Application of lean scheduling and production control in non-repetitive manufacturing systems using intelligent agent decision support

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Lean Manufacturing (LM) is widely accepted as a world-class manufacturing paradigm, its currency and superiority are manifested in numerous recent success stories. Most lean tools including Just-in-Time (JIT) were designed for repetitive serial production systems. This resulted in a substantial stream of research which dismissed a priori the suitability of LM for non-repetitive non-serial job-shops. The extension of LM into non-repetitive production systems is opposed on the basis of the sheer complexity of applying JIT pull production control in non-repetitive systems fabricating a high variety of products. However, the application of LM in job-shops is not unexplored. Studies proposing the extension of leanness into non-repetitive production systems have promoted the modification of pull control mechanisms or reconfiguration of job-shops into cellular manufacturing systems. This thesis sought to address the shortcomings of the aforementioned approaches. The contribution of this thesis to knowledge in the field of production and operations management is threefold: Firstly, a Multi-Agent System (MAS) is designed to directly apply pull production control to a good approximation of a real-life job-shop. The scale and complexity of the developed MAS prove that the application of pull production control in non-repetitive manufacturing systems is challenging, perplex and laborious. Secondly, the thesis examines three pull production control mechanisms namely, Kanban, Base Stock and Constant Work-in-Process (CONWIP) which it enhances so as to prevent system deadlocks, an issue largely unaddressed in the relevant literature. Having successfully tested the transferability of pull production control to non-repetitive manufacturing, the third contribution of this thesis is that it uses experimental and empirical data to examine the impact of pull production control on job-shop performance. The thesis identifies issues resulting from the application of pull control in job-shops which have implications for industry practice and concludes by outlining further research that can be undertaken in this direction

Implementação Ferramentas e Liderança Lean , Quick Wins - Caso de Estudo

Objetivo: Este estudo foi realizado numa pequena e média empresa portuguesa do setor da metalomecânica, onde o Lean Management foi implementado através de várias ferramentas Lean (LT) e suas variantes. Este estudo envolveu dois objetivos principais: o primeiro demonstra como as LT permitem um grande impacto durante a fase de implementação, produzindo assim grande influência quer em termos de organização, quer em termos de resultados operacionais, bem como no contexto da motivação dos colaboradores. Sendo que o segundo objetivo consistiu na introdução de mudanças de procedimento baseadas na ferramenta gestão de recursos humanos através da liderança Lean. O foco para estas duas situações, é alcançar um aumento de 5% na taxa de ocupação na área de maquinagem, assim como um aumento de 10% no número de horas trabalhadas, com uma redução de 10% em relação aos custos de produtos defeituosos por hora, isto no primeiro trimestre de 2019, além da melhoria da perceção dos colaboradores na implementação das LT em 2,5%. Metodologia/abordagem: a metodologia de pesquisa é uma pesquisa-pesquisa/ação, desenvolvida pelo professor Kurt Lewin do MIT que passa por ciclos de cinco estágios: Diagnóstico; Planeamento; Implementação; Avaliação; Conclusões. Resultados: quanto aos quatro objetivos acima mencionados, observou-se: um aumento de 8,5% na taxa de ocupação das máquinas; assim como um incremento de 30,2% do número de horas trabalhadas; com uma redução de 27, 9% em custos não qualidade hora produzida no período. A perceção dos colaboradores teve um efeito de 6,1% de melhoria. Limitação/implicação da pesquisa: o estudo é limitado a uma pequena e média empresa (PME) portuguesa no sector metalomecânico. Originalidade/valor do caso de estudo: As ferramentas Lean podem ser implementadas de forma rápida e fácil e rapidamente compreendidas pelos colaboradores. Foi criada uma motivação adicional para o seu uso e obtenção de resultados operacionais muito satisfatórios em toda as áreas de produção.Purpose: This study was performed in a Portuguese Small and Medium-sized Enterprise (SME) in a metalworking sector, where Lean Management has been implemented through several Lean Tools (LT) and their variations. This study comprised two main goals: The first demonstrates how LT allow the highest impact during the implementation phase, thus producing great influence, both in terms of organization and operational results, as well as in the context of employees’ motivation. The second goal consisted of introducing procedure changes based on the Management of Human Resources through Lean Leadership tool. The goal for these two objectives is to achieve a 5% increase in the occupancy rate in the machining area, as well as an increase of 10% in the number of hours worked, with a reduction of 10% in the costs of defective products per hour in the first quarter of 2019. The study also intends to improve plus to improving the perception of employees in the implementation of the LT in 2,5%. Methodology/Approach: The research methodology is a Research-Research/ Action, developed by Professor Kurt Lewin of MIT that goes through cycles of five stages: Diagnosis; Planning; Implementation; Evaluation; Conclusions. Findings: Regarding the five objectives above mentioned, it was observed: an increase of 8.5% in machine occupancy rate; as well as an increase of 30.2% in number of hours worked; with a reduction of 27.9% in non-quality hourly costs produced in the period. Employee perception had a 6,1% improvement effect. Research Limitation/implication: The study is limited to Portuguese Small and Mediumsized Enterprise (SME) in the metalworking sector. Originality/Value of case study: Lean tools can be rapidly and easily implemented and quickly understood by the workers. It was induced an additional motivation in the employees for its use and achievement of quick and very satisfying results in every production and manufacturing areas