Inspection Interval Optimization
Inspection Interval Optimization
(OP)
Would anyone be able to help, using Excelt, to calculate an inspection interval optimized to catch a certain percentage (95% in this case) of failures?
Below is a small portion of my data set, but for example if I have failures occurring at the cycles listed below, how do I calculate the inspection interval that would give me 95% confidence or allow only 5% of failures to go unpredicted? In this case cost isn't a factor, only preventing the interruption.
Cycles at which a failure occured:
49
273
574
854
1077
1354
1704
2009
2075
2221
2331
2428
2519
2571
2633
2777
2915
3016
3080
3374
4286
Thanks in advance, please let me know if I can provide any more info
Below is a small portion of my data set, but for example if I have failures occurring at the cycles listed below, how do I calculate the inspection interval that would give me 95% confidence or allow only 5% of failures to go unpredicted? In this case cost isn't a factor, only preventing the interruption.
Cycles at which a failure occured:
49
273
574
854
1077
1354
1704
2009
2075
2221
2331
2428
2519
2571
2633
2777
2915
3016
3080
3374
4286
Thanks in advance, please let me know if I can provide any more info





RE: Inspection Interval Optimization
http://www.oracle.com/technetwork/middleware/cryst...
RE: Inspection Interval Optimization
There are companies that sell that type of software
TTFN
I can do absolutely anything. I'm an expert!
homework forum: //www.engineering.com/AskForum/aff/32.aspx
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Inspection Interval Optimization
www.cpkinfo.com/files/Weibull_calculator.xls
www.barringer1.com/jan09prb_files/Weibull-Analysis...
http://connected-knowledge.com/2013/08/01/how-to-m...
http://www.samos.aegean.gr/actuar/dlekkas/environm...
http://www.lifetime-reliability.com/store/reliabil...
http://www.qualitydigest.com/print/23237
This one requires a purchase
http://www.lifetime-reliability.com/store/reliabil...
http://www.lifetime-reliability.com/store/reliabil...
TTFN
I can do absolutely anything. I'm an expert!
homework forum: //www.engineering.com/AskForum/aff/32.aspx
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Inspection Interval Optimization
RE: Inspection Interval Optimization
TTFN
I can do absolutely anything. I'm an expert!
homework forum: //www.engineering.com/AskForum/aff/32.aspx
FAQ731-376: Eng-Tips.com Forum Policies forum1529: Translation Assistance for Engineers
RE: Inspection Interval Optimization
RE: Inspection Interval Optimization
From which I deduce that,
5% of the items fail within 1700 cycles 95% last longer than 1700 cycles.
10% of the items fail within 2000 cycles
67% of the items fail within 2600 cycles
90% of the items fail within 3000 cycles
If you test every item for 1700 cycles you can be reasonably sure that you've caught enough failures that 95% will last longer than that.
Now it appears that only 50% of those that didn't fail during the test will last for up to 3000 cycles. Problem is that you've already expended a little more than 50% of that life cycle in testing. Not a very reliable product once past that testing phase.
However if you establish that the lifetime is 1500 cycles,it seems that 90% of all items will last that long.