X hits on this document

104 views

0 shares

0 downloads

0 comments

11 / 26

Origin

Detection Phase Re-occuring

Frequency

Detection Time Fixing Time Delay Time Loss Time Quantity

Parts Cost ($)

Labor Cost($)

Material Cost($)

Opportunity Cost($)

Origin indicates the stage at which the root cause of the failure lies in Figure 1.

Detection indicates the stage at which the failure has occurred and been identified.

Re-occurring indicates whether the failure is a one time event or could reoccur during the life time of the system. Failures that have root causes in design,

Manual for Life Cost Based FMEA

Table 5. Life Cost Based FMEA Table

Input

Output

  • Frequency indicates how often the failure occurs. Failures that originate in design, manufacturing, or assembly are assumed to be one time event failures and the probability of occurrence is assigned to the frequency variable. Failures that originate in assembly or operations reoccur during the life time of the system, thus frequency of failure during a one year period is assigned to this variable. Frequency will be discussed in more detail in Section 3.2.

1

50

180

15

112,500

1

50

38,400

3,000

125,000

1

1250

1,280

5,000

62,500

1

50

115,200

4,500

250,000

manufacturing, or prescribed in this

to have random failures throughout the lifetime of years for the magnets in the International Linear

in

4

0

5

4

0

5

2

0

3

8

0 10

Failure Mode Root Cause of Failure Too many loads on circuit Water passage is blocked Damaged coil Thermal swtich trip due to overheating Water sprayed on to coil

installation stages

column.

Failures

are usually one time errors and “1” is that have root causes in assembly and

operation stages are most the system. This lifetime

likely is 30

Magnet turned off

Oper Oper

30

21

Magnet turned off

Inst TR

1

4 0.5

Magnet turned off

Oper Oper

30

32

Collider (ILC) which we Table 6 under this column

are for

using as an failures that

example. Thus, “30” is prescribed originate during the operation stage.

0.5

Effect of Failure Magnet turned off

Oper Oper 30 0.001

  • Quantity indicates the total number of components/systems affected by the failure. It describes whether a failure affects an individual component, a batch, a sector, or the entire system. “1” is assigned to isolated failures that happen randomly. Manufacturing failures may affect a whole batch of parts that are going through the manufacturing process together, resulting in scrapping the entire batch and re-manufacturing. A manufacturing failure detected during the installation stage would require all of the components to be replaced. An event such as an earthquake may affect magnets in a whole accelerator region or just a couple of sectors, depending on the earthquake magnitude.

  • Parts Cost is the actual material cost to fix the failure if it is done through parts replacement. If the failure is a water hose leak and the hose needs to be replaced, the actual cost of the hose, $50, is taken as the value of the parts cost.

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

11/26

January 2009

Document info
Document views104
Page views105
Page last viewedTue Jan 17 21:25:12 UTC 2017
Pages26
Paragraphs948
Words9183

Comments