Planned maintenance

Planned maintenance - (PM) or schedule maintenance, is the third pillar of Total productive maintenance (TPM). Its role is developing the effectiveness of operational equipment due to increasing its reliability, performance and reducing maintenance costs and equipment defects with the benefit of scheduled maintenance tasks to assure optimum use of the capacity of an enterprise.

The benefits of planned maintenance

Planned maintenance activities include any maintenance work which is scheduled in advance, f.e. changing the oil in a vehicle. Planned Maintenance is a scheduled maintenance activity or professional service visit to ensure correct operating of the equipment and its components. Planned maintenance involves three elements: disciplined planning of maintenance tasks, information tracking of equipment and process condition and plans, and schedule compliance to the maintenance plan. Most maintenance departments do not plan to fail but they just simply fail to plan and accordingly really fail. Planning insures that future equipment failures will require reactive response because the cost of breakdown maintenance is mostly higher than preventive mainteance The advantages of planned maintenance are:

• improving equipment capability and reliability - increasing the mean-time-between-failures (MTBF),
• improving equipment maintainability by reducing sporadic maintenance time - reducing the mean-time-to repair (MTTR),
• reduced maintenance costs,
• improved workplace safety,
• increasing equipment's life.

Maintenance Related Downtime

A key purpose of proactive maintenance is indetifying potential failures with acceptable arrangement to plan and schedule the corrective work before actual failure occurs. If the maintenance function is successful unscheduled maintenance related downtime will be reduced. Useful key performance indicators associated with asset downtime attributable to maintenance are:

• Unscheduled downtime (hours),
• Scheduled downtime (hours),
• Shutdown overrun (hours).

Predictive Maintenance 4.0

The application of big data analytics in maintenance represents the fourth level of maturity in predictive maintenance:

• Level 1: Visual inspections: regular physical inspections of equipment and structure; conclusions are based completely on investigator's judgement.
• Level 2: Instrument inspections: periodic inspections; conclusions are based on a combination of investigator's jud0gement and equipment's read-outs.
• Level 3: Real-time condition monitoring: regular real-time auditing of assets, with alerts which are given based on pre-established guidelines or critical levels.
• Level 4: continuous real-time monitoring of assets, with alerts which are sent based on prognostic techniques, for example regression analysis.

Footnotes

Planned maintenance — recommended articles

Types of control system — Maintenance management — Total productive maintenance — Control plan — Maintenance strategy — Autonomous maintenance — Organization of production — Line balancing — Validation master plan

References

• Nyman D., Levitt J., 2006, Maintenance Planning, Scheduling &Coordination, Industrial Press Inc.
• McKone K. E., Schroeder R. G., Cua K. O., 2001, The impact of total productive maintenance practices on manufacturing performance, Journal of operations management, vol. 19, p. 39-58.
• Raposo S., de Brito J., Fonseca M., 2013, Planned Preventive Maintenance Activities: Analysis of Guidance Documents, Springer-Verlag

Author: Sylwia Kotysz

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