Preventive Maintenance
PMPreventive Maintenance (PM) is regularly scheduled work performed on equipment to lessen the likelihood of it failing.
Preventive Maintenance (PM) is a proactive maintenance strategy. It involves performing scheduled maintenance tasks on equipment while it is still operational. This approach contrasts with reactive maintenance, where repairs are only made after a machine breaks down. PM tasks are triggered by time intervals, usage hours, or production cycles.
On a shop floor, a PM program follows a documented schedule. For example, a CNC machine's coolant levels and concentration are checked weekly. A stamping press might be lubricated after every 10,000 cycles. A conveyor belt motor could be scheduled for replacement every five years, regardless of its current condition. These tasks are often managed using a Computerized Maintenance Management System (CMMS) to generate work orders and track completion.
The main goal of PM is to reduce unplanned downtime. By addressing potential issues before they cause a failure, manufacturers can improve equipment reliability and extend its lifespan. This also leads to better production consistency, improved workplace safety, and lower overall maintenance costs compared to expensive emergency repairs.
A metal fabrication shop schedules PM for its press brake. Every 250 hours of operation, a technician inspects hydraulic fluid, tightens connections, and calibrates the backgauge. This regular service prevents a sudden hydraulic failure during a large production run.
How is PM different from predictive maintenance (PdM)?
PM is based on a fixed schedule (time or usage). PdM is based on the actual condition of the equipment, using sensors and data analysis to predict failures.
What is the first step to starting a PM program?
Begin by creating an inventory of critical assets. Then, consult equipment manuals for the original equipment manufacturer's (OEM) maintenance recommendations.
How do I know if my PM schedule is effective?
Track key performance indicators like Mean Time Between Failures (MTBF) and total downtime. An effective PM program will show an increase in MTBF and a decrease in unplanned downtime.
Can you perform too much PM?
Yes. Over-maintenance increases costs for labor and parts without adding value. It can also introduce new problems if tasks are performed incorrectly.
What software helps manage PM?
Computerized Maintenance Management Systems (CMMS) are designed to schedule, track, and document PM tasks and work orders.
Computerized Maintenance Management System
CMMSA Computerized Maintenance Management System (CMMS) is software that organizes, schedules, and tracks all maintenance activities for a facility's equipment.
Downtime
Downtime is any period when a machine or production line is scheduled to run but is not producing goods.
Mean Time Between Failures
MTBFMean Time Between Failures (MTBF) is the average time a piece of equipment operates before it breaks down.
Predictive Maintenance
Predictive maintenance uses data analysis and monitoring tools to detect potential equipment failures before they happen.
Total Productive Maintenance
TPMTotal Productive Maintenance (TPM) is a strategy that makes equipment maintenance a shared responsibility for all employees to improve productivity.