Seven Categories of Wastes in Unproductive Manufacturing Practices

The seven wastes are categories of unproductive manufacturing practices identified by Taiichi Ohno, the father of the Toyota Production System (TPS). The categories are an integral part of the TPS (known as lean production in North America).

Following are the seven wastes, as categorized by Taiichi Ohno:

• Overproduction -- Manufacture of products in advance or in excess of demand wastes money, time and space.
• Waiting -- Processes are ineffective and time is wasted when one process waits to begin while another finishes. Instead, the flow of operations should be smooth and continuous. According to some estimates, as much as 99 percent of a product's time in manufacture is actually spent waiting.
• Transportation -- Moving a product between manufacturing processes adds no value, is expensive and can cause damage or product deterioration.
• Inappropriate processing -- Overly elaborate and expensive equipment is wasteful if simpler machinery would work as well.
• Excessive inventory -- Storing and maintaining more products and components than necessary wastes resources.
• Unnecessary motion -- Resources are wasted when workers have to bend, reach or walk distances to do their jobs. Workplace ergonomics assessment should be conducted to design a more efficient environment.
• Defects -- Inspecting and quarantining inventory takes time and costs money.