Pierre De Lit

A multiple objective grouping genetic algorithm for assembly line design

The purpose of this paper is to describe some of the main problems concerning assembly line design. The focus will be on the following steps: (1) the input data preparation, (2) the elaboration of the logical layout of the line, which consists in the distribution of operations among stations along the line and an assignment of resources to the different stations, (3) finally the mapping phase using a simulation package to check the obtained results. This work presents a new method to tackle the hybrid assembly line design, dealing with multiple objectives. The goal is to minimize the total cost of the line by integrating design (station space, cost, etc.) and operation issues (cycle time, precedence constraints, availability, etc.). This paper also presents in detail a very promising approach to solve multiple objective problems. It is a multiple objective grouping genetic algorithm hybridized with the multicriteria decision-aid method PROMETHEE II. An approach to deal with users preferences in design problems is also introduced. The essential concepts adopted by the method are described and its application to an industrial case study is presented.

A multiple-objective grouping genetic algorithm for the cell formation problem with alternative routings

This paper addresses the cell formation problem with alternative part routings, considering machine capacity constraints. Given processes, machine capacities and quantities of parts to produce, the problem consists in defining the preferential routing for each part optimising the grouping of machines into manufacturing cells. The main objective is to minimise the inter-cellular traffic, while respecting machine capacity constraints. To solve this problem, the authors propose an integrated approach based on a multiple-objective grouping genetic algorithm for the preferential routing selection of each part (by solving an associated resource planning problem) and an integrated heuristic for the cell formation problem.

Integrated Design of a Product Family and Its Assembly System

Integrated Design of a Product Family and Its Assembly System presents an integrated approach for the design of a product family and its assembly system, whose main principles consider the product family as a fictitious unique product for which the assembly system is to be devised. It imposes assembly and operation constraints as late as possible in the design process to get liberties in the system design, and adapts the product family at each design stage to integrate the new constraints related to the successive design choices.Integrated Design of a Product Family and Its Assembly System is an important, must-have book for researchers and Ph.D. students in Computer-Integrated Manufacturing, Mechanical Engineering, and Manufacturing, as well as practitioners in the Design, Planning and Production departments in the manufacturing industry. Integrated Design of a Product Family and Its Assembly System is also suitable for use as a textbook in courses such as Computer-Aided Design, Concurrent Engineering, Design for Assembly, Process Planning, and Integrated Design.

Dealing with User's Preferences in Hybrid Assembly Lines Design

Abstract This work presents a new method to address the hybrid assembly line design problem with multiple objectives. The aim is to assign a set of tasks to stations and select the resources to perform each of them. The goal is to minimize the total cost of the line by integrating design and operation issues. The authors used a grouping genetic algorithm to tackle the problem, hybridised with a branch-and-cut algorithm and the multi-criteria decision-aid method Promethee IT. The paper presents the method that assigns tasks to stations and selects assembly equipment for each station. It also introduces the way to deal with users preferences in design problems. The essential concepts adopted by the method are described. The application of the algorithm to an industrial case study is also presented.

An assembly-oriented product family representation for integrated design

This paper presents a product family representation model which was developed during a research project called CISAL, the purpose of which was to propose an integrated approach for the design of product families and their assembly system. This model is able to deal with partial information from the design of the product family, a situation that often occurs at early stages of the concurrent design of products and production means. The proposed model is assembly-oriented, because the project covered design for assembly, assembly planning, and line layout issues. In fact, it was developed on the basis of the design methodology itself. An originality of the design approach-which impacted the proposed model-is to decompose the product into so-called functional entities defined by the designer. The product family is then seen as an assembly of functional entities that can be analyzed, designed, and further assembled separately. Component variants are aggregated into generic components, and links between components become generic. The paper presents the essential concepts related to this product family representation, before showing their application to an illustrative industrial case study: a family of signaling relays.

Selecting Material Handling Equipment with Promethee

The authors present a comprehensive approach to select material handling equipment (MHE) at assembly line design stage. They defined a two-level MHE typology, namely generic types and specific equipment, to describe the numerous available systems. Based on this description, the system identifies the most suitable equipment in two stages. At the primary stage the performances of basic types are evaluated for the considered problem. Having chosen one (or more) generic equipment, specific information is used to evaluate and select the appropriate specific one. The main originality of this work is the application of a multicriteria decision-aid method, called PROMETHEE II, embedded into a decision tree. At each selection stage (node of the tree), eligible solutions are ranked according to a global evaluation of their performance for the considered parameters. The ranking is computed thanks to criteria and weights, allowing the user to accurately describe the selection process. Industrial case studies, which validate the approach, are presented.

Conclusions and Further Work

This final chapter concludes the book by presenting its main ideas and results in section 10.1. Possible further research topics are pointed out in section 10.2.

Product Family and Assembly Line Design Methodology

Product and assembly system design may be two interrelated processes, as the authors mentioned in section 1.3.2. In this chapter the authors describe the proposed methodology, having product family (PF) and assembly line design interacted. A short introduction to concurrent engineering (CE) is given in section 3.1. Before describing the proposed methodology for the concurrent design of pfs and their assembly system in section 3.3, some reflections on concurrent design and on optimisation problems are presented in section 3.2. Section 3.4 is devoted to conclusions.

Detailed Design for Assembly and Assembly Planning

Once the preliminary assembly planning (AP) has been performed, a detailed design for assembly (DFA), combined with a detailed AP, can be undertaken. The design of the generic components (GCs) is further specified, the joining processes are determined, the operating methods are chosen, and potential equipment is selected for each operation. Several these topics are still areas of research in our team at the present time. The authors will thus only outline the essential features of the several topics to tackle and mention former results at the basis of future improvements.

Description of Product Families

In the concurrent design of products and assembly lines paradigm, the description of the products in a product family (PF) is an essential data in the design process: all subsequent analyses are based on this description.