What is Lean Manufacturing?:Extended Entry

Lean manufacturing is often referred to as lean production or just "lean". It was developed in the early 1900's as a method to reduce waste while producing goods. Taiichi Ohno and Eiji Toyoda are given credit for developing the Toyota Production System (TPS) which is known as lean manufacturing. The TPS system was developed between 1948 and 1975. Ironically the idea for lean manufacturing came to Toyoda when he was in a supermarket. He observed the simple idea of creating an automatic drink re-supplier, when a customer wants a drink he takes it and it is replaced with another.

Toyota defines waste as being three-form, muri (overburden), mura (inconsistency), and muda (eliminate waste). Muri or overburden is considered to be all the unreasonable work that management assigns upon workers and machines due to poor organization. Some examples of muri are carrying heavy weights, dangerous tasks (behavior-based safety issues), and working at a significantly faster than normal pace. Muri defines this work as pushing a person or machine to a pace beyond their normal limits. Muri is associated with the preparation or planning phase of the production process.

Mura or inconsistency focuses on the implementation and elimination of fluctuation of scheduling. This usually falls to the operations level to schedule the quality and volume of the production process. Finally, muda or waste elimination is dealt with after the process is completed. Management oversees muda and should consider how to eliminate the deeper causes of muda formed in muri and mura. Once the causes are determined, management will then use them in the next project and slowly begin eliminating all waste together.

Muda has 7 different kinds of variables that will help to eliminate or reduce the production of waste.
1. Over-production
2. Waiting
3. Transporting
4. Inappropriate Processing
5. Unnecessary Inventory
6. Unnecessary/Excess Motion
7. Defects

Over-production.
Many companies manufacture an item before it is needed. This is considered a waste because it costs the company money and decreases the quality and productivity of the manufacturing process. Overproduction results in higher costs for storage, excessive lead times, and it makes detecting the defects quite difficult. The solution for overproduction is to stop producing materials and only produce what can be immediately sold or shipped.

Waiting.
Waiting refers to the waste of goods that are not moving. As you already may be aware, much of a product's life is spent waiting for the next phase. The reason this is considered a waste is because the good should never be waiting. If they are waiting it is due to poor material flow, long production runs, or travel distances.

Transporting.
Moving your product from one location adds no value to your product. Many products are damaged or lost, casing a waste of money. Transporting also requires the use of material handlers, and this also adds no value to the product. This is one waste that is difficult to reduce or eliminate. Mapping the flow of your product may be one way you can gain a greater understanding of the transportation phase and learn how to reduce the costs.

Inappropriate Processing.
Several companies purchase high precision equipment to do a simple job. High precision equipment often leads to over-production of goods.

Unnecessary Inventory.
Excessive inventory is a direct result of overproduction and waiting. Having excessive inventory will lead to increased lead times, limited floor space, and poor communication. Too much inventory often masks problems from other areas as well.

Unnecessary / Excess Motion.
This phase is often related to behavior-based safety. It is the unnecessary bending, stretching, walking, lifting and reaching of an employee. Often the motion is not due to the employees behavior, but the machine they are operating may be manufactured poorly and the employee is unable to turn a knob (or something similar) without using poor ergonomics. This waste leads to health and safety issues, which obviously lead to bigger problems.

Defects.
Defects in the manufacturing process are a tremendous cost to a company. Any small defect directly impacts your bottom line and effects inventory, scheduling, inspection, and other factors. A minor defect can cost your company more than the entire manufacturing cost to begin with.

As technology has grown, so has the "seven wastes". Employees have now been added as an eighth waste. Many companies do not employ their staff for their creative skills, only for their muscles and nimble fingers. Several organizations have learned that by capitalizing on their employees creative skills, they can eliminate some of the other wastes all together.

By evaluating the seven wastes, you can determine where your company is lacking and where you can reduce or eliminate waste altogether. Toyota implemented their TPS program and reduced costs and leadtime and improved the quality of their products. Now, Toyota is one of the world's largest companies. In fact, Toyota is as profitable as all the other car companies combined and in 2007 they because the largest car manufacturer! This is quite an accomplishment for a company who was once just a small auto manufacturer. This is why several other companies have adopted lean manufacturing. Successful implementation of lean manufacturing is the key to your company's success at reducing waste.

Besides the 7 waste approach of Toyota, there is another approach to lean manufacturing. Many companies have developed "tools" to assist in the identification and the elimination of waste. These tools are often called value stream mapping, 5-S, Kan-ban and poka-yoke. The goal of both approaches is to reduce waste, the only difference is how you go about achieving the goal. Again, it all boils down to successful implementation.

Successful implementation will expose the quality problems which exist within the company and you will identify how to reduce the waste the problems are causing. For some companies, the focus on waste reduction only looks at one small problem at a time instead of a system-wide approach. Depending upon which type of managers you have, both approaches can be successful and both will reduce or eliminate waste.

The main principles involved in both approaches include: "pull processing, autonomation, perfect first-time quality, waste minimization, load leveling, continuous improvement, flexibility, building and maintaining a long-term relationship with suppliers, visual control, and production flow. The principles are the same, but Toyota's approach is considered to be a "need" driven focus, not something that is based on theoretical framework.

Originally lean manufacturing was called "just in time". This changed to the term lean manufacturing and it is now called TPS. Many credit Toyota for having a human touch to their automation process. They are given this credit because their production machines have enough intelligence to recognize when they are working abnormally and they have a system that flags themselves for needing human attention. This means that humans only have to focus on the abnormal, fault, or conditions versus the normal production. It removes the day-to-day routine element that causes disinterest in many humans, therefore causing defects to occur.

In the end, lean manufacturing is "focused on getting the right things, to the right place, at the right time, and in the right quantity to achieve perfect work flow while minimizing waste and being flexible and able to change." The concepts of lean manufacturing need to be understood, embraces, and appreciated by the employees who build the products. If the employees do the concepts, they will pass them onto the entire process and deliver the value to the product. Management is again the biggest factor in lean manufacturing.

Weak management will not understand how to implement the tools of lean manufacturing and it will not benefit anyone. Lean manufacturing is simple to understand and easy to do. It is all about making the work simple, easy to manage, and understandable for the employees.

Several companies have adopted the Toyota mentoring process called Senpai and Kohai. Senpai and Kohai are essential elements of Japanese age-based status relationships. They are similar to a family relationship, which is decided upon age. In western culture, Senpai and Kohai can be compared to the concept of a mentor. This mentoring approach works like this: an older sibling begins a company and mentors their younger sibling; the younger sibling will eventually have enough insight to become the mentor to the older sibling. It is a process of "thinking up and down" the organizational structure. Employee A effects the steps of Employee B who effect Employee C and so on. This process has been taken by Toyota and it has helped their suppliers to improve their production as well.

There is another mentoring approach which is similar to Senpai and Kohai, it is called "Lean Sensei". Lean Sensei encourages your company to seek out outside, third-party experts who will provide coaching, advice, and unbiased opinions to your company.

Of course you do not need to implement a mentoring approach to make lean manufacturing successful, it is just an added tool to increase your company's potential to reduce waste and improve performance.