dCOMSATS Institute of Information Technology, Sahiwal

Define and discus the difference b/w preventive maintenance and condition base maintenance and also out line parameters ? "That moment when even a dog can lose that much weight but you can't"

Submitted To

Dr Zahiruddin Shaikh Chief EngineerCIIT, Sahiwal

Submitted By

Saad Ur RehamnFa11-BME-B3-065

Grade ...Checked by.......

Department of Mechanical Engineering

Preventive Maintenance Definition: Preventative maintenance (or Preventive Maintenance ) is maintenance that is regularly performed on a piece of equipment to lessen the likelihood of it failing. Preventative maintenance is performed while the equipment is still working, so that it does not break down unexpectedly.Preventive maintenance (PM) is a fundamental, planned maintenance activity designed to improve equipment life and avoid any unplanned maintenance activity. This maintenance includes: Systematic inspection Detection Correction Prevention of incipient failuresPreventive maintenance is the foundation of the entire maintenance strategy. Unless the PM program is effective, all subsequent maintenance strategies take longer to implement, incur higher costs, and have a higher probability of failure.Preventive maintenance aims to: Eliminate unnecessary inspection and maintenance tasks Implement additional maintenance tasks when and where needed Focus efforts on the most critical itemsIn addition, preventive maintenance measures can drastically reduce errors in day-to-day operations, as well as increase the overall preparedness of plants in the case of an emergency.The ideal preventive maintenance program would prevent all equipment failure before it occurs.In preventive maintenance, equipment is repaired and serviced before failures occur. The frequency of maintenance activities is predetermined by schedules. The greater the level of preventive maintenance required, the higher the failure consequences. Condition-Based Maintenance (CBM)Definition: In predictive maintenance a machine is taken for maintenance only when its status or condition so demands. therefore, this type of maintenance is also known as condition-based maintenance.Condition Based Maintenance (CBM) is a maintenance strategy that uses the actual condition of the asset to decide what maintenance needs to be done. CBM dictates that maintenance should only be performed when certain indicators show signs of decreasing performance or upcoming failure. Checking a machine for these indicators may include non-invasive measurements, visual inspection, performance data and scheduled tests. Condition data can be gathered at certain intervals, or continuously (as is done when a machine has internal sensors). CBM can be applied to mission critical and non-mission critical assets.Example:

Motor vehicles come with a the manufacturer-recommended interval for oil replacements. These intervals are based on manufacturers' analysis, years of performance data and experience. However, this interval is based on an average or best guess rather than the actual condition of the oil in your specific vehicle. The idea behind CBM is to replace the oil only when a replacement is needed, and not on a predetermined schedule.

In the case of industrial equipment, oil analysis can perform an additional function too. By looking at the type, size and shape of the metal particulates that are suspended in the oil, the health of the equipment it is lubricating can also be determined.Advantages of Condition Based Maintenance

CBM is performed while the asset is working, this lowers disruptions to normal operations Reduces the cost of asset failures Improves equipment reliability Minimizes unscheduled downtime due to catastrophic failure Minimizes time spent on maintenance Minimizes overtime costs by scheduling the activities Minimizes requirement for emergency spare parts Optimized maintenance intervals (more optimal than manufacturer recommendations) Improves worker safety Reduces the chances of collateral damage to the systemThe 3 Phases of Condition Based Maintenance

1. Surveillance - monitoring the equipment condition to detect developing problems2. Diagnosis - isolating the root cause of the issue and developing a corrective plan based on priority, equipment condition and its remaining life3. Remedy - performing the corrective actionParameters that justify performance over preventive maintenance Condition Based Maintenance (CBM) is just that - maintenance actions based on the condition of equipment vs maintenance actions based on time or breakdowns. Condition Monitoring (CM) is the path to CBM. CBM is a maintenance strategy and CM is the tool we use to accomplish it. All condition based maintenance is pro-active, but not all pro-active maintenance is condition based. Pro-active could be changing out a lightbulb before it burns out, but that doesn't mean that the condition warrants it. So pro-active is not necessarily condition based. CM is the time based monitoring of an asset with a technology. Technologies such as vibration analysis, thermography, ultra sound, oil analysis, etc. are applied to detect faults in the equipment as early as possible. This can be as complicated as an automatic permanently installed system, or a time based portable application accomplished manually or as simple as a motor bearing temperature displayed on a DCS (Distributive Control System). The readings and/or data from these systems are analyzed and the current condition of the asset can be determined. Condition Based Monitoring (CBM) This most commonly refers to on-line or live monitoring of equipment, but it can also refer to regular scheduled spot checks and trending of data determine the condition of the asset. This is often referred to with Vibration (VA) or Motor Circuit Analysis (MCA). "Predictive Maintenance" used interchangeably with Condition Based Maintenance, however I believe that it is more accurate to use it synomymously with Condition Monitoring. ie. we use predictive maintenance to accomplish our condition based maintenance strategy, or, we use condition monitoring to accomplish our condition based maintenance. (same-same, but in this case it may be more apt to call it Predictive monitoring.) One last thought. To most people, all of these terms are synonymous with each other, and it's an exercise in futility to try and explain that to someone who is not in the industry (usually.) So just pick the term you'd like the best and go with it. Even after the proof of years and gazillions of dollars saved, it's still hard to get people to buy into the 'predictive maintenance' idea, especially when budget dollars are flying back and forth, so focus on success, not terminology.http://sextubefilms.com/search/indian-college/