Lean Manufacturing

The Lean Manufacturing System was designed to produce high-quality products at the lowest possible cost. Today it is considered an improvement on traditional mass production systems. Lean manufacturing was first used by the Japanese automobile manufacturer Toyota. It has spread throughout the world to industries that produce a wide variety of products.

The lean manufacturing system is different from other systems in that it is built around people, not machines. It seems that over the years, manufacturers had forgotten that workers had a brain. Mechanization had gone too far. Workers had been pushed to the point where they were beginning to rebel.

For the United States that all began to change in the 1980s when factories began to adopt the lean manufacturing system. Workers were no longer asked to park their brains outside the factory. They began to perform a variety of jobs. Every worker essentially became a quality inspector. As a result, production and quality improved, and their jobs became more fulfilling.

These are the important elements of lean manufacturing systems include:

Continuous improvement
Just-in-time inventory management
Teamwork
The use of work cells

Continuous Improvement or Kaizen. Continuous improvement is based on the idea that details are important and that it is always possible to make a good system even better. The Japanese call this way of thinking Kaizen (kie´-zăn).

When problems occur, they are viewed as opportunities for improvement. Unlike the old assembly lines, employees working in a lean manufacturing plant are encouraged to identify small problems and share their ideas about possible solutions. Employees are encouraged to stop the assembly line until a problem is identified, diagnosed, and solved. This was unheard of in the old assembly lines. Using the principles of kaizen, the workers' goal is to continuously make small improvements in the way they do their work every day.

In factories utilizing the Lean Manufacturing System, employees are valued for their skill, knowledge, and problem solving abilities.

Just-in-Time Inventory. Keeping large quantities of parts on hand is expensive. Sometimes a large amount of storage space is required and unneeded parts may be wasted. In a just-in-time system, only the correct amount of parts needed is kept on hand. For small parts it can be done by having two bins of each part in the assembly area. When one bin is emptied, parts from the second bin are used and another bin is ordered.

Manufacturers want parts delivered just when they need them for production (JIT). This saves them the expense of maintaining a large inventory for long periods of time. Inventory is the term for materials held in stock.

Other times, when parts are delivered in large amounts, they must arrive exactly when they are needed for production. They must not arrive too early because they will have to be stored, which is expensive. They must not arrive too late or it will stop the production. They must arrive just in time.

Teamwork. Teamwork is also an important component of lean manufacturing. Factories now want people who can think and learn. Again, this was not the case on old assembly lines.

However, they are not hired just for their brains. They are also hired because they will fit with a team. In Lean Manufacturing it is critical for workers to be able to rely upon each other.

While each person may have his or her own task, in lean manufacturing that task will have more of an affect on the tasks of other people.

Work Cells. The importance of being able to work as part of a team carries over to the work cells that are often used in lean manufacturing. The ability and desire to work cooperatively with others is important because work cells usually involve groups of people working together in small areas. The cell contains all of the equipment needed to make the products. Parts are delivered just in time.

In work cells, communication is easy since everyone is nearby. In many industries, the use of work cells has helped to bring about significant increases in quality.