When does Preventive maintenance become a fallacy?

Preventive maintenance become fallacy when;

a). Insufficient yearly budget for manpower, spareparts and working tools,

b). non-agreeable for plant shutdown timing or requirement,

c). frequent PM causing "opportunity loss" to produce more products with better profitability.

I will add here one points:

1- if the preventive maintenance cost became more than the corrective maintenance cost, that means there is some thing wrong. 

Preventive maintenance bocome a fallacy when it doesn't have the following:1- Management commitment to arrange skilled team, spare parts and planned down time for maintenance activities2- A well skilled team to do it3- A strategy to address the preventive maintenance tasks.And there is more things which make a maintenance non added value, but here the space is llimited to talk about.

The objective of any manufacturing/production plant is to minimize costs while it maximizes quality and delivery ;to ensure this the plant should run effectively.Thus it should be well maintained.

Maintenance is a tool to achieve these objectives hence it must remain the integral part of the production or manufacturing function.While plant maintenance is and remains an important service function of an efficient production system ,some methodologies applicable in this case may become an inevitable fallacy if not well initiated.

Now,Preventive maintenance becomes a logical choice if and only if the following two conditions are met;

#1,The component in question has an increasing failure rate.In other words,the failure rate of a component increases with time,thus implying wear and tear.Preventive maintenance of a component that is assumed to have an exponential distribution(which implies a constant failure rate) does not make sense!

#2,The overall cost of the preventive maintenance action must be less than the overall cost of a corrective action.

Note;In the overall cost fro a corrective action,one must include ancillary tangible and or intangible costs such as downtime costs,loss of production costs,lawsuits over the failure of safety of critical item, loss of goodwill etc.

It is paramount therefore to make it explicitly clear that if a component has a constant failure rate ie defined by an exponential distribution,then maintenance of the component will have no effect on the components failure occurrences.