Preventive maintenance for a small factory: a starter plan

In a small factory, it is easy to slip into breakdown maintenance. A machine stops, somebody calls the fitter, the fitter finds the part, and production waits.

Nobody plans for it to be this way. It happens because every day there is an order to ship, and a machine that is still running never feels urgent.

Preventive maintenance is the way out. The Lean Enterprise Institute describes it as regularly scheduled checking and overhauling of equipment, to reduce breakdowns and make machines last longer. You check and service machines on a schedule, before they fail, instead of after.

You do not need a maintenance department to start. A starter plan has 5 parts:

1. A list of your machines, ranked by how much each one matters.
2. Short daily checks done by the operator.
3. Weekly and monthly checks done by your maintenance person.
4. A spares stock based on what would hurt most to wait for.
5. A logbook, reviewed once a month.

We run film and tape lines on our own plant in Jaipur, and we have supplied packaging machines to customers abroad. My view from both is simple. The plan does not have to be clever. It has to be done every single day.

Step 1: List every machine and rank it

Walk the factory with a notebook and write down every machine, including the ones nobody thinks of as production machines. The air compressor, the generator, the water pump and the weighing scales all belong on the list. When the compressor stops, half the factory can stop with it.

For each machine, note:

Then rank each one into 3 groups.

1. A means a breakdown stops dispatch or a whole line.
2. B means output slows down, but there is a workaround.
3. C means it can wait a day or two without real harm.

Your plan starts with the A machines. Keep that list short. If more than a handful of machines are ranked A, go through the list again and be strict.

If a manual is missing, ask the maker for a copy now. Do not wait for the breakdown to discover it is missing.

Step 2: Daily checks by the operator

The person who runs the machine every day knows its normal sound better than anyone. Total Productive Maintenance (TPM), the approach that grew out of preventive maintenance in Japan, builds on that. In the Lean Enterprise Institute's definition of TPM, operators take part in routine maintenance through daily jobs such as cleaning, lubricating, tightening and inspecting.

A daily check should take 5 to 10 minutes at the start of the shift, with the machine switched off and isolated where the check needs hands near moving parts.

1. Clean the machine. Cleaning is when you notice the oil leak, the cracked guard and the missing bolt.
2. Look at the gauges, oil level windows, belts and guards.
3. Listen when it starts. A new knock or squeal is often the earliest warning you will get.
4. Notice heat. If a motor or bearing housing runs hotter than usual, use an infrared thermometer if you have one. Never use your hand.
5. Lubricate only the points marked on the machine, with the oil the manual names.
6. Tighten what is safe for the operator to tighten, and report everything else.

Keep each checklist to about 10 lines, printed and hung on the machine, with a tick box and a signature for each day. A checklist that takes half an hour will be ticked without being done.

Here is what a daily list for a typical air compressor can look like. Adjust it to your own model's manual.

1. Drain water from the receiver tank, or check that the automatic drain is working.
2. Check the oil level, if your compressor has an oil sight glass.
3. Note the pressure on the gauge when it cuts out.
4. Listen for air leaks near the compressor and the dryer.
5. Look at the air filter indicator.

Step 3: Weekly and monthly checks by maintenance

These need a trained fitter or electrician. Take the intervals from each machine's manual. If the manual is lost, start with your fitter's experience and adjust the intervals from what the logbook shows after a few months.

One simple habit helps a lot. Walk the compressed air lines during the lunch break, when the floor is quiet, and listen. Leaks you cannot hear during the shift are easy to hear then.

For a quick accuracy check, keep a known weight next to your scales and weigh it once a month. Write the reading in the logbook. Formal calibration is still a separate job for an approved agency, where your customers or the law require it.

Step 4: Stock the right spares

Spares fall into 3 groups.

1. Wear parts that you replace regularly: belts, blades, heater elements, bearings, seals, fuses and filters. Keep a minimum stock and a reorder level for each.
2. Slow-to-arrive parts for A machines: control boards, timers, drives, special motors and imported sensors.
3. Everything else, which you buy when it is needed.

For group 2, ask one question about each part.

If this part failed tonight, when would the replacement be fitted? If the answer is longer than you can afford to stop that machine, keep one in stock.

Electronics deserve special attention. When we supplied our paper bubble machine to a customer in the UK, I wrote the troubleshooting notes myself, and they were about the timers and the control board. Electronic parts are small, cheap-looking and easy to forget. For an imported machine they can also be the slowest parts to arrive. Store them in their anti-static bags, in a dry cupboard, with the machine's name on the label.

One more rule.

When somebody takes a spare from the shelf, the reorder starts that same day. An empty shelf is how a two-hour repair becomes a three-week stoppage.

Step 5: Keep one logbook per machine

A paper register next to the machine is enough. Each entry needs:

1. Date and time the machine stopped.
2. What happened, in the operator's words.
3. Time it started again.
4. What was done, and by whom.
5. Parts used.

Once a month, sit with the logbooks for 1 hour.

Find the 3 faults that repeat most. For each one, ask why it keeps happening, and keep asking until you reach a cause you can act on. A belt that breaks every month is often more than a belt problem. Look for a misaligned pulley, or a belt of the wrong size that was bought because it was available.

The stoppage times in the logbook also tell you how many machine hours you lose to breakdowns. Our guide to OEE for small factories shows how to turn those minutes into a number you can track every week.

Step 6: Give each machine an owner

This step takes the longest, because it changes habits, not machines.

The TPM way is to make the operator responsible for the machine's daily care, while the maintenance staff handle repairs, overhauls and improvements. A good way to begin is a thorough first cleaning of one A machine, done together by the operator, the fitter and the supervisor. Tag every problem you find: the loose bolt, the leak, the missing guard, the gauge nobody can read. Then fix the tags, one by one.

That first cleaning also gives you the daily checklist. The problems you found are exactly what the operator should look for every morning.

Small visual marks make the checks faster.

1. Mark the correct range on every gauge with green tape.
2. Mark the minimum and maximum levels on every oil sight glass.
3. Draw a paint line across important nuts and bolts. If the line breaks, the nut has moved.

Safety comes before all of this. Switch off and isolate a machine before anybody cleans it or reaches inside. If a machine can start while a hand is inside it, nothing else in this plan matters.

What preventive maintenance will not fix

I want to be honest about the limits, because a plan sold as magic gets dropped in 3 months.

1. It costs time. You will stop running machines to check them, and many checks will find nothing wrong. That is normal, and it is usually cheaper than an unplanned stop.
2. It cannot fix a machine that is run beyond its rated capacity every day.
3. It cannot fix poor raw material that jams or damages the machine.
4. It needs somebody to check that the checks happen. Without that, the tick boxes fill up and the machines do not change.

Paper and a spreadsheet are enough for the first year. If you later move to an ERP, look for a maintenance module that can schedule these checks. Our guide on choosing an ERP for a small manufacturer covers what to ask.

Your first month

1. Week 1: make the machine list and rank it.
2. Week 2: do a thorough first cleaning of your 3 A machines, and write their daily checklists.
3. Week 3: start the daily checks and the logbooks.
4. Week 4: hold the first monthly review, and fix the checklist lines that turned out to be useless.

Then add the next machines. Which machine in your factory would hurt most if it stopped tonight? Start there tomorrow morning.