Maintenance Methodology Systems in Manufacturing

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Maintenance Methodology

Introduction:

What is maintenance and why is it performed? Past and current maintenance practices in both the private and government sectors would imply that maintenance is the actions associated with equipment repair after it is broken.

The dictionary defines maintenance as follows: “the work of keeping something in proper condition; upkeep.” This would imply that maintenance should be actions taken to prevent a device or component from failing or to repair normal equipment degradation experienced with the operation of the device to keep it in proper working order. Unfortunately, data obtained in many studies over the past decade indicates that most private and government facilities do not expend the necessary resources to maintain equipment in proper working order. Rather, they wait for equipment failure to occur and then take whatever actions are necessary to repair or replace the equipment. Nothing lasts forever and all equipment has associated with it some predefined life expectancy or operational life. For example, equipment may be designed to operate at full design load for 5,000 hours and may be designed to go through 15,000 start and stop cycles.

The need for maintenance is predicated on actual or impending failure – ideally, maintenance is performed to keep equipment and systems running efficiently for at least design life of the components. The curve can be divided into three distinct: infant mortality, useful life, and wear-out periods.

MAJOR MAINTAINENCE METHODS:

Every facility that produces a consumer product has some requirement for maintenance or upkeep of their machinery. Depending upon the product and, to some extent, the size of the facility, this maintenance activity may be continuous in nature or periodic. Some maintenance activities may consume a significant portion of the facility expenses and manpower. Facility maintenance activities generally fall into three categories: Breakdown, Preventive, and Predictive. Each category has particular costs associated and specific benefits.

Reactive Maintenance (Breakdown Maintenance):

Reactive maintenance is basically the “run it till it breaks” maintenance mode. No actions or efforts are taken to maintain the equipment as the designer originally intended to ensure design life is reached.

Advantages:

• Low cost.
• Less staff.

Disadvantages:

• Increased cost due to unplanned downtime of equipment.
• Increased labor cost, especially if overtime is needed. • Cost involved with repair or replacement of equipment.
• Possible secondary equipment or process damage from equipment failure. • Inefficient use of staff resources.

Advantages to reactive maintenance can be viewed as a double-edged sword. If we are dealing with new equipment, we can expect minimal incidents of failure. If our maintenance program is purely reactive, we will not expend manpower dollars or incur capital cost until something breaks. Since we do not see any associated maintenance cost, we could view this period as saving money. The downside is reality. In reality, during the time we believe we are saving maintenance and capital cost, we are really spending more dollars than we would have under a different maintenance approach. We are spending more dollars associated with capital cost because, while waiting for the equipment to break, we are shortening the life of the equipment resulting in more frequent replacement. We may incur cost upon failure of the primary device associated with its failure causing the failure of a secondary device. This is an increased cost we would not have experienced if our maintenance program was more proactive. Our labor cost associated with repair will probably be higher than normal because the failure will most likely require more extensive repairs than would have been required if the piece of equipment had not been run to failure. Chances are the piece...
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