what ard the differences or relations between preventive maintenance & predictive maintenance?

Answer 1

preventive - maintenance job done periodically or time based.
predictive - maintenance job done based on what the machine's history or trends tell you.

for example, in preventive maintenance you plan to change a filter every 3 months no matter what. after 3 month when you want to change the filter, you may realize that the filter is still very good.

this may lead you to study how long the lifespan of the filter could last. So based on the study you made, you can predict when is the best and economical time to change the filter.

this is what we call predictive maintenance

Answer 2

Look carefully at the words and understand them.

Preventive maintenance is used as a preventive measure ie: to prevent failures. As has been mentioned before, low value parts and equipment can be on a preventive maintenance schedule. Oil changes, filter replacements etc can be done on a time based process. That is based on pure statistics. If you know roughly when a part fails (D90 life) you can change the part before the failure can occur.

There is a problem with that approach. Firstly a part may still fail before the next replacement. But if its not a critical failure you might tolerate it. Secondly if you replace it too often or too late you'll keep having failures despite the replacement schedule. Most importantly, this method is time based. So irrespective of whether the machine is used more or less, the part will be replaced at certain time intervals.

In predictive maintenance on the other hand you predict when the part is going to fail. In most cases these are expensive parts and are critical to the working of the machine. For instance you cant keep changing the blades on aircraft turbines. They are too expensive and the replacement procedure is long and painful. So you check the blades for any signs of cracks, fatigue or creep. If the blade shows those signs, only then do you replace it.

This method allows you to change the part only when its needed. However you have to check the "health" of the part more often.

Answer 3

Very very similar. Preventative maintenance might involve saying, "this part is know to fail prematurely, let's put a stronger one in or let's at least check it."

Predictive maintenance says "This part normally lasts 500 hours of service, so let's replace it at 400 hours so we never have a failure."

Answer 4

same as above

Answer 5

perfect answer above:)