Issues relating to the bowl phenomenon in unpaced lines have been studied extensively; however, no previous paper has determined optimal bowl configurations of mean processing times for a given line length and buffer capacity under realistic operating conditions. The authors have discovered bowl-shaped configurations that perform better than perfectly balanced lines for systems of at least 30 workstations in length with interstation buffer capacities of up to one unit. Solid evidence confirms an earlier conjecture that the optimal two-level (i.e. flat-bottomed) allocation of mean processing times performs no worse than the optimal multi-level configuration. Information useful to the industrial engineer has been obtained through an examination of the maximum amount of imbalance that still provides some productivity benefit. It has been found that the amount of imbalance in a line can generally be double the imbalance in a optimal bowl and still perform better than the balanced line. This study also contradicts earlier conclusions in that the bowl phenomenon is still appropriate for smaller confficients of variation and greater buffer capacities.
