An important part of keeping your clients loyal is to deliver the right value at the right time to them. Looking for a way to achieve this, in the middle of the 20th century, Toyota developed a method called “continuous flow”. It is an alternative to the commonly accepted way of batching work when managing a process.
In this section, you will be able to learn how to make the most of continuous flow by implementing some of the methods Lean has to offer.
What Is Continuous Flow?
Continuous flow is a Lean method that allows you to move a single product through every step of your process instead of grouping work items into batches. The method is called this way because it allows you to send goods to the market continuously. This provides you with the opportunity to deliver value more often to your customers.
It is as simple as it sounds. Once you start working on a product, you keep focused on it until it is ready to be delivered to your customer.
At first, the concept of continuous flow may sound less efficient than processing work in batches because, with it, you are delivering smaller amounts of value to the market at a time. However, it actually allows you to provide value to customers more often and reduce the time they spend waiting to receive their order.
In addition, it is a fantastic way to minimize the waste of your process. Continuous flow is especially useful for reducing inventory costs and the wait time of your work items.
What Is Takt Time?
To make the most of continuous flow, you need to define a takt time for your assignments.
Takt time is the rate at which a product needs to be completed in order to meet customer demand. The term originates from the German word “takt”, which literally means “pulse” or “beat”.
Briefly explained, your takt time is your sell rate.
For example, if your company has a takt time of 2 days, you need to finish producing a product every 2 days because, on average, a customer is buying your product every 2 days.
You can calculate takt time by dividing the total available time for production by the required production units.
Often confused with cycle time, takt time is one of the most important metrics for maintaining a continuous flow. It allows you to utilize your capacity in the best possible way to meet customer demand.
What Is Heijunka?
To help you optimize your workflow continuously for takt time, Lean offers a production leveling solution called Heijunka.
As demand is rarely steady, you need to adapt your process to any fluctuations. Heijunka is a method for reducing the unevenness (Mura) of your process and preventing overburden (Muri). It means “leveling” and is critical for maintaining a stable Lean system.
Heijunka allows you to produce intermediate goods at a steady rate so that you can satisfy fluctuations according to your average customer demand. For that purpose, the method has two ways of leveling production:
- Leveling by volume
- Leveling by type
Leveling by volume
In its pure form, Lean teaches us to pull work only when there is a demand for it, or in other words, when it is requested by customers. However, in some industries, processing work this way is not practical when there is a constant stream of new orders. Irrelevant of your industry, it is highly unlikely to receive an equal amount of orders each day or even week or month.
To achieve a continuous flow of work, Heijunka provides you with the opportunity to level your production volume depending on the average demand.
So if you receive 10 orders per week on average but their number is fluctuating by the day (e.g., Monday 5; Tuesday 1; Wednesday 2, etc.), you need to adjust your capacity to meet the average demand. In a continuous flow, this would mean producing 2 products per day (in case of a 5-day work week) to meet demand.
Leveling by type
Things can be quite tricky when you are producing a portfolio of products and distributing capacity according to demand. Facing this issue, Toyota found a way to ensure a steady workflow that meets customers’ demands by implementing a Heijunka box.
Basically, it is a system that visualizes the demand for each product, and according to the average demand, it levels a production sequence for achieving an optimal flow.
What Is Jidoka?
Meeting demand is important, delivering a product with an unquestionable value is even more so. This is where Jidoka comes in. It is a method for ensuring the built-in quality of a product. Also known as “autonomation”, Jidoka allows you to stop the production process as soon as you see an imperfection.
It has 4 distinctive steps:
- Discover an abnormality
- Stop the production process
- Fix the immediate problem
- Investigate and correct root cause
Although it may temporarily disturb your process's continuous flow, implementing Jidoka will help you ensure that the product you are delivering meets the quality expectations of your customers.
Continuous flow is an important part of Lean management and Lean product development in particular. By optimizing your work process to deliver the right value to your customers at the right time, you will be more likely to ensure their loyalty and grow your business.