What is heijunka? Key tools to achieve production levelling
Heijunka is a principle that any company pursuing operational excellence can apply. It helps the entire supply chain — from suppliers to the warehouse — run at a predictable pace. This lean manufacturing concept focuses on production smoothing or levelling. It enables staff, equipment and facilities to work efficiently, avoiding disruptions caused by daily manufacturing fluctuations.
In this post, we explore the meaning of heijunka, the types of production levelling and how this technique benefits efficiency. We’ll also explain how to implement heijunka and why it’s critical for stable operations.
Heijunka definition
Heijunka, a Japanese term meaning “levelling,” is a production scheduling method from the Toyota Production System. Its goal is to balance both the volume and variety of manufactured products, reducing variability and creating a steady workflow.
As part of lean manufacturing, it allows companies to optimise inventory management and respond to customer needs effectively. It encourages small-batch production and schedules orders based on demand,
helping curb waste and make workflows more predictable.
Heijunka falls under lean methodology, a management philosophy geared towards continuous improvement and creating stable, fine-tuned workflows. It’s particularly helpful for smoothing fluctuations in demand (through smaller production batches), creating more stable workloads and shrinking raw material, work-in-progress and finished goods inventories.
Benefits of heijunka
Production levelling creates a smoother workflow, preventing spikes and inefficiencies. Applying heijunka brings businesses several advantages:
- Consistent material flow. With production running at a steady pace, companies minimise urgent situations and bottlenecks while streamlining operational capacity. Overload cycles and idle periods are eliminated.
- Smaller inventory. Fewer raw materials are stored thanks to better forecasting and supplier coordination.
- Greater flexibility. Small-batch manufacturing allows faster adaptation to changing demand.
- Production control. Maintaining a rhythm based on takt time and reducing sudden peaks simplifies manufacturing management and monitoring.
- Lower costs. Overproduction and operational interruptions are minimised, boosting overall profitability.
How to implement production levelling (heijunka)
Heijunka stabilises manufacturing against demand fluctuations through two complementary approaches: levelling by volume (total workload) and levelling by product type (mix). Both aim to maintain a steady workflow, but each addresses different dimensions of variability.
Production levelling by volume
Volume levelling centres on managing the total workload, preventing fluctuations from daily demand. By calculating the average demand over a period and producing at that constant rate instead of following daily peaks and valleys, companies eliminate both overloads and idle time.
Production levelling by product type
Product-mix levelling considers the variety of products or services requested by customers. Instead of manufacturing large quantities of item A before moving to B, a business produces a small representative batch of all items (A, B, C and D) in short, repeatable cycles. This avoids large production runs and thus the need for excessive inventory.
Heijunka examples
The following heijunka examples illustrate how each levelling strategy turns unstable processes into smooth workflows:
Example of production levelling by volume
Imagine a manufacturing centre producing a standardised item with uneven weekly demand: Monday 400 units, Tuesday 100, Wednesday 250 and Thursday 50, totalling 800 units.
Without levelling, Monday would overwhelm staff and machines, while Thursday would leave resources idle. Heijunka proposes a constant daily output of 200 units, evening out the workload.
Example of production levelling by product type
Consider a plant that makes three motorcycle models (A, B and C). Every 10 days, dealerships order six units of A, three of B and one of C.
Traditional batch production would manufacture all units of A first, then B and finally C, a common approach in economies of scale. The sequence would look like this: A, A, A, A, A, A, B, B, B, C.
With heijunka applied by product type, each model is produced in proportion and interleaved, for instance: A, B, A, A, C, A, B, A, B, A.
This tweak would cut lead times for models B and C while maintaining flexibility for demand changes.
Tools to optimise heijunka
Implementing heijunka or production levelling, relies on specific tools that help plan, visualise and maintain a stable flow. Companies traditionally managed this smoothing with visual tools; today, specialised digital solutions can further improve it.
Heijunka board or box
The heijunka box or board is a visual tool for organising production in regular intervals, distributing product types evenly over the planning horizon.
Typically, columns represent time periods (hours, shifts, days), while rows correspond to different products. Visual cards or signals indicate what to produce and when, avoiding peaks, smoothing variability and sustaining flow on the shop floor.
Digital tools and execution software
In complex industrial environments, heijunka is often reinforced with digital solutions that automate planning and ensure adherence. MES (manufacturing execution system) and advanced planning and scheduling (APS) software translate heijunka logic into levelled production schedules aligned with real resource capacity.
Warehouse management systems (WMSs) also support heijunka by guaranteeing materials are available exactly when needed. For example, Easy WMS synchronises raw material and semi-finished product flows with production lines via the WMS for Manufacturing module for stable, uninterrupted output.
Heijunka: An ally for operational excellence
Heijunka goes beyond production scheduling — it’s a strategy for operational excellence. By levelling volume and product variety in production, companies eliminate irregularities, alleviate stress on resources and minimise waste.
Stable manufacturing rates benefit the entire internal chain, simplifying warehouse and logistics flow planning, optimising capacity utilisation and ensuring continuous responsiveness to market demand.
Heijunka in 5 questions
What is heijunka?
Heijunka is production levelling or production smoothing. This lean manufacturing technique evens out the effects of fluctuating demand to streamline manufacturing processes. It cuts costs by removing production imbalances, promotes small-batch manufacturing and processes mixed orders at a steady pace. As a result, companies operate with minimal inventory, uniform workloads and operational flexibility.
What does heijunka mean?
Literally, the Japanese word heijunka translates as levelling or smoothing. Originating from the Toyota Production System, it was developed to handle variable demand without spikes or downtime. By levelling production, Toyota stabilised processes, reduced inventories and enhanced operational efficiency.
What is the purpose of the heijunka production system?
The main goal of heijunka is to level production to lessen the impact of fluctuating demand, preventing peaks and valleys in manufacturing as well as resource overload. Heijunka creates a constant, predictable flow to reduce inventory, increase operational flexibility and lower costs.
How is production levelling (heijunka) applied?
Heijunka smooths production by creating a continuous, even workflow. It achieves this by levelling production by volume, maintaining a pace based on average demand and by product type, manufacturing mixed small batches in a repeatable, balanced sequence.
What is a heijunka board?
A heijunka box or board is a visual tool that organises production into regular intervals. Columns represent time, rows represent product types and Kanban cards guide sequenced, small-batch production runs to maintain a consistent, predictable flow.