Scheduling in a no-wait flow shop to minimise total earliness and tardiness with additional idle time allowed

Abstract

Scheduling jobs in a no-wait flow shop with the objective of minimising total earliness and tardiness is the problem addressed in this paper. Idle time may be needed on the first machine due to the no-wait restriction. A model is developed that shows additional idle can be inserted on the first machine to help reduce earliness. Several dispatching heuristics previously used in other environments were modified and tested. A two-phased procedure was also developed, estimating additional idle in the first phase, and applying dispatching heuristics in the second phase. Several versions of an insertion improvement procedure were also developed. The procedures are tested on instances of various sizes and due date tightness and range. The results show the two-phase heuristics are more effective than the simple rules, and the insertion search improvement procedure can provide considerable improvements.

KEYWORDS:

• Scheduling
• heuristics
• flow shop
• earliness and tardiness
• no-wait

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work is financed by National Funds through the Portuguese funding agency, FCT – Fundação para a Ciência e a Tecnologia, within project UIDB/50014/2020. The funding source had no involvement in the conduct of this research or in the preparation of this article.

Notes on contributors

Jeffrey Schaller

Jeffrey E. Schaller received his PhD in operations management from the College of Business Administration, University of Florida, USA, in 1996. He held various operations management positions in several companies, and is currently a full professor at the Department of Business Administration, Eastern Connecticut State University, USA. His main research interests include scheduling, lean production and cellular manufacturing.

Jorge M. S. Valente

Jorge M. S. Valente received his PhD in management science from the Faculdade de Economia, Universidade do Porto, Portugal, in 2005. He is an associate professor at Faculdade de Economia, Universidade do Porto, Portugal. His main research interests consist in the application of exact and heuristic algorithms to scheduling problems.