Production runs more smoothly when there are the precise quantity of parts needed to create a certain number of cars. Discover why Heijunka boosts productivity in the Toyota Production System by reading on.
Heijunka (translation: production leveling or smoothing): Production leveling, also known as finding and maintaining average production levels, is a strategy used to support Just-In-Time (JIT) production. Over time, it is used to smooth out production in all departments as well as that of the supplier.
Heijunka is significant for production sequencing as well. For instance, if the factory’s ordering system were to simultaneously send batches of high-spec models down its assembly line, workers would need to coordinate a large number of difficult construction chores not present in less well-equipped automobiles.
By manufacturing a variety of models within each batch and guaranteeing that there is an inventory of product commensurate to the variability in demand, the Toyota Production System leverages Heijunka to address the first issue.
Additionally, by sequencing components to be available in the proper quantity and at the appropriate time, as well as by keeping changeover times for crucial processes like die changes in steel presses as brief as possible—often as little as three minutes—the disruption of production flow is minimized.
In This Article...
How does heijunka function and what is it?
Heijunka is a Lean technique for decreasing the possibility of overburden and minimizing unevenness in a production process. Heijunka is a Japanese word that literally translates to “leveling.” It can assist you in responding to fluctuations in demand and making the greatest use of your capacity.
You can stop creating work in batches and start processing orders in response to consumer demand by deploying Heijunka. As a result, your inventory expenses will be lower because you won’t have as many things on hand to buy when demand is low.
On the other hand, because you will be producing value in accordance with your takt time, or more simply put, your average sell rate, your process and the team will be safeguarded from overload when demand goes up.
Toyota is the most well-known corporation to use Heijunka. The Japanese automaker has long since given up working in batches in favor of scheduling the assembly of automobiles in a production line to occur as needed.
Heijunka gives you the ability to produce and provide value to your customers at a constant rate so that you may respond to changes in accordance with your typical demand. The approach includes two options for leveling production for that purpose:
- Volume leveling
- grading types
In TPS, what is heijunka?
Heijunka, which is pronounced hi-JUNE-kuh, is a method for minimizing unevenness in a production cycle, which also minimizes waste. It is a major lean manufacturing technique that was first applied by the Toyota Production System (TPS) to increase production efficiency. The word “leveling” comes from the Japanese language. Toyota came to the realization that batching isn’t sustainable and that production systems can’t continually satisfy occasional orders without experiencing uneven productivity levels, variable quality, and overworked equipment and workers, all of which lead to waste.
In the United States, heijunka is frequently referred to as production leveling, but both names refer to the same thing: minimizing production inequalities by avoiding batching, which reduces inventory, lowers capital costs, and lessens employee overwork. You may produce goods steadily with Heijunka, which enables you to respond to changes based on your typical demand. Leveling by volume and leveling by product type/type are the two ways it accomplishes this.
- Heijunka advises that you should level your production according on the volume of requests you often receive. For instance, leveling production by volume gives you the best chance to control inventory if your custom garment business receives 500 orders for gray shirts each week, but the number of shirts varies by day during the week. Say, for example, that on Monday you get 200 shirt orders, 100 on Tuesday, 50 on Wednesday, 50 on Thursday, and 100 on Friday. You would need to produce an inventory of 100 shirts every Monday in order to level demand utilizing heijunka. After that, you would produce 100 shirts every day.
- Leveling by type/product: In practice, it’s unlikely that you’ll be producing the same thing every day. Let’s say that each week, your custom garment business receives a variety of requests for colored T-shirts. Orders for orange (O), red (R), gray (G), and black (B) shirts arrive one week. The production schedule might be as follows: OOOOORRRGGBB. A typical mass production organization would wish to reduce waste that is related to equipment changeover.
Customers do, however, frequently alter their orders, and demand and volume fluctuate. What if a buyer determines that the orange shirts should actually be gray? What if demand for gray shirts suddenly declines while demand for black shirts increases? The average mass producer would then be forced to scramble to figure out how to produce more gray shirts while the orange shirts would just remain in stock. A heijunka production schedule would look something like this: OORGBOORGBOR, with the emphasis added to ensure efficient changeover times and popular items remain in a buffer inventory.
What are heijunka’s two components?
A Japanese tool called a heijunka is used to balance production. Variation (or Mura) in the process occurs when a workstation or production line generates multiple items with various processing times. When the various products of the mix are balanced in the available time, the fluctuation in the quantity of effort can be minimised.
This Lean approach runs counter to many conventional ways of thinking because the balancing exercise results in more changes, which by themselves do not provide value. The Production Wheel and the Heijunka Box are two examples of ways to depict the production interval, and this article will discuss why choosing to balance anyway may be beneficial.
The interval in which all products will be created, the fixed order of products, the predetermined inventory policy, the variable number of items for each product, and the direction for improvement are the minimum of five components of HEIJUNKA (5).
A set period of time during which the product family can be manufactured will be the Heijunka’s initial result. One can determine how many production cycles can be made while still satisfying every customer by analyzing the total demand and change over times. The Yamazumi can be used to do this. The constant order of items at that interval decreases the variety of change-overs required during each product cycle. A switch from product type 3 to type 2 or from type 2 to type 1 won’t be necessary if product types 1, 2, and 3 are constantly produced in that order. The variance of Change over time is lessened in this manner. When turnaround durations differ between items, aim to design a sequence that gets rid of the longest turnarounds. By doing this, the waste (muda) required to produce each product is also decreased.
The definition of the raw material inventory policies is made easier by the predetermined sequence. The size of inventory buffers can be determined once the workstation’s production interval has been established (see: supermarket and FIFO).
The number of goods per category may still change within the defined interval and the fixed sequence. This gives you flexibility to respond to changes in customer demand. The length of the interval has a significant impact on how quickly people respond to changes. The impact on the work’s content will be lessened as the interval gets shorter because one may react more quickly.
The Heijunka finally demonstrates the future improvement’s direction. Every Lean Tool aims to assist you in identifying the following area for improvement (Floyd (2010) and Rother (2010)). The process of defining a set order of goods or cutting the interval may raise problems that need to be resolved. It is important to look at the themes of complexity and variation because they both promote waste (muda).
What are the fundamental tenets of heijunka?
Heijunka’s definition is: “leveling, equating, relieving, and harmonising. The Heijunka principle is quite potent and pushes us to comprehend the “What we can do to strive to balance the load or demand moving through our operations. The peaks and troughs are what we want to avoid.
What benefits does heijunka offer?
It would also be helpful to consider standardizing the components that go into different goods as well as the processes used to generate the products in order to create work streams that save changeover time. Teams will benefit from applying 5S principles in this endeavor.
Simply expressed, this means that before applying heijunka, the team must have made some lean process improvements. The manufacturing schedule will then be leveled, which will enable Heijunka to further improve the situation.
A crucial component of any Lean deployment is heijunka. It enables businesses to achieve predictability via balancing product demand, flexibility through the ability to adapt to shifting consumer tastes, and stability through long-term averaging of production volume and type. With them in place, businesses can profit from:
- happier and more productive workers as a result of removing or preventing overwork and idle time
- leveled demand for suppliers and upstream techniques
- Customers are happy when they get the things they want when they want them.
- lower costs as a result of inventory
- increased machine reliability as a result of leveled load
In fact, by using heijunka, businesses may run consistently at a level that is best for the overall success of their enterprise.
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What are heijunka and jidoka?
leveling heijunka production. • Hoshin planning: Organized planning that concentrates on a few pressing issues at once. • Jidoka: Ji stands for the worker, do for motion or work, and ka for action; when combined, they signify “automation with a human mind.”
What does Toyota’s kaizen mean?
Kaizen (the philosophy of continual improvement) and respect for and empowerment of people, particularly line employees, are the two pillars of the Toyota way of doing things. The success of lean depends entirely on both.