Análise de diferentes técnicas de sequenciamento da produção em um ambiente de produção para estoque controlado pelo sistema S-DBR
Data
2023-07-26
Autores
Rays Filho, Isidoro
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
Em ambientes Make-to-Stock parte considerável das empresas enfrentam problemas tais como vendas perdidas, clientes insatisfeitos, baixa rotatividade, alto investimento e obsolescência do estoque. Para lidar com isto, a Teoria das Restrições (TOC) traz que se deve programar a produção conforme a restrição, focando no fluxo e subordinando os demais recursos. Em situações onde o recurso restritivo tem capacidade estritamente superior à demanda, a TOC propõe realizar o planejamento da produção através do Tambor-Pulmão-Corda Simplificado (S-DBR). O S-DBR aplicado à ambientes MTS tem como foco principal garantir a disponibilidade dos produtos. Mas seria o BM a forma de sequenciamento mais efetiva? Para responder a esta pergunta, construiu-se um modelo no software Anylogic representando uma linha de produção fictícia, comparando o desempenho do BM com outras regras tais como o RO (Roun-Out Time), o FIFO (First-In-FirstOut) e o SPTR (Sortest-Process-Time), através de indicadores Fill Rate e OTIF. Os resultados permitem concluir que o Buffer Management, cuja premissa é priorizar as ordens de reposição com base na penetração do Target Level, foi a melhor regra de sequenciamento. Além disso, a regra FIFO apresentou bons desempenhos, mostrando a efetividade do planejamento do SDBR. O RO apresentou o terceiro melhor desempenho, como a sua utilização é mais complexa que o FIFO, acaba não justificando sua escolha. As regras baseadas na lógica SPTR obtiverem o pior desempenho, devido a trabalharem em direção oposta ao método S-DBR/MTA, pois priorizam ordens com menor tempo de processamento, ou seja, justamente aqueles que abastecem estoques relativamente mais altos.
In Make-to-Stock environments, a considerable part of companies faces problems such as lost sales, dissatisfied customers, low turnover, high investment, and inventory obsolescence. To deal with this, the Theory of Constraints (TOC) brings that production should be scheduled according to the constraint, focusing on the flow and subordinating the other resources. In situations where the constraining resource has a capacity strictly higher than the demand, TOC proposes to perform production planning through the Simplified Drum-Buffer-Rope (S-DBR). The S-DBR applied to MTS environments has as its main focus to guarantee the availability of products. But would BM be the most effective form of sequencing? To answer this question, a model was built in Anylogic software representing a fictitious production line, comparing the performance of BM with other rules such as RO (Roun-Out Time), FIFO (First-In-First-Out), and SPTR (Sortest-Process-Time), through Fill Rate and OTIF indicators. The results allow us to conclude that Buffer Management, whose premise is to prioritize replenishment orders based on Target Level penetration, was the best sequencing rule. In addition, the FIFO rule performed well, showing the effectiveness of S-DBR planning. The RO presented the third best performance, as its use is more complex than FIFO, it ends up not justifying its choice. The rules based on SPTR logic obtained the worst performance, due to working in the opposite direction to the S-DBR/MTA method, as they prioritize orders with shorter processing time, i.e. precisely those that supply relatively higher stocks.
In Make-to-Stock environments, a considerable part of companies faces problems such as lost sales, dissatisfied customers, low turnover, high investment, and inventory obsolescence. To deal with this, the Theory of Constraints (TOC) brings that production should be scheduled according to the constraint, focusing on the flow and subordinating the other resources. In situations where the constraining resource has a capacity strictly higher than the demand, TOC proposes to perform production planning through the Simplified Drum-Buffer-Rope (S-DBR). The S-DBR applied to MTS environments has as its main focus to guarantee the availability of products. But would BM be the most effective form of sequencing? To answer this question, a model was built in Anylogic software representing a fictitious production line, comparing the performance of BM with other rules such as RO (Roun-Out Time), FIFO (First-In-First-Out), and SPTR (Sortest-Process-Time), through Fill Rate and OTIF indicators. The results allow us to conclude that Buffer Management, whose premise is to prioritize replenishment orders based on Target Level penetration, was the best sequencing rule. In addition, the FIFO rule performed well, showing the effectiveness of S-DBR planning. The RO presented the third best performance, as its use is more complex than FIFO, it ends up not justifying its choice. The rules based on SPTR logic obtained the worst performance, due to working in the opposite direction to the S-DBR/MTA method, as they prioritize orders with shorter processing time, i.e. precisely those that supply relatively higher stocks.
Descrição
Palavras-chave
Sequenciamento, Simulação, Produzir para disponibilidade, Gerenciamento do pulmão, Teoria das restrições, Theory of constraints, Sequencing, Simulation, Make-to-Availability, Buffer management