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)
Serviceability Aesthetics Safety Perceived quality Performance Features Reliability Conformance Durability What is Quality Nine 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. Quality Dimensions
What is Quality • Different meaning: • Designer – features, safety • Manufacturer - conformance • Distributor - perceived quality, serviceability • Customer - reliability, aesthetics, safety
Managing Quality • Define User Requirements • what the person using the product needs • Product Characteristics • product specification used by the manufacturer • Measurable Quality Attributes • a characteristic that is either present or absent in • the product and can be measured
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 REQUIREMENTS Easy to hold Easy to Open Leak-proof Non-Toxic CHARACTERISTICS Weigh less than 100g Screw on cap Rubber seal Food grade plastic
Customer requirements - Bottle ATTRIBUTES Wall Thickness Thread geometry Thickness of seal Type of plastic PROCESSES Mould Dimensions Shot Weight Material Spec Mould Temperature Cooling time Assembly method etc.
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 Cycle Plan – Do – Study – Act
Deming Cycle • 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
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
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
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 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
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
Scatter Diagrams Negative Correlation ‘y’ decreases as ‘x’ increases
Scatter Diagrams Weak Correlation Another factor may be the cause of the problem.
Scatter Diagrams No Correlation Random arrangement of plotted points.No relationship between ‘x’ and ‘y’.
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
Plots 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: • Cost of conformance • Putting measures in place • Running quality system • Cost of non-conformance • Errors • Waste • Warranty claims etc.
The Cost of Quality Total cost of non-conformance Cost of non-conformances Warranty claims Rejects & Scrap Errors & Waste Poor Service/Delivery Loss of Customers etc Total cost of conformance Cost Cost of conformance Quality systems Process control Reliability etc Cost of conformance Cost of non-conformance Cost of non-conformance > cost of conformance
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