Fifty years of the bowl phenomenon

Marsillac

Journal of Manufacturing Systems

et al. 2019

Self Cite

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Section: Work and Variability Allocation Along The Linementioning

confidence: 60%

Section: Throughputmentioning

confidence: 99%

Serial production line performance under random variation: Dealing with the ‘Law of Variability’

Marsillac

Journal of Manufacturing Systems

et al. 2019

Self Cite

“…However some research (e.g. Conway et al 1988;McNamara et al 2016) has pointed to the value of incorporating more realistic characteristics into the task of line design since real life unpaced assembly lines can never be truly balanced and will inevitably suffer breakdown failures. Furthermore, previous research has shown that serial production line performance can be significantly affected by different mixtures of mean time to failure (MTTF), mean time to repair (MTTR) and buffer capacity (Battini et al 2009;Colledani et al 2010;Patti and Watson 2010;Assaf et al 2014;, complementing the overall efficiency rate (reliability) of the machines.…”

Section: Introductionmentioning

confidence: 99%

Performance of merging lines with uneven buffer capacity allocation: the effects of unreliability under different inventory-related costs

2020

Cent Eur J Oper Res

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This simulation study investigates whether machine efficiency, mean time to failure (MTTF) and mean time to repair (MTTR) significantly affect the performance of uneven buffer capacity allocation patterns for merging lines. Also studied is the trade-off between increasing throughput via bigger buffers and their associated inventory-related costs, since previous studies have shown that higher overall buffer capacity and higher average inventory content result in higher throughput. Results suggest that an ascending buffer allocation pattern (concentrating buffer capacity towards the end of the line) produces higher throughput in shorter, more unreliable lines; whereas the balanced pattern shows better performance in longer, more reliable lines. Increasing average buffer capacity per station and/or having higher average buffer content was found to be more cost-effective in lines with lower machine inefficiency, shorter MTTF and MTTR, and longer lines. Results differed between reliable and unreliable lines since reliable lines were particularly penalised by buffer capacity investiment/maintenance costs due to a relatively low increase in throughput resulting from the addition of extra buffer capacity.

“…In manual, unpaced lines, the operators at each station can work at different MTs for several reasons: they can vary their speed according to their motivation level, physical capacity, task complexity or due to an uneven work allocation along the line. Furthermore, previous studies have shown that the best design for single serial lines in terms of throughput rate is to arrange mean operation times (MTs) in a 'bowl' shape (McNamara, Shaaban, and Hudson 2016;Hillier and Boling 1966) and to allocate BC as evenly as possible (McNamara, Shaaban, and Hudson 2013;Lambrecht and Segaert 1990); whereas studies on merging lines (McNamara et al 2018;Shaaban, McNamara, and Dmitriev 2017) have suggested that a bowl pattern for MT and a balanced pattern for BC are not the best for merging lines.…”

Section: Introductionmentioning

confidence: 99%

“…They termed this effect as the 'bowl phenomenon'. Since then, the phenomenon was repeatedly retested, with varying degrees of support (McNamara, Shaaban, and Hudson 2016). More recent studies on single serial lines have shifted to imbalance patterns, rather than just the bowl phenomenon (see Das et al 2010;McNamara, Shaaban, and Hudson 2013;Shaaban, McNamara, and Hudson 2015;Hudson, McNamara, and Shaaban 2015;Hillier 2013;Shaaban and Hudson 2009).…”

Section: Introductionmentioning

confidence: 99%

Influence of unbalanced operation time means and uneven buffer allocation on unreliable merging assembly line efficiency

International Journal of Production Research

2018

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Unbalanced, unreliable (UR), unpaced, merging assembly lines are simulated in this study with varying line lengths, buffer storage capacities, imbalance degrees and unequal mean operation time configurations and uneven buffer capacity (BC) allocation. This paper contributes to the literature by suggesting that, in many cases, imbalance can improve merging lines' performance, as compared to a corresponding balanced merging line. It was found that an inverted bowl or descending patterns for mean operation times (MTs), and an inverted bowl (concentrating BC towards the centre of the line) or an ascending pattern for buffer allocation, result in higher throughput (TR). In terms of average buffer level (ABL), the best pattern is a monotone decreasing order regarding MTs and a monotone increasing order with respect to BC allocation. Additionally, it was found that when considering a profit function, the best performing patterns for UR lines tend to be the patterns that reduce ABL, even when considering very low inventory holding costs; contrary to the behaviour of the profit function in reliable lines, which suggests that either patterns that increase TR or reduce ABL can lead to a good performance, depending on the values of the unitary inventory holding costs.