What is Muda?

The word “muda” is Japanese for waste. The word is commonly used within corporations all over the world that are in the midst of lean manufacturing excellence.

There are many Japanese words in use today at companies throughout the world implementing lean manufacturing. Kaizen (meaning small, incremental improvement) is the most popular, followed by the word muda.

Lean manufacturing originated in Japan, and a few of the concepts have kept their Japanese word associated with the meaning of the concept. The word “muda” became popular because it has additional meaning than just the word “waste” which has been used in manufacturing industries.

Traditional manufacturing companies thought of “waste” as material waste. Material waste reduction is often one of the largest opportunities for manufacturers. However, muda has the meaning of any type of waste throughout the entire system. Lean manufacturing principles generally identify 7 or 8 different types of waste.

The seven most commonly identified wastes lean manufacturing are:

Material (scrap & reword)
Inventory
Transportation
Motion
Waiting
Overprocessing
Overproduction

The eighth waste is the waste of intelligence. This is wasting the intellectual capital in the organization. It is the waste of not involving everyone in the improvement efforts.

The goal of a lean manufacturing implementation is to eliminate every bit of the above eight wastes from the system. The eight wastes are described below, including how they integrate into the overall lean manufacturing implementation.

Overproduction waste is the product made that may not be sold. Even if it is eventually sold, the warehouse space and time value of money is wasted until it is sold. An example would be a quantity produced of 1050 when the customer will only take 1000. The overproduction is either scrapped or stored (both wastes) for later use.

Inventory is often one of the largest wastes in a company. Inventory occupies valuable floor space and ties up cash, which often costs a corporation 8% - 12% per year. The cost of obsolescence is also large in many companies. Products become obsolete or the customer decides not to take the product. Even with a purchase order, forcing customers to take product they don’t need or want is often detrimental to the business relationship. Some inventory becomes damaged as a result of being moved or stored over time. One of the largest “hidden costs” of inventory is the cost of moving and counting it. Inventory is often moved from production, staging, warehouse, shipping, and trucking, all of which is expensive. The lean manufacturing system either eliminates or minimizes the inventory through the use of tools such as “pull systems”, “continuous flow”, “takt time”, and “value stream mapping”.

Another identified waste is the “waste of waiting”. The waste of time spent waiting is very large in almost every business. Workers wait on product, instructions, supervisors, engineers, inspection, and each other. Supervisors wait on workers and co-workers, engineers, maintenance, etc. Lean manufacturing systems eliminate this waiting through many tools including value stream mapping, process maps, line balancing, Ishikawa diagrams, and many others.

Motion waste is also very large in most businesses. For example, a lot of time is lost when professionals walk to a printer many times per day. Machinery operators and maintenance technicians traditionally incur large amounts of wasted motion. Operators walk to retrieve tools that should be positioned closes to their point of use. Mechanics often wear a path to the maintenance shop for gathering tools. The waste of motion is often largest in office and white collar settings, as these activities have often been untouched by improvement initiatives over the years. Lean manufacturing tools reduce motion waste through the systems of “5S”, value stream mapping, SMED setup reduction, kanban, standardized operations, and root cause problem solving methods.

Over-processing waste is providing more product or features than necessary. For example, if a customer wants a product made a certain minimum thickness but the manufacturing process adds material to produce a larger one, the additional amount is waste.

All of the seven wastes comprise what is known as “muda” in lean manufacturing. Muda reduction takes management commitment and employee involvement. Muda often occurs in small chunks throughout an organization and over time. It takes the effort of every employee to find and eliminate muda.

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