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What is Preventive Maintenance? :What is Preventive Maintenance? Preventive maintenance is plannedmaintenance of plant and equipment that is designed to improveequipment life and avoid any unplanned maintenance activity. PreventiveMaintenance includes painting, lubrication, cleaning, adjusting, and minorcomponent replacement to extend the life of equipment and facilities. Itspurpose is to minimize breakdowns and excessive depreciation. It is themaimtanance before any breakdown. In its simplest form, preventivemaintenance can be compared to the service schedule for an automobile.

Reasons for Preventive Maintenance :Reasons for Preventive Maintenance

Increased Automation

Business loss due to production delays

Reduction of insurance inventories

Production of a higher quality product

Just-in-time manufacturing

Reduction in equipment redundancies

Cell dependencies

Minimize energy consumption Need for a more organized, planned environment

Objectives of Preventive Maintenance:Objectives of Preventive Maintenance( i ) To minimize the possibility of unanticipated production interruption ormajor breakdown by locating or uncovering any condition which may leadto it.(ii) To make machine tools always available and ready for use.(iii) To maintain the optimum productive efficiency of the machine tools. (iv) To maintain the operational accuracy of the machine tools.(v) To reduce the work content of maintenance jobs.(vi) To achieve maximum production at minimum repair cost.(vii) To ensure safety of life and limb of the machine tool operators.(viii) To maintain value of machine tools (by periodic inspections, repairs,overhauls etc.)

Advantages of Preventative Maintenance:Advantages of Preventative Maintenance

Safety . Machinery that is not well-maintained can become a safetyhazard. Preventive maintenance increases the margin of safety by

keeping equipment in top running condition. Lower cost . A modern and cost-effective approach to preventive

maintenance shows that there is no maintenance cost optimum.However, maintenance costs will decrease as the costs forproduction losses decreases. Obviously, no preventive maintenanceaction is performed unless it is less costly that the resulting failure.

Reduction in failures and breakdowns . Preventive maintenanceaims at reducing or eliminating unplanned downtime, therebyincreasingmachine efficiency. Downtime is also reduced when the preventivemaintenance process gives maintenance personnel sufficientwarning so repairs can be scheduled during normal outages.

Extension of equipment life . Obviously, equipment that is cared forwill last longer than equipment that is abused and neglected.

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Improved trade-in/resale value of equipment . If the equipment is tobe sold or traded in, a preventive maintenance program will helpkeep the machine in the best possible condition, therebymaximizing its used value.

Increased equipment reliability . By performing preventive

maintenance on equipment, a firm begins to build reliability into theequipment by removing routine and avoidable breakdowns.

Increased plant productivity . Productivity is enhanced by thedecrease in unexpected machine breakdown. Also, forecastshutdown time can allow the firm to utilize alternate routings andscheduling alternatives that will minimize the negative effect ofdowntime.

Fewer surprises . Preventive maintenance enables users to avoidthe unexpected. Preventive maintenance does not guaranteeelimination of all unexpected downtime, but empirically it has

proven to eliminate most of it caused by mechanical failure. Reduced cycle time . If process equipment is incapable of running

the product, then the time it takes to move the product through thefactory will suffer. There is a strong correlation between preventivemaintenance and cycle-time reductions as well as near-perfect on-time delivery rates.

Increased service level for the customer and reduction in thenumber of defective parts. These have a positive direct effect onstock-outs, backlog, and delivery time to the customer.

Reduced overall maintenance . By not allowing machinery to fallinto a state of disrepair, overall maintenance requirements are

greatly decreased.

Disadvantages of Preventive Maintenance :Disadvantages of Preventive Maintenance( i ) Breakdowns generally occur at inopportunate times. This leads topoor, hurried maintenance and excessive delays in production. (ii) Reduction of output.(iii) Faster plant deterioration.(iv)Increased chances of accidents and less safety to both workers andmachines.

(v) More spoilt material.(vi)Direct loss of profit.( vii)Unplanned downtime can't be excluded. (viii) Labour intensive.(ix) Unneeded maintenance of some component.