5S and 7 wastes according to Toyota

5S
and the seven types of wastes
according to
TOYOTA

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Toyota developed its production system, striving for Excellence, with a keen sensitivity to waste.
This quest for excellence gave birth to most of the "japanese" methods, among which the 5S approach.

The seven types of waste are:

1. Waste from overproduction
2. Waste from waiting times
3. Waste from transportation and handling
4. Waste related to useless and excess inventories
5. Waste in production process
6. Useless motions
7. Waste from scrap and defects

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For enterprises not yet in a state of excellence, wastes are opportunities of gain the 5S help to harvest.

Waste from overproduction

It may sound surprizing, but many companies are producing more than necessary because they loose parts, products, material! Without order, care and discipline in storage, inventories will fill all available space. Temporary storing a batch in a non defined / dedicated area is risky, as someone could move the batch without care nor notice In such a case, it is likely to loose its track, all ending in a waste of raw material, energy and man power.

It may lead to a double waste if the lost batch requires to produce a new one be delivered!

Eliminating the wasted space and valuable surface by excess inventories and overproduction is another potential improvement.

5S can be used to setup rules for storing, define space and places. These rules have to be widely communicated so that everyone knows where is what, why and for how long. While continuously improving the situation, the rules have to be updated and stick to the newest state.

Waste from waiting times

Waiting is a consequence of poor synchronization between process stages or bad preparation. Waiting for parts, material, tools, instructions, etc... can be caused by a lack of rules about storage places, when people have to search everywhere.

Are the item you are waiting for realy necessary ? If they're not, if they do not add value to the job or the product, it it wise to try to eliminate them or at least reduce the wait time and storage distances.

Computers with plenty and poorly ordered data on hard disk drives slow down.
Did you consider directories and files as candidates for 5S?

Searching for files or documents will cause waiting time. A simple trick will help: draw a colored slant line on the back of the files:

The place of any missing file is immediately visible
A file in wrong place displays a broken line

Better than numbering, which requires to read and "translate" the information, the color line is a part of visual management: fast and simple.

All search is reduced if the searcher knows where to search.

Waste from transportation and handling

The necessity to move and transport can be caused by the previously mentioned wastes. All transportations may not be eliminated, but they have to be kept to the very minimum.

Looking for a pallet truck to move crates or pallets is a common occupation in the workshops. People most often claim for more trucks, but a proper set of rules, parking areas and discipline to bring them back after use is enough to solve availability problems.

Waste related to useless and excess inventories

"Useless"! the name itself gives the solution.
In the 5S way, anything that is useless is to be eliminated. In case of inventories, the gain is the value of the goods stored and the regained spaces, which must be dedicated preferably to value creating activities.

Paper documents and their numerous copies, catalogues and calendars of previous years, files and data, dry and worn out pens and pencils... all excess inventories!

Waste in production process

Procedures and work guides which are not constantly updated are likely to let useless operations be performed in the process. Sorting and ordering applies also in the sequences of the process and the related documents.

This type of waste is also common in administration processes and office work. Old rules still remain even if the causes of their creation disapeared a while ago. As long as nobody will update the set of rules, everyone will carry on, sticking to the olds with application and discipline(!!).

Useless motions

Ergonomics of the work place is certainly the most popular and "visibles" application of the 5S. The layout and display of the area will follow the 5S logic, favoring availability of necessary items, distance of reach, ease for tending...

Among useless motions, do not forget the walks to search for missing items, data, instructions, complementary information...

Waste from scrap and defects

Number of defects and quality problems can be directly linked to the work place state:

Assembly mistakes (parts mismatch) due to jammed work table with parts from differents models / series
Forgotten parts in assembly, the parts could not be seen in the mess on the table
Scratches on parts by scap form the work table (burrs, dirt, parts...)
spoiled parts, useless because dirty, scratched...
Assembly mistake by not following the right sequence

Sort and arrange with the ABC Method

Anything which is of frequent use is class A. It must be handy, available, ready for use. If A items cannot be held handy, they must be stored and kept as close as possible to avoid waiting, searching and long distance for fetching.

Less frequently used items are class B. They may be put further, but must be quickly reachable and available, and exept distance, must be in the same state as A class items.

Anything that is of non frequent use is class C. These items must not jam the closest storage space. C class items must be stored away while be kept in usable state.

C class items should be checked to confirm they're still useful and not kept only "in the case". If the usage is not certain, these items shoud be disposed.

Author, Chris HOHMANN, is managing partner in an international consulting firm.

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