100-Metodos-de-Qualidade-Total

92 100 METHODS FOR TOTAL QUALITY MANAGEMENT
Scale Interpretation
1 Minor
2 Low
3 Low
4 Moderate
5 Moderate
6 Moderate
7 High
8 High
9 Very high
10 Catastrophic
4 Estimate how likely it is that each potential failure will happen. A scale
of 1-10 is used as before:
Scale Interpretation Likelihood
1 Remote Effectively 0
2 Very low 1 in 20,000
3 Low 1 in 10,000
4 Moderate 1 in 2,000
5 Moderate 1 in 1,000
6 Moderate 1 in 200
7 High 1 in 100
8 High 1 in 20
9 Very high 1 in 10
10 Very high 1 in 2
5 Multiply the outputs from stages "2, 3 and 4 together to generate a risk
priority number (RPN). The RPN will lie between 1 and 10,000. If each
stage gave a result of 5 the RPN would be 125.
6 Rank the potential by the RPN. Two rules are then used. First, no
potential failure can have an RPN of greater than 700; secondly, no
individual output from stages 2, 3 or 4 can exceed 7. These rules show
which potential failures must be investigated.
Benefits
Failure mode and effect analysis gives a structured way of assessing
possible failures and which areas to investigate first. A major advantage is
that it does this at an early stage in both products and processes.
Example
A company making plastic mouldings was examining a new process: the
hot water annealing of nylon injection-moulded components. Two possible