Preventive maintenance is planned servicing carried out on a fixed schedule before equipment fails, based on running hours, production cycles or calendar time. It covers lubrication, inspection, part replacement, alignment and calibration. Indian manufacturing plants that run it properly see fewer unplanned stoppages, longer equipment life and more predictable maintenance spend. The programme is measured on MTBF, MTTR, PM compliance rate and breakdown frequency.
- The cost comparison most plants get wrong. Preventive maintenance is compared against doing nothing. It should be compared against what last year's breakdowns actually cost.
- Start with 20 percent of your equipment. Rank machines by what happens when they stop. Build the programme around the critical few.
- OEM intervals are a starting point, not the answer. If a bearing fails at eight months and the manual says twelve, trust your own failure history.
- A schedule nobody follows is worse than no schedule. PM compliance below 80 percent means the programme exists on paper only.
- Preventive maintenance does not know machine condition. It works to a calendar. Condition monitoring closes the gap between visits.
- Four numbers tell you if it is working. MTBF, MTTR, PM compliance rate and breakdown frequency. Track monthly, judge on trend.
Ask a plant manager why preventive maintenance keeps getting postponed. The answer is usually budget.
Look at the numbers and something else shows up. The maintenance budget is tracked carefully. The cost of breakdowns is not tracked at all.
Last year's failures cost you lost production hours. Idle operators. Overtime to recover the schedule. Rush freight on spare parts. Sometimes a late delivery penalty.
Almost nobody adds that up.
When plants do add it up, the preventive maintenance budget looks small by comparison.
This guide covers what preventive maintenance involves. Why Indian plants struggle to adopt it. How to build a schedule that gets followed. And how to know if it is working.
What is preventive maintenance?
Preventive maintenance means servicing equipment on a schedule. You do the work before anything breaks.
You inspect. You lubricate. You replace worn parts.
You do this whether the machine is showing problems or not.
The schedule is set by running hours, production cycles or calendar time. Whichever fits the equipment.
How it compares to other maintenance types
| Type | When work happens | Cost pattern | Downtime risk |
|---|---|---|---|
| Breakdown maintenance | After the machine fails | Low until it fails, then high | High and unplanned |
| Preventive maintenance | On a fixed schedule | Steady and predictable | Low |
| Condition-based maintenance | When a reading crosses a limit | Medium, needs monitoring setup | Low |
| Predictive maintenance | When data forecasts a failure | High setup, lower running cost | Very low |
Most Indian plants run a mix.
Preventive maintenance on critical equipment. Breakdown maintenance on low-value machines where failure costs little and repair is quick.
That mix is sensible. Running preventive maintenance on every machine wastes labour on equipment that does not matter.
For a fuller picture of how these approaches work together, read our guide to breakdown maintenance in plants.
What preventive maintenance actually involves
The term covers a lot of different work. Here is what a programme usually includes.
Lubrication schedules
Bearings, gearboxes, chains and slideways need grease or oil at set intervals.
Too little causes wear. Too much causes heat and seal damage. Both shorten life.
Vibration checks
Rising vibration signals bearing wear, shaft misalignment or imbalance.
Readings are taken at fixed points. They are compared against a baseline taken when the machine was healthy.
Belt and chain inspection
Tension, wear and alignment get checked.
A slipping belt costs output long before it snaps.
Alignment verification
Couplings and shafts drift out of alignment over time.
Misalignment increases power draw. It heats bearings. It cuts component life.
Filter and fluid replacement
Hydraulic filters, air filters, coolant and oil are changed on schedule.
Contaminated hydraulic fluid damages pumps and valves. That damage is expensive.
Electrical inspection
Loose terminals, degraded insulation and overheating connections are found through visual checks and thermal imaging.
A hot terminal today is a failure next month.
Calibration
Gauges, sensors and measuring instruments are checked against reference standards.
An out-of-calibration sensor makes every other check unreliable.
Why Indian plants struggle to adopt preventive maintenance
Most plant managers know it works. Adoption is still uneven.
Four reasons come up again and again.
Cost pressure
Preventive maintenance costs money before anything has gone wrong.
That is a hard spend to justify when budgets are tight and the machine is still running.
The comparison that matters is different. What does one hour of unplanned downtime cost on that line?
Multiply that by last year's failures.
That number is usually larger than the preventive maintenance budget. It is just harder to see. It sits across production, HR and logistics rather than in one line item.
Many plants only see the full picture after a plant maintenance audit puts numbers against it.
Downtime cost is not measured
Most plants track what maintenance costs. Far fewer track what breakdowns cost.
The full cost includes lost production. Idle labour. Rush freight on spares. Overtime to recover the schedule. Sometimes penalty clauses on customer delivery.
Until that number exists, preventive maintenance looks like an expense. Not an avoided loss.
Shortage of skilled technicians
Preventive maintenance needs people who can read a vibration trend.
People who hear early bearing noise. People who can judge whether a belt has another month in it.
That skill takes years to build.
Many plants do not have enough of these people. Training takes time they cannot spare from production.
This is one reason plants bring in skilled maintenance manpower instead of building the capability in house.
Moving from reactive to planned
A plant that has always run on breakdown maintenance has habits built around it.
Firefighting gets noticed. Quiet prevention does not.
Changing that takes management commitment. Not just a schedule on the noticeboard.
How to build a preventive maintenance schedule
A schedule that gets followed starts with what matters most. Not with everything at once.
Step 1. Rank equipment by criticality
List every machine. Score each one on what happens if it stops.
A press that halts the whole line ranks higher than a standby compressor.
A single-source machine with no backup ranks higher than one of four identical units.
Start with the top 20 percent.
Step 2. Pull the OEM intervals
Machine manuals specify service intervals for lubrication, filter changes and inspection.
This is your baseline.
Step 3. Check your own failure history
If a bearing fails every eight months and the manual says twelve, trust your own data.
OEM intervals assume standard operating conditions.
Your plant may run hotter, dustier or at higher duty than the manual assumed.
Step 4. Write the task list
For each machine, write down exactly what gets checked. How often. By whom. With what tools.
Vague tasks get skipped.
"Check the gearbox" means nothing. "Check oil level against sight glass, top up with ISO VG 220 if below mark" gets done.
Step 5. Assign and schedule
Put tasks against named people and specific dates.
Fit them into planned stoppages, shift changeovers or weekend windows where possible.
Step 6. Record everything
Every completed task gets logged. Every finding gets recorded, including the ones where nothing was wrong.
Without records you cannot see whether the programme is working.
You also cannot adjust intervals based on evidence.
Measuring whether preventive maintenance is working
Four numbers tell you the truth.
MTBF — Mean Time Between Failures
Average running time between breakdowns. As preventive maintenance takes effect, this should rise.
MTTR — Mean Time To Repair
How long it takes to get equipment back into production after a failure. Good spares management and trained technicians bring this down.
PM compliance rate
The percentage of scheduled tasks completed on time. Below 80 percent means the schedule exists on paper only.
Breakdown frequency
Number of unplanned stoppages per month. This should fall as the programme matures.
Track all four monthly.
A single month tells you little. The trend over six months tells you everything.
When preventive maintenance is not enough
Preventive maintenance works to a calendar. It does not know the actual condition of the machine.
That creates two problems.
You service equipment that did not need it yet. That wastes labour, parts and machine availability.
You also miss failures that develop between visits. A bearing that starts to fail two weeks after a service will not be caught until the next one.
For critical high-value equipment, condition monitoring closes that gap.
Vibration analysis, thermal imaging and oil analysis report the actual condition. Not the assumed one.
Read more on why predictive maintenance fails in Indian plants and the mistakes that stop it working.
Where preventive maintenance programmes break down
Schedules built for everything at once
Trying to cover every machine from day one means nothing gets done properly. Start with critical equipment.
Tasks written too vaguely
"Inspect motor" gets interpreted differently by every technician. Specify what to check and against what standard.
No feedback loop
Findings get recorded but never reviewed. If the same fault appears three times, the interval or the method needs changing.
Compliance not tracked
Nobody measures whether scheduled work actually happened. Tasks quietly get skipped during busy weeks.
Production always wins
When the line is running, maintenance windows get cancelled. Without management backing, the schedule collapses under production pressure.
Frequently asked questions
What is the difference between preventive and predictive maintenance?
Preventive maintenance follows a fixed schedule regardless of machine condition. Predictive maintenance uses sensor data to forecast when a failure is likely and schedules work accordingly.
How often should preventive maintenance be carried out?
Intervals depend on the equipment, its duty cycle and operating environment. OEM manuals give the baseline. Your own failure history should adjust it.
Does preventive maintenance reduce overall maintenance cost?
It increases planned spend and reduces unplanned spend. For critical equipment, the reduction in downtime cost is usually larger than the increase in servicing cost.
What is a good PM compliance rate?
Above 90 percent is strong. Below 80 percent means tasks are being skipped and the programme is not delivering what it should.
Which equipment should be covered first?
Rank machines by what happens when they stop. Equipment that halts the whole line, has no backup, or has long lead times on spares should come first.
Can preventive maintenance be outsourced?
Yes. Many plants outsource scheduling, execution and reporting to a specialist team while keeping equipment ownership and production control in house.
How long before results show?
Breakdown frequency usually starts falling within three to six months of consistent execution. MTBF improvement takes longer because it needs enough running time to measure properly.
Does preventive maintenance work on old machines?
Yes. Intervals often need to be shorter than the original manual specifies. Older equipment has more wear, so inspection frequency matters more.
Get preventive maintenance running at your plant
SGK India sets up and runs preventive maintenance programmes for manufacturing plants across India.
We handle equipment criticality ranking, schedule design, execution, spares planning and monthly KPI reporting.
Explore our plant equipment maintenance servicesWritten by Amit Pal
Maintenance Engineering Specialist, SGK India
Amit Pal works with manufacturing plants across automotive, steel and heavy engineering sectors. He sets up preventive maintenance schedules and tracks MTBF and MTTR performance on site.
