There are several key lean manufacturing principles that need to be understood in order to implement lean. Failure to understand and apply these principles will most likely result in failure or a lack of committment from everyone in your organization. Without committment the process becomes ineffective. 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

One of the most critical principles of lean manufacturing is the elimination of waste (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

Although the above mentioned types of waste were originally geared toward manufactuing, they can be applied to many different types of business. The idea of waste elimination is to review all areas in your organization, determine where the non-value added work is and reduce or eliminate it.

Continuous Improvement

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 Improvment promotes constant, necessary change toward achievment of a desired state. The changes can be big or small but must lend itself toward improvement (often many small changes are required to achieve the target). The process truly is continual as there is always room for improvement.

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 Humanity

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 these people the business does not succeed. 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.

Most people want to perform well in their jobs. Not only do they go to work to earn a living, but they also want to develop a sense of worth in their work. 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 humanityphilosophy will appreciate their workers efforts and keep them in high regard.

Some of the methods to ensure your people know you respect them is through constant communication, praise of a job well done, listening to their ideas and helping out when necessary.

Levelized Production

As mentioned on the home page, the foundation of lean manufacturing is levelized production. The basis of this principle is that the work load 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 productiontakes into consideration both forecast and history. The key ingredient for this lean manufacturing principle is utilization of a pull system.

Just In Time Production

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 conjuction 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.

Quality Built In

The last key lean manufacturing principle that I would like to touch on is Quality Built In. 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 a major consideration.

Automation with a human touch falls within this principle. Machines that can detect defects and stop production are an excellent example of this principle. Part profile mistake-proofing, which prevents an operator from mis-orienting parts, is another excellent example. In Lean Manufacturing (or any other system), the focus must be on doing it right the first time.

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 on the left to navigate through more lean definitions, tools and concepts that will help you understand and implement lean.

This link, Kanban Just-In-Time at Toyota: Management Begins at the Workplacewill also help increase your knowledge of lean manufacturing principles. It is a good book for someone looking to understand the basic concepts of the Toyota Production System (the basis for lean manufacturing). It doesn’t go into much detail about how to implement, but it does a good job of explaining the fundamentals in an easy to understand way (in true Japanese style using analogies).