The optimal number of used machines in a two-stage flexible flowshop scheduling problem

Enrique Gerstl, Gur Mosheiov*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

11 Scopus citations


We study practical scheduling problems with a major decision referring to the number of machines to be used. We focus on a two-stage flexible flowshop, where each job is processed on the first (critical) machine, and then continues to one of the second-stage parallel machines. Jobs are assumed to have identical processing times, and are processed in batches. A setup time is required when starting a new batch. We consider two objective functions: minimum makespan and minimum flowtime. In both cases, a closed form expression for the optimal number of machines to be used is introduced, and a unique and unusual sequence of decreasing batch sizes is shown to be optimal.

Original languageAmerican English
Pages (from-to)199-210
Number of pages12
JournalJournal of Scheduling
Issue number2
StatePublished - Apr 2014

Bibliographical note

Funding Information:
Acknowledgments This paper was supported in part by The Recanati Found of the School of Business Administration, and by The Charles Rosen Chair of Management, The Hebrew University, Jerusalem, Israel.


  • Deterministic
  • Flowshop
  • Flowtime
  • Makespan
  • Scheduling
  • Sequencing


Dive into the research topics of 'The optimal number of used machines in a two-stage flexible flowshop scheduling problem'. Together they form a unique fingerprint.

Cite this