Week 9: Quality and Maintenance Management

Question 1

What are the definitions of quality(5)?

Answer 1

• The transcendent approach: ‘innate excellence’ e.g. Rolls Royce
• The manufacturing-based approach: ‘free of errrors’ e.g. Swatch
• The user-based approach: ‘fit for purpose’
• The product-based approach: ‘measurable set of characteristics’
• The value-based approach: balance between cost and price e.g. EasyJet

Question 2

What causes a perception of quality?

Answer 2

Gaps between customers’ expectations and their perception of the products and services they receive

Question 3

What is gap 1?

Answer 3

The customer’s specifications - Operation’s specifications

Question 4

What is gap 2?

Answer 4

The managements’s concept - Organisation’s specifications

Question 5

What is gap 3?

Answer 5

Organisation’s specification - Actual product

Question 6

What is gap 4?

Answer 6

Image of product - Actual product

Question 7

What are the 6 steps of a quality management plan?

Answer 7

1. Define the characteristics of the product
2. Decide how to measure each characteristic
3. Set quality standards
4. Control the quality against those standards
5. Find and correct causes of errors
6. Continue to make improvements

Question 8

What characteristics can be defined for a product(5)?

Answer 8

• Functionality - how well the product does its job
• Appearance - sensory characteristics of the product
• Reliability - consistency of the products performance over time
• Durability - the total useful life of the product assuming occasional repair or modification
• Recovery - the ease with which problems with the product can be resolved

Question 9

What are variables?

Answer 9

Characteristics which are easily quantifiable as continuous real numbers

Question 10

What are attributes?

Answer 10

Characteristics which are assessed by judgement (i.e. have two states right or wrong, OK or NEVER OK)

Question 11

What are the 3 major decisions within quality control?

Answer 11

1. Where should the quality be controlled?
2. How should the checks be performed?
3. Check every item or take a sample?

Question 12

What is SPC?

Answer 12

Statistical Process Control is a technique that monitors processes as they produce products or services and attempts to distinguish between natural variation in process performance and unusual causes of variation

Question 13

What is acceptance sampling?

Answer 13

Acceptance sampling is where batches of products are inspected to decide whether the entire batch should be accepted.

Question 14

What are the two error types?

Answer 14

Error Type I (producer’s risk): false positives, when the sample indicates a trait in the population while the real population does not possess that trait

Error Type II(consumer’s risk): false negatives, when the sample does not indicate a trait in the population that possesses that trait

Question 15

For acceptance sampling what is the formula for the probability of accepting a batch?

Answer 15

n(C)k p1^(n-k)p2^(k)

n - number of good
k - number of faulty
p1 - probability of good
p2 - probability of bad

Need to sum these up if k>0

Question 16

What are the 3 types of maintenance?

Answer 16

1. Breakdown maintenance
2. Preventive maintenance
3. Corrective or predictive maintenance

Question 17

What is the definition of breakdown maintenance?

Answer 17

Breakdown maintenance is where equipment is serviced or repaired only when it fails

Question 18

What is the definition of preventive maintenance?

Answer 18

Preventive maintenance is where equipment is either periodically inspected, serviced, cleaned or when on-line monitoring of equipment is carried out to use expensive parts to the limit of their service (and no longer)

Question 19

What is the definition of corrective or predictive maintenance?

Answer 19

Corrective or predictive maintenance is where equipment and components are improved so that reliable preventive maintenance can be carried out