Preventive maintenance process flowchart (scheduled PM)

What the preventive maintenance process flowchart (scheduled pm) process is

Preventive maintenance is work done to a schedule rather than to a fault. The trigger comes from the asset register (a calendar interval, or a meter target such as run hours, cycles or kilometres) and the whole point of the process is that the work order exists before the machine needs it. The chart below follows one PM from schedule generation to closure: the work order raised in advance, the downtime slot agreed with production, the parts kitted by stores, the machine handed over and isolated, the task list worked through against its checklist, a functional test, handback, and the records that set the next due date.

This is scheduled maintenance only. There is no fault report at the top of the chart and no breakdown path through it. If a machine has already stopped, or an operator has reported a fault, that belongs to reactive and corrective maintenance, which starts from a work request rather than from the schedule. The two processes meet at exactly one point here: the 'Defects found?' decision. Anything the technician finds that is outside the PM scope leaves this chart as a separate corrective work order, to be planned, prioritised and resourced in its own right. Keeping that boundary visible is what stops a two-hour PM quietly becoming a six-hour repair nobody scheduled.

Three decisions carry the process. The trigger decision settles whether the job is due by calendar or by usage, which matters because the two behave very differently when a machine sits idle for a month. 'Defects found?' decides what leaves the chart as corrective work. 'Machine performs to standard?' decides whether the asset goes back to production, and it sits in the Quality lane rather than the technician's on purpose: the person who did the work should not be the only person who signs it off. The final steps close the loop by feeding what was found back into the interval on the register, which is what separates a maintenance programme from a recurring calendar reminder.

What this flowchart covers

In this template

• Five swimlanes (Maintenance planner, Operator / production, Stores, Technician and Quality) across six phases: schedule, plan and prepare, handover, execute PM, test and handback, and records and review
• An 'Interval or meter trigger?' decision at the top, so one chart covers both calendar-based PM and usage-based PM, where run hours logged by the operator against the asset bring the job forward or push it back
• The planning half that most maintenance charts skip: a work order raised ahead of the due date, a downtime slot agreed with production, and Stores kitting parts and consumables against that work order before anyone approaches the machine
• Handover and isolation as separate steps in separate lanes: production hands the machine over, the technician isolates and locks off, and isolation is only removed and guards refitted once the task list is complete
• A 'Defects found?' decision that routes anything outside the PM scope onto its own corrective work order in the planner's lane, so PM hours and defect trends stay separable and the booked window is not absorbed by unplanned repair
• Handback on evidence: a functional test, a Quality 'Machine performs to standard?' decision with a rectify-and-retest loop, production accepting the machine back, then the work order record, meter reset, an interval adjustment from the findings, and closure

When to use this template

• You are writing or rewriting a PM procedure and need one picture of the handoffs between planning, production, stores, maintenance and quality
• Scheduled PMs are being deferred or completed late and you need to see whether they stall at the trigger, the downtime slot or the parts kit
• You are configuring or migrating a CMMS and want the process agreed before work order types, task lists, meters and PM frequencies are set up
• Maintenance and production disagree about downtime, so the slot negotiation, the handover and the handback need to be explicit and owned
• An auditor, insurer or certification body has asked for a documented description of how scheduled maintenance is planned, carried out and recorded

How it works

1. Rename the lanes to your roles

   Replace Maintenance planner, Operator / production, Stores, Technician and Quality with the roles that genuinely exist in your organisation. On a small site the planner and the technician are often the same person: merge those lanes rather than drawing a handoff that never happens.

2. Write your trigger rule onto the first decision

   State which assets are time-based and which are usage-based, what the meter actually counts (run hours, cycles, distance, throughput) and who is responsible for logging it. If your CMMS raises the PM on whichever comes first, say so on the chart.

3. Set the planning lead time

   Decide how far ahead of the due date the work order is raised. It has to be long enough to order non-stock parts and get into the production plan. A work order that appears on its due date is already late, and that single number explains most missed PMs.

4. State the isolation and handover rule

   Record what isolation the asset needs, who applies and removes the lock, whether a permit to work is required, and how stored energy in pneumatics, hydraulics and suspended loads is dealt with. Note where the signed handover and handback are recorded.

5. Decide what happens to defects

   Agree the rule for work found during the PM: what may be fixed inside the booked window, what is raised as a corrective work order and planned separately, and what stops the machine going back into service. Also agree who grades the urgency.

6. Define the record and the meter reset

   List what the completed work order must carry — task list results and readings, parts used, labour and downtime — and state whether the next due date runs from the completion date or from the original due date. Those two rules produce very different schedules over a year.

7. Walk it against a completed PM

   Take two or three finished PM work orders, one that went to plan and one that overran, and trace them through the chart. Any step people describe that is not drawn, or drawn but skipped in practice, is the finding worth acting on before you publish it.

Frequently asked questions

What are the steps in a preventive maintenance process?

The PM schedule is generated from the asset register and the job becomes due either on a calendar interval or on a meter reading logged against the asset. The planner raises a work order in advance, agrees a downtime slot with production and has stores kit the parts. Production hands the machine over, the technician isolates and locks it off, then works through the PM task list against its checklist. Anything found outside the PM scope becomes a corrective work order. Isolation is removed, guards are refitted, a functional test is run and checked against the standard, production accepts the machine back, and the work order is recorded, the meter reset, the interval adjusted if the findings justify it, and the record closed.

What is the difference between preventive, corrective and reactive maintenance?

Preventive maintenance is scheduled by time or usage and is carried out whether or not anything appears to be wrong. Corrective maintenance restores a known defect and can be planned, which is exactly what the 'Defects found?' branch of this chart hands off. Reactive or breakdown maintenance starts after the failure, from a fault report rather than from the schedule. Condition-based and predictive maintenance sit alongside these: the work is still planned, but the trigger is a measurement such as vibration, temperature or oil analysis rather than a date or a meter target. This template covers the time- and usage-triggered case only.

Should a PM be triggered by a calendar interval or by a meter reading?

Match the trigger to what actually drives the failure. Ageing, corrosion, lubricant degradation and statutory examination dates track elapsed time, so a calendar interval fits. Wear driven by use — bearings, belts, filters, cutting tools — tracks run hours, cycles or distance, so a meter fits better and stops you servicing a machine that has been standing idle. Many systems support whichever comes first, which is a reasonable default for assets with both failure modes. Usage triggers only work if the readings are logged reliably, so put that step in someone's lane rather than assuming it.

What is PM schedule compliance and how is it measured?

It is the proportion of scheduled PMs completed within their agreed window, and it is the usual health check on a maintenance programme. It only means something once you have defined the window — the grace period either side of the due date — and a rule for deferrals, including who may approve one and how many times a job may be pushed. Organisations set their own target rather than working to a universal figure. Measured without a defined window, compliance can be reported as high while jobs drift weeks past their due date.

How do you know whether a PM interval is right?

Use the evidence the process produces. Several cycles in a row that find nothing at all suggest the interval is shorter than it needs to be. Failures arriving between PMs suggest it is too long, or that the task list is checking the wrong things. Corrective work orders raised from PM findings, and any condition monitoring data, tell you which. Change the interval on the asset register, with a named approver, rather than adjusting one work order. Some intervals are not yours to move: statutory examinations, and manufacturer or warranty requirements, set their own frequency regardless of what you find.