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

Sabry Shaaban, Rodrigo Romero-Silva

Research output: Contribution to JournalArticle


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.
Original languageEnglish
Pages (from-to)1-36
JournalCentral European Journal of Operations Research
Publication statusE-pub ahead of print - 19 Jan 2020



  • Simulation
  • Unreliable machines
  • average buffer level
  • inventory costs
  • throughput
  • unbalanced lines

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