Manual assembly operations are sensitive to human errors that can diminish the quality of final products. The paper shows an application of human reliability analysis in a realistic manufacturing context to identify where and why manual assembly errors occur. The techniques SHERPA and HEART were used to perform the analysis of human reliability. Three critical tasks were selected for analysis based on quality records: (1) installation of three types of brackets using fasteners, (2) fixation of a data cable to the assembly structure using cushioned loop clamps and (3) installation of cap covers to protect inlets. The identified error modes with SHERPA were: 36 action errors, nine selection errors, eight information retrieval errors and six checking errors. According to HEART, the highest human error probabilities were associated with assembly parts sensitive to geometry-related errors (brackets and cushioned loop clamps). The study showed that perceptually engaging assembly instructions seem to offer the highest potential for error reduction and performance improvement. Other identified areas of action were the improvement of the inspection process and workers’ provision with better tracking and better feedback. Implementation of assembly guidance systems could potentially benefit worker’s performance and decrease assembly errors.

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This study was conducted in a warehouse at a vaccine production centre where improvement to existing storage and working conditions were sought through the construction of a new refrigerated store section (2-8C°). Warehousing tasks were videotaped and ergonomics analysis tools were used to assess the risk of developing MSDs. Specifically, these tools were the Rapid Entire Body Assessment (REBA) and the NIOSH equation. The current plant layout was sketched and analyzed to find possible targets for improvement trough the application of general work space design and ergonomics principles. Seven of the eight postures evaluated with REBA had a total score between 8 and 10, meaning a high risk, and only one was at a medium risk level. Nine of the eleven manual material handling tasks analyzed with the NIOSH equation had a Lifting Index between 1.14 and 1.80 and two had a recommended weight limit of 0kg, indicating a need for job redesign. Solutions included the redesign of shelves, the design of a two-step stair and a trolley with adjustable height; also, changes in work methods were proposed by introducing a two-workers lifting strategy and job rotation, and, finally, a restructuring of plant layout was completed.

BACKGROUND: Fatigue and workload experienced by aircraft de-icing personnel have been largely neglected in occupational health and safety research. OBJECTIVE: To provide an initial assessment of fatigue and workload among de-icing ground crews. METHODS: Company records were used to reveal possible relationships between different variables (age, seniority, truck type, and work shift). A group of 20 volunteer participants (17 men and 3 women) rated their level of fatigue before and after one shift using the Samn-Perelli fatigue scale. Workload was evaluated using the NASA-TLX method at the end of the shift. RESULTS: The average fatigue experienced by de-icing worker was significantly greater (P = 0.043) for the technicians in open-basket trucks than for the ones in trucks with a cabin (4.43 vs 3.37). Furthermore, there was a significant age difference (P = 0.048) in the perceived level of fatigue (4.1 vs 3.1), with younger workers (< 30 years) reporting a higher level than older workers (30 years). Overall NASA-TLX score were not significant (P > 0.05) for any of the factors tested: type of truck, shift and age. CONCLUSIONS: The results suggest that particular attention should be paid to young technicians and technicians working in open-basket trucks, since the fatigue levels reported in association with these factors were higher.

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In sectors such as aerospace manufacturing, human errors in the assembly of complex products can negatively impact quality, productivity, and safety. Until now, the analysis of assembly errors has focused more on the immediate human‐system interface and less on broader organizational factors. This article presents a case study‐based analysis of assembly errors in the aeronautical industry using the systemic methods AcciMap and Systems‐Theoretic Accident Model and Processes (STAMP). We seek to provide the company with elements to build a quality improvement strategy that considers human factors and ergonomics from a systemic perspective. The data and information necessary to conduct the analysis came from a project carried out at an aerospace manufacturing facility over a period of 12 months. The team had direct and recurrent access to primary data sources and communication with various stakeholders. A total of 31 influencing factors were identified with AcciMap at different levels within the manufacturing system. STAMP made it possible to model the sociotechnical control structure of the assembly process and identify several control flaws leading to hazards. The analysis shows that systemic methods require a high level of understanding of the manufacturing system and access to relatively high amounts of data and information. Therefore, direct contact with the field and stakeholders is crucial. Training quality specialists on systemic methods could support its use and help to close the gap between theory and practice. Globally, the field of quality in manufacturing could benefit from using systemic methods when deemed necessary.

La ergonomía es considerada, en la actualidad, una disciplina científica consolidada, que se expande continuamente a nivel global. Este escenario actual es el resultado de diferentes visiones que han permeado la evolución de la ergonomía. En este artículo se hace un recorrido histórico de la ergonomía como disciplina, tomando en cuenta la escuela de los factores humanos y la escuela de la ergonomía de la actividad. Se presentan los orígenes de estas escuelas, sus paradigmas subyacentes y se realiza una comparación entre ellas. Las reflexiones presentadas en el artículo en torno a la ergonomía parten de la idea que, desde las diferencias y la diversidad, se erige el desarrollo. Los autores de este artículo son partidarios de abordar la ergonomía como una única disciplina, reconociendo la convergencia y la complementariedad entre las dos escuelas. Más allá de las diferencias existentes, la práctica de la ergonomía debe enfocarse en el diseño de los sistemas de trabajo, tomando como eje central al ser humano. Se espera que estas reflexiones permitan a los profesionales de la ergonomía y de otras diciplinas afines ganar mayor comprensión de cómo abordar la actividad humana para transformarla positivamente.

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