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Manual for Life Cost Based FMEA

6. How to Interpret and Use Results

The failure cost for each failure scenario will be calculated on each row of the Lifecycle Cost based FMEA sheet (Table 5). Labor cost and Material cost are the expected direct cost for the failures. Opportunity cost does not incur an extra cost to run the ILC but it is expenses lost due to the collider not operating. The failure cost is also plotted after running the Monte Carlo simulation (Figure 5) You should consider mitigating the high failure costs (sum of labor and material costs) through 3 different strategic abatements:

6.1 Higher reliability

This approach is taken for failures that have high frequency. If it is a component failure, you should consider using a component with a higher MTBF or making the system redundant to achieve an overall higher reliability. You will need to conduct a lifecycle cost analysis to compare the two different possibilities and conduct trade-off analysis.

6.2 Design for serviceability

This approach tries to reduce the downtime of the collider and reduce the fixing time. You may consider relocating components or sub-systems with higher failure frequency to a location that is more accessible once the cover is opened up. Designing special tools or jigs to make the components more serviceable is another possibility.

6.3 Design diagnostic capability

This approach can be effective for failures that can be predicted with an early detection system. Sensors are quite affordable these days and alerting the user ahead of the actual failure can be quite economical for cases where higher reliability is not feasible. Printers for example alert the user the toner is low 500 pages before it stops printing. Thus, the user has ample time to order a new set of toner and replace it before the printer becomes inoperable.

6.4 Examples of Regular FMEA and Life Cost-Based FMEA

Spencer took part in a regular FMEA process on a water-cooled electromagnet for a particle accelerator (Bellomo, 2000; Rago, 2002). Both authors developed the life cost- based FMEA using systems of electromagnets and permanent magnets (Rhee, 2003; Rhee, 2004).

FMEA MANUAL By S. Rhee and C.M. Spencer


January 2009

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