What is Heijunka?

Heijunka is a Lean method used to improve the efficiency of production systems. In this blog post, we will discuss the definition of Heijunka and how to apply it in a production system.

What is the Heijunka Technique?

Heijunka, a Japanese word, means production leveling. In lean manufacturing, this concept is defined as a stockless production method that is not affected by demand fluctuations, where each model or variety can be produced in each shift and consecutively.

The aim of the Heijunka technique is to level production in order to better align the flow of a process with customer demands, minimize waste, and reduce batch operations. Production leveling enables more efficient use of resources by eliminating unnecessary steps and optimizing processing times.

The Heijunka technique does not set the production level based on fluctuating customer orders. Instead, it takes the demand over a given period and balances it so that the same mix and quantity of products is produced every day. To implement the Heijunka production system effectively, it is necessary to make more frequent model changes by shortening set-up times. In other words, it is necessary to apply the SMED approach.

Why is Leveling of Production Important?

The focus of lean manufacturing is on reducing waste and increasing value to the customer. Mura, one of the types of waste, means inequality. Last-minute changes in the production process, an unplanned delivery process, machines breaking down in the production process, etc. can cause inequalities in production.

At the same time, assuming that a production system varies according to customer orders, overtime may be worked to complete production. Overproduction can occur. The next day, production stops or decreases when customer demand decreases. These situations cause a flow inequality. A production environment that fluctuates according to customer demand is unsustainable for the team and damaging to the business in the long run.

In short, a production system cannot be stable if production levels are not equal. The Heijunka technique addresses exactly this problem.

How to Implement Heijunka?

In order for a company to successfully implement the heijunka technique, it must continue its lean journey steadily. This is because a levelized production system is made possible by the development of a solid Lean culture. In addition, the following practices need to be adopted:

• SMED (Single Minute Mold Exchange)
• Small Party Sizes
• Kanban production system (in accordance with customer demands and driven by the team interacting directly with customers)
• Knowing the customer, understanding their needs and expectations

There are two ways to implement the Heijunka method: leveling by volume and leveling by type.

Leveling by Volume

The Heijunka method allows you to organize production according to the average order volume you usually receive. This approach makes the production process more balanced, minimizing the effects of sudden fluctuations in demand.

If the average demand is 2,000 units per week, but the number of units produced varies by day, applying Heijunka will be beneficial.

For example, the average demand is 2,000 units per week. However, if the production number fluctuates by day, such as 200 on Monday and 300 on Tuesday, implementing Heijunka will ensure a stable flow in production.

Leveling by Type

It allows you to balance production according to the average demand for each product in the portfolio and organize your work accordingly. Thanks to Heijunka, businesses produce enough of each product to meet customer demand.

What is a Heijunka Board?

The Heijunka box is a tool for visualizing work items and planning the production sequence. It specifically aims to meet the average customer demand for each product. This system visually represents the orders for each product and optimizes and balances the production flow.

What are the Benefits of the Heijunka Technique?

• Provides balance in production and increases efficiency.
• A more balanced production flow eliminates the need to hold unnecessary stock and reduces costs.
• Prevents overproduction.
• It prevents overloading employees by distributing their workload in a more balanced way. Thus, improving work quality.
• Ensures that deliveries are made on time.
• Increases capacity and reduces investment costs.
• Makes it easier to adapt to changes in the production plan.

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