What Is Preventive Maintenance (PM)?
Also known as: PM, planned maintenance, scheduled maintenance, preventative maintenance
Definition
Preventive maintenance (PM) is planned servicing of equipment at set time or usage intervals, such as lubrication, inspection or part replacement, performed before a failure occurs to reduce unplanned downtime and extend asset life.
Preventive Maintenance (PM) Explained
A PM program defines for each asset a set of tasks and a trigger. Triggers are either time-based (every 30 days) or usage-based (every 500 run hours, every 100,000 cycles) using meter readings. When the trigger is reached, the system generates a work order from a job plan that lists tasks, estimated labor, required parts and safety steps.
In SAP the schedule lives in a maintenance plan (transaction IP10 schedules it) that generates orders from task lists. In IBM Maximo the Preventive Maintenance application generates work orders from a PM record, job plan and optional meters. Oracle EAM, Infor EAM, IFS and Dynamics 365 have equivalents. In a CMMS the same logic exists under names such as PM schedule or recurring work.
Good PM is selective. Time-based tasks suit parts with age-related wear, such as lubrication and filters. Many failures are random and not prevented by fixed-interval work, and each intrusive PM can itself introduce errors. That is why reliability-centered maintenance and condition-based maintenance exist: to decide which tasks truly reduce risk and to replace some fixed intervals with measured condition.
PM compliance, the share of scheduled PMs completed on time, is the standard health metric. A related caution: high compliance with poor task content produces a busy but ineffective program. Review tasks against failure history, not just completion rates.
Why It Matters
- Reduces unplanned stoppages on equipment with predictable wear, protecting delivery dates.
- Allows maintenance to be scheduled around production, with parts and people ready.
- Is often required by safety, quality or regulatory regimes for lifting equipment, pressure systems and calibrated instruments.
- Gives a baseline against which condition-based and predictive approaches can be compared.
In Practice
A CNC machining center has a spindle lubrication PM every 250 run hours. The meter reading comes from a machine hour counter. At 250 hours the CMMS generates a work order with a job plan (2 labor hours, one filter, one grease cartridge) and reserves the parts. If the work is deferred three times, the overdue report flags it, and failure history is checked for spindle bearing faults to see whether the interval is wrong.
Frequently Asked Questions
What is the difference between preventive and predictive maintenance?
Preventive maintenance acts on a fixed schedule or usage count regardless of condition. Predictive maintenance acts when measured condition, such as vibration or temperature trends, indicates a failure is developing.
What is PM compliance?
It is the percentage of scheduled preventive maintenance tasks completed within an allowed window of their due date. Many plants track it weekly, but it measures execution, not whether the tasks are the right ones.
Does ERP generate PM work orders?
ERPs with a maintenance module do, such as SAP and Oracle. Other ERPs rely on a separate CMMS to generate PM orders and pass costs and parts requisitions back through integration.
Related Terms
CMMS (Computerized Maintenance Management System)
A CMMS (Computerized Maintenance Management System) is software that records equipment, schedules preventive maintenance, issues and tracks maintenance work orders, and manages spare parts, so a maintenance team can plan work and keep a history of every repair.
Work Order
A work order is the ERP document that authorizes production of a defined quantity of an item by a due date. It snapshots the bill of materials and routing, drives material issues and labor reporting, and collects actual cost for the job.
TPM (Total Productive Maintenance)
TPM (Total Productive Maintenance) is a company-wide approach to equipment reliability that shifts routine care to operators, builds structured planned maintenance, and targets the elimination of breakdowns, speed loss, and defects caused by equipment condition.
Condition-Based Maintenance (CBM)
Condition-based maintenance (CBM) triggers maintenance when a measured indicator of equipment health, such as vibration, temperature or oil contamination, crosses a defined limit, instead of on a fixed calendar or run-hour schedule.
Reliability-Centered Maintenance (RCM)
Reliability-centered maintenance (RCM) is a structured analysis that determines, for each asset function and failure mode, the most effective maintenance strategy, such as preventive, condition-based, redesign or run-to-failure, based on consequence and failure behavior.
Go Deeper
Manufacturing Downtime Cost Calculator
Combine lost contribution margin, idle labor, and absorbed overhead into a defensible monthly and annual downtime cost - with recovery effects modeled.
Free ToolPredictive Maintenance ROI Calculator
Compare baseline unplanned downtime cost against predictive maintenance monitoring cost to see net annual savings across your asset fleet.
Preventive Maintenance and ERP: Closing the Loop
Preventive maintenance ERP integration guide: CMMS-ERP data flows, meter-based PM triggers, MRO inventory, scheduling impact, and AI-driven predictive maintenance.
AI Predictive Maintenance with ERP Integration
Integrate AI predictive maintenance with your ERP system. Reduce unplanned downtime by 45% using sensor data, ML models, and automated work order generation.
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