Transcript Equipment Productivity - Pakistan Engineering Council

Equipment Productivity
By T.A. Khan
January 2008
Overall Equipment Effectiveness
In an ideal factory, equipment would operate 100
percent of the time at 100 percent capacity, with
an output of 100 percent good quality.
In real life, however, this situation is rare.
The difference between the ideal and the actual situation is due to
losses. Calculating the overall equipment effectiveness (OEE)
rate is a crucial element of any serious commitment to reduce
equipment- and process-related wastes through total productive
maintenance (TPM) and other lean manufacturing methods like
Operational Excellence, Six Sigma or World Class Manufacturing.
OEE (The six big losses)
Performance
Availability
Total Operating time
A
B
C
D
Quality
E
Net
time
*No
scheduled
Operating
production
Running
time
Target
* Failures
* Setup
Output
* Minor
Stoppages
Actual
Output
* Reduced
Stoppages
Lost
Actual
Output
effectiveness
* Scrap/
F
Good
Output
OEE
rework
=
* Startup
losses
B/A
X
Availability rate
D/C
X
Performance rate
F/E
Quality rate
Schedule Losses
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Losses Due to Planning
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Forecasting
Initial Capacity Planning
Production Planning
Execution
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Skills
Machine Condition
Material Quality
Forecasting
Principles of Forecasting
Forecasts are rarely perfect
Forecast accuracy is:
higher for shorter
time horizons
Grouped forecasts are more accurate than individual items
Step-by-Step
1. Decide what to forecast:
Level of detail, units of analysis & time horizon required
2. Evaluate & analyze appropriate data
Identify needed data & whether it’s available
3. Select & test the forecasting model
Cost, ease of use & accuracy
4. Generate the forecast
5. Monitor forecast accuracy over time
Types of Forecasting Methods
Qualitative methods:
Forecasts generated subjectively by the forecaster
Quantitative methods:
Forecasts generated through mathematical modeling
Qualitative Methods
Future
•Strengths:
–Incorporates inside information
–Particularly useful when the
future is expected to be very
different than the past
•Weaknesses:
–Forecaster bias can reduce
the accuracy of the forecast
Past
Types of Qualitative Models
Type
Executive
opinion
Characteristics
Strengths
Weaknesses
A group of managers Good for strategic or One person's opinion
meet & come up with new-product
can dominate the
a forecast
forecasting
forecast
Market
research
Uses surveys &
Good determinant of It can be difficult to
interviews to identify customer preferences develop a good
customer preferences
questionnaire
Delphi
method
Seeks to develop a
consensus among a
group of experts
Excellent for
Time consuming to
forecasting long-term develop
product demand,
technological
changes, and
Quantitative Methods
•Strengths:
•Consistent and objective
•Can consider a lot of data at once
• Weaknesses:
•Necessary data isn’t always available
•Forecast quality is dependent upon data quality
Types of Quantitative Methods
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Time Series Models:
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Assumes the future will follow same patterns as
the past
Causal Models:
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Explores cause-and-effect relationships
Uses leading indicators to predict the future
Capacity Planning
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Initial Capacity Planning
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How Much Do we need? (Volume)
When do we need? (Time horizon)
Where to make? (Location)
Capacity Expansion
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Lead Strategy
Lag Strategy
Average
Initial Capacity Planning
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Capacity decisions are important because:
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1. They have an impact on the ability of an
organisation to meet future demands.
2. There is a definite relation between capacity &
operating costs.
3. Initial investments depends upon capacity
decisions.
4. It involves long term commitment of resources.
Capacity Planning
What kind of capacity is needed?
(Intended product or services)
How Much is needed?
Three Basic
Question
(The agony of too much &
too little CAPACITY.)
When it is needed?
(Opportunity missed is opportunity lost)
How much?
Total Annual cost ($000)
Cost-Volume Analysis
1000
900
800
700
600
500
400
300
A
B
C
D
200
100
0
0
2
4
6
8
10
12
Output in 1000 units
14
16
18
20
Capacity Expansion
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Volume & certainty of anticipated demand
Strategic objectives for growth
Costs of expansion & operation
Incremental or one-step expansion
Capacity Expansion Strategies
Capacity lead strategy
Units
Capacity
Capacity lag strategy
Units
Demand
Capacity
Demand
Time
Time
Average capacity strategy
Units
Incremental vs. one-step expansion
Units
Capacity
One-step
expansion
Demand
Time
Incremental
expansion
Demand
Time
Strategies for Meeting
Non-Uniform Demand
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Build up inventory
Back-ordering
Smooth demand through marketing
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increase price to reduce demand
decrease price to increase demand
Strategies for Meeting
Non-Uniform Demand
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Vary capacity
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overtime
extra shifts
subcontracting
hiring and layoffs
Operational Losses
Loss
Categories
The Six Big Losses
Downtime (lost
availability)
Equipment failures. Setup and adjustments
Speed losses (lost Idling and minor stoppages. Reduced speed operation
performance)
Defect losses (lost Scrap and rework Start-up losses
quality)
OEE (TPM)
Implementing TPM means striving toward
a vision of the ideal manufacturing
situation, a vision that encompasses
zero breakdowns
zero abnormalities
zero defects
zero accidents
The path to this ideal situation is a process
of continuous improvement that requires
the total commitment of everyone in the
company, from operators to top
management.
OEE (TPM)
Total productive maintenance (TPM) was first defined in 1971
by the Japan Institute of Plant Maintenance (JIPM). TPM is a
company wide strategy to increase the effectiveness of
production environments
The difference between the ideal and the actual situation, in
factory operations, is due to losses. Equipment operators face
the results of these losses on a daily basis. TPM gives them the
tools to identify the losses and make improvements.
A key strategy in TPM is identifying and
reducing what we call the six big losses.
Maintenance Management
Business Objectives & Strategy
A formalised Framework,
accepted by senior mngt.,,
within which decisions on
maintenance are taken.
Maintenance
Policy
Production Objectives & Strategy
Maintenance Objectives
Maintenance Strategy
•Preventive
•Corrective
The organisation of
maintenance activities within
an agreed policy
Plant & Equipment
•Asset register
•Classification
•Criticality
•Operating Regimes
Information
Resources
Procedures
Organisation
Control system
•Management
•Technical
•Manuals
•Drawings
•Analysis
•Parts/ Tools
•Services
•Facilities
•Equipment
•Diagnostics
•Planning
•Scheduling
•Technical
•Accountability
•Communication
•Structure
•Support
•Partners
•Measurement
•Reports
•Tracking
•Action
People
People
Trade skills, Engineering Skills, Management Skills, Safety,
Training & development, Leadership
Values, Rewards, Recognition,
Sanctions
THE ELEMENTS OF OVERALL
EQUIPMENT EFFECTIVENESS
The availability rate is the time the
equipment is really running, versus the
time it could have been running.
A low availability rate reflects
downtime losses:
• Equipment failures
• Setup and adjustments
The performance rate is the quantity
produced during the running time,
versus the potential quantity, given the
designed speed of the equipment.
A low performance rate reflects
speed losses:
• Idling and minor stoppages
• Reduced speed operation
The quality rate is the amount of good
products versus the total amount of
products produced.
A low quality rate reflects defect
losses:
• Scrap and rework
• Startup losses
Overall Equipment Effectiveness
(OEE)
Set-up
Inconsistent Times,
Insufficient skills.
Poor Planning &
scheduling, Different methods,
Poor tooling, Poor start up controls
Missing parts, Insufficient support,
Excess start-up adjustment
Availability
losses
Overall
Equipment
Effectiveness
Performance
losses
Breakdown
Lack of maintenance,
Low operator interest,
problems,
Poor Training, Design Problems,
Minor
Stoppages
Material not available,
Change over at start/end
Jams/misfeeds/
overloads,
operator error,
operator absence
Speed
losses
Start-up
losses
Quality
losses
In process
losses
Unclear design specs.,
Poor Training,
not knowing of
Inferior Material
poor maintenance history,
incorrect settings,
Speed deliberately reduced, inconsistent Material
Poor machine changeover, Inconsistent materials,
lists,
Waiting for temp. - pressures,
No start-up check
Minor adjustments
Temperature & pressure changes,
inconsistent materials,
Process not followed,
poor calibration,
Gauges not calibrated properly.
We recommend that the operator collect the daily data about
the equipment for use in the OEE calculation. Collecting this
data will
•teach the operator about the equipment
•focus the operator’s attention on the losses
•grow a feeling of ownership of the equipment
The shift leader or line manager is often the one who will
receive the daily operating data from the operator and
process it to develop information about the OEE. Working
hands on with the data will;
•give the leader/manager basic facts and figures on the
equipment
•help the leader/manager give appropriate feedback to
the operators and others involved in equipment
improvement
•allow the leader to keep management informed about
equipment status and improvement results