Combining Process Selection and Lot Sizing Models for Production Scheduling of Electrofused Grains

Abstract

This work presents an optimization model to support decisions in the production planning and control of the electrofused grain industry. A case study was carried out in a Brazilian company with the aim of helping to increase productivity and improve customer service concerning meeting deadlines. A mixed integer linear programming model combining known models of process selection and single-stage lot sizing were applied to the production scheduling of electrofused grains. Optimizing this scheduling is not a simple task mainly because of the scale of the equipment setup times, the diversity of the products and the deadlines of the order due dates. A constructive heuristic is also proposed as an alternative solution method, particularly for large-sized instances. The results show that the model and the heuristic can produce better solutions than the ones currently used by the company.

Lot Sizing in Production Scheduling at a Personal Protection Equipment Company

“…Another study examined the lot sizing and selection processes [19] to determine a production schedule that minimized shortages of items based on the choice of a production process over a certain period, where each process defined by the company is able to produce a mixture of products at different quantities.…”

“…A mixed integer model is solved using general-purpose optimization software written in the GAMS modeling language, with a branch and cut method in the CPLEX solver. It is common for a production schedule to be modified several times in response to urgent orders and unexpected equipment failures, thus highlighting the importance of a modeling approach capable of generating efficient production programs in a feasible amount of time was adapted a mixed integer linear programming model to determine the production schedules for PPE [19]. The results from the model were compared to two existing practices used by the company, revealing that the model was effective and greatly improving the ability of the company to provide items on time.…”

“…Due to the difficulty in estimating the shortage costs, a model that minimizes the slackness of production is adapted [19]. The proposed model is designed to optimize production, meet the requests within the agreed upon time, schedule production and distribute the manufactured products according to their production capacity over the planning horizon.…”

Otimização da programação da produção de bebidas à base de frutas por meio de modelos de programação inteira mista

“…The lot-sizing and scheduling problems have been widely used in several productive sectors (e.g., Araujo et al, 2008;Almada-Lobo et al, 2008;Luche et al, 2009;Toso et al, 2009;Santos & AlmadaLobo, 2012;Marinelli et al, 2007;Kopanos et al, 2010, among many others). Some studies are found in the production of non-alcoholic drinks such as soft drinks, water, tea and juice, but most of these studies consider soft drink production lines.…”

Métodos heurísticos para um problema de planejamento da produção em uma indústria química

“…Sendo assim, o problema de dimensionamento de lotes nesses casos também deve investigar qual a escolha ideal de processos para encontrar a solução ótima. Em Luche et al (2009), foi tratado um problema real de planejamento e controle da produção de grãos eletrofundidos, em uma indústria brasileira que enfrenta dificuldades práticas para a obtenção de um planejamento factível, devido ao curto prazo de entrega e a pedidos adicionais que ocorrem semanal ou quinzenalmente. A esses fatores acrescentam-se o longo tempo de preparação de máquinas, permitidos apenas ao final do expediente diário, e uma caracterís-tica própria do problema desta empresa, em que cada processo resulta em quantidades distintas de diversos produtos, os quais são diferenciados pela granulosidade dos grãos eletrofundidos.…”