The 5 Principles of Lean and How to Apply Them

What is Lean manufacturing?

Lean manufacturing is a methodology that focuses on continuous improvement to eliminate sources of waste in a production process. This leads the process to become efficient and drive maximum value for the customer. 

Most individuals who work in a manufacturing environment are very familiar with Lean principles, but those who do not may be completely unaware of this powerful concept. Whether or not you are already familiar with Lean, it can be extremely valuable to understand how to apply the principles of Lean manufacturing, not only to your work, but also throughout your daily life.

Throughout this article, I will explain the five principles of Lean manufacturing, highlight key Lean tools that you can use to apply these principles, and provide examples of each principle in both the manufacturing environment and daily life. With this information, you will have the foundation needed to complete any task more efficiently in order to save time, organize your space, build better habits, and achieve your goals.

What is the history of Lean manufacturing?

The Lean manufacturing method has evolved from the Toyota Production System (TPS) that began development in the 1940s. The TPS was based on two key pillars: “Just-in-Time” production and jidoka.

“Just-in-Time” production relies on producing material for the customer on an as-needed basis. This eliminates waste from excess inventory and drives process efficiency. Some restaurants are good examples of this process in everyday life; they prepare each meal after a customer places an order which saves time and food waste from producing extra meals in advance.

The other pillar of the TPS is jidoka. Jidoka is a Japanese word that roughly translates to “automation with a human touch”. This means that a process should be stopped immediately when a defect is detected. A team should then investigate and resolve the root cause of the defect. This process is iterated whenever a defect is discovered to drive continuous improvement. Jidoka therefore reinforces the development of human skills to drive efficient technological advancement. 

After the TPS became widely popular, John Krafcik created the term “Lean” in 1988 in his article titled, “Triumph of the Lean Production System”. Then, James P. Womak, Daniel T. Jones, and Daniel Roos created the five principles of Lean as we know them today in their 1991 book titled, “The Machine that Changed the World”. 

Now, you’re probably wondering…

What are the five principles of Lean?

1. Define Value

What does defining value mean?

These are similar criteria to what we may consider when we are, for example, looking to buy a new car. In this case, we are also concerned about whether the car is in our budget, how quickly we will receive the car, and whether the car has the functionality and specifications that we need, such as number of seats, automatic versus manual transmission, etc.

You can also use this concept of defining value in order to successfully achieve any goal you may have. For example, if you have the goal of running a marathon, you will have a better chance in succeeding at this goal if you determine what will bring value to the process. In the case of personal goals, you are the customer and should spend time researching what methods or tools will provide the best and most efficient results. If you plan to run a marathon, this would include things such as weekly mileage, running pace, nutrition, hydration, running gear, and proper sleep. For example, you may find that running a long run each weekend provides more value towards your end goal than strength training. This may be the opposite if someone were looking to build muscle.

2. Map the Value Stream

What is value stream mapping?

Once the customer’s requirements are clear, the producing company should focus on maximizing value for the customer while minimizing waste. This will allow them to create the most efficient process. One method that can be used to identify potential sources of waste in a process is value stream mapping.

Value stream mapping is a process where the company identifies each step that currently occurs to create a product for the customer. A cross-functional team should complete this analysis to ensure that it captures all details and perspectives. This allows everyone to have a very clear understanding of the current flow of the process. 

Based on this, each step can be designated as either value add or non-value add for the customer. The non-value add steps can then be further broken down into necessary and unnecessary steps. All non-value add steps are considered a waste. Therefore, the company should put actions in place to reduce the necessary non-value add steps and eliminate the unnecessary non-value add steps. 

Applications of value stream mapping

A simple example of a value stream map in a manufacturing environment is given below. This map identifies the flow of material and information throughout a fabric production process so that delays or bottlenecks can be identified. Some of these delays are identified in red. This includes long changeover times, waiting periods, or excessive transportation time from one step to the next.

We can also use value stream maps in our everyday lives. For example, you can see a value stream map for baking cookies for a party below. In this case, the largest bottlenecks are the time required to mix the dough by hand and the time it takes to roll the dough into balls for baking. Once you’re able to identify these bottlenecks in the value stream map, you can look into ways to improve them. This could look like buying a stand mixer to speed up the mixing process or recruiting a friend to help roll the dough into balls.

3. Develop Flow

What is flow?

Now that the value stream map is complete, the company can use this tool to develop a better flow for the process. A process with good flow is efficient and contains no delays or bottlenecks.

One way flow can be improved is by eliminating the non-value add steps that the team identified in the value stream map. This may look like moving workcells and equipment to a more optimal position to minimize the movement of material or people. Therefore, developing flow leads to massive reductions in many waste categories, commonly known in Lean as the 8 wastes. These 8 wastes fittingly follow the acronym DOWNTIME:

In some form, improving the flow of a process helps to reduce all 8 of these waste categories.

One Lean tool that can assist with this is the 5S process. The 5S process promotes organization in a workcell to drive productivity. For example, a team should remove all unnecessary tools from the area and place the remaining tools in the most optimal positions to drive efficiency. 5S also requires the development of methods to sustain this organization through audits and behavioral changes. 

By making a process more efficient, the cycle time to produce a product decreases. This will then drive the business cost down and help customers receive products faster.

Applications of flow

One example of developing flow in a manufacturing environment is by moving the storage location for materials or moving process equipment so that everything required for a particular process is as close to each other as possible. This helps limit transportation waste related to moving materials throughout the facility.

An example of developing flow in daily life is organizing your kitchen so that each tool is located near where you typically use it. For instance, you may put pans in the cabinet closest to the stove or cups in the cabinet closest to the refrigerator. This eliminates extra motion while preparing food or drinks which helps reduce the time required for the task.

4. Introduce a Pull System

What is a pull system?

After developing flow in a process, it becomes easier to introduce a pull system. A pull system relies on a trigger, such as a customer order, before the production process begins. Therefore, this process mirrors TPS’s “Just-In-Time” production process as discussed earlier in this article. 

This process limits the inventory of work in progress (WIP) and other materials. As one of the 8 wastes of Lean, inventory is extremely expensive for a company due to storage costs, the cost of the inventory itself, and the opportunity cost of the money used to purchase the raw materials. Therefore, pull systems help drive better communication within an organization and reduce waste as compared to push systems where material is produced “Just-in-Case” a customer orders it.

Applications of a pull system

Pull systems in manufacturing are seen when a production process only begins after a customer places an order. For example, Toyota has mastered this process as a result of the Toyota Production System. By carefully monitoring their demand, raw material usage, and equipment usage, they are able to accurately schedule new raw material shipments and act upon triggers to fulfill customer orders “just in time.” This helps reduce inventory, and therefore, overall process cost.

We can also apply a pull system in our everyday lives when purchasing routine items. For example, if you routinely purchase milk, you likely are prompted to buy another carton only when you are close to running out. If you instead purchased three cartons of milk all at once “just in case” you need it, you will probably find yourself wasting a lot of money on spoiled milk.

5. Practice Continuous Improvement

What is continuous improvement?

The final and most valuable principle of Lean is continuous improvement, also known as Kaizen. Once a company has evaluated and applied the first four principles of Lean, it is imperative that they sustain these procedures and further improve them as more information arises. 

Lean will always be an iterative process in the pursuit of perfection. Every person in a company must consistently look for areas for improvement every day. Therefore, in order to drive continuous improvement, it is extremely important that companies develop Lean as a culture for the entire organization rather than one or a few departments. For example, if the company does not include representation from every group while creating a value stream map, there will be details of the process missing that will make it impossible to achieve ideal flow. 

One way that teams can organize projects to drive a continuous improvement mindset is through using the PDCA cycle. PDCA stands for Plan, Do, Check, Act and is an iterative process that follows the steps below: 

Even if a solution is successful, it is important that the team uses their findings to continually refine the process or similar processes. This is where the iterative part of the PDCA comes in.

Applications of continuous improvement

An example of practicing continuous improvement in a manufacturing environment is completing a daily stand up meeting where a cross-functional team gets together briefly to discuss open action items for improvements.

An example of practicing continuous improvement in daily life can be through journaling every night. This can help you track your progress towards your goals and define actions you can take to improve. For instance, you may have a goal of exercising 5 days a week for at least 30 minutes. If you find through daily journaling or habit tracking that you are struggling to meet this goal, you can implement actions to help you succeed. This may be something as simple as setting your exercise clothes out the night before you plan to work out or changing the timing of your workouts. 

How do you maintain a Lean mindset?

Now that you know the five principles of Lean manufacturing and some tools that you can use to apply them, you may be thinking: “This all sounds great in theory, but how do I maintain this in my daily life?” You are definitely not alone in this thought. Most company’s largest issue when it comes to implementing Lean principles is maintaining these ideas for the long-term.

Implement audits

As an example, we can analyze the 5S process that I discussed earlier. Recall that this process involves organizing an area so that only the necessary tools are present and located in the optimal position for efficiency. If you have ever struggled to keep your bedroom organized for more than a day, you can probably imagine that 5S is generally simple to do but difficult to maintain. In order to keep employees from slowly reverting the area back to the previous disorganized state, it is vital to develop audit systems with specific people responsible for ensuring the area is left in its organized state at the end of each day. 

You can adopt a similar system in your daily life by auditing your day-to-day habits. For example, if you are trying to achieve a new goal such as learning a musical instrument, you can create a practice schedule that you plan to follow and then audit this process. This may look like recording reasons why you missed a practice session or listing what time of day you practiced so that you can refine your process.

Set clear goals and remain consistent

Ultimately, a cultural mindset change on all levels of an organization is required to successfully implement Lean. If one department or person is not consistently acting in a manner that supports the principles of Lean, the system will fail. To avoid this, a company must set clear goals and a clear path to achieve them and must share this information with the entire organization.

The same is true if you want to implement the concepts of Lean to become more organized and efficient in your daily life. Without clear goals and a consistent mindset towards continuous improvement, Lean will always fail. On the other hand, if you are able to implement these concepts consistently, you will see tremendous benefits for your overall productivity and organization in any area of life.

Can you think of any situations where you have applied, or could apply, Lean principles in your daily life? Please leave your ideas in the comments below!