Chapter 3 Designing Quality into Products and Services Dr. Ayham Jaaron.
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Transcript of Chapter 3 Designing Quality into Products and Services Dr. Ayham Jaaron.
Chapter 3
Designing Quality into Products and Services
Dr. Ayham Jaaron
Objectives
use the Management Tools to organize and communicate information.
discuss Quality Function Deployment (QFD) and its role in product and service design.
discuss Design for Six Sigma (DSS). discuss Taguchi robustness concepts. calculate reliability for a system. discuss ways in which system reliability can be improved. use the risk assessment tools of Fault Tree Analysis (FTA)
and Failure Mode and Effects Analysis (FMEA).
Designing Quality into Products and Services
Must be designed to satisfy and delight the customer
Design begins with input from the customer
Two approaches: Seven management tools Quality function deployment
Reliability
The Seven Management Tools
• Affinity Diagram• Tree Diagram• Process Decision Program Chart (PDPC)• Matrix Diagram• Interrelationship Digraph• Prioritization Matrix• Activity Network Diagram
Affinity Diagram
Similar to a cause and effect diagram
Organizes ideas and facts into categories
Ideas with affinities for each other are placed in the same category
Affinity Diagram
Affinity Diagram for Roger’s Take-Out Pizza
Product Service Cost Features
Extra Value 30 Min. Max. Wait Lower Price More Topping Variety
Delivered Hot Friendly Drivers No Delivery Charge More Crust Variety
Courteous Order Takers Coupons with Order
Affinity Diagrams help to organize ideas and facts whichhave an affinity for each other into categories. In this example,Lower Price and No Delivery Charge have an affinity andare placed into the Cost category.
Tree Diagram
Partial Tree Diagram for Roger’s Take-Out Pizza
Category Objective Strategy
Extra MeatExtra Value
More Cheese
Product Fresh Vegetables
Heated Compartmentsin Delivery Vans
Delivered HotInsulated Boxes
Optimum Routing30 Min. Max. Wait
Batch Delivery Employee Training
Service Friendly Drivers Driver Rotation
Employee TrainingCourteous Order Takers
Secret Shoppers
Tree Diagrams facilitate planning actions shown on theaffinity diagram.
Process Decision Program Chart (PDPC)
A framework for developing contingency plans
Starts with a tree diagramNegative outcomes are considered
for each branchContingency plans are listed
Process Decision Program Chart
Partial Process Decision Program Chart for Roger’s Take-Out Pizza
Possible ContingencyCategory Objective Strategy Outcomes Plan
30 Min. Max. Wait Computer-Based Continued Training
Employee Training High TurnoverService Friendly Drivers
Driver Rotation Longevity Raises
Courteous Order Takers
Job Enrichment
Matrix Diagram
Graphically depicts relationships between concepts
Shows relationship between desired objectives and possible actions
Strength of relationship is indicated by shading
Matrix Diagram Partial Matrix Program Chart for Roger’s Take-Out Pizza
Improved Improved Improved Improved Action Employee Kitchen Delivery Controls
Objective Training Process Process
30 Min. Max. Wait
Friendly Drivers
Courteous Order Takers
KEY: Strong relationship
Moderate relationship
Weak relationship
Interrelationship Digraph
Depicts causal relationships among the categories in the affinity diagram
Arrows indicate which factors are drivers of other categories
Interrelationship Digraph
Interrelationship Digraph for Roger’s Take-Out Pizza
Service
Product Cost
Features
Prioritization Matrix
Allows the comparison of quantitative and qualitative data in the same analysis
Dimensions are the categories for the affinity diagram
Dimension must be assigned a weightEach company is rated for the dimension
on a scale of 1-10 with 10 being best
Prioritization Matrix
Prioritization Matrix for Roger’s Take-Out Pizza
Category Weight Roger’s
Raw Score
Roger’s
Wtd. Score
X-O’s
Raw Score
X-O’s
Wtd. Score
Difference
Wtd. Score
Product 0.30 7 2.10 8 2.40 +0.30
Service 0.25 6 1.50 7 1.75 +0.25
Cost 0.25 8 2.00 6 1.50 -0.50
Features 0.20 9 1.80 7 1.40 -0.40
TOTAL 1.00 7.40 7.05
Activity Network Diagram
Also known as PERT and CPM Program Evaluation & Review Technique
(PERT) Critical Path Method (CPM)
A project planning and control tool
Activity Network Diagram
Activity Network for Evaluation of Heated Compartments in Delivery VansRoger’s Take-Out Pizza
3 Prepare Order Heaters Install in Prototype Train Design 2 3 Evaluate Prototype Drivers1 2 5 6 7
4 2 4
Order Hi-Capacity 1 1 Install inBattery & Alternator Prototype
4
Quality Function Deployment (QFD)
Developed in Japan by Professor Yoji Akao
Quality is defined by the customerCustomer’s definition of quality is
considered in the product/service design process and production process
Quality Function Deployment (QFD)
West Wing-customer requirementsSecond Floor-translates customer
requirements into design requirementsMain Floor- correlation of design
requirements with customer requirements
Attic-interrelationship of the design requirements (what are the tradeoffs)
Quality Function Deployment (QFD)
Basement-contains target values or specifications for the design requirements
East Wing-comparison of the product or service under design with leading competitors
Applying QFD House of QualityExample….climbing suit
QFD Example
In the following example, the customer requirement ofvalue is operationalized for a pizza in terms of meat, cheese,vegetables, and price. As the quantities of meat and cheeseincrease, customer value strongly increases. As the quantity of vegetables increases, customer value increases.As price increases, customer value decreases.
The House of Quality
Value
Taste
Delivered Hot
1 2 3 4 5
Design Requirements
CustomerRequirements
TargetValues
R = Roger’s PizzaX = Competitor X-OA = Competitor Ace
(5 is best)
Correlations++ Strong Positive+ Positive0 Negative00 Strong Negative
Che
ese
Veg
etab
les
++ ++ + 00
++ ++ ++ 0 +
00 ++
00
00
00
20 g
ms.
/sq.
in.
Fre
sh d
aily
$2.9
9 fo
r L
arge
30 m
in.
max
imum
Insu
late
d bo
x
A R X
A R X
R X A
QFD-Four-phased Approach
Uses a series of stages to translate customer requirements into:
Parts characteristics Key process operations Production equipment settings
QFD-Four-phased Approach
Figure 3.9. Four-Phase QFD Model
Design for Six Sigma (DFSS)
Developed at General Electric in 1997An extension of the standard Six Sigma
MethodologyProactive SIX SIGMA goal is 3.4 defects per million
opportunity (DPMO)No standard approach5-interconnected phases
Define, measure, analyze, design, & verify
Taguchi Robustness Concept
Advocated designing robustness into products and systems
Robustness: the condition of product/process design that remains relatively stable
Three steps System design Parameter design Tolerance design
Results in more reliable products than can be produced economically.
Reliability
Key part of design processDefinition: The probability the product or
service will perform without failure for a specified period of time.
3 dimensions of reliability Probability
Will perform on a given trial (successful trials)Will last for a given length of time
Definition of failure Prescribed operating conditions
Reliability Life Characteristic Concepts
Failure rate is the number of failures per unit of time
Graphically depicted failure is usually the bathtub curve Early stage failure
Occurs early in the product/services lifeThese are usually the result of design,
manufacturing or use error.
Reliability Life Characteristic Concepts
Expected Normal Life A pattern of constant and relatively low failure
rates Usually result of design limitations, changes in
the environment and damage from day-to-day use or maintenance
End-of-Life Failure Product exceeds the intended life expectancy Usually results from daily wear and stress
Bathtub curve
Mean Time Between Failures
The average time between failuresCan be modeled by a negative
exponential distributionExponential distribution can determine:
Probability of failure before a certain time Probability of a product lasting at least
until a certain time
Mean Time Between Failures
To determine the probability that failure will not occur before a certain time:
P(no failure before T) = e -T/MTBF
Where:e = natural logarithm, 2.7183….
T = time in service before failure MTBF = mean time between failures
Risk Assessment Tools and Risk Prevention
Failure Mode and Effects Analysis Used to examine a product at the
system or subsystem levels Can be expanded to include:
SafetyEffect on downtimeAccessRepair planningDesign changes
FMEA Worksheet
Risk Assessment Tools and Risk Prevention
Faulty Tree Analysis A tool used to identify possible causes
for potential operating hazards or undesired events.
Can you suggest some examples?
Error Proofing
Japanese call it poka-yokeCan be incorporated into services
(e.g. failure to proceed in filling partial applications).
Class work (7 minutes)
In groups of 5 students, can you think of other three poke-yoke measures that can be used in products/services?
Share these with your colleagues.
Examples:
File cabinets.Electric socketsCars electronic door lock; won’t
operate if door is open.Anti-Braking System.Lawn mowers.Washing machine won’t work if door is
open to prevent injury.
Summary
Quality has to be incorporated into the design
First step is to focus on the customerSeven Management Tools and
Quality Deployment Function are tools to help incorporate customer input into the design process
Summary
Design for Six Sigma builds on traditional Six Sigma methodology
Robustness and reliability are related concepts
Reliability can be improved by: Increasing reliability of individual
components Building redundancy into the system
Summary
Tools can address potential failure modes for products and services Failure Mode and Effects Analysis Faulty Tree Analysis