Page 182 - DMGT524_TOTAL_QUALITY_MANAGEMENT

Unit 12: Failure Mode and Effect Analysis

5 Low probability of detection Notes
6 Moderate probability of detection
7 Moderately high chance of detection
8 High probability of detection
9 Very high chance of detection
10 Almost certain chance of detection

Occurrence Rating (OR)
The potential occurrence rating was defined in terms of the time that the system may run
between fault occurrences and from that we could reduce the number of documents between
occurrences of the particular fault. The assumption made here was that, on average, around
15,000 documents were processed per week.

Occurrence Definition of Frequency in Running Time Probability in Number
Rating of Documents
10 Almost inevitable – there is a 1 in 2 chance of the fault > 1 in 1000
occurring in one day
9 Very high – once per day 1 in 2000
8 Repeated failure – once per week 1 in 15,000
7 High – once every 2 weeks 1 in 30,000
6 Moderately high – once per month 1 in 60,000
5 Moderate – once every 3 months 1 in 180,000
4 Relatively low – once every 6 months 1 in 350,000
3 Low – once per year 1 in 700,000
2 Remote – once every 2 years 1 in 1.5 million
1 Nearly impossible – less than once in 8 years < 1 in 5 million
Section Failure Modes
The following table gives an example of some of the failure modes identified in a section
that includes a mechanism for separating notes.
SR = Severity Rating
DR = Detection Rating
OR = Occurrence Rating
RPR = Risk Priority Rating
Where RPR = SR*DR*OR.

Item Failure Mode SR DR OR RPR
1 Failure to feed notes 1 1 9 9
2 Stream feed of notes 4 1 6 24
3 Skewed feed of notes 6 1 6 36
4 Note damage (fold, tear) induced 6 1 8 48

This process was repeated for all failure modes and for all sections of the machine giving
a complete picture of the risks associated with the mechanism design. Those failure modes
with the highest Risk Priority Ratings were given the most immediate attention and
design changes were identified to either, reduce the probability of occurrence or, to increase
Contd...

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