Otimização da alocação de produtos em uma estrutura de armazenagem flow-rack utilizando programação linear inteira mista

Abstract

The storage process for product stocking is an essential element for the logistics sector, especially in the pharmaceutical industry. In this sector, as in others, the quality of medicines must be ensured for use with assured quality. One of the solutions used is the Flow-rack storage structure, which has staggered compartments that allow continuous flow. Thus, the product allocation process can be optimized to maximize flow efficiency, considering constraints such as load capacity and product output frequency requirements. Various optimization methods can be applied. Linear optimization, considered in this work, seeks to find the best solution considering a linear objective function subject to a set of linear constraints. To solve the optimization problem, some tools have been applied, such as Mixed Integer Programming (MIP). Thus, this work applies MIP in the optimization of product allocation in a Flow-rack considering multiple objectives and constraints simultaneously in a metal storage structure, observing ergonomics and aiming at production improvement. The Solving Constraint Integer Programs (SCIP) and Google Linear Optimization Package (GLOP) solvers were implemented based on branch and-bound, assuming an allocation problem similar to the backpack, classic in the literature and the Constraint Programming with Satisfiability (CP-SAT) that integrates constraint proggramming techniques with boolean Satisfiability (SAT) resolution methods. The results showed that the SCIP and CP-SAT solvers allocated the products meeting all the established criteria, such as the backpack capacity, and the correct use of all the products indicated in the project.