What Is Heijunka (Production Leveling)?
Also known as: production leveling, level scheduling, heijunka box, load leveling
Definition
Heijunka is a lean technique that levels production by smoothing both volume and product mix over time, so the plant builds a steady, repeating pattern instead of reacting to order spikes with large batches and overtime.
Heijunka (Production Leveling) Explained
Customer demand is uneven, but a plant that builds exactly what arrives each day swings between overload and idle capacity. Heijunka absorbs the variation by scheduling a smoothed pattern based on average demand, using a small finished goods buffer or flexible capacity to cover differences. Mura, the unevenness in workload, is the waste it targets.
Leveling has two parts. Volume leveling spreads total quantity evenly across periods. Mix leveling sequences different products in small repeating lots, for example A, B, A, C rather than all of A then all of B. This requires short changeovers, which is why heijunka depends on SMED.
A heijunka box is a physical grid of slots by time and product, where kanban cards are placed to release work in the leveled sequence. In ERP terms, the closest equivalents are repetitive or rate-based scheduling and a leveled master production schedule. Examples include kanban and repetitive modes in SAP, kanban and pull configuration in Infor SyteLine and Infor LN, and rate-based production plans in many mid-market systems. Planning fences and time fences help keep the leveled plan stable.
Heijunka does not suit every business. Make-to-order shops with highly variable products and long setups often cannot level mix, and may focus on leveling workload and capacity instead.
Why It Matters
- Reduces overtime, idle time and expediting caused by demand swings.
- Lowers inventory and lead time by avoiding large batches.
- Makes supplier demand smoother and more predictable.
- Stabilizes the schedule so other lean tools like kanban work well.
In Practice
A line gets weekly orders of 400 of product A and 100 of product B. Rather than building A on Monday to Thursday and B on Friday, the plan builds in repeating cycles of four A to one B each hour. Because changeovers have been cut by SMED, the pattern is feasible, and component usage becomes steady.
Frequently Asked Questions
What does heijunka mean?
It is Japanese for leveling, and in lean it means leveling production volume and mix.
What is a heijunka box?
A grid of time slots and product types that holds kanban cards, used to release work in a leveled, repeating sequence.
Why does heijunka need fast changeovers?
Mixing products in small repeating lots only works if switching between them is quick, which is why it relies on SMED.
Can ERP schedule heijunka?
Rate-based, repetitive and kanban features, plus a stable leveled master schedule, approximate it. Many plants combine them with a physical heijunka board.
Related Terms
Kanban
Kanban is a visual pull system in which a card, bin, or electronic signal authorizes production or replenishment of a specific part only after downstream consumption, capping inventory at the number of signals in circulation.
SMED (Single-Minute Exchange of Die)
SMED (Single-Minute Exchange of Die) is a structured method developed by Shigeo Shingo for reducing equipment changeover time to under ten minutes, primarily by converting setup steps that require the machine stopped into steps performed while it still runs.
MPS (Master Production Schedule)
An MPS (master production schedule) is the time-phased statement of which end items a plant will produce, in what quantities, and in which periods. It is the anchor demand input MRP explodes into component requirements.
Takt Time
Takt time is the rate at which a process must complete one unit to meet customer demand, calculated as available production time divided by demand for that period. It sets the pace a line must sustain, not the speed it can achieve.
Lean Manufacturing
Lean manufacturing is a production philosophy derived from the Toyota Production System that maximizes customer value by systematically identifying and eliminating waste, defined as any activity that consumes resources without adding value the customer would pay for.
Go Deeper
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Free ToolCycle Time & Capacity Calculator
Translate cycle time, parallel stations, shift pattern, and realistic utilization into hourly, daily, and annual production capacity.
SyteLine Kanban and Lean Manufacturing Setup
Configure Kanban replenishment and lean manufacturing in SyteLine with pull signals, kanban sizing, supermarket setup, and integration with MRP planning.
SyteLine Master Production Scheduling Best Practices
Master production scheduling in SyteLine with planning bill configuration, time fence management, rough-cut capacity checks, and schedule stabilization techniques.
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