Literally translated, the Japanese term heijun-ka means “leveling,” though for the purposes of lean manufacturing, a more accurate translation would be “production smoothing.” Heijun-ka seeks to reduce uneven production, and in doing so, eliminate waste and improve efficiency. It helps smooth out the workload to eliminate unevenness (mura) and overburden (muri).
Businesses employing heijun-ka frequently rely on a production system in which they can switch from one product to another at will and with minimal downtime. Though a system like this may lack the overall production capacity of more dedicated, single-purpose production systems, it makes up for this deficit by offering the freedom to rapidly create a small batch of a product when and if customer demand emerges. This supports the just-in-time method of production.
Not only does this reduce the material wastes and inevitable production surplus’ inherent to large batch production, it also limits day-to-day production variation.