project & quality management quality management
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Project & Quality Management Quality Management. Quality Management. Quality and quality attributes Quality problem-solving tools Product life cycle Quality and cost Reliability. What is Quality. ‘Conformance to specification’ ‘Fitness for purpose’ ‘Meeting customers requirements’ - PowerPoint PPT PresentationTRANSCRIPT
Project & Quality Management
Quality Management
Quality Management
• Quality and quality attributes
• Quality problem-solving tools
• Product life cycle
• Quality and cost
• Reliability
What is Quality
• ‘Conformance to specification’
• ‘Fitness for purpose’
• ‘Meeting customers requirements’
• ‘Doing things right first time’
• The features and characteristics of a product or service which bear upon its ability to satisfy a stated need’ (BS 4778)
What is Quality
• Serviceability
• Aesthetics
• Safety
• Perceived quality
Nine Quality Dimensions
• Performance
• Features
• Reliability
• Conformance
• Durability
Quality Dimensions
Performance– A product’s primary operating characteristics
Features– Additional items to the basic specifications
Reliability– The probability a product operates correctly for
a given time frame under specified conditions
Quality Dimensions
Conformance– How well physical and performance
characteristics meet established standards
Durability– How long the product lasts before it needs to
be replaced
Serviceability– The ease of getting a product serviced or
repaired. After sales service.
Quality Dimensions
Aesthetics– How well the product looks, feels, smells or
tastes
Safety– Assurance that the customer will not be injured
or hurt when using the product
Perceived Quality– Subjective assessment based on image,
advertising or brand names.
What is Quality
Different meaning:
• Designer – features, safety
• Manufacturer - conformance
• Distributor - perceived quality, serviceability
• Customer - reliability, aesthetics, safety
Define User Requirementswhat the person using the product needs
Product Characteristicsproduct specification used by the manufacturer
Measurable Quality Attributesa characteristic that is either present or absent in
the product and can be measured
Managing Quality
Example – Mobile Phone
User Requirements:Portable, Appearance, Calls, Texts, Pictures, etc.
Product Characteristics:Weight, Shape, Colour, Screen/picture resolution, memory etc.
Quality Attributes:Exact weight, pixels, size of memory,
wireless range etc.
Quality Attributes
Characteristics measured to control the quality of the product.
Once defined, the manufacturing processes needed to achieve them and the means to measure them can be determined.
Example - Drink Bottle
Customer requirements
Product characteristics
Quality Attributes
Manufacturing processes
Customer requirements - Bottle
Customer requirements - Bottle
Easy to holdEasy to Open
Leak-proofNon-Toxic
REQUIREMENTS
Weigh less than 100gScrew on capRubber seal
Food grade plastic
CHARACTERISTICS
Customer requirements - Bottle
Wall ThicknessThread geometryThickness of seal
Type of plastic
ATTRIBUTES
Mould DimensionsShot Weight
Material SpecMould Temperature
Cooling timeAssembly method
etc.
PROCESSES
Problem Solving Tools – Why?
Ideal quality attribute not always achievable in practice.
Quality management strives to improve the process by all means possible:
→ collecting data
→ analysing data
→ suggesting ways to improve it
Problem Solving Tools
•Used to identify underlying trends in data that are not readily apparent otherwise
•Used to suggest solutions
•Emphasis is on Systematically describing the process and its problems
•Used as part of a PDSA cycle.
PDSA Cycle
• Deming CyclePlan – Do – Study – Act
Plan• Analyse current situation• Gather data• Use problem solving tools to unravel problem• Suggest solution
Do • Put trial or pilot solution in place• Usually on some small part of the process
Deming Cycle
Study • Critically evaluate trial solution• Examine problems or opportunities
Act • Implement solution in a standardised manner:
Formally adopt as standard procedure Fully document
• Begin next cycle of PDSA
Deming Cycle
Problem Solving Tools
• Flow charts
• Bar Chart
• Cause and effect diagrams
• Scatter diagrams
Flow Charts
Purpose:• describes the process to which the problem
belongs • Understand all the stages of the process and
how they relate to one another
Helps to:• Eliminate duplicate or unnecessary steps• Identify critical areas• Identify areas that need improvement
Example: PCB Project
Checksheet \ Tally Charts
• Simple method of gathering data
• Useful when a lot of data needs to be gathered quickly by observation
• Can be used to show cumulative list of problem areas
Checksheet \ Tally Chart
Tally Chart of problems in PCB project
Problem by category Total
Dry joint 1111 1111 1111 1111 1111 1111 1111 1111 1
1111 1111 1111 1111 1111 1111 11
1111 1111 1111 1111 1111 1
1111 1111
1111
111
111
11
33
26
21
8
4
3
3
2
Over solder
Not soldered
Incorrect placement
Faulty component
Tracks Damaged on PCB
Design error in circuit
Heat damage to component
Bar Chart
• Useful for showing distribution of data e.g. sizes of a manufactured component.
• Can be used to pinpoint causes of error
Two Machines Making the Same Part
0
1
2
3
4
5
6
7
19.7 19.8 19.9 19.9 20 20.1 20.2 20.3 20.4
Machine A
0
1
2
3
4
5
6
7
19.7 19.9 20 20.2 20.4
Machine B
Target size 20mm
Measured sizes distributed around this value
Machine B: approx same distribution but centred around 20.2mm
Suggests tool setting error
Cause and Effect Diagram
• Used to identify causes of problem
• Sometimes called ‘fishbone’ diagram
Cause and Effect Analysis
Causes usually attributed to:
• Materials• Machinery• Methods• People
3Ms and P
Case study: Soldering Problems
Soldering Problems – more detail
Soldering Problems – third pass
Scatter Diagrams
Useful for establishing (or dispelling) a causal link between two factors
Possible outcomes are:• Positive correlation• Negative correlation• Weak correlation• No correlation
Scatter Diagrams
Positive Correlation
‘y’ increases as ‘x’ increases
Positive correlation = O.87
0
5
10
15
20
25
0 1 2 3 4 5 6 7 8 9
Scatter Diagrams
Negative Correlation
‘y’ decreases as ‘x’ increases
Negative correlation = - 0.97
0
10
20
30
40
50
60
70
80
90
100
0 1 2 3 4 5 6 7 8 9
Scatter Diagrams
Weak Correlation
Another factor may be the cause of the problem.
Weak correlation = - 0.5
0
10
20
30
40
50
60
0 1 2 3 4 5 6 7 8 9
Scatter Diagrams
No Correlation
Random arrangement of plotted points.
No relationship between ‘x’ and ‘y’.
No correlation = - 0.06
0
10
20
30
40
50
60
0 1 2 3 4 5 6 7 8 9
Example:
Small drills used to drill PCBs in a
Technology project
Increasing drill size:• Reduces breakages• Reduces time taken to drill hole
• Increases likelihood of bad joint
Data:
Drill Dia No. bad Joints
Time taken per hole
No. Drills Broken
0.8 6 30 sec 7
0.9 7 25 sec 6
1.0 12 15 sec 5
1.2 15 10 sec 5
Plots
02468
10121416
0.8 0.9 1 1.1 1.2
Drill Diameter
No
. D
efe
cti
ve
Jo
ints
0
2
4
6
0.8 0.9 1 1.1 1.2
Drill Diameter
Nu
mb
er
of
Bre
ak
ag
es
Plots
0
5
10
15
20
25
30
0.8 0.9 1 1.1 1.2
Drill Diameter
Tim
e t
ak
en
to
dri
ll h
ole
What the optimum size drill to use?
Compromise will be involved
No ‘right’ answer
Degradation of Quality Attributes
Product characteristics:
•Waterproof
•Resistant to corrosion
Quality attributes:
•Effectiveness of seal between
casing and lid
•Corrosion resistance of material
Pond Alarm Unit
Degradation of Quality Attributes
Ideal situation:Unit completely waterproof and Corrosion resistant.
Design stage
– student choices made re: materials and manufacturing processes
Cover – plastic on a CNC router
Casing – tinplate and soldered
Degradation of Quality Attributes
Degradation factors:
•how accurately the parts are manufactured
•tolerance achieved
•bending the tinplate
•soldering technique
•flux may cause some surface corrosion
Degradation of Quality Attributes
Compromise:
•function satisfactorily in the rain but not when submerged
•last a specified number of years
The Cost of Quality
Quality costs money• Time• Resources• People
The Cost of Quality
Two costs associated with quality:
1. Cost of conformance• Putting measures in place• Running quality system
2. Cost of non-conformance• Errors• Waste• Warranty claims etc.
The Cost of Quality
Cost of non-conformances
Warranty claimsRejects & ScrapErrors & WastePoor Service/DeliveryLoss of Customersetc
Cost of conformance
Total cost of non-conformance
Cost of non-conformance
Cost of conformance
Quality systemsProcess controlReliability etc
Total cost of conformance
Cost of non-conformance > cost of conformance
Cos
t
Product Life Cycle – 4 Stages
Introductory•Product expensive•Recover cost of development•Minimal profits•People not aware of product
Growth•Product is successful•Adopted by mass market•Still expensive •Strong demand
Product Life Cycle – 4 Stages
Maturity•Sales and profits stabilise•Competing products enter market•Prices fall
Decline•Sales and profit decrease
Product Life Cycle
Sales
Profit
Quality and Market Share
The quality of the product plays a large part in its market share.
Premium-quality products usually:• have large market shares• are early entrants to their markets. • charge premium prices for their product.
Quality and Market Share
• Quality improvement can reduce profitability, i.e. the amount of profit per product, due to increased costs.
• The increase in market share will normally cancel out the extra cost involved
Quality, Market Share and Costs
Higher prices
Improved qualityof design
Higher Perceived value
Increased market shareIncreasedrevenues
Improved quality of conformance
Lower manufacturing and service costs
Higher profitability
Simple statistical measures
Useful and common methods of measuring the central tendency of a variable:
•The Mode
•The Median
•The Mean
Simple statistical measures
Mode
Is the most common value from a group.
The following are drill sizes in mm
2 2 3 3 3 4 4 4 4 5
The mode is 4mm which is the most common value, appearing on four occasions
Simple statistical measures
Median
Is the middle value when all outputs are arranged in numerical order.
2 2 3 3 3 4 4 4 4 5
In the example above, the middle values are 3mm and 4mm, so the median would be 3.5mm, halfway between 3mm and
Simple statistical measures
valuesofnumber
togetheraddedvaluesindividualtheall
mmmean 4.310
5444433322
Mean
Is the average value represented by the following equation:
Classification of Quality Costs
• Prevention costs• Planning & operation of a quality system
• Appraisal costs
• Monitoring & inspecting the product
• Internal Failure costs
• Failure costs associated with non-conformance. Detected before it leaves factory
• External Failure costs
• Cost of non-conformance after delivery
Example: Quality Costs
Classification of Quality Costs
PCB Cost Housing Cost
Prevention CostsPractice of correct soldering techniqueLearn to use PCB and circuit design software
1 Day1 Day
Prevention CostsSet up gauge blocks to measure casing opening.Correct tolerance of mating parts
1 hour2 hours
Appraisal costsInspection of solder joints Check component placement against drawingSimulation of circuit
1 hour½ hour1 hour
AppraisalMeasure and inspect before assembly
½ hour
Internal FailureReplacement ICReplacement PCBRework time
€5 €11 Day
Internal FailureReworkScrap material
2 Days€5
External FailureLoss of marks
? External FailureLoss of marks
?