Waste
There are three broad types of waste
- Muri (overload or overburden) Improving the flow or smoothness of work.
- Mura (unevenness, irregularity or inequity) Unreasonable work that imposes because of poor organization.
- Muda (non-value-adding work) Eliminating non-value adding activity.
Linkup between these three wastes
Muri (overload or overburden)
Definition
- All unreasonable work that management imposes on workers & machine because of poor organization
Causes
- Lack of standardize work
- Improper planning & design
- Improper ergonomics & safety
- Lack of repeatable processes or machine
- Unreasonable length of time
Results
- Cause downtime, defects, delays & even disasters
- Dissatisfaction
Mura (unevenness, irregularity or inequity)
Definition
- The wild fluctuations due to extreme highs (peaks) & lows (valleys) in production scheduling
Causes
- Poor production leveling
- Poor production scheduling/shifting
- Poor production planning
- Discontinuous flow
- Pull system not followed
Results
- Cause periods of overload & long idle time
- Poor quality
The seven deadly Muda (waste)
Taiichi Ohno identified seven types of waste
- Overproduction
- Inventory
- Transport
- Waiting time
- Motion
- Over Processing
- Defects
The steps to effective waste elimination are
- Make
waste visible (obvious wastes & hidden wastes)
- Be
conscious of the waste
- Be
accountable for the waste
- Measure
the waste
- Eliminate
or reduce the waste
Overproduction
Definition
- Producing more than what is needed
- Producing faster than what is needed
Causes
- Working ahead of customer or process
- Volume incentives (sales, pay, purchasing)
- High capacity equipment
- Line imbalance; poor scheduling/planning
Results
- Produced in excess quantities
- Made before customers need them
- Excess Inventory
- Excess Transportation
- Hides available capacity
Excess Inventory
Definition
- More materials or information than is required
- Components, WIP & finished product not being processed
Causes
- Over-production; imbalanced line
- Big batch sizes; long lead times
- Local optimization (turf mentality)
- High rework rate
- JIT incapable suppliers
Results
- Requires excess space
- Costs money & ties up capital
- Search & damage transport system
- Hides defects& increase deterioration
Transportation
Definition
- Unnecessary material movement
- Unnecessary tools or equipment movement
Causes
- Poor route planning
- Distant suppliers
- Complex material flows; poor layout
- Disorganized workplace; line imbalance
Results
- Loss of traceability
- Damaged goods
- Increased lead time
- Excess costs
- Storage space
Waiting time
Definition
- Man & material idle or waiting time
- Machine idle or waiting time
Causes
- Unsynchronized processes; line imbalance
- Non- “Full” work process
- Over-staffing
- Unscheduled machine downtime; long set-up
- Material or manpower shortage or delay
Results
- Over Production
- Over Processing
- Idle resources
- Non-value added work
Excess Motion
Definition
- People or equipment moving or walking more than is required
Causes
- Poor layout, housekeeping & work flow
- Disorganized work place & storage locations
- Unclear, non-standardized work instructions
- Unclear process & materials flow
Results
- Unnecessary walking
- Poor ergonomic conditions
- Part transfer
- Reaching, stopping & walking to locate/ pick up parts/tools
Over Processing
Definition
- Non-value added man processing
- Non-value added machine processing
Causes
- Unclear customer specifications
- Frequent engineering changes
- Excessive quality (refinements)
- Inadequate value analysis/value engineering
- Unclear work instructions
- Unnecessary documentation
Results
- Increased processing time & costs
- Incorrect process/equipment
- Excessive use of resources
Defects/Rework
Definition
- Processing due to the production of defects
- Processing due to rework or repair of defects
- Materials used due to defect and rework
Causes
- Unclear customer specifications
- Incapable process & lack of process control
- Unskilled personnel
- Departmental rather than total quality
- Incapable suppliers
Results
- Customer Dissatisfaction
- Non-Value added work
- Extra costs & space
- Extra inspections/checks
Other Muda (waste)
Later an eighth waste was defined by Womack is
- "Waste of Unused Human Talent"
- Manufacturing goods or services that do not meet customer demand or specification
Geoffrey Mika in the book of “Kaizen Event Implementation
Manual” added three more forms of waste that are now universally accepted
- Working to the wrong metrics or no metrics
- Not allowing worker to contribute ideas & suggestions (Participative Management)
- Improper use of computers; not having the proper software & training
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