Waste comes in three main forms:
-
Mura or waste due to variation
-
Muri or waste due to overburdening or stressing the people, equipment or system.
-
Muda also known as the “seven forms of waste”.
The following are the wastes most commonly associated with Lean.
-
Transportation: Is there unnecessary (non-value added) movement of parts, materials, or information between processes?
-
Waiting: Are people or parts, systems or facilities idle - waiting for a work cycle to be completed?
-
Overproduction: Are you producing sooner, faster or in greater quantities than the customer is demanding?
-
Defects: Does the process result in anything that the customer would deem unacceptable?
-
Inventory: Do you have any raw materials, work-in-progress (WIP) or finished goods that are not having value added to them?
-
Movement: How much do you move materials, people, equipment and goods within a processing step?
-
Extra Processing: How much extra work is performed beyond the standard required by the customer?
Sometimes you will also hear “the disengagement of people" identified as a form of muda.
Muda comes in two flavors called Type-1 muda and Type-2 muda. What’s the difference? In both cases it fails to meet all three criteria for value-added as defined by your customer.
-
Type I muda — Non-value added, but necessary for the system to function. Minimize this until you can eliminate it.
-
Type II muda — Non-value added and unnecessary. Eliminate this first!
