Design and Scheduling of Electroplating Facilities

Abstract

This paper tackles the Cyclic Hoists Scheduling Problem. This problem is often encountered in electroplating facilities when mass production is required. Then a repetitive sequence of moves is searched for the hoists. We more precisely deal with a global optimization problem that simultaneously considers the design and the scheduling of such production lines. It consists in studying systems integrating several transportation resources, called hoists, by minimizing the cycle time, while minimizing the number of hoists used. To achieve these goals, we use an evolutionary approach. The encoding of one solution is based on the representation of the empty moves of the hoists. To evaluate each individual. we propose a linear programming model. This one both verifies the satisfaction of constraints and provides the best cycle time for the considered number of hoists. After describing the operators and parameters of the evolutionary algorithm we developed, we illustrate and discuss the performances of our modelling with a benchmark example.

Genetic Algorithm Based Approach for the Multi-Hoist Design and Scheduling Problem

“…Hence, to our best knowledge, the CHDSP with both objectives of minimizing the fleet size and minimizing the cycle time has only and first be tackled by Manier and Lamrous [1] and [28]. In these studies, the fleet size was a variable of the problem.…”

“…The empty move based encoding approach [1] is a novel and interesting approach to encode the solutions for the CHDSP. Previous studies have always used the hoist loaded moves to encode the solutions.…”

“…1). This paper considers the design and scheduling problem in electroplating facilities where the production is cyclic (Manier and Lamrous [1]). We call it the Cyclic Hoist Design and Scheduling Problem (CHDSP).…”

“…The assignment of a hoist number to the line with a respective moving sequence to every hoist is done due to an encoding approach based on empty moves. This one extends the initial encoding proposed by Manier and Lamnous in 2006 [1]. An MILP model is used to evaluate the feasibility of the moving sequences and to compute the period of the cycle.…”

Collision-Free Based Model for the Cyclic Multi-Hoist Scheduling Problem

“…The underlying idea is to be able to reconfigure the physical system in the event of series' change, in order to maintain optimal steady-state operation for each new production. In particular, our work focused on transport resources and we have previously studied joint optimization (minimization) of the couple number of hoists and cycle time [1], [2]. To the best of our knowledge, the joint optimization problem was not studied with both latter objectives together, and the idea is to provide a decision support system that enables to choose the best couple of parameters regarding productivity and cost objectives.…”