The Japanese term, heijunka, also known as level-loading, production leveling, or production smoothing, facilitates system stability by addressing workload unevenness (mura) by leveling both volume and mix over time (see figure 1).

Heijunka also serves as a pacing mechanism for operations, often reflected in the use of heijunka, leveling, or schedule boxes, which are typically designed using pitch intervals (see my previous column “Pitch, Takt Image Math”).

Successful heijunka reduces lead time, inventory, and workers’ physical and psychological stress that can accompany fluctuating workloads. Some prerequisites include quick changeovers, capable processes, standardized work (or at least defined work content), good visual management, and a solid understanding of customer demand—volume, mix, and variation (see L. M. Loucke’s post, “Demand segmentation graph”).

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