Mathematical modelling for process design of walking worker assembly line in productivity and ergonomics perspectives

Al‐Zuheri, Atiya; Xing, Ke; Luong, Lee

doi:10.1504/ijise.2013.052923

Cited by 8 publications

(8 citation statements)

References 27 publications

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“…The results also revealed that the average energy expenditure rates for an activity in the case of the normal (1.03 kcal/min) and hard production standard times (1.19 kcal/min) were less than the maximum value, 1.2 kcal/min, for light repetitive tasks involving both arms in a previous study 17 ) . The energy expenditure value reported by Garg et al 17 ) is used as a reference because it serves as a reliable benchmark in estimating energy expenditure 7 , 18 ) . In contrast, the average activity energy expenditure rate obtained in the case of the very hard production standard time (1.36 kcal/min) exceeded the reference value, which suggested that the workers were exposed to a higher risk of WMSDs.…”

Section: Discussionmentioning

confidence: 99%

The effects of energy expenditure rate on work productivity performance at different levels of production standard time

et al. 2015

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[Purpose] The purpose of this study was to investigate the effects of energy expenditure rate on work productivity performance at different levels of production standard time. [Subjects and Methods] Twenty industrial workers performed repetitive tasks at three different levels of production standard time, normal, hard, and very hard. Work productivity and energy expenditure rate were recorded during the experimental tasks. [Results] The work productivity target was not attainable for the hard and very hard production standard times. This was attributed to the energy expenditure rate, which increased as the level of production standard time became harder. The percentage change in energy expenditure rate for the very hard level (32.5%) relative to the normal level was twice that of the hard level (15.5%), indicating a higher risk of work-related musculoskeletal disorders for the harder production standard time. The energy expenditure rate for the very hard production standard time (1.36 kcal/min) was found to exceed the maximum energy expenditure rate recommended for light repetitive tasks involving both arms (1.2 kcal/min). [Conclusion] The present study shows that working with an energy expenditure rate that is either equal to or above the maximum energy expenditure rate of the tasks results in decreased work productivity performance due to the onset of physical fatigue and a higher risks of work-related musculoskeletal disorders.

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Section: Discussionmentioning

confidence: 99%

The effects of energy expenditure rate on work productivity performance at different levels of production standard time

et al. 2015

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“…Other studies of the same authors develop mathematical models considering the structural variables of WW for its optimization, with stochastic task times [26] and a mixed model production [27,28] illustrate the influence of workers' variability and different patterns of imbalances in output, while [29] provides a work-sharing protocol that considers discrete tasks and worker crossovers. At last, considering the impact of task time variation and models variation, [30] investigate the effects of sources of randomness on model validation as an abstraction for the real system, while [31] addresses the balancing problem for multi-model WW assembly systems. & WW Bucket Brigade system analysis and optimization.…”

Section: Literature Reviewmentioning

confidence: 99%

Walking worker vs fixed worker assembly considering the impact of components exposure on assembly time and energy expenditure

Calzavara

Faccio

Persona

et al. 2021

Int J Adv Manuf Technol

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Recently, the need for assembly systems of better following the market demand has led to the spread of alternative solutions with respect to the traditional fixed worker strategy. Walking worker systems, where operators move across the line to produce the finished product, are gaining always more interest. In this paper, a comparison between the fixed worker (FW) and the walking worker (WW) assembly strategies is provided, by taking into account their differences both in terms of performed activities during assembly and of material exposure at the assembly workstations. The evaluation is carried out through the proposal of a mathematical model, to understand the impact on assembly time and on operators’ energy expenditure. The behavior of the model is investigated both with a parametric analysis and a real case study. The results show that the FW is the best one when the system is working at its maximum throughput, while the WW strategy turns out to be preferable for the lower values of market demand, both from a time and an energy expenditure perspective.

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“…While not worsening hugely the efficiency of the line, it is shown by the case studies presented in this paper that the new model is able to balance efficiently and keep the exposure levels in the upper levels of extremity ergonomic measures under control. Al Zuheri et al (2013) delved into ergonomically assembly line balancing issues of the workers whose tasks include walking and increased the line efficiency. Bautista et al (2016a) and Bautista et al (2016b) came up with a set of line balancing models that take into account temporal and spatial features in addition to combining the ergonomic risk features.…”

Section: Literature Reviewmentioning

confidence: 99%

Ergonomi̇k Montaj Hatti Dengeleme İçi̇n Yeni̇ Bi̇r Model Öneri̇si̇

Kahya¹,

Şahin²

2019

Mühendislik Bilimleri Ve Tasarım Dergisi

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Assembly line balancing is a problem where tasks assign to stations in compliance with precedence constraints and as far as possible to balance delays. Assembly lines which is not designed properly in an ergonomic way cause not only productivity loss but also work-related muscoloskeletal disorders on workers. To prevent such problems, it should be aimed to catch acceptable level for each workstation's risk score and assign ergonomic risks equivalently among workers. In this study, for assembly line balancing problem, a new model approach is tackled, which constitute stations by consider ergonomic risk scores in addition to cycle time and precedence constraints. In order to compare proposed model with a classical assembly line balancing technique, a performance criterion which is combination of cycle time and ergonomic risk score were defined. The developed model was applied in a factory's oven assembly line. In the assembly line, task times were measured, precedence diagram was constructed and ergonomic risk levels were evaulated by using REBA method. When balancing lines with using Longest Operation Times technique, performance score was %25.61 but when it comes to balance with developed model performance score was obtained %18.25. It has been detected that developed model provides 7.41% improvement in line's total performance.

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Mathematical modelling for process design of walking worker assembly line in productivity and ergonomics perspectives

Cited by 8 publications

References 27 publications

The effects of energy expenditure rate on work productivity performance at different levels of production standard time

The effects of energy expenditure rate on work productivity performance at different levels of production standard time

Walking worker vs fixed worker assembly considering the impact of components exposure on assembly time and energy expenditure

Ergonomi̇k Montaj Hatti Dengeleme İçi̇n Yeni̇ Bi̇r Model Öneri̇si̇

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