Heijunka: Techniques and Tools for Implementation

In today’s manufacturing world, efficiency, consistency and adaptability is key to success. Batch production methods are inefficient and wasteful. One philosophy that solves these problems is Heijunka, the founding principle of the lean manufacturing method. Heijunka means ‘levelling’ in Japanese and is all about balancing and stabilizing production to match customer demand. This ensures labour, equipment and materials are not over or underutilized. By applying Heijunka strategically you can reduce waste and optimize production.

This article goes into detail about Heijunka, what it is, the methods, history and real world applications across various industries. It also looks at how digital technology is enhancing Heijunka practices with new tools and strategies to improve manufacturing systems. By the end of the article you will know what Heijunka is and how its principles can transform your manufacturing processes if you want to be more efficient and flexible.

What is Heijunka?

Heijunka is a production levelling system to create a smooth flow of production processes. The main goal of Heijunka is to avoid the inefficiencies caused by overproduction and underproduction – the so called ‘peaks’ and ‘valleys’ of production – to match customer demand. Overproduction can lead to excess inventory and storage problems and reduced customer buying rate while underproduction can lead to shortages and unfulfilled orders and customer dissatisfaction. By levelling production over time Heijunka ensures the stability of the production process by preventing these extremes.

Origins of Heijunka

Heijunka is a key element of the Toyota Production System (TPS), which was developed in the mid-twentieth century by Toyota engineers, including Taiichi Honno. The TPS was designed to eliminate the inefficiencies inherent in traditional production methods and aimed to create a flexible, efficient system that could respond to customer demand without overloading workers and machines. Heijunka was inspired by observations of US supermarkets where a ‘pull’ system ensured that goods were in stock based on demand. This system allows businesses to reduce waste by producing only what is needed and when it is needed, and enable them to efficiently meet customer demands while maintaining high quality and low cost.

Importance of Heijunka

Heijunka is crucial for manufacturing as it allows you to:

1. Reduce Waste: By matching production to actual customer demand Heijunka reduces overproduction and underutilization both of which are forms of waste. With Heijunka resources are used more efficiently and products are produced in the right quantities to meet demand.
2. Increase Efficiency: By levelling production workflows are smoothed out, downtime, weaknesses and equipment downtime are reduced. Overall productivity and operational efficiency improves.
3. Improve Customer Satisfaction: Level production schedules mean timely deliveries and consistent product quality. Customers get their orders on time which increases their satisfaction and loyalty to the brand.
4. Employee Happiness: No overwork during peaks and no idle time during troughs. Heijunka creates a more balanced work environment which leads to better employee morale.

Key Techniques of Heijunka

To implement Heijunka in your production facility you need to use specific techniques to level production:

1. Leveling by Volume

Leveling by volume means producing the same number of units over a set period. Instead of producing a lot of one product one day and a little of the same product on the same process the next day, you want to split total production across all workdays. This keeps the workflow steady, prevents overloading and uses capacity optimally.

Example: A factory needs to produce 700 units of a product per week. Instead of producing 200 units one day and 50 the next, averaging production volume is leveled by splitting 700 units across all 7 working days with a daily target of 100 units. This keeps it consistent and minimizes the risk of overrun capacity.

2. Leveling by Product Type

When a facility produces multiple products, leveling by product becomes necessary to avoid focusing too much on one product leveling and neglecting others. This technique keeps the product mix balanced and prevents production bottlenecks caused by product variety imbalance.

Example: A dairy plant producing milk, butter and ice cream can level its production by determining the optimal production quantities of each product based on historical sales demand data. These quantities are then split into daily production targets, so all product types are produced at the same level throughout the month.

3. Heijunka Scheduling

Heijunka scheduling is the process of creating detailed production plans that balance customer orders and volume and type of products to be produced. Production schedules are visualized using tools like Heijunka boards, heijunka boxes or specialized software. These schedules help manufacturers follow a consistent pattern and can be adjusted if customer demand or production needs change.

Tools for Implementing Heijunka

To implement Heijunka effectively, manufacturers rely on several tools that help plan, monitor, and adjust production levels in real-time.

1. Heijunka Box

A Heijunka board (or Heijunka box) is a simple physical tool to visualise the production schedule. It’s a grid with time periods on one axis and product types on the other. Cards or folders representing specific tasks are placed in the grid and updated as tasks are completed. This board gives a visual overview of the production progress, so workers and managers can see and adjust the workflow as needed.

2. Kanban Board

Kanban boards are often used in conjunction with Heijunka to track tasks and smooth the workflow. Kanban boards are divided into columns, like “To Do”, “In Progress” and “Completed” and each task is represented by a card that moves through the columns as it progresses. Kanban boards give a clear overview of the production stages and allow teams to see and solve bottlenecks in the process.

3. Digital Solutions

In today’s digital world manufacturing is using more and more advanced software solutions to implement Heijunka. Enterprise Resource Planning (ERP) systems and specialized production management software allow companies to analyze demand, create schedules and track production. Digital solutions make Heijunka more accurate, automate routine tasks and improve communication between departments.

4. Value Stream Mapping (VSM)

Value Stream Mapping (VSM) is a tool to identify waste and inefficiencies in the production process. It gives a detailed view of the material and information flow from start to finish and helps manufacturers to see where the production line can be leveled better. VSM is used in conjunction with Heijunka to see the opportunities for optimization before the production leveling is applied.

Real-World Applications of Heijunka

Toyota Production System

Heijunka was born in Toyota and Toyota’s application of Heijunka in the Toyota Production System (TPS) is the benchmark for Heijunka. Toyota levels production to the schedule and uses just-in-time (JIT) so only makes what’s needed, when needed. This eliminates waste, improves quality and allows Toyota to be agile to customer demand fluctuations.

FPZ

FPZ, an Italian manufacturer of blowers and pumps, applied Heijunka as part of their lean transformation. They implemented Heijunka boards and Kanban systems and reduced production errors, streamlined the workflow and eliminated waste. This resulted in shorter production lead time and times, cost savings and improved customer satisfaction.

Healthcare

In the healthcare sector Heijunka is used to manage patient admissions and allocate medical staff. Hospitals can level patient inflows so healthcare professionals are not overwhelmed during peak times and not idle during slow times. This improves patient care and reduces waiting times and overall efficiency.

Logistics and E-Commerce

E-commerce companies like Amazon apply Heijunka to their order fulfillment processes. By leveling workloads in distribution centers and scheduling delivery routes they ensure timely delivery and minimize operational bottlenecks.

Pharmaceutical Industry

Pharmaceutical companies use Heijunka to manage production of products with varying demand cycles. By leveling production schedules they can ensure a steady supply of critical medicines while minimizing waste and expiration. This also helps them to be compliant with regulations and get medicines to patients on time.

Energy

In the renewable energy sector Heijunka is used to balance energy production from wind and solar with customer demand. Companies in this sector use storage and predictive analytics to smooth out supply and demand fluctuations, optimize grid operations and capital costs and get a steady energy supply.

Challenges and Solutions

Heijunka has many benefits, but it can be tough to implement. Common obstacles include:

• Complex Production Environments: Some facilities produce multiple products with very uneven demand patterns which makes production leveling hard. To fix this use advanced data analytics to identify demand trends and optimize production schedules.
• Resistance to Change: Employees will resist new ways of working, especially if they are used to the old ways. To overcome this, organizations should invest in full training programs and show the benefits of Heijunka to get buy in from employees and managers.
• Initial Costs: Setting up Heijunka boards, digital systems and employee training requires upfront investment. But the long-term benefits of cost savings and efficiency justify the initial investment.
• Demand Variability: Customer demand can be unpredictable which makes it hard to maintain stable production. To fix this, organizations can build flexibility into the production systems and maintain buffer inventory to absorb demand spikes.
• Supply Chain Disruptions: Unexpected supply chain disruptions can break production schedules. Having robust contingency plans and diversified supplier networks can help mitigate these risks.

Heijunka and the Future of Manufacturing

Heijunka continues to evolve with advancements in technology. The rise of Industry 4.0 technologies such as the Internet of Things (IoT), artificial intelligence (AI), and robotics is providing new opportunities to enhance Heijunka practices. These technologies enable real-time data collection, predictive analytics, and automated scheduling, improving production efficiency and flexibility.

Industry 4.0 Integration

• IoT: IoT sensors in machines can provide real time production data, so manufacturers can adjust schedules on the fly.
• AI: AI powered predictive analytics can forecast demand more accurately so production levels match future market needs. AI can also identify production schedule inefficiencies and suggest improvements.
• Robotics: Automation systems including robots and cobots (collaborative robots) offer more flexibility in production. These systems can be reprogrammed quickly to adapt to Heijunka schedule changes so output is consistent.
• Cloud Based Solutions: Cloud technology enables collaboration across departments and supply chain partners. Centralizing data and tools in the cloud makes it easier to roll out Heijunka across global operations.
• Digital Twins: Digital twin of the manufacturing process. Simulate Heijunka before changing physical systems.

Conclusion

Heijunka is not just a production method, it’s a philosophy of lean. By levelling production volumes and product types it tackles waste reduction, efficiency improvement and being able to respond to customer demand in time. Heijunka has been applied successfully in industries like automotive, healthcare, pharmaceuticals and energy.

As technology advances Heijunka’s potential to improve efficiency and flexibility grows exponentially. By combining its principles with digital tools and Industry 4.0 technology businesses can achieve new levels of operational excellence. Businesses that adopt Heijunka will not only gain a competitive advantage but also help create a more balanced industrial landscape.