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Practical guide · TPM and maintenance

Preventive vs predictive maintenance, and the other types, explained

Short answer

Preventive maintenance is work done on a fixed schedule, by time or by usage, to stop equipment failing. Predictive maintenance is work done when the measured condition of the equipment shows it is wearing out. Reactive maintenance waits for the failure. Planned maintenance means the work is prepared ahead, and autonomous maintenance and total productive maintenance (TPM) share the care with operators. You choose per machine, not per plant.

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Preventive vs predictive maintenance in one table

The difference is the trigger. Preventive maintenance starts because the calendar or a usage count says it is due. Predictive maintenance starts because a reading, such as vibration, temperature or oil condition, says the part is deteriorating.

Six ways to look after equipment
TypeWhat it isWhat triggers the workWhen it fitsIllustrative exampleCost profile
ReactiveFix it after it breaks, also called run to failureThe breakdown itselfCheap, non-critical items that are easy to replaceReplacing a failed indicator lampLow upkeep cost, but each failure is unplanned and often rushed
PreventiveInspect, lubricate, adjust or replace parts at set intervalsTime or usage, such as monthly or after a set run countWear that follows a steady pattern and is cheap to serviceGreasing a gearbox and changing its filter every quarterSteady, predictable spend, with some parts changed early
PredictiveService the machine when its measured condition says it is neededA reading that crosses an agreed limitCritical assets where failure gives warning and a reading is practicalReplacing a bearing when its vibration trend climbsNeeds readings and skill to interpret them, but parts last longer
PlannedAny maintenance that is prepared in advance: job, parts, tools, people and timeA schedule or a finding, then preparation before the stopEvery strategy above except pure run to failureA crew with the parts staged for a Saturday shutdownShorter stops and fewer rush orders
AutonomousOperators clean, inspect, lubricate and tighten their own machinesA daily routine and what the operator noticesEvery machine with an operator on itWiping down a filler, then tagging a small leakLittle spend, mostly time, and it frees technicians for harder work
TPMA plant-wide system that makes operators, maintenance and management jointly responsible for equipmentIts pillars, such as autonomous and planned maintenanceA plant that wants fewer breakdowns, small stops and defects togetherOperators on daily care, technicians on planned workAn investment in routines and training, repaid over time

Planned maintenance is not a rival to the others. It is how you organise them: preventive and predictive tasks, and repairs you can see coming, are all planned when the work is prepared before the machine stops. The preventive vs predictive differences post goes into each in depth.

Why preventive maintenance is important

Preventive maintenance is important because it turns a surprise into a scheduled job. A planned stop at a convenient time costs less than a breakdown in the middle of an order, and it catches wear while the repair is still small.

The cost is that some parts get changed a little early. The benefits of preventive maintenance post covers them. To start a routine, the preventive maintenance checklist gives you tasks, frequencies and sign-off.

Planned maintenance and planned downtime, with examples

Planned maintenance is maintenance prepared before it starts, with the steps, parts, tools, skills and time worked out. Planned downtime is the stop that goes with it: time a machine is deliberately stopped on a schedule. Because it is known in advance, the production plan can allow for it.

  • Scheduled preventive maintenance, such as a lubrication and inspection round.
  • Changeovers between products.
  • Cleaning stops, trials and breaks that stop the line.

Plants decide for themselves which of these count against OEE, so write the rule down and apply it everywhere. See what is planned downtime and what is planned maintenance, and how the rule feeds the OEE calculation. Planned downtime is the opposite of unplanned downtime, which is the stop nobody scheduled; reducing machine downtime shows how to attack that.

Autonomous maintenance and TPM

Autonomous maintenance is the TPM pillar in which operators take on basic care of their own machines: cleaning, inspecting, lubricating and tightening, and reporting anything abnormal. It is usually introduced in seven steps, starting with an initial clean. The routine is often shortened to CILR, for clean, inspect, lubricate, retighten. Start with the autonomous maintenance checklist, and see the autonomous maintenance page and the seven steps post.

TPM is total productive maintenance: the plant-wide approach that makes operators, maintenance and management jointly responsible for keeping machines in top condition. It is organised in pillars, and OEE is its usual measure of progress.

People often search for "total preventive maintenance". The method is called total productive maintenance. Preventive maintenance is one of the tools inside it. The total productive maintenance post covers the pillars, and the TPM software guide shows what to look for in a tool for each pillar.

How to choose a strategy for each machine

Choose by asset, using three questions. How much does it hurt if this machine stops? How does it usually fail? What does it cost to look after? Rank your machines first with the equipment criticality analysis.

  1. 1

    Rank by criticality

    Ask what stops if this asset stops: the line, the customer order, safety, quality. Put the machines that stop the most at the top.

  2. 2

    Look at how it fails

    If wear follows time or usage, a schedule works. If failure gives warning in a reading you can take, predictive work fits. If failure is random with no warning, neither helps much, so keep a spare and fix it fast.

  3. 3

    Weigh the cost of failure against the cost of care

    Spend more care where a failure is costly and less where it is cheap. A cheap, non-critical part can run to failure on purpose.

  4. 4

    Review after each failure

    A failure that surprised you means the strategy for that machine was wrong. Change it and record why.

An illustrative example: one packaging line

This example is made up. A packaging line has three machines that matter and each gets a different answer.

One line, three strategies (illustrative)
MachineHow it mattersHow it failsStrategy
Guide rail motorCheap, and a spare sits on the shelfWithout warning, rarelyReactive: swap it when it fails
Gearbox on the main conveyorStops the whole lineWears steadily with running timePreventive: lubricate and inspect on a schedule, change the filter on a set interval
Main drive bearingStops the line and takes a day to replaceGets noisy and hot before it failsPredictive: take readings on a route, plan the change when the trend climbs

On all three, the operator does the daily CILR check and tags what looks wrong. The team then prepares each job, which makes the work planned. A record of readings and findings can be kept on the condition monitoring route sheet and the weekly maintenance schedule.

Common mistakes

  • Using one strategy for the whole plant. Different machines fail in different ways.
  • Treating predictive as better in every case. It adds cost and skill, and a cheap asset does not need it.
  • Servicing on a calendar a machine does not follow, so parts are changed early or failures still arrive between visits.
  • Not logging stops with a reason, so there is no evidence to pick a strategy. The equipment downtime log is a place to start.
  • Never reviewing. A strategy chosen once and never checked drifts out of date.

LeanSuite covers the operator side and the loss side of this: its autonomous maintenance checklists and its loss and cost views. It does not diagnose machines for you; the readings are taken and entered by your team.

Go deeper

This page is the short version. These guides cover each part in full.

All our articles on this subject are in the tpm and maintenance topic.

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FAQ

Questions about preventive vs predictive maintenance

  1. Preventive maintenance is done at set intervals of time or usage, whether or not the part needs it. Predictive maintenance is done when a measured condition, such as vibration, temperature or oil condition, shows the part is deteriorating. Preventive follows the calendar and predictive follows the machine. Predictive avoids changing good parts but needs readings and someone to interpret them.

  2. Neither is better everywhere. Use preventive maintenance where wear follows time or usage and the service is cheap. Use predictive maintenance on critical assets where failure gives warning in a reading you can take. Use reactive maintenance on cheap, non-critical parts. Most plants run a mix, chosen machine by machine.

  3. It turns breakdowns into scheduled jobs. A planned stop at a convenient time costs less than a failure in the middle of an order, wear is caught while the repair is small, and parts and people can be ready. The trade-off is that some parts are replaced a little early.

  4. Planned maintenance is maintenance prepared in advance: the job is defined and the steps, parts, tools, skills and time are worked out before it starts. It covers preventive and predictive tasks and repairs that can be prepared ahead. In TPM it is also one of the pillars.

  5. Scheduled preventive maintenance, changeovers, cleaning stops, trials, breaks and meetings that stop the line, and planned shutdowns for larger overhauls. They are known in advance, so the production plan can allow for them. Each plant decides which count against OEE and should write the rule down.

  6. Autonomous maintenance is the TPM pillar in which operators take on basic care of their own machines: cleaning, inspecting, lubricating, tightening and spotting abnormalities early. It is usually introduced in seven steps, starting with an initial clean. It frees maintenance technicians for planned and more skilled work.

  7. TPM stands for total productive maintenance, not total preventive maintenance. It is a plant-wide approach that makes operators, maintenance and management jointly responsible for equipment, aiming for no breakdowns, no small stops, no defects and no accidents. Preventive maintenance is one tool used inside it.

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