Group Technology Cells Research Articles

Understanding the Design Continuum Between Group Technology and Fractal Cell Designs for Manufacturing Systems Through the Central Backup Cellular Manufacturing System

Understanding the Design Continuum Between Group Technology and Fractal Cell Designs for Manufacturing Systems Through the Central Backup Cellular Manufacturing System

Lean Startup Approach on Product Design and Manufacture Facility Planning in Uncertain Business Climate

Successful companies can provide the products that suit to consumer desire. There are two approaches in the product manufacturing process which are Product Development Process and Lean Startup. This study aims to demonstrate the conception of Lean Startup and its application in product design particularly in uncertain business climate. After comparing the two methods, Lean Startup approach is appropriate since the validation process in each product development process will certainly increase the possibility of products that suit to the consumer desires and reduce the time needed starting from product design to the market. In order to support Lean concept in the whole processes, there are two techniques that might be applied to support lean operational system, which are the formation of one worker multiple machine (OWMM) cells and Group Technology (GT) cells.

Realising competitive advantage [bicycle manufacture - manufacturing engineering and management

Students at Cranfield Manufacturing Systems Centre helped Brompton Bikes formulate a strategy to meet rapid sales growth. The students took up Operations Excellence MSc, a two-year part-time programme based on the Cranfield MSc in Engineering and Management of Manufacturing Systems, include the Realising Competitive Manufacture module, which is set out to consolidate and embed the knowledge and skills developed throughout the two-year programme. Guided by StratNav process, the students analysed the product families of Brompton, established the basis on which they compete in the market place, and then benchmarked against key competitors. The top five developments identified to be needed by Brompton are: the formation of group technology cells, creation of a robotic brazing facility, and training and recruitment initiatives for production staff.

Forming GT cells incrementally using GRASP

Most research in cell design assumes that the entire plant is converted into group technology cells at once. However, empirical findings in recent papers suggest otherwise, that is, most industries have converted only part of the plant into manufacturing cells and most cells in industries are created and implemented sequentially over time. In this paper, we develop a mathematical model and a heuristic approach based on greedy random adaptive search procedures (GRASP) to address incremental cell formation problem. The methodology allows forming cells gradually and converting a fraction of the plant into cells.

GT cells design and implementation in a glass mould production system

Cellular production is maintained to be a popular manufacturing and management philosophy, which is increasingly interested and intensified. In this study, group technology cells design and implementation project in a real life glass mould production system is described. All the stages of the project, the difficulties encountered, the strategies developed that overcome these difficulties and the performance improvements after the implementation of cellular production are explained in detail.

An approach to the design of a hybrid organization of workshops into functional layout and group technology cells

Cell formation is a widely recognized way of structuring certain types of manufacturing systems so as to improve their efficiency. Unfortunately, in many cases, the characteristics of the workshop are such that grouping certain machines into cells would actually improve the performance of the shop, but certain other machines would be more efficiently used in functional cells (i.e. cells composed of machines of the same type). The resulting organization is called ‘hybrid’. The problem addressed here is how to define the cells of a workshop so as to design a hybrid system? We suggest a constrained multi-criteria approach, which favours cells for the parts that are regularly manufactured over time (i.e. stable parts) and that have a great contribution to the traffic of parts in the workshop. This problem is addressed using evolutionary computation. An evolutionary programming algorithm is proposed and illustrated on a test example with a known optimum.

An approach to the design of a hybrid organization of workshops into functional layout and group technology cells

An approach to the design of a hybrid organization of workshops into functional layout and group technology cells

Structuration d'ateliers hybrides

The cell formation is a method to structure workshops, which generally, increases their performances. However, in many cases, the performances can be improved if some machines are organized in cells, and others are organized in functional departments. Such an organization is called hybrid. The problem is to know how to define cells in order to create a hybrid system. We propose a multi-criteria approach under constraints. The first criterion contributes to grouping machines so that stable parts are manufactured in group technology cells. The second criterion is concerned with inter-cell moves, which have to be minimized. An evolutionary approach is used to tackle this problem. An evolutionary programming approach is proposed and evaluated on two test problems.

The trade-off between intracell and intercell moves in group technology cell formation

This paper presents a new method of generating adaptive ruled layers for rapid prototyping (RP) processing of complex parts. To increase the accuracy and reduce the build time, an adaptive ruled layer approximation of the stereolithography (STL) models and multiaxis path planning for rapid prototyping are proposed. In this paper, a new method of constructing ruled layers from slicing STL points is developed to approximate the STL models with better surface accuracy. A technique of surface error analysis is presented to find the maximum errors at different layers of RP parts. By finding the RP surface errors, adaptive ruled layers are generated for the RP process of the STL CAD models. Using the constructed ruled layers of the STL models, the multiaxis material removal process is integrated with traditional RP processes to achieve better surface accuracy and to reduce the total RP build time. Computer implementation and illustrative examples are presented.

The trade-off between intracell and intercell moves in group technology cell formation

Abstract In cellular manufacturing, machines are organized into compact and independent product-based group technology (GT) cells. Production in smaller GT cells not only reduces travel distances but also facilitates better material and production control. Cell compactness and cell independence are two basic requirements of efficient GT cells. Most cell formation procedures consider maximizing cell independence as the objective. In doing so, these procedures impose an upper limit on cell size as a threshold value for cell compactness. This paper views cell compactness and cell independence in terms of intercell and intracell move costs. The trade-off between intracell and intercell move costs is explained in detail. A nonlinear mathematical model and simulated annealing algorithm are developed that minimize the total intracell and intercell move costs. In the calculation of move costs, production quantity, effect of cell size on intracell move, effect of sequence of operations, and multiple non-consecutive visits to the same machine are considered. The results are compared with published results.

Group technology cell formation considering operation sequences and production volumes

In this paper a new approach for minimizing intercell part flows in cellularmanufacturing is proposed. Two types of production data-based part-machine incidence matrices (PMIMs) are developed to reflect the real-field data such as the operation sequences and production volumes of the parts to be manufactured. The type I production data-based PMIM represents the actual flows to or from machines by parts. A 0?1 linear formulation using the type I production data-based PMIM is developed to minimize the total intercell flows. Once the type I production data-based PMIM is obtained, a type II production data-based PMIM is constructed to reflect the actual intercell flows by bottleneck parts requiring operations outside its corresponding cell. Computational results with the well known data sets in literature show that the proposed production data-based PMIMs can be used as the fundamental replacements over the classical binary PMIM in the cell formation problem, and the mathematical model based on the new PMIMs reflecting the real-field data can be applied effectively to proper medium-sized cell formation problems.

A hierarchical model for the cell loading problem of cellular manufacturing systems

A hierarchical cell loading approach is proposed to solve the production planning problem in cellular manufacturing systems. Our aim is to minimize the variable cost of production subject to production and inventory balance constraints for families and items, and capacity feasibility constraints for group technology cells and resources over the planning horizon. The computational results indicated that the proposed algorithm was very efficient in finding an optimum solution for a set of randomly generated problems.

Formation of general GT cells: an operation-based approach

In this paper, we study the formation of general Group Technology cells based on the operation requirements of parts and operation capabilities of machines. Parts are first grouped into families by using a similarity coefficient based on common operation types. An integer model is then developed to solve the problem of machine group selection. The model takes into account machine cost, variable production cost, setup cost, and intracell material handling cost. A greedy heuristic, a minimum increment heuristic and a simulated annealing heuristic are proposed for solving the model more efficiently. The computational results have shown that the heuristic methods perform well when compared to the optimal solutions. The effect of changing cost structure on the performance of heuristic procedures is also investigated.

Design and scheduling of hybridmulti-cell flexible manufacturing systems

The objective of this paper is to minimize machine duplication by increasing its utilization, minimize intercell moves, simplify the scheduling problem and increase the flexibility of the manufacturing system. An integrated approach of design and scheduling alternative hybrid multi-cell flexible manufacturing systems (MCFMSs) in four steps will be presented in this paper. The first step is the implementation of branch and bound techniques which provide tools to design group technology (GT) cells. The second step is balancing the inter-cell workload of GT cells which leads to a hybrid MCFMS with better utilization of the machines. The problem of the exception machines and their utilization and workload balance will be solved within the MCFMScentre. Thus the performance of GT cells can be improved by transferring workloads from a congested (bottleneck) machine in one cell to an alternative one, a less congested (exception) machine in another cell within a group of GT cells forming a MCFMS centre. The third step is the group scheduling; a proposed heuristic method will be used for the scheduling of a family of parts with the objective of minimizing the maximum completion time of each part. The problem of scheduling under MCFMS can be reduced by considering the scheduling of each family of parts. Finally, the flexibility of the system will be enhanced by selecting appropriate machine tools and flexible material handling equipments. This approach is both effective and efficient-it has generated a hybrid MCFMS centre which includes several alternatives, for some benchmark problems in much shorter time than algorithms previously reported in the literature. In addition, the method is conceptually simple and easy to implement.

Performance evaluation in production flow analysis

For the last 20 years, the scientific community has been suggesting routeing clustering algorithms for the identification of manufacturing group technology cells. Considering the variety of the proposed algorithms, the fair question of the evaluation of these algorithms within the frame of a flow reorganization method is raised. The results of the evaluation studies of these algorithms sometimes seem contradictory. We claim that the observed discrepancies are linked to the choice of the data samples which are used for these studies. In order to clarify this statement, we have undertaken to study rigorously the influence of some parameters characterizing the data on two important- as well as inseparable in the field of cell formation- performance measures. In this article, the relations between the data and these two performance indicators are shown; furthermore, the consequences of these relations on the evaluation procedures of the cell formation methods are also discussed.

A Group Technology-Based Modelling Approach to Computer Aided Process Planning

This paper reports on the design of a computer aided process planning system (CAPP-GT) for the parts manufactured in a group technology cell. The software incorporates various modules for part families description, sequence modelling, rule based tool selection, statistical model for time estimation and finally for report generation and editing. All this modules are built around a technological data base and a knowledge base formalizing the group technology cell experience.

Group technology cell design: a case study

Abstract Rising production costs, combined with competitive pressures, have resulted in an increased focus on the need for effective manufacturing planning and control. To remain competitive, organizations are exploring new ways for increasing productivity while reducing work-in-progress inventories and product lead time. This article describes a case study of the successful introduction of production cells in a company engaged in small batch production. The company is described and its manufacturing problems presented. Following a detailed analysis of the utilization of machines in the company's machine shop, a new manufacturing technique, giving improved work flow, is proposed.

Heuristics for operator scheduling in Group Technology cells

We devised heuristic approaches for operator scheduling in manned Grouped Technology (GT) cells. The heuristic approach consists of (1) Cycle Switching Rules (CSR) to deal with production environments covering a longer decision horizon, and (2) Dynamic Scheduling Rules (DSR) to deal with environments covering a shorter decision horizon. They differ in information requirements and decision horizons. In simulation experiments, we show that there is a predictable trade-off between the quality of the resulting schedule and the information content of heuristics used.

Scheduling and order release in a single-stage production system

We develop a set of scheduling heuristics that integrate order release, group scheduling, and order sequencing for a make-to-order manufacturing facility organized into group technology cells. The procedures take into account both order due dates and sequence-dependent setup times. Simulation experiments are used to compare the performance of the procedures to current practice. Results show that the new scheduling policies, which consider setup times as well as due dates in both order release and job sequencing decisions, substantially improve due date performance and show that both order release policies and dispatching rules have significant effects on system performance.

Performance of Fuzzy ART neural network for group technology cell formation

This study investigates the performance of Fuzzy ART neural network for grouping parts and machines, as part of the design of cellular manufacturing systems. Fuzzy ART is compared with ART1 neural network and a modification to ART1, along with direct clustering analysis (DCA) and rank order clustering (ROC2) algorithms. A series of replicated clustering experiments were performed, and the efficiency and consistency with which clusters were identified were examined, using large data sets of differing sizes and degrees of imperfection. The performance measures included the recovery ratio of bond energy and execution times, It is shown that Fuzzy ART neural network results in better and more consistent identification of block diagonal structures than ART1, a recent modification to ART1, as well as DCA and ROC2. The execution times were found to be more than those of ART1 and modified ART1, but they were still superior to traditional algorithms for large data sets.