ii. improving processes
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© Fred Van Bennekom, Great Brook, 2003 Slide 1
II. Improving Processes
© Fred Van Bennekom, Great Brook, 2003 Slide 2
II. Improving Processes
Quality Control– Inspection
– SPC
– Capability Analysis
Total Quality Management (TQM) or Continuous Quality Improvement (CQI)– Fishbone Diagrams
– Pareto Analysis
– Scatter Plots
– Check Sheets
Business Process Reengineering (BPR)
© Fred Van Bennekom, Great Brook, 2003 Slide 3
Learning or Experience Curve
Cost per Unit
Cumulative Number of Units from Plant
x 2x 4x
Px
P2x
The cost of a unit after cumulative output doubles, compared to the prior cost per unit.
E.g., 70% learning curve indicates the cost per unit
decreases by 30% with each cumulative doubling.
© Fred Van Bennekom, Great Brook, 2003 Slide 4
Sources of Learning
Individual– The worker naturally gets better at a task
– Plateau effect
Organizational – Developing better processes
– Improving technology & equipment
– Working with suppliers
– Working with customers
Learning doesn’t “just happen”
© Fred Van Bennekom, Great Brook, 2003 Slide 5
Improving the “Factory”
Factory as Laboratory– Performing R&D in the Manufacturing Plant– Chaparral Steel
• Leonard-Barton, Dorothy, “The Factory as a Learning Laboratory,” Sloan Management Review, Fall 1992, pp. 23-38.
The Service Factory– Incorporating Service Attributes into the Factory– Inviting Customer to the Factory
The Exchange of Ideas– Services learning efficiency from Manufacturing– Manufacturing learning effectiveness from
Services
© Fred Van Bennekom, Great Brook, 2003 Slide 6
Stages of Knowledge of Process & Quality Control
None – ignorance Know a good outcome from bad Know the characteristics that describe a quality
outcome Prioritization of these quality characteristics Know the variables that lead to these outcomes Know the impact of individual variables Know the interaction effects among variables Able to measure the variables Able to control process to achieve quality
outcomes – repeatedly & consistently
Art
Science
© Fred Van Bennekom, Great Brook, 2003 Slide 7
Quality Assurance — When to Inspect?
INPUT PROCESS OUTPUT
RAW MATERIALSPURCHASED PARTS
BEFORE A COSTLY OPERATIONBEFORE A COVERING OR CLOSING OPERATIONBEFORE AN IRREVERSIBLE PROCESS
FINISHED GOODS
© Fred Van Bennekom, Great Brook, 2003 Slide 8
Quality Assurance
Achieved through– Inspection
• 100% inspection, sampling inspection– Process Control
Amount of Inspection
Co
st
Cost of Inspection
Total Cost
Cost of passing Defects
Optimum
© Fred Van Bennekom, Great Brook, 2003 Slide 9
Competing Quality Control Concepts
Inspect quality in– Acceptable Quality Levels (AQLs)
– Sample from a Lot
– Decision Rule: if X are good, accept the Lot
– Used both for outgoing and incoming testing
– Philosophy: It’s okay to ship s***
Build quality in– Statistical Quality Control (SPC)
– Inherent Capability Analysis
© Fred Van Bennekom, Great Brook, 2003 Slide 10
Inherent Capability Analysis
Determine the inherent capability of the process to produce goods at some quality level.– Gather historical data on a process
– If most output (+/-3falls within Design Specs, then process is capable
– Six-Sigma Quality Level: when 12 output (+/- 6falls within Design Specs
© Fred Van Bennekom, Great Brook, 2003 Slide 11
Six Sigma Philosophy
Goal: reduce variability in a process to the point where the resulting product becomes more – Robust in use (good for the customer)
– Easier to design because parts can be “spec’d” to tighter tolerance
– Less expensive to manufacture due to lower quality failures (also good for the customer!)
Quality Level at 6 sigma– 3.4 defects per million opportunities
© Fred Van Bennekom, Great Brook, 2003 Slide 12
Six Sigma
The Philosophy– Build to Customer Critical To Quality (CTO) criteria
– Fact-driven, measurement-based
– Structured problem solving approach
– Define, Measure, Analyze, Improve, Control (DMAIC)
– Improvement projects become part of everyone’s job
The Players– Champions: Manager in the project area
– Master Black Belts: Mentors the project teams
– Black Belts: Full time team leader, trainer, facilitator
– Green Belts: Team members
© Fred Van Bennekom, Great Brook, 2003 Slide 13
Statistical Process Control
Capable processes also must be controlled SPC distinguishes 2 types of variability
– Normal (Random) variability
– Abnormal (Structural) variability
How to apply SPC– Construct charts (and update occasionally!)
– Collect data regularly – sampling plan
– Observations outside of limits indicate the process potential is “out of control”- statistically
– Find “assignable causes”
© Fred Van Bennekom, Great Brook, 2003 Slide 14
Developing Control Charts
Identify the process you want to study Check whether the process is running OK Take sample outputs at some fixed intervals For each sample - calculate the Average and the Range After taking sufficient samples,
Calculate the average of the sample averages, and of the ranges
Calculate the Std. Dev.s for both. Set the UCL (Upper Control Limit) at Average + 3*Std.Dev. Set the LCL (Lower Control Limit) at Average - 3*Std. Dev.
© Fred Van Bennekom, Great Brook, 2003 Slide 15
Control Charts
Variable Control Chart (assumes normal distribution) Range Chart p - chart
– also known as fraction defective chart (assumes binomial distribution)– s.d. = SQRT(f.d.*(1 - f.d.)/n) {f.d. = fraction defective}
c - chart– also known as defective chart (assumes Poisson distribution)– s.d. = SQRT(mean)
For any control chart: UCL (Upper Control Limit) = mean + z*s.d. LCL (Lower Control Limit) = mean - z*s.d.
where z is set to reflect the assurance that the process is in control.
© Fred Van Bennekom, Great Brook, 2003 Slide 16
Statistical Process Control Charts
Upper Control Limit
Lower Control Limit
1 2 3 4 5 6
Observation Block
x
x
x
x
x
x
xx
7 8
Center line
© Fred Van Bennekom, Great Brook, 2003 Slide 17
SPC – Types of Measures
Attributes– Physical measures: weight, height, size
Characteristics– Proportion defective
© Fred Van Bennekom, Great Brook, 2003 Slide 18
TQM Defined
American Society of Quality Control
– Simply put, TQM is a management approach to long term success through customer satisfaction
– TQM is based on the participation of all members of an organization in improving processes, products, services, and the culture they work in.
– TQM benefits all organization members and society.
© Fred Van Bennekom, Great Brook, 2003 Slide 19
The Start of TQM...
Everything started by Walter Shewhart– Bell Labs in the 1920s– Developed the concept of Statistical Process
Control– Two young scientists working with him:
• W. Edwards Deming• Joseph Juran
© Fred Van Bennekom, Great Brook, 2003 Slide 20
W. Edwards Deming
Key Arguments– The basic cause of sickness in American industry and
resulting unemployment is failure of top management to manage.
– Everyone doing his[/her] best is not the answer. It is necessary that people know what to do.
– Drastic change is required. The responsibility for change rests on management. The first step is in learning how to change.
– Quality and productivity are not to be traded off against each other.
– Productivity is a by-product of quality and of doing the job right the first time.
© Fred Van Bennekom, Great Brook, 2003 Slide 21
W. Edwards Deming’sFourteen Points
1. Create constancy of purpose
2. Adopt the new philosophy
3. Cease dependence on mass inspection
4. Don’t award business on price tag alone
5. Improve constantly the system of production and
service
6. Institute training
7. Institute leadership
© Fred Van Bennekom, Great Brook, 2003 Slide 22
W. Edwards Deming’sFourteen Points
8. Drive out fear
9. Break down barriers between staff areas
10. Eliminate slogans, exhortations, and targets for
the workforce
11. Eliminate numerical quotas
12. Remove barriers to pride of workmanship
13. Institute a vigorous program of education and
retraining
14. Take action to accomplish the transformation
© Fred Van Bennekom, Great Brook, 2003 Slide 23
Deming’s Seven Deadly Diseases
1. Lack of constancy of purpose
2. Emphasis on short-term profits
3. Evaluation by performance rating, merit rating,
or annual performance review
4. Mobility of management
5. Running a company on visible figures alone
6. Excessive medical costs
7. Excessive costs of warranty, fueled by lawyers
that work on contingency
© Fred Van Bennekom, Great Brook, 2003 Slide 24
Quality Management
DOCUMENT CHANGESIMPLEMENT IN REST OF
THE ORGANIZATION
PLAN
DOACT
CHECK
IDENTIFY AND ANALYZE THE PROBLEM
DATA COLLECTIONPARETO ANALYSISFLOW CHARTSCAUSE AND EFFECT DIAGRAMSCONTROL CHARTS
IMPLEMENT CHANGES ON A SMALL SCALE
EVALUATE NEW DATA
CONTINUOUS IMPROVEMENT - THE DEMING WHEEL
© Fred Van Bennekom, Great Brook, 2003 Slide 25
Joseph Juran
The users of a product or service should be able to count on it to do what it’s supposed to do!
Five dimensions of Fitness for Use– Quality of Design
– Quality of Conformance
– Availability
– Safety
– Field Use
Costs of Quality
© Fred Van Bennekom, Great Brook, 2003 Slide 26
Quality Dimensions
Design Quality– Characteristics of the product’s original design
Conformance Quality– Building products (or delivering services) to the
specifications of the product designers
© Fred Van Bennekom, Great Brook, 2003 Slide 27
Costs of Quality
Prevention Appraisal Internal Failures External Failures
© Fred Van Bennekom, Great Brook, 2003 Slide 28
More Gurus
Crosby - Quality is Free Feigenbaum - Total Quality Control (1954) Taguchi - Robust Manufacturing Ishikawa - Total Quality Control the Japanese Way
© Fred Van Bennekom, Great Brook, 2003 Slide 29
Taguchi’s Quality Imperatives
Quality losses are mainly external product failure Robustness results primarily from product design Robust products have strong signal-to-noise ratio Use experimental design to test component part
interaction effects Quality Loss Function: square of deviation from target
value X cost of countermeasure Just in spec = just out of spec Trivial deviation from target will “stack up” Reduction in field failures will reduce factory failures
© Fred Van Bennekom, Great Brook, 2003 Slide 30
Taguchi vs. Zero Defects
Who’s the better shot?
• Consistent• Predictable• But not on target
• On target• More variability
© Fred Van Bennekom, Great Brook, 2003 Slide 31
Garvin’s Dimensions of Quality
Performance Features Reliability Conformance
“Managing Quality: The Strategic and Competitive Edge,” David Garvin, 1988.
Durability Serviceability Aesthetics Perception
© Fred Van Bennekom, Great Brook, 2003 Slide 32
Quality Dimensions
Tangible Goods– Safety
– Durability
– Reliability
– Aesthetics
– Conformance
– Performance
– Serviceability
Services– Reliability
– Responsiveness
– Assurance
– Empathy
– Tangibility
© Fred Van Bennekom, Great Brook, 2003 Slide 33
Malcolm Baldrige National Quality Award
Created by Public Law 1987 Named after a Secretary of Commerce Three Purposes
– 1. To encourage quality in American industry
– 2. To promote quality awareness and continuous improvement
– 3. To recognize companies that demonstrate successful quality strategies and quality achievement
© Fred Van Bennekom, Great Brook, 2003 Slide 34
Lean Production
A combination of multiple tool sets– JIT production (cellular manufacturing)
– Safe workplace (5Ss)
– Pursuit of perfection
– Visual management
– Empowered teams
– Six sigma
© Fred Van Bennekom, Great Brook, 2003 Slide 35
Six Sigma vs. Lean – Complementary
Six Sigma Remove variation from
processes to achieve uniform flow
Problem/project focus Research projects with
longer timeline (3-4 months)
Higher complexity with root cause unknown
Lean Remove waste, rework,
inventory to reduce flow time
Flow focused– Remove bottlenecks– Material velocity
Immediate results(1-2 weeks)
Low complexity with known solutions
© Fred Van Bennekom, Great Brook, 2003 Slide 36
Lean Production
JIT production (cellular manufacturing) Heijunka: Level workloading Pursuit of perfection Visual process management Empowered teams Kaizen: Continuous improvement involving everyone Poka Yoke: mechanism to stop defects or make errors
obvious
© Fred Van Bennekom, Great Brook, 2003 Slide 37
Lean Concepts
Kaizen: Continuing improvement involving everyone Poka Yoke: mechanism to stop defects or make errors obvious Heijunka: Level production loading across all product
variations Kanban: “Signboard” signal to authorize production Andon: “Lantern” – board that signals quality issue Jidoka: autonomation 5 Ss
Sources: www.superfactory.com, www.tpmonline.com
© Fred Van Bennekom, Great Brook, 2003 Slide 38
Other Kaizen Tools: 5 Ss
Step Name Action Catch Phrase
1Sort
(Seiri)Remove unnecessary items
from the workplace “When in doubt, throw it out”
2Straighten, Set in Order
(Seiton)Locate everything at the point
of use“A place for everything, and
everything in its place”
3Sweep, Shine
(Seiso)Clean and eliminate the
sources of filth“The best cleaning is to not
need cleaning”
4Standardize
(Seiketsu)Make routine and standard for
what good looks like“See and recognize what
needs to be done”
5Self-discipline, Sustain
(Shitsuke)Sustain by making 5S second
nature“The less self-discipline you
need, the better”
Source: http://www.kaizen-consulting.com/training_5s.htm
© Fred Van Bennekom, Great Brook, 2003 Slide 39
Mudas – 7 WastesThe 7 Wastes – Definition Examples Causes Countermeasures
Over-|production Producing more than the customer needs right now
Producing product to stock based on sales forecastsProducing more to avoid set-upsBatch process resulting in extra output
ForecastingLong set-ups“Just in case” for breakdowns
Pull system schedulingHeijunka – level loadingSet-up reductionTPM
Trans-portation
Movement of product that does not add value
Moving parts in and out of storageMoving material from one workstation to another
Batch productionPush productionStorageFunctional layout
Flow linesPull systemValue Stream organizationsKanban
Motion Movement of people that does not add value
Searching for parts, tools, prints, etc.Sorting through materialsReaching for toolsLifting boxes of parts
Workplace disorganizationMissing itemsPoor workstation designUnsafe work area
5S, Point of Use StorageWater SpiderOne-piece flowWorkstation design
Waiting Idle time created when material, information, people, or equipment is not ready
Waiting for partsWaiting for printsWaiting for inspectionWaiting for machinesWaiting for informationWaiting for machine repair
Push productionWork imbalanceCentralized inspectionOrder entry delaysLack of priorityLack of communication
Downstream pullTakt time productionIn-process gaugingJidokaOffice KaizenTPM
Processing Effort that adds no value from the customer’s viewpoint
Multiple cleaning of partsPaperworkOver-tight tolerancesAwkward tool or part design
Delay between processingPush systemCustomer voice not understoodDesigns “thrown over the wall”
Flow linesOne-piece pullOffice KaizenLean Design
Inventory More materials, parts, or products on hand than the customer needs right now
Raw materialsWork in processFinished goodsConsumable suppliesPurchased components
Supplier lead-timesLack of flow, Long set-upsLong lead-timesPaperwork in processLack of ordering procedure
External kanbanSupplier developmentOne-piece flow linesSet-up reductionInternal kanban
Defects Work that contains errors, rework, mistakes or lacks something necessary
Scrap, ReworkDefectsCorrectionField failureVariationMissing parts
Process failureMis-loaded partBatch processInspect-in qualityIncapable machines
GembaSigmaPokayokeOne-piece pullBuilt-in quality3PJidoka
Source: www.Gemba.Com
© Fred Van Bennekom, Great Brook, 2003 Slide 40
Bibliography
The Six Sigma Way (ISBN 0-07-135806-4) by Pande, Neuman, and Cavanaugh
The Power of Six Sigma (ISBN 0-7931-4434-5) by Subir Chowdhury
Six Sigma (ISBN 0-385-49437-8) by Harry and Schroeder.
The Six Sigma Handbook (ISBN 0-07-137233-4) by Pyzdek is more technical and becoming the 'handbook' for Black Belts.
The Machine that Changed the World, James Womack
www.6-sigma.com www.sixsigma.co.uk www.sixsigmasystems.com www.isixsigma.com www.shawresources.com/pdf/Choosing%2
0a%20Quality%20Improvement%20Methodology.pdf
www.ge.com/en/commitment/quality/whatis.htm
http://www.swmas.co.uk/Lean_Tools/The_7_Wastes.php
http://www.kaizen-consulting.com/training_7w.htm
© Fred Van Bennekom, Great Brook, 2003 Slide 41
More References
http://www.strategosinc.com/just_in_time.htm– A GREAT summary of manufacturing improvement concepts from Ford
to lean. A MUST READ. http://hbswk.hbs.edu/item.jhtml?id=2646&t=operations http://www.kaizen-consulting.com/training_5s.htm http://www.kaizen-consulting.com/training_7w.htm
– This site from Gemba Research does a nice job of summarizing lots of the TPS tools and concepts.
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