Metodologías de estandarización del trabajo, diseño antropométrico y 8Ds como estrategia de mejora de procesos de manufactura: estudios de caso

This document presents two case studies that apply Industrial Engineering tools such as standardization of work, study of times and movements, line balancing, anthropometric design of workstations, and the 8 Disciplines (8Ds) method. The first four tools are applied in a printing press in order to increase productivity and optimize the well-being of workers. On the other hand, the 8Ds method is applied in a manufacturing company in order to reduce the number of engine defects. In the specific case of the printing press, it has 150 operators, who have manual and mechanical tasks in the box assembly department with four production lines. The current capacity is 350 boxes per day, but the demand is 650 units and the company has to pay a lot of overtime. Using the standardization of work, studying the movements of workers, time, and redesign of workstations, the main objective was to increase rates of productivity and well-being of workers. After applying those tools, inefficient movements in operators decreased from 230 to 78, eliminating 66% of unnecessary movements, standard time at a workstation decreased from 244 to 199 seconds (18.44%) for each assembled box, and the production rate increased by 63.2%, that is, 229 units per assembly line per day, and overtime was reduced to zero. Therefore, the integration of standardized work, the study of times and movements, the balancing of production lines, and anthropometric design, allow increasing the sustainability of the company and the well-being of operators by making better use of the human factor, eliminating overtime and increasing production capacity. On the other hand, in the case of engine defects, it is known that, currently, customer satisfaction is a key element for the survival and competitiveness of manufacturing companies. In the case discussed in this research, the company files several customer complaints due to faulty custom cable assemblies that are integrated into one motor. The objective of this case study is to find a solution to this problem, as well as to prevent its recurrence by implementing the 8Ds method to: 1) Develop a team, 2) Describe the problem, 3) Develop an interim containment action , 4) Determine and verify root causes, 5) Develop permanent corrective actions, 6) Define and implement corrective actions, 7) Prevent recurrences, and 8) Recognize and congratulate teamwork and individual contributions. Therefore, a software tool is proposed to perform a bump test on assembly lines. After testing, the problem was successfully detected andreduced , since of 67 engines that were identified as having problems, 51 were redesigned before being shipped to customers, reducing the number of defective products by 75%, while the remaining 16 engines were replaced by new engines. In conclusion, the research objective was achieved, as well as the 8Ds method proved to be a useful model to increase employee motivation and participation during the problem solving process.Este documento expone dos estudios de caso que aplican herramientas de Ingeniería Industrial tales como estandarización del trabajo, estudio de tiempos y movimientos, balanceo de líneas, diseño antropométrico de estaciones de trabajo y el método de las 8 Disciplinas (8Ds). Las primeras cuatro herramientas se aplican en una imprenta con la finalidad de aumentar la productividad y optimizar el bienestar de los trabajadores. Por otro lado, el método de las 8Ds se aplica en una empresa de manufactura con la finalidad de disminuir el número de defectos en motores. En el caso específico de la imprenta, ésta cuenta con 150 operadores, que tienen tareas manuales y mecánicas en el departamento de ensamblaje de cajas con cuatro líneas de producción. La capacidad actual es de 350 cajas por día, pero la demanda es de 650 unidades, y la compañía paga muchas horas extras. Utilizando la estandarización del trabajo, estudiando los movimientos de los trabajadores, el tiempo y el rediseño de las estaciones de trabajo, el objetivo principal era aumentar los índices de productividad y el bienestar de los trabajadores. Después de aplicar esas herramientas, los movimientos ineficientes en los operadores disminuyeron de 230 a 78, eliminando el 66% de los movimientos innecesarios, el tiempo estándar en una estación de trabajo disminuyó de 244 a 199 segundos (18.44%) para cada caja ensamblada, y la tasa de producción aumentó en 63.2%; es decir, 229 unidades por línea de montaje por día, y las horas extra se redujeron a cero. Por lo tanto, la integración del trabajo estandarizado, el estudio de tiempos y movimientos, el balanceo de líneas de producción, y el diseño antropométrico, permiten aumentar la sostenibilidad de la empresa y el bienestar de los operadores al hacer un mejor uso del factor humano, eliminar las horas extra, y aumentar la capacidad de producción. Por otro lado, en el caso de los defectos en motores, se sabe que, hoy en día, la satisfacción del cliente es un elemento clave para la supervivencia y la competitividad de las empresas de manufactura. En el caso tratado en esta investigación la empresa presenta varias quejas de los clientes debido a ensambles defectuosos de cables personalizados que están integrados en un motor. El objetivo de este estudio de caso era encontrar una solución a este problema, así como prevenir su recurrencia mediante la implementación del método de las 8Ds, para: 1) Desarrollar un equipo, 2) Describir el problema, 3) Desarrollar un interino acción de contención, 4) Determinar y verificar las causas raíz, 5) Desarrollar acciones correctivas permanentes, 6) Definir e implementar acciones correctivas, 7) Prevenir recurrencias, y 8) Reconocer y felicitar el trabajo en equipo y las contribuciones individuales. Por lo tanto, se propone una herramienta de software para realizar una prueba funcional en las líneas de ensamblaje. Después de la prueba, el problema se detectó y redujo con éxito, porque de 67 motores que fueron identificados con problemas, 51 fueron rediseñados antes de ser enviados a los clientes, lo que disminuyó la cantidad de productos defectuosos en un 75%, mientras que los 16 motores restantes fueron reemplazados por nuevos motores. En conclusión, el objetivo de la investigación se logró, y el método 8Ds demostró ser un modelo útil para aumentar la motivación y la participación de los empleados durante el proceso de resolución de problemas

Improving a Manufacturing Process Using the 8Ds Method. A Case Study in a Manufacturing Company

Customer satisfaction is a key element for survival and competitiveness in industrial companies. This paper describes a case study in a manufacturing company that deals with several customer complaints due to defective custom cable assemblies that are integrated in an engine. The goal of this research is to find a solution to this problem, as well as prevent its recurrence by implementing the eight disciplines (8Ds) method in order to: (1) develop a team, (2) describe the problem, (3) develop an interim containment action, (4) determine and verify root causes, (5) develop permanent corrective actions, (6) define and implement corrective actions, (7) prevent recurrences, and (8) recognize and congratulate teamwork as well as individual contributions. Therefore, a software tool is proposed to conduct a functional test on assembly lines. After the test, the problem was successfully reduced and detected, because from 67 engines that were identified with problems, 51 were redesigned before being sent to customers, consequently decreasing the number of defective products by 75%, whereas the remaining 16 engines were replaced by new engines. In conclusion, the research goal was accomplished, and the 8Ds method proved to be a helpful model with which to increase employees’ motivation and involvement during the problem-solving process

Efectos de las características físicas y psicológicas de los empleados en el desempeño de los sistemas de manufactura

One of the main challenges in Macroergonomics is to develop a universal model to measure macroergonomic compatibility. As a first step to develop such model, it is necessary to validate the construct of macroergonomic compatibility (MC). MC refers to the ability of the different work system components and elements to complement the capabilities and limitations of employees in order to achieve companies’ goals. In that regard, to achieve this step, this paper analyzes the effects of MC of physical and psychological characteristics of employees over the performance of manufacturing systems measured by the clients, production processes, and the organizational performance of companies. Data was obtained from 188 employees of manufacturing systems by means of the Macroergonomic Compatibility Questionnaire (MCQ) in Chihuahua, Mexico. Also, data is analyzed to propose and test a hypothetical causal model of the relationships among the variables by using a Structural Equation Modeling (SEM) approach. Employees’ physical characteristics (weight, height, strength) are considered as independent variable. The highest direct effects values (ß) were found from physical characteristics to psychological characteristics (0,49), from clients to organizational performance (0,45), and from psychological characteristics to motivation and needs. Also, the highest total effects were found from physical characteristics to motivation and needs (0,517) and psychological characteristics (0,488) and from clients to organizational performance (0,454). Results of this model offer relevant knowledge to develop macroergonomic strategies for manufacturing systems in order to increase their competitiveness and support the design and improvement of these systems.Uno de los principales desafíos en Macroergonomía es desarrollar un modelo universal para medir la compatibilidad macroergonómica (CM). Como primer paso para desarrollar dicho modelo, es necesario validar el constructo de CM. CM se refiere a la capacidad de los elementos y componentes de un sistema de trabajo de considerar y complementar las capacidades y limitaciones de los empleados para así, alcanzar los objetivos de las compañías. En este sentido, este artículo analiza los efectos de las características físicas y psicológicas de los empleados sobre el desempeño de los sistemas de manufactura medidos mediante los clientes, procesos de producción, y el desempeño organizacional de la empresa. Los datos se obtuvieron de 188 empleados de sistemas de manufactura mediante el Cuestionario de Compatibilidad Macroergonómica (CCM), en el Estado de Chihuahua, México. El análisis de los datos se realiza para proponer y probar un modelo hipotético causal de las relaciones entre las variables a través de un Modelo de Ecuaciones Estructurales (MES). Las características físicas (peso, estatura, fuerza) son consideradas como variables independientes. Los mayores efectos directos fueron de las Características físicas sobre las Características psicológicas (0,49), de los clientes sobre el desempeño organizacional (0,45), y de las características psicológicas sobre la motivación y necesidades de los empleados. Los mayores efectos totales fueron de las características físicas sobre motivación y necesidades (0,517) y sobre características psicológicas (0,488), y de la variable clientes sobre el desempeño organizacional (0,454). Esto genera conocimiento relevante para el desarrollo de estrategias macroergonómicas que permitan incrementar la competitividad de los sistemas de manufactura y apoyar y mejorar el diseño de estos sistemas

Cadena de Suministro Esbelta - Una revisión bibliométrica

This article presents a bibliometric review of the documents identified in the Scopus database on lean supply chains. VOSviewer software and the Bibliometrix platform were used to analyze 451 articles identified using the search equation TITLE-ABS-KEY ("lean supply chain" OR TITLE-ABS-KEY ("lean supply")). The results indicate that the number of papers on this topic is increasing. The primary authors are Moyano-Fuentes, J. and Tortorella, GL; however, Christopher and Towill are the most cited authors. The leading journals that publish this topic are the International Journal of Six Sigma and International Journal of Production Economics. By contrast, the most productive universities are the Federal University of Santa Catarina in Brazil and the University of Jaen in Spain. The keywords most used by the authors were "supply chain management" and "lean supply chain”, with the former being the origin of many others. The most productive countries on this topic are the United States of America and the United Kingdom; however, the most cited are the same, but in the reverse order. Given that 37 papers on SSC have already been published by 2023, six more than by 2022, this topic will continue to interest academics and scientists.En este artículo se presenta una revisión bibliométrica de documentos identificados en la base de datos Scopus sobre cadena de suministro esbelta. Se hace uso del software VOSviewer y la plataforma Bibliometrix para el análisis de 451 identificados con la ecuación de búsqueda TITLE-ABS-KEY ("lean supply chain") OR TITLE-ABS-KEY ("lean supply")). Los resultados indican que la producción de documentos en este tópico está en aumento, los principales autores son Moyano-Fuentes, J. y Tortorella, GL; sin embargo, Christopher y Towill son los autores más citados. Las principales revistas que publican este tópico son el International Journal of Six Sigma y el International Journal of Production Economics, mientras que las universidades más productivas son la Universidad Federal de Santa Catarina en Brasil y la Universidad de Jaen en España. La palabra clave más usadas por los autores son “supply chain management” y “lean supply chain”, siendo la primera la primera la que da origen a muchas otras. Los países más productivos en este tópico son Estados Unidos de America y Reino Unido; sin embargo, los más citados son los mismo, pero en orden inverso. Dado que en este año 2023 ya se tienen publicados 37 documentos sobre CSE, seis más que el año 2022, se concluye que este tópico continuará siendo de interés para académicos y científicos

Applying the Plan-Do-Check-Act (PDCA) Cycle to Reduce the Defects in the Manufacturing Industry. A Case Study

Defects are considered as one of the wastes in manufacturing systems that negatively affect the delivery times, cost and quality of products leading to manufacturing companies facing a critical situation with the customers and to not comply with the IPC-A-610E standard for the acceptability of electronic components. This is the case is a manufacturing company located in Tijuana, Mexico. Due to an increasing demand on the products manufactured by this company, several defects have been detected in the welding process of electronic boards, as well as in the components named Thru-Holes. It is for this reason that this paper presents a lean manufacturing application case study. The objective of this research is to reduce at least 20% the defects that are generated during the welding process. In addition, it is intended to increase 20% the capacity of three double production lines where electronic boards are processed. As method, the Plan-Do-Check-Act (PDCA) cycle, is applied. The Pareto charts and the flowchart are used as support tools. As results, defects decreased 65%, 79%, and 77% in three analyzed product models. As conclusion, the PDCA cycle, the Pareto charts, and the flowchart are excellent quality tools that help to decrease the number of defective components

Cognitive Ergonomics Evaluation Assisted by an Intelligent Emotion Recognition Technique

The study of the cognitive effects caused by work activities are vital to ensure the well-being of a worker, and this work presents a strategy to analyze these effects while they are carrying out their activities. Our proposal is based on the implementation of pattern recognition techniques to identify emotions in facial expressions and correlate them to a proposed situation awareness model that measures the levels of comfort and mental stability of a worker and proposes corrective actions. We present the experimental results that could not be collected through traditional techniques since we carry out a continuous and uninterrupted assessment of the cognitive situation of a worker