The Seven Forms of Waste

The Seven Forms of Waste

In this lesson, you’re expected to learn about the different types of waste in lean management.

Arguably, the most significant component of the Lean philosophy is its focus on the elimination of waste.
Enlarged version:
[Optional] The Seven Types of Waste (Muda)
Read this article to learn more:
1) Over-Production

Over-production is producing sooner, faster, or in greater quantities than customer’s want.

• According to Toyota, producing more than is immediately needed by the next process is the greatest source of waste.
• Over-production can prevent other essential activities from taking place.
• Over-produced items end up as inventory or scrap, therefore creating more waste.
• Example: buying vegetables for one month on a weekly shopping trip.

Improvement action: produce only what customers want, when they want it.
2) Waiting

This form of waste involves people or machines in a queue while another cycle is being completed.

• The amount of waiting time of items, disguised by operators who are kept busy producing WIP that is not needed at the time is not an obvious form of waiting waste.
• Waiting can often be avoided, as most machines do not need supervision.
• Essential waiting time can be filled productively (e.g. sub-assembly, quality checks, material handling etc.)

Example: arriving an hour early for a meeting.

Improvement action: rebalance activities to remove waiting, then make essential waiting visible.

3) Transport

Transport waste is the unnecessary movement of parts or people between processes.

• Moving items around the operation, together with the double and triple handling of WIP, does not add value.
• It often results from a poor system design and/or layout.
• It can create handling damage and cause delays.
• Layout changes which bring processes closer together, improvements in transport methods, and workplace organization can all reduce waste.

Example: building a dining room and kitchen at opposite ends of a house.

Improvement action:
 minimize the transportation steps by gathering the work content using continuous flow processing.
4) Process

Over-processing is processing beyond the standard required by the customer

• The process itself may be a source of waste. Some operations may exist only because of poor component design or poor maintenance and so could be eliminated.
• It may result from internal standards that do not reflect true customer requirements.
• It may be an undesirable effect of an operators’ pride in their work.
• It often arises when standards are difficult to define (e.g. polishing, finishing, and painting).

Example: stirring an already fully mixed cup of coffee.

Improvement action:
 provide clear, customer-driven standards for every process.
5) Inventory

Inventory waste is raw material, work-in-progress or finished goods that does not add value to the final customer. 

• All inventory should become a target for elimination. However, it is only by tackling the causes of inventory that it can be reduced.
• It is often a symptom of other problems in the system that are hidden behind rising stock levels.
• It increases operational costs and manufacturing lead-time.

Example: clothes taken on vacation, not worn, and then brought back at the end of the vacation.

Improvement action:
 improve planning and commit to reduce unnecessary ’comfort stocks’.
6) Defects

Rework is the repetition or correction of a defective process.

• Rework is the consequence of failing at meeting the ‘do it right the first time’ expectation.
• It can be caused by inadequate methods, materials, machines, or manpower.
• It requires additional resources so that normal processes are not disrupted.

Example: returning a plate to the sink after it has been poorly washed.

Improvement action:
 improve process capability by analyzing and resolving the root causes of rework.
7) Motion

Motion waste is the unnecessary movement of people or machines within a process.

• An operator may look busy but sometimes no value is being added by the work.
• Simplification of work is a rich source of reduction in the waste of motion.
• Manual and machine work cycles both often comprise unnecessary motion elements.
• Unnecessary motion can also be caused by a layout not being optimized for varying customer demands.

Example: locating the refrigerator outside of the kitchen.

Improvement action: 
arrange tooling, equipment, and parts around workstations and use standardized procedures to minimize motion.
[Optional] What are the different types of waste in Lean?
Watch this 2-minute video by Orbus to learn more:
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