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7 main source of losses

KZK Solutions /kzoli62/
Published by Z. Kovács in Lean · 3 August 2021
Tags: QSLean
In this article, let's get acquainted with the 7 loss factors mentioned by Lean Manufacturing.

One of Lean Manufacturing's most important goals is to remove these loss factors from our processes.

But what exactly is the loss of Lean Manufacturing Week
(7 Mudas)?

How could the loss report be described?

The easiest way to describe a loss is "Something that has no added value." The buyer is reluctant to pay for any activity he did not ask for, which he did not want to receive, which was not necessary.

There are 7 types of Loss

Let's look at the list of losses:

1. Definition of loss

"All activities that contribute to the cost but do not produce value."

Taiichi Ohno,
Toyota's production
founder of the system.

2. Seven types of loss

1. Waiting time
2. Overproduction
3. Delivery
4. Motion
5. Rework
6. Stock
7. Over-Processing

2.1. Waiting time

The wasted time that is generated when material, information, people, or equipment are not ready.


  • To return a forwarded file.
  • Customer Answers.
  • Machine repair
  • Information, documents.
  • Material or parts.

How often do we spend the time waiting for another class, organization, supplier or engineer to respond? During this time, the machine will not produce any value. We tend to perform activities during this time that we also do not need, but we still do something.

This is probably one of the major losses during Lean Manufacturing.

2.2. Overproduction

Produce more products or information that the customer is currently requesting.

Provide more information than the customer is currently requesting.


  • Extra production to avoid re-setting the machines or being set for "malfunctioning."
  • Produce reports that nobody reads.

The most serious of the 7 losses. Overproduction supplies too many or too early products. This is usually done to avoid long lead times, bad supplier relationships, and other reasons.

Over-production leads to a high-level inventory mask or many problems within the organization.

The goal is to do just what you need to do for the customer.

This philosophy is Just in Time (JIT), but not many companies work with this principle!

2.3. Transport

Delivery of PRODUCT or INFORMATION that does not produce value.


  • Collect a Bunch of Signatures.
  • Move material from one workstation to another.
  • Moving parts out of and out of the warehouse.

Transportation is the movement of materials from one place to another, a loss that gives zero value to the product. Why would this customer be useful or why would you want to pay for an operation that does not add value?

Transport costs can reach a very high proportion in the production of the product, so it is logical to minimize or eliminate them.

2.4. Movement



  • Searching for materials or files.
  • Searching for parts or tools.
  • Handling of papers.

Movement of people or machines that is not small cannot be easily accomplished. This is like raising heavy objects that could be avoided by modifying the design of the machine, thus reducing the stress effect on workers.

These wasteful movements must be avoided.

2.5. Rework / Defect product

It is something material that is missing or something important missing.


  • Lost Records
  • Missing information
  • Waste / Scrap
  • Defective product

The most obvious among the losses, though not always the easiest to recognize before they reach customers. The cost of errors that make a quality mistake is much more than we think. Every defective product requires duplication or replacement, wasting resources and materials, creating paperwork, leading to loss of customers.

The defective product should be prevented if possible, better than preventing them from recognizing them, for execution poka-yoke systems and automation can help.

2.6. Stock

More information, material, and finished products than the customer just need. Unfinished work.


  • Ongoing projects, modifications or corrective actions
  • Work in Progress (WIP)
  • Finished product
  • Raw material

Under inventory costs, we mean money, raw material tied to each piece of product, unfinished or finished product, which the manufacturer must bear until it is actually sold.

Stocks need to be stored, replaced, packing materials, these must be delivered, which is both a cost factor.

These processes increase the likelihood that the product is damaged during transport, possibly outdated.

2.7. Over processing

An endeavor or activity that does NOT produce value for the buyer.


  • Manufacture of newspapers and papers
  • Too narrow tolerances
  • Multiple cleaning

Overwork is where the techniques, equipment, too tight tolerances and processes we use are not the ones required by the customer.

All of these things cost us a lot of time and money.

One of the best examples of excessive processing in most companies is the "mega-machine", which can make an operation faster than anything else. These are usually very expensive monsters. Small, practical machines do not break the flow, do not cause any waiting time.

3 Final Thoughts

  • An activity that does not produce a value is like throwing money into the trash.
  • If we can not eliminate the waste, it must be minimized.
  • Use the "5 Why?" Tool. Five times ask "Why?" To see if the activity is worth doing.

According to my experience, I have added two more to 7 mudas so far, so we can talk about 9 mudas. In more detail, I may be talking later in another article.

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