Analysis of flexibility in lot sizing problems

• Grant number: 14/22816-5
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: May 01, 2015
• End date: June 30, 2018
• Field of knowledge: Engineering - Production Engineering - Operational Research
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Silvio Alexandre de Araujo
• Grantee: Diego Jacinto Fiorotto
• Host Institution: Instituto de Biociências, Letras e Ciências Exatas (IBILCE). Universidade Estadual Paulista (UNESP). Campus de São José do Rio Preto. São José do Rio Preto , SP, Brazil
• Associated research grant: 10/10133-0 - Cutting, packing, lot-sizing and scheduling problems and their integration in industrial and logistics settings, AP.TEM
• Associated scholarship(s): 15/18325-9 - Analysis of Flexibility in Lot Sizing Problems, BE.EP.PD

Abstract

The lot sizing problem consists of determining the quantity of products to be produced in each period of a finite time horizon, in order to meet the demand an optimize an objective function, for example, to minimize costs. We have not found in the literature works that make a detailed study about adding flexibility in lot sizing problems. Note that in the supply chain literature, for example, it has been shown that adding flexibility on the production process can provide good results. In this research project we intend to help fill this gap in the lot sizing literature with the study of flexibility from two different sources.The first source of flexibility is machine flexibility. In the standard lot sizing problem on parallel machines, each item can be produced on any of the machines and incurs a setup cost and time before production. In this case we have complete machine flexibility. However, in practice, it can be very costly to install machines that have complete flexibility, especially if the products are very different. Therefore, it might be interesting to only implement a limited amount of flexibility (each machine can produce only certain types of items). We intend to study the value of machine flexibility in lot sizing models and determine what the best flexibility configuration would be for a given budget in order to balance the benefits and costs of flexibility.A second source of flexibility is Bill-Of-Material (BOM) flexibility. In this case, we consider a lot sizing problem of a final product that can be produced by blending different ingredients. The Bill-Of-Material (or recipe) indicates which components (or ingredients) are used and in which proportion. In some productive process there is some flexibility with respect to the proportion imposed for each of the ingredients, where it can vary between a minimum and maximum level instead of being fixed. This provides flexibility in the production planning process. We will analyse these new lot sizing models that take into account the flexibility in the BOM. (AU)