Maintenance Resources

Monday, January 11, 2010

Some definition and Confusions:


There are few terms which create unnecessary confusion and debates which should not be. Here are logics
Debates: Root cause analysis=  Outcome is One and only actionable cause. Pic is self explanatory (Hats off to copy write owner, I am just sharing it)



OEE = Over all Equipment efficiency. This indicator is multiplication of productivity (man-machine), equipment quality rate, equipment reliability (Availability) rate.

For a given time, in gives the projection of use of man machine potential and the scope of improvement.
Debates: What to consider, shift time or 24 Hrs (Machine potential is 24 Hrs.). of time ?
ð     It is management to decide how many Hrs. it need to run the shift. We just calculate what is the potential of “ready to dispatch”  production for that given time.
ð     So, OEE will be calculated depends upon a particular facility operating time.

Debates: For a assembly line with different product rate of individual machine, what will be total available time?
=> Consider Whole line as a single machine and calculate the rest. If one machine affects the product output rate then aggregate OEE of individual machines will give wrong picture.

MTBF = Mean time between failure = total machining time / no. of stops
Debates : how to calculate plant MTBF ?
=> Don’t calculate available time as no. of machine X available time. Again it will give wrong projection. Idea behind plant MTBF is to know rete of breakdowns of plant. So, available time will be as same as available time of a line.(MAX 24 Hrs)




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