Thomas L'Eglise

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 heuristic to generate a precedence graph between components for a product family

The authors present a pragmatic approach to structure a product family into several independent sub-assemblies and to generate its precedence graph. These tasks are performed on a unique product model, based on a liaison diagram formalism. This formalism has been extended to deal with product families, offering a valid solution for all the variants of the family, also called product variants. Through a relevant description of the physical links between components, it is possible to propose a methodology that considerably reduces the amount of input data. This approach has been applied to several industrial case studies, among which isa family of car alternators, presented in this paper.

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.

Functional entities: A concept to support product family and assembly system design

This paper is dedicated to the adaptation of product and assembly line design tools and methodology to product families. The main originality resides in the systematic decomposition of the family into so-called functional entities defined by the designer. The family is then considered as an assembly of entities which can be further designed and analysed separately. The paper presents the essentials on these concepts and describes their effects on subsequent design tools such as design-for-assembly, assembly planning or line layout.

Recycling of electric and electronic end-of-life devices: economical assessment study in Brussels, Belgium

The authors present in this paper the result of a study they conducted for the Brussels Institute for the Environment. The object of this study was to define the possible recycling options for discarded electrical and electronic devices in a city like Brussels. By studying the legal aspects but also the current situation in Brussels, they established the needs in terms of facilities and by visiting similar activities in Europe, they established the options that could present an economic, environmental and social interest. They developed an economic simulation package, in order to evaluate the costs and benefits of those possibilities. They finally proposed the amount for the recycling fees that should be integrated into the selling price of new products, allowing the recycling options to be economically viable.