Unbalanced unpaced serial production lines have been the subject of continued interest over the last half a century. Research into these systems taking a diversity of approaches has given rise to a variety of insights which may be of increasing relevance in a context of fast-changing production and flexibility needs. By mapping the major conclusions reached in the area of unpaced asynchronous unbalanced lines over time and from diverse sources, this review identifies some possible future avenues of research that can usefully advance knowledge in this domain.
