Seven Wastes Model of Taiichi Ohno and Flow Process Chart - Industrial Engineering

Waste Elimination is part of industrial engineering since the discipline began. Waste elimination is part of productivity improvement. Productivity of inputs will increase when their waste is eliminated.

Taiichi Ohno in Toyota Industrial Engineering practice, has identified certain types of waste for particular attention and doubled the productivity of Toyota in comparison to US companies of that day. Thus best practices of tackling these 7 wastes were developed in the Toyota Motors. Shigeo Shingo of JMA was a teacher and consultant to Toyota in this endeavor.

In strategic management text of Thompson and Strickland, best practices implementation in value chain activities is an important step in strategy execution process. Companies world over are trying implement waste elimination practices developed in Toyota in their companies.

Seven Wastes - Taiichi Ohno - page 19 - Toyota Production System

   Waste                          -                   Methods to prevent it.

Waste of overproduction - One cannot produce without a production Kanban. Managing demand 

                                           variability. Reducing time between order receipt and starting of production.

Waste of time on hand (waiting)  - Multiple machines to an operator, all producing as per tact time.

Waste in transportation - Machines in line or flow placed close together

Waste of processing itself - Standardized Methods (plan the process well - process planning)

Waste of stock on hand (inventories) - JIT system - low inventory - SMED - Poka-Yoke

Waste of movement (of workers) - Machine layout changes so that an operator handling multiple machines does not waste movement. Can there be control unit for all the machines at one place only?

Waste of making defective products - Problem solving approach to produce zero defects. 5 Why approach to find where the problem or defect occurred in the earliest stage. Educating and training operators by other team members and management.



Seven Waste Model is also expressed as TIMWOOD

T – Transport – Movement of material, people
I – Inventory – Stock of materials, parts, and finished items
M – Motion – movement of hands and other body parts in operating machines of hand tools
W – Waiting – Men and machines waiting for parts or instructions
O – Over production – Making more than is IMMEDIATELY required
O – Over processing – Tighter tolerances or higher grade materials than are necessary
D – Defects – Items scrapped and rework

Compare the seven waste model with flow process chart

Flow process chart recommends recording and examining 5 items.

Process -   will examine  1.Waste of processing itself,  2. Waste of overproduction

Inspection -  3. Waste of making defective products  - The inspection is only shown as a stage in flow process chart, It needs to be augmented with a record of defects or defectives found during inspection.

Transport - 4. Waste in transportation, 5. Waste of movement (of workers)

Temporary delay - 6. Waste of time on hand (waiting)

Permanent storage - 7. Waste of stock on hand (inventories)

Thus we can see, flow process charts has provided the foundation for analyzing the seven wastes proposed by Taiichi Ohno.

But subsequent persons have indicated Eighth Waste.

Wastage of physical and mental skills of people.

Alan Mogensen identfied this gap in industrial engineering theory and introduced work simplication workshops to involve operators and supervisors in productivity improvement. Subsequently, suggestions scheme became popular. Japanese managers brought more improvements and made operators given large number of suggestions and provided forums for participation.

Please think over this statement of Taylor.

Respect for People - F.W.Taylor -  The Principles of Scientific Management.

Under scientific management the "initiative" of the workmen (their ingenuity) is obtained ...  to a greater extent than is possible under the old system; and in addition to this improvement on the part of the men, the managers assume ... new duties. 

https://nraoiekc.blogspot.com/2013/08/the-principles-of-scientific-management.html

Narayana Rao proposed Ninth waste.

9th Waste - Wastage of Machine Potential, Capability and Power - Wasting Machine's Potential Productivity

Industrial engineering has ignored wastage of potential of machines and equipment even though Taylor has advocated right from his piece rate system paper that for productivity improvement both machine and man are to be analyzed and improved.

Wastage of potential of the machine is recognized in the OEE calculation. Still IEs are yet to develop the area.

9th Waste - Wasting Machine's Potential Productivity -- Elimination - Essential Industrial Engineering Activity

An Interesting exchange of LinkedIn comments regarding Overprocessing

Basant Pandole

Production Engineer | Injection Moulding Specialist | Manufacturing Excellence | Lean Six Sigma | Team Leadership As a Production Engineer at Ganesh Gouri Industries Pvt Ltd, I bring extensive expertise in inj. moulding

https://www.linkedin.com/posts/basant-pandole-29b60117b_leanmanufacturing-manufacturingexcellence-activity-7438260259225264128-d_3k

In modern manufacturing, data-driven decisions and process efficiency play a critical role in achieving operational excellence.

Process Cycle Efficiency (PCE) = [value-added time/total lead time]*100 

My comment

So is reducing value added time a bad thing?

Reply by Shahrukh Irani

I help any high-mix low-volume (HMLV) manufacturer customize their implementation of Lean

Good point Professor. Reducing VAT corresponds to reduction of the waste of over-processing (one of O's in TIMWOODS). 

Reply be me.

Shahrukh Irani,   Thank you professor - Each processing operation is subjected the question - eliminate? If the processing is required it is to be simplified - means machine time reduction and man time reduction are to be attempted. I have written these two points in a post of mine.

Waste of processing itself - Standardized Methods (plan the process well - process planning)

Over processing in TIMWOODS - O – Over processing – Tighter tolerances or higher grade materials than are necessary.

Seven Wastes Model of Taiichi Ohno and Flow Process Chart - Industrial Engineering

https://nraoiekc.blogspot.com/2013/01/chapter-seven-wastes-model-2013-edition.html

Reply by Basant Pandole

Narayana Rao KVSS,  Great question. In Lean, the goal isn’t to reduce value-added work but to eliminate waste around it so the process flows faster and the ratio of value-added time within total lead time improves.

Reply be me.

Basant Pandole,  Lean is also under criticism. Most of the operations management books now say Lean and TQM are not delivering results as promised and hyped. Totally neglecting value added operations and focusing remaining activities was beneficial for Toyota at that time because Ohno said their value adding steps are no worse than American competitors. So they are creating waste or unnecessary expenditures in other activities. The lean brigade simply generalises it to all companies and in all countries and at all times.

I support Shahrukh Irani's explanation and thank him.

Bibliography

Seven Wastes
http://accountability.wa.gov/leadership/lean/documents/2012_Lean_Conference/Thinking_Tools_Techniques/24/The%207%20Wastes.pdf

Seven Wastes Tool
http://www.gcu.ac.uk/media/gcalwebv2/theuniversity/supportservices/pace/documents/Seven%20Wastes.pdf

Lean for Government: Eliminating the seven wastes
http://ntrs.nasa.gov/search.jsp?R=20120016881

Lean in Government
http://www.epa.gov/lean/government/

Seven Wastes in Preventive Maintenanee Programs
http://www.techcorr.com/news/Articles/Article.cfm?ID=2450


Updated 15.3.2026, 25.3.2022, 18.10.2021, 23 August 2017, 15 November 2013