Feasibility heuristics for surrogate relaxation to the lotsizing problem in small foundries

• Grant number: 20/10069-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2020
• End date: September 30, 2021
• Field of knowledge: Engineering - Production Engineering - Operational Research
• Principal Investigator: Victor Claudio Bento de Camargo
• Grantee: Iago Pinheiro de Freitas
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 16/01860-1 - Cutting, packing, lot-sizing, scheduling, routing and location problems and their integration in industrial and logistics settings, AP.TEM

Abstract

This project aims to study the production planning problem in small foundries that have variable demand for orders and final products (molded items) that demand different raw materials (alloys), generating greater challenges for planning. Different mathematical models, heuristics and other methods have been studied to size the production lots, either to produce the items individually or to prioritize the fulfillment of orders completely. A Surrogate relaxation proposed in the literature can quickly find solutions that are good lower bounds for traditional models. However, the solutions do not meet all the constraints of the original models and may generate infeasible solutions. Thus, the objective of the project is to effectively solve the problem of infeasibility of the mentioned relaxation by implementation and testing of two heuristics: a heuristic derived from the knapsack problem and a fix-and-optimize heuristic.