Learn all about Muda (7 wastes of lean) with examples from manufacturing and service industry. It is very easy to remember all the 7 wastes by just remembering TIMWOOD. MUDA is a Japanese word, which means “Waste”. Muda are non value added (NVA) activities in the workplace.
NVAs add cost, effort and time but add no value to the product or service. Waste points to problems within the system and root cause needs to be found and eliminated.
Muda is a very important concept in Lean manufacturing concept and Kaizen. Understanding of Non Value Adds (NVA) is central to Lean and let’s quickly understand this before moving forward.

Value Added Activity

  • Any activity that changes the form, fit, or function of a product/transaction
  • or Something customers are willing to pay for

Non-Value-Added Activity

  • Any activity that absorbs resources but adds no value is a Waste
  • All other actions and unwanted features are by definition — WASTE

So, all activities which are not adding any value are NVAs in a process. This can be an unnecessary step, repetitive step or idle time in the process. Idle time here means that no activity is performed, and resources are kept idle. NVAs are common in all kind of processes. Though it is very difficult to remove 100% of the NVA where ever human intervention is there, but we can reduce it with automation and other techniques.

Now days we are experiencing huge amount of automation in services sector as well, till some time back it was limited to manufacturing only. With automation we try to automate repetitive activities or activities which are based on some logic flow. All this improves efficiency and makes the process leaner.

7 Types of Muda explained

We should aim to eliminate all unnecessary wastes but we also have some necessary wastes like transport, minimum inventory etc. These necessary wastes should be identified and minimized, targets should be set for upper limit and tracked.

There are 7 types of Muda or waste :

1. Overproduction : Producing more goods/parts that is actually required. This can happen because of rejects, capacity of machinery or the staff does not want a low inventory

Overproduction is characterized by:

  • Producing more than is needed by the next process or customer
  • Producing earlier than needed by the next process or customer
  • Producing faster than is needed by the next process or customer

Producing too early is as bad as producing too late. Parts need to be available at a certain location at a certain time according to the customer’s schedule. Having the product too early, too late or in quantities that are too much, will result in undesirable consequences.

Whenever we produce extra, we need to store it and it will increase our storage cost. At times, customer requirements or specification also change and if we had produced extra stuff then we may end up discarding all that. This will lead to huge losses.

In service industry also if we don’t do proper effort estimation then we may hire extra resources and train them for the job. This is an example of overproduction in service industry. This overproduction involves hiring and training costs as well as waiting cost. Waiting is another Muda, explained later in this post.

2. Inventory : Inventory can include finished goods to be shipped, semi finished products, raw material kept in waiting and some of the work in progress(WIP). Extra inventory costs money which does not add any value to the product, this extra cost can due to various factors like storage cost, working capital cost, damages etc. If the inventory is not used then it is a complete waste.

All inventory is equivalent to locking up precious working capital. As we store them, many a times inventory gets damaged due to various reasons including multiple or wrong handling by staff or natural reasons.

If inventory is not stored properly then it can create obstacles on the shop floor, with time it will gather dust and deteriorate. In case of change in customer requirement, inventory can become obsolete.

As explained earlier in a service industry, all trained staff adds up to inventory if not used. This is also known as bench strength.

3. Repairs/rejects/defects : It is expensive to have rejects or repair work. It cannot be used by the customer and additional cost is required to make them usable. The repair or rework of defective parts involve a second or multiple attempts at producing a good item.

This is the simplest one to understand for anyone new to Lean. This is basically a product or service not meeting the specifications as per the process design or customer laid out requirements. When we get into such a situation then a proper Root Cause Analysis (RCA) is required before we restart the production. This is required to ensure that the plant doesn’t produce any more rejects.

Any complaint or repeat complaint is a big cost for any company as it involves not only monetary loss but also loss of reputation known as hidden cost of poor quality (learn more about COPQ).

Having rejects on a continuous flow line defeats the purpose of continuous flow manufacturing. Line operators and maintenance will be used to correct problem, putting the Takt time off course.

4. Motion : Incorrect layouts in office or factories can result into unnecessary movements and delays. The physical activities of operators must be analyzed to reduce loss due to motion.

Any motion or movement during production consumes time, which adds up to overall cycle time. As cycle time increases, the cost of operations increases. An example of motion could be that the employee working on station 1 must move 10 feet to get another part and time wasted in doing this activity is Motion Muda. We can try to change the layout to reduce these 10 feet to may be 3 feet to eliminate the requirement of walking.

Operators should not have to walk excessively, lift heavy loads, bend awkwardly, reach too far, repeat motions. The efficient use of human body is critical to the well being of the operator.

He layout of the workplace should be designed to take advantage of proper ergonomics. Each workplace should be analyzed for ergonomics and motion requirements.

In the service industry, I have seen employees toggling between multiple screens to get the required information. This can be easily automated or put on a single screen. This not only saves lot of time but also increases accuracy levels.

5. Processing : This refers to modifying a work piece or piece of information. This also refers to unnecessary steps in the process or removing some unneeded attributes or feature.

Some examples of Processing Muda :

  • Adding an extra handling process due to lack of space
  • Performing an inspection step since all inspection is non value add
  • Repeating product changes that are unneeded
  • Maintaining extra copies of information

What I have found as the most common reason for over processing is either poor training of staff or poorly defined operating procedures. This is common to both manufacturing as well as service environment. Value Stream Mapping (VSM) is a very effective tool to remove unnecessary steps in a process.

6. Waiting : This happens when the operator is waiting due to machine issues, lack of parts or downtime. Waiting can also happen due to long lead times and set ups.

Some examples of Waiting Muda :

  • Idle time
  • Breakdowns in machinery
  • Long changeover times
  • Wrong scheduling of work
  • Batch flow of materials
  • Long and unnecessary meetings

One of the most common reasons for Waiting in Service industry is wrong forecasting of work and scheduling issues. Wrong forecasting results into extra deployment of resources and then people wait for work.

7. Transport : Transport of product is a waste. Some transport will be needed but the lesser the better. Moving a product adds no value and it cause damages as well.

All forms of transport are Muda. This describes the use of conveyors, forklifts, pallet movers and trucks. This can be caused by poor plant layout, use of batch processing, long lead times, large storage areas or scheduling problems.

How to Remember 7 wastes

People always find it difficult to remember the 7 types of Muda and here, I will introduce a very simple but effective way keeping this in your mind. I learnt this from one of my trainers and it is the abbreviation of all 7 Muda.

This is called TIMWOOD.

TIMWOOD : One simple way of remembering 7 wastes is to just keep in mind TIMWOOD.

T – Transport

I – Inventories

M – Motion

W – Waiting

O – Over production

O – Over Processing

D – Defects

Examples of Muda, Seven wastes

Motion :-Incorrect layouts office,factory etc.
Lack of proximity of Machines.
Offline resources

Waiting :-Machines/processors waiting forwork
Long lead times and set ups

Overproduction :-Large batches & Inventory
Planning for 100% utilization of machines and labor
Producing more goods then market demond

Processing :-Poor machine maintenance
Unnecessary Processing Steps
Longer Lead times

Repairs/Rejects :-Long delays for troubleshooting
Costly rework
Dissatisfied downstream customers

Inventory :-Stock of raw materials, WIP & Finished Goods
Additional space requirement

Transport :-Unnecessary movement
Extra handing
Moving Inventory

I hope you have understood the above concept and if you want to learn more such tools then go for a Six Sigma course from Simplilearn. The course is aligned to IASSC and ASQ exam, integrates lean and DMAIC methodologies using case studies and real-life examples.

There is another good online Six Sigma Green Belt course from Coursera. This course is from University System of Georgia and is well recognized.

If you want to learn new age data science techniques, then one good starting point is Data Science course from Simplilearn. Data Science is emerging very fast and early movers will always have advantage.


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