There are several key lean manufacturing principles that need to be understood in order to implement lean. Failing to understand and apply the Lean principles correctly may result in a lack of commitment from everyone in the organization. Without commitment the process becomes ineffective. The commitment must be embraced by the top leaders and communicated to the entire company.  The full understanding and commitment to lean principles will foster a common approach and strategy throughout the organization.

This page reviews some of the more critical lean manufacturing principles and should help you get started. Consider these to be the “guiding principles” of lean manufacturing as there are others that have not been included.

Elimination of Waste – 7 waste

One of the most critical principles of lean manufacturing is the elimination of waste.  Waste is also known as muda in the Toyota Production System. Many of the other principles revolve around this concept. There are 7 basic types of waste in manufacturing:

Over Production

Waste of Unnecessary Motion

Waste of Inventory

Production of Defects

Waste of Waiting

Waste of Transportation

Waste of Overprocessing

The elimination of waste allows the company to focus on the core value-add activities for the customer. Every Lean Manufacturing principle is ultimately geared towards bringing more value to the end customer.

Originally, the lean waste were intended to be focused only on manufacturing processes.  The lean industry has now applied the lean approach in many different types of businesses and industries.  The idea of eliminating wasted activities in your organization is not limited by the type of processes.  All organizations have the opportunity to identify waste and eliminate it.

Continuous Improvement – Kaizen

Continuous Improvement (commonly referred to by the Japanese word kaizen) is arguably the most critical principle of lean manufacturing. It should truly form the basis of your lean implementation. Without continuous improvement your progress will cease. As the name implies, Continuous Improvement promotes constant, necessary change toward achievement of a desired state. Big and small improvements will be necessary to bring significant change to a process. (often many small changes are required to achieve the target). The process truly is continual as there is always room for improvement.

The Kaizen approach is often described as the PDCA problem solving cycle.  The constant trial and error process of the PDCA cycle allows for quick kaizen improvement and learning. Continuous Improvement should be a mind-set throughout your whole organization. Do not get caught up in only trying to find the big ideas. Small ideas will often times lead to big improvements.

Respect For People

The next lean manufacturing principle has to do with people. The most valuable resource to any company are the people who work for it. Without the people, businesses do not succeed.

Toyota describes their lean principle of Respect for people as one of their two pillars of the Toyota Way. The respect for people principle is made up of Respect and Teamwork.  This approach allows the company to leverage and utilize the collective problem solving capability of the employees to drive improvement.

When people do not feel respected, they tend to lose respect for the company. This can become a major problem when you are trying to implement lean.  Team members need to feel safe, secure, and challenged within their jobs.

Most people want to perform well in their jobs. The employees want to earn a decent living and have a sense of worth while working. They want to feel like they have contributed to the company goals, like their work and effort has meant something. A company supporting a respect for humanity philosophy will appreciate their workers efforts and keep them in high regard.

Levelized Production – Heijunka

One of the foundational lean principles of lean manufacturing is levelized production. The basis of this principle is that the workload is the same (or level) every day. Most manufacturing companies are at the mercy of their customers for orders. Before producing product, they wait to get orders. This leads to increased delivery lead time which may not satisfy customer requirements.

On the other end of the spectrum, some companies will produce based strictly on a forecast. This may result in excess product that is not required by the customer.  Levelized production, or Heijunka, takes into consideration both forecast and history. There are many different ways to implement the principle of Levelized Production (Heijunka), depending on the industry and company.

Focusing on a levelized production schedule will make it easier for a company to implement other Lean manufacturing principles.

Just In Time Production – JIT

The next key principle to mention is Just In Time (JIT) production. The basis behind this principle is to build what is required, when it is required and in the quantity required. Working in conjunction with levelized production, this principle works well with kanbans (a pull system). It allows for movement and production of parts only when required. This means components are not used in product that is not required and no time is wasted building unsaleable product.

The JIT lean principle along with Jidoka (Quality built in) are the two pillars of the Lean manufacturing house.  JIT uses continuous flow and takt time to connect production directly with the pace of the customer sales.

Quality Built In – Jidoka

Another key lean manufacturing principle is Quality Built In, or Jidoka. The idea behind this principle is that quality is built into the manufacturing process. Quality is built into the design of the part. Quality is built into the packaging. Throughout all areas of the product, from design to shipping, quality is built into the process.

Jidoka builds quality into the process through detection or prevention.  Each lean manufacturing process will be designed to highlight any abnormality so that the employee can stop the process.  Stopping the process so that the problem can be fixed is a key part of the Jidoka lean principle.

Automation with a human touch falls within this lean manufacturing principle. Machines that can detect defects and stop production are an excellent example of this principle. There are many examples of equipment that have the prevention or detection capability build directly into them.

In Lean Manufacturing (or any other system), the focus must be on doing it right the first time.

Lean Management System

The lean manufacturing industry continues to learn more about what is necessary to be successful with a lean system.  The lean management principle has become increasingly important as we learn the critical role of management in creating a lean culture.

Leadership must design and own the management system so that problems will be highlighted and communicated. A well designed lean management system will encourage employees to solve problems and improve the process.

More Principles

As mentioned at the beginning of this page, there are other lean manufacturing principles. We have made mention of those that we consider critical based on our experience. Use the browser above to navigate through more lean definitions, tools and concepts that will help you understand and implement lean.

This book, Kanban Just-In-Time at Toyota, will also help increase your knowledge of lean manufacturing principles. This is a good book for understanding the basic concepts of the Toyota Production System, the basis for lean manufacturing. The book does a good job of explaining the fundamental principles of Lean manufacturing.