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Series Editor

Hisham Abou-Kandil

Production and Maintenance Optimization Problems

Logistic Constraints and Leasing Warranty Services

Nidhal Rezg

Zied Hajej

Valerio Boschian-Campaner

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Introduction

I.1. Motivation and literature review

The improvement of industry involves the reduction of costs and maximization of customer satisfaction. Satisfying customer demands in a timely fashion has become difficult due to the random nature of such demands, a problem compounded by machine failures and low system availability. High system availability, minimal machine failure and customer satisfaction cannot be achieved without good management and a good knowledge of how to address problems while making decisions. These decisions are generally associated with three levels of hierarchical planning: strategic, tactical and operational planning.

The allocation of resources can become necessary over long periods of time, as purchase costs can become prohibitive. Subcontracting and leasing have become very important for many manufacturing enterprises because of the advantages that these solutions can bring. Such industrial solutions are becoming increasingly popular, for example subcontracting the workforce to perform certain tasks (maintenance, supervision, audit, etc.) or leasing workstations in order to produce the required quantities of products.

Several industrial constraints imposed on companies have led to the revision of integrated maintenance production strategies. Such strategies are adopted in order to develop and optimize new, integrated maintenance-based production strategies, taking into account certain industrial constraints, such as logistics, quality, warranties, and subcontracting. Through the development of such maintenance/production strategies produced under constraints, we can gain an overview of the maintenance strategies and production decisions required to balance industrial system availability, productivity and customer satisfaction.

I.2. Overview of the topic

This book explores several maintenance and production optimization problems, taking into account certain industrial constraints.

Chapter 1 covers an integrated production and maintenance optimization strategy for a forecasting production and maintenance problems. The production system is composed of a single machine M1 subjected to random failure. In order to satisfy the random demand, under given service level, subcontracting assures the rest of the production through machine M2 with transportation delay. An analytic study of the problem has been proposed using a sequential determination of the economical production plan for which an optimal preventive maintenance strategy has been calculated based on minimal repair. Firstly, an economic production plan of principal and subcontracting machines was obtained, which minimizes the total cost of production and inventory for the cases with and without returned products under service level and subcontracting transportation delay. Secondly, a joint maintenance strategy is determined according to the optimal production plan, under various constraints for production rates, transportation delay and returned production deadlines. Numerical results are presented to highlight the application of the developed approach and sensitivity analyses show the robustness of the model.

Chapter 2 presents a stochastic production, maintenance and delivery problem for a deteriorating manufacturing system. Under stochastic demand, in terms of service level, product return and delivery time, this book proposes a mathematical formulation based on quadratic modeling. Production and maintenance policies are developed in order to study the influence of delivery time on the planning of production, maintenance and delivery activities. Simulation results are presented to illustrate the exploitation of the proposed approach.

In Chapter 3 we develop a mathematical model based on the forecasting production/maintenance optimization problem, to study lease contracts with basic and extended warranties based on win-win relationship between the lessee and the lessor. The influence of production rates in equipment degradation and consequently on the total cost by each side during the finite leasing period is stated in order to determine a theoretical condition under which a compromise-pricing zone exists under different possibilities of maintenance policies.

Chapter 4 presents presents a control policy of a manufacturing system under cost, availability and quality constraints. The production system consists of a two machines and two buffers and produces conforming and non-conforming products. A preventive maintenance strategy is developed in order to determine the instants at which preventive maintenance has to be performed on each machine, and both buffer inventory levels. A simulation, experimental design and multi-criteria analysis are presented to prove the adopted approach.