Group Technology Classification Research Articles

A Design for Assembly application with dynamic information retrieval from case database

Design for Assembly (DFA) is a Concurrent Engineering constituent that gained a lot of attention due to fast and measurable benefits. The main principle of DFA is to foresee assembly problems at the design stage based on the experience regarding functionality, materials and machine availability. The work presented in this paper, named RFA - Redesign for Assembly, adds a way to explicitly register and retrieve experiences as part of the design process. It starts from an initial design, then RFA leads the designer through a detailed assessment towards an improved design according to previous experiences. Experience representation was done using a Group Technology classification concept that helps assign a primary-key for a Case Based Teaching underlying system. A supporting system has been implemented in order to try out RFA. DFA scholars have used RFA and proved that experience retrieval is easily and intuitively incorporated in the design process. The paper presents a study about the DFA methodology, reviews existing solutions (methods and software) from the literature and details the RFA architecture, implementation and tests. RFA shows potential for a new design culture based on knowledge sharing, but also, as a repository for a very valuable asset, i.e. problem-oriented assembly-related design experience.

Framework of a computer-aided short-run SPC planning system

Statistical process control (SPC) is recognized as a technique to achieve cost-effective quality control through continuous manufacturing process improvement. But with growing demand for small-batch and high-variety products in the current dynamic market, the involved manufacturing processes are becoming more complex, variable, and flexible, which are not suitable for implementing SPC in the traditional way. Hence, short-run SPC is applied instead. Planning is a critical phase in the implementation of short-run SPC, which includes the formation of part families and the determination of corresponding data collection. To ensure homogeneity of the family members, this paper addresses preliminary analysis on the characteristics and applications of pertinent factors, and statistical analysis for SPC-based part family formation. To improve the efficiency of SPC planning and the adaptation for computer-integrated manufacturing, a framework for a computer-aided short-run SPC planning system is proposed using group technology classification and coding concepts. This invokes a 29-digit hybrid code appended to the Opitz coding scheme. Further, a supportive database is also proposed to facilitate coding information retrieval and system updating. A case study is shown with data collected from injection-mold manufacturing, which typically involves small-batch processes.

Automated design-to-cost: integrating costing into the design decision

While the concepts of design for manufacturability and concurrent engineering have made significant advances in integrating the design function with other areas in the firm, there are still major gaps in timely and accurate costing information available to designers. Our research develops a conceptual model and working prototype of a new application for blending product design and cost accounting, that of automated design-to-cost. The purpose of the application is to provide rapid and dynamic feedback during the design process regarding estimated final product cost of a new part design. The system first calculates the cost of a new part design directly from existing computer-aided design, accounting, and other computer-integrated manufacturing databases. It then finds and displays, along with their costs, all existing parts that are similar or ‘near’ to the proposed part. The model developed was successfully implemented as a prototype. It is able to integrate and process information from the diverse databases of feature-based modelling computer-aided design, group technology classification, computer-aided process planning and activity-based costing. Copyright

Representing group technology classification and coding techniques with object oriented modeling principles

The purpose of this paper is to show the common basis of several object-oriented design modeling principles as compared with those used in classification and coding (C&C) for group technology applications. Five types of decision tree (E-trees, N-trees, X-trees, D-trees, and C-trees) are shown to be in exact correspondence with the object-oriented modeling principles generalization with disjoint subclasses, generalization with overlapping subclasses, classification, generalization with restriction, and aggregation, respectively. In addition, C&C modeling and subsequent database implementation are shown to be enhanced through application of such object-oriented modeling principles as association and role names. Finally, a case study is presented that illustrates the application of these principles in the design and implementation of a C&C system for abrasive flow machining.

Group technology classification and coding system design: Considerations and extension to robotic end-of-arm-tooling

This paper discusses a number of the basic notions associated with the development and implementation of group technology oriented classification and coding systems. As well, an example system, designed to performed design retrieval and reference for a subset of tooling required for manufacture, is presented. In particular, this system was developed for retrieving and referencing the database of robotic end-of-arm-tooling (EOAT) designs. The discussion includes the overall code development strategy, the template for the interactive graphical user interface, and the details of the proposed EOAT classification and code structure. The graphics interface and the overall retrieval system were implemented on the INTERGRAPH MicroStation environment. These modules were written in the C programming language, with prototype development accomplished on a microcomputer. Finally, examples are used to demonstrate the capabilities of the system, and discussion concerning implementation issues is included.

A group technology classification and coding scheme for discrete manufacturing simulation models

Simulation experts know very well that there are similarities between the models they build for different manufacturing systems. This article describes a group technology (GT) classification and coding scheme for discrete manufacturing simulation models, which was developed by observing those similarities. The scheme is modified and validated by reviewing application-oriented simulation studies from the literature. Clustering analysis is used to form the first GT code scheme. The GT scheme serves as a basis for creating a model base consisting of generic models. These generic models permit development of an intelligent simulation environment. Specific user models can now be constructed by modifying and configuring the generic models rather than building them from scratch, reducing the effort and skill expected of the user in the process of model construction. A surprisingly small number of truly distinct model types is found.

Integration of a group technology classification and coding system with an engineering database

Integration of a group technology classification and coding system with an engineering database

Adoption and implementation of group technology classification and coding systems: insights from seven case studies

Abstract Results are reported from an empirical study of classification and coding (CC) system usage among manufacturers. The investigation, selection, justification, implementation and operation of CC systems by six user firms are presented in case study form. A case history of a former CC system user is also presented. User characteristics and experiences are compared and analysed across the seven cases. The paper concludes with managerial and research implications regarding CC system selection, justification, implementation and usage.

Flexible automated material handling system

This paper discusses the development of an expert system based on axis orientation of the parts in a three dimensional system. For any part fed to a machine cell, the material handling planning system presents the part to the assembly robot in the desired orientation. Group Technology classification and coding method is used for part identification, as well as for the feeding mechanism design.

Integration of a group technology classification and coding system with an engineering database

Five tools that apply group technology concepts to an engineering database were investigated and compared. The purpose of the investigation was to select the tools with the best ranking in the areas of cost, flexibility, and ease of use. These tools were applied to engineering data from an aircraft structural composites classification and coding schema. The tools include (1) a vendor supplied GT software package, (2) a GT classification schema mapped onto a relational database, (3) a GT classification and coding schema mapped onto a relational database, (4) a vendor supplied GT software package interfaced with a relational database, and (5) a custom developed GT package which directly accesses a relational database. It was concluded from a comparison of five GT design tools that the custom developed GT package was the most advantageous design tool based on evaluation factors which included cost, flexibility, and user-friendliness.

Multiobjective cluster analysis for part family formations

Abstract This paper presents an efficient computerized method for forming group technology part families using a goal programming based multiobjective clustering analysis with a group technology classification and coding system. The success of group technology applications rests on the effective formation of part families and subsequent efficient retrieval of part family data for rationalization of design and manufacturing. Due to the magnitude of this task, it is necessary to use a computer. A mathematical model and computer program were developed to improve the efficiency of applying this method in practice. The proposed method was tested and proved using actual industrial data.

Enterprise integration in manufacturing

Abstract Automation in manufacturing through Integrated Computer Assisted Manufacturing (ICAM) is very much supported by several computer software packages for the different manufacturing functions. Notable among them are: engineering design and drafting, finite element analysis, solid modelling, group technology-classification and coding, process planning, NC tape preparation, manufacturing resources planning, scheduling and shop floor control. Some of these functions are integrated in a few software packages. By enterprise integration it is meant that access to any functional software package to perform a required function should be possible from any computerized work station within the enterprise. Without the integration, information has to be transferred from one department to another orally or in “hard copy.” This form of information transfer is comparatively unproductive. Therefore integration of the different functions in an enterprise starting from order entry to shipping, if achieved, will increase the total productivity of an enterprise. The ultimate objective of enterprise integration is to create a factory to operate without paper. This paper discusses a possible approach and problems associated in integrating the enterprise functions in manufacturing.