in-plant transportation equipment

Abstract The cost of handling material is a vital factor in the facilities design process, whether it is for a new facility or for the redesign of an existing facility. Handling activities generally account for 30 to 40% of production costs, but in some industries they can be as high as 70%. Well designed handling systems are thus crucial for reduced costs and increased profits. A key task in the material handling system design process is the selection and configuration of equipment for transport and storage in a facility. Material handling equipment selection is a complex, tedious task, and there is usually more than one good answer for any particular situation. A number of good quantitative techniques are available to aid the industrial engineer in determining layout design with the aim of reducing material handling cost. Unfortunately, there are few tools other than checklists to aid the engineer in the selection of appropriate, cost-effective material handling equipment. Analytical models are not ofte...

The pallet packing problem for non-uniform box sizes

We consider an important problem in the design of material handling systems in a flexible manufacturing environment; that of robotic palletization when the boxes to be palletized are of varying dimensions. The problem is formulated as a zero-one integer programming problem. The mathematical model includes the issue of multiple pallets and the orientation of boxes on the pallet. An illustrative problem is solved.

The material handling system design of integrated manufacturing systems

In this paper, a two-stage hierarchical decision scheme is proposed for the problem of material handling system (MHS) design during the initial design phase of integrated manufacturing systems. The first stage deals with selection of material handling equipment to perform various transportation and handling activities, and specification of their important parameters. A parametric minimum convex cost multicommodity flow formulation is proposed for the problem. The second stage deals with the topological design of the MHS. A discrete directed network design on a plane formulation is proposed. Results from graph theory for the above formulation are discussed, and their implications for the topological design of the MHS are pointed out.

Design of an automated guided vehicle-based material handling system for a flexible manufacturing system

SUMMARY Automated guided vehicle (AGV)-based material handling systems (MHSs), which are widely used in several flexible manufacturing system (FMS) installations, require a number of decisions to be made. These include the number of vehicles required, the track layout, traffic pattern along the AGV tracks, and solving traffic control problems. This paper addresses the key issues involved in the design and operation of AGV-based material handling systems for an FMS. The problems arising from multi-vehicle systems are analysed, and strategies for resolving them are examined using analytical and simulation models.

Simulation system for material handling system design

The increasing use of computers to control material handling systems has generated a surge of interest in the general field of material handling. One of the most important and powerful tools available for design and/or study of the operation of complex systems and processes is simulation. Simulation has proven to be an extremely effective tool for addressing a wide variety of facility planning, design, scheduling, operations control and material handling problems. In material handling, exact analytical solutions are available for certain classes of problems only. Analytical models are inherently limited to a relatively low level of complexity, and as such cannot be employed for the analysis of most real life material handling situations. The need for more research attention to the development of realistic analytical models in this area is obvious. Additionally the size and complexity of most material handling systems defy exact deterministic analysis and it is within this context that simulation assumes an even greater importance. That simulation models have a number of limitations cannot be denied, but in view of the relative absence of powerful, realistic analytical models, simulation models are the only viable alternatives, provided that due attention is paid to the questions of model validity and experimental design. Although there have been a number of successful applications of simulation in designing material handling systems, these have been mostly of specific and limited scope, research of more comprehensive and general nature has been nearly absent until quite recently. Several commercial simulation packages and/or languages are available and may be used or adapted for simulating some material handling problems, yet none of these have been designed specifically to deal with material handling problems. This paper describes a software system specifically addressed to the important issues of the design of new or improved material handling systems, as well as the operation of existing systems. Tradiationally a major drawback with simulation has been the great amount of time and effort required to develop a model, this can be alleviated by the development of an interative, easy to use, material handling simulation system, such as the one described in this paper. Relevant representative research is presented, followed by description and general discussion of the system. The system is written entirely in FORTRAN 77 and requires no knowledge of programming to use, and will be made available to interested practitioners and researchers.

Mechanized material handling systems design and routing

Tinker AFB (TAFB) is the prime Air Force rework facility for jet engine parts that support standard engines. The wear and tear on the engine parts of the various aircraft currently produces about 10 million individual requirements annually for part inspection and subsequent discard or rework. Past practices have resulted in extremely long flow times for rework and a burgeoning requirement for conveyor capacity. A new concept, called the Modular Repair Center (MRC), is being implemented to correct the problem. The MRC's have most of the processes necessary to inspect and repair components of a given engine assembly. They have the advantage of reducing the number of long moves, giving more accountability for quality and better tracking. A large network model of TAFB facility has been developed to determine the required work-in-process storage, conveyor capacity, shortest routes for parts to flow from one MRC to another and the maximum flow along each conveyor section. The model was analyzed using Floyd's shortest route algorithm. It resulted in reducing the “bottlenecks” on certain conveyor sections by rerouting some of the flow along low density traffic links and thus reducing the need for extra converyor capacity. Simple formulas were designed to estimate the number of pallets generated by disassembly and each MRC to provide the demand requirements for conveyor capacity.

Mechanized material handling systems design and routing

Tinker AFB (TAFB) is the prime Air Force rework facility for jet engine parts that support standard engines. The wear and tear on the engine parts of the various aircraft currently produces about 10 million individual requirements annually for part inspection and subsequent discard or rework. Past practices have resulted in extremely long flow times for rework and a burgeoning requirement for conveyor capacity. A new concept, called the Modular Repair Center (MRC), is being implemented to correct the problem. The MRC's have most of the processes necessary to inspect and repair components of a given engine assembly. They have the advantage of reducing the number of long moves, giving more accountability for quality and better tracking. A large network model of TAFB facility has been developed to determine the required work-in-process storage, conveyor capacity, shortest routes for parts to flow from one MRC to another and the maximum flow along each conveyor section. The model was analyzed using Floyd's shortest route algorithm. It resulted in reducing the “bottlenecks” on certain conveyor sections by rerouting some of the flow along low density traffic links and thus reducing the need for extra conveyor capacity. Simple formulas were designed to estimate the number of pallets generated by disassembly and each MRC to provide the demand requirements for conveyor capacity.

Advanced Material Handling

With the advent of automation in manufacturing and warehousing, material handling is being seen as a focal point of total system integration and control. In contrast to mechanical design problems, this paper addresses current issues in the design and operation of material handling systems from an overall systems viewpoint. Topics reviewed include automated storage and retrieval systems, order picking, order sortation and accumulation, and transportation. The purpose is to overview essential issues, describe representative research, and identify critical needs for future study.