MTBF
Mean Time Between Failure
Way to quantify the performance of a machine or part.
MTBF = (Total Time of all Parts run) / (Total number of failures)
Good if all parts fail.
Bad if very few of the parts fail. It is very deceptive in this case.
Way to quantify the performance of a machine or part.
MTBF = (Total Time of all Parts run) / (Total number of failures)
Good if all parts fail.
Bad if very few of the parts fail. It is very deceptive in this case.
A hypothetical machine generally runs between 60 and 100 hours before failing.
If you run 3 of them for a total of 240 hours, and all 3 fail, you have a MTBF of 80 hours per failure. Makes sense.
If you run 100 of them in an application where the job is complete after 50 hours, at which point you don't run it again, it is possible that only 10 or so will fail. MTBF could be about (90*50 + 10*25) / (10) = 475 hours per failure. This is insane, since you would be lucky if a single tool made it to 200 hours or continuous operation.
If you run 3 of them for a total of 240 hours, and all 3 fail, you have a MTBF of 80 hours per failure. Makes sense.
If you run 100 of them in an application where the job is complete after 50 hours, at which point you don't run it again, it is possible that only 10 or so will fail. MTBF could be about (90*50 + 10*25) / (10) = 475 hours per failure. This is insane, since you would be lucky if a single tool made it to 200 hours or continuous operation.
MTBF by guided fox July 7, 2006
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