Tuesday, August 22, 2017

Seven Wastes Model



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


   Waste                          -                   Method

Waste of overproduction - One cannot produce without a production Kanban

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

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

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.

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.

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


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 23 August 2017, 15 November 2013


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