Total productive maintenance (TPM): meaning, the 8 pillars, autonomous maintenance, OEE and a worked example

What is TPM (total productive maintenance)?

TPM means total productive maintenance. Each word does work. Total: everyone who touches the machine has a part, from the operator on nights to the plant manager. Productive: the target is output, so a machine that runs all shift at two thirds of its rated speed is a TPM problem even though it never broke. Maintenance: the means is keeping equipment in the condition it was designed to run in.

The old split says operators run the machine and maintenance fixes it. TPM ends that split. The operator who stands at the filler for eight hours is the first to hear a new noise, see a drip or feel a guard working loose, so the operator does the basic care: clean, inspect, lubricate and tighten, and tag anything abnormal. The technicians, freed from small jobs, plan the bigger maintenance work and go after the reasons machines fail.

TPM comes from Japan. Seiichi Nakajima of the Japan Institute of Plant Maintenance (JIPM) set it out in a short book, published in English as Introduction to TPM (Productivity Press, 1988). The first JIPM award for it is usually credited to Nippondenso, a Toyota parts supplier, in 1971. Our summary of Nakajima's book covers what it argues and where it has dated.

TPM has other meanings outside the plant. In computing it is a trusted platform module, a security chip in a PC. On the shop floor it always means total productive maintenance, and you will also see it written as total productivity maintenance or total product maintenance. Same idea.

Autonomous maintenance: the 7 steps

Autonomous maintenance is the pillar most people picture when they hear TPM. Operators take over the basic care of their machine in seven steps, and a team moves to the next step only when the current one holds, usually checked by an audit.

1. 1

   Initial cleaning and inspection

   Operators and a technician clean the machine down to bare metal, together. Cleaning is how they find things: every leak, loose bolt, crack, worn part and hard-to-reach point gets a tag and goes on the tag log.

2. 2

   Remove sources of contamination and hard-to-reach areas

   Stop the dirt at its source (a split seal, a spill from the conveyor above, a missing cover), and make every point that has to be cleaned, checked or greased easy to reach.

3. 3

   Set cleaning, lubrication and inspection standards

   Write down what is cleaned, lubricated and checked, how, with what, how often and in how many minutes. The first version is provisional; operators test the times on a real shift.

4. 4

   General inspection

   Technicians teach operators how each main system works (drives, pneumatics, hydraulics, electrics, fasteners) and what failure looks like, often through one-point lessons. Operators then inspect each system as part of the daily check.

5. 5

   Autonomous inspection

   Operators run the full inspection on their own, from a check sheet they helped write, and the cleaning and inspection standards are merged into one routine that fits the time available.

6. 6

   Standardization

   The routine is extended to the area around the machine: tools, spare parts, materials and quality checks each get a standard place and a standard check.

7. 7

   Autonomous management

   Operators run and improve their own standards, track their machine's losses and take part in improvement work, with maintenance as the support behind them.

The daily routine that comes out of steps 3 to 5 is usually called CILR or CILT (clean, inspect, lubricate, retighten or tighten). CILR in manufacturing shows a filled checklist, and the autonomous maintenance example walks one machine through the steps.

What a first clean turns up (illustrative)

A crew of three operators and one technician spends two hours on the first clean of a bottle filler. They hang 38 tags. Each tag is sorted by who can fix it: the operator, or maintenance.

The closing matters more than the hanging. Operators judge TPM by whether their tags get fixed. If the maintenance tags from the first clean are still open two months later, the second clean finds fewer tags because nobody bothers. The AM step audit checks whether a team has really finished a step before it moves on.

A TPM example, worked out in numbers

This example is illustrative. A bottle filler is the model machine. It is planned to run two shifts of 450 minutes, five days a week: 2 x 450 x 5 = 4,500 minutes a week. Its ideal cycle time is 0.5 minutes a case, so at full speed with no stops it would make 9,000 cases a week. The team logs one baseline week.

Next, turn the lost 24.9% into minutes and give each loss an owner. This is the loss map the pillars work from.

Over the next twelve months the pillars work on the filler. The first clean and the tags close out leaks and loose guide rails; the operators' CILR routine and new PM tasks on the capper drive bring breakdowns down to 5 stops, 225 minutes. A SMED event cuts each changeover from 45 to 36 minutes, so 5 changeovers take 180. Cleaning the photo-eyes every shift and fixing the infeed jam point cut small stops and slow running to 300 minutes. A torque check on the capper at every changeover brings rejects down to 140 cases.

Two things to take from the numbers. First, no single pillar did it. The breakdown work took 180 minutes a week off breakdowns (405 - 225), and the other changes took off another 166.5: 45 from setup, 87 from small stops and slow running, and 34.5 from rejects (69 fewer cases x 0.5). Together that is the 346.5 minutes of the gain. Second, the extra 693 cases are only worth money if they can be sold or let the line run fewer overtime shifts. Put the gain into the plan before claiming it. The OEE calculator and the downtime cost calculator turn your own figures into the same sums.

TPM vs RCM vs preventive maintenance, and TPM vs TQM

These terms get mixed up because they overlap. Preventive maintenance is a kind of task. Reliability-centred maintenance (RCM) is a method for choosing tasks. TPM is a way of organising the whole plant around its equipment, and it uses both.

TPM vs TQM. Total quality management aims at quality across the whole company, from design to service, and is run through the management system. TPM aims at the equipment and is run through the pillars at the machine. They share the habits of everyone taking part and of working on causes, and the quality maintenance pillar is where they meet: the machine conditions that make defects are found and held.

TPM in lean manufacturing. Lean cuts inventory between processes, and with little stock to cover a stop, a machine that breaks down stops the next process within minutes. TPM is the part of lean that makes machines dependable enough for just-in-time flow. The lean tools hub shows where TPM and OEE sit beside 5S, SMED, kanban and the rest.

TPM and predictive maintenance. A predictive task (vibration, oil analysis, thermography) is triggered by a measured condition rather than by the calendar. It belongs inside the planned maintenance pillar. Preventive vs predictive maintenance compares the trigger types.

Common TPM mistakes

• Calling it a maintenance program. If production managers do not give operators time for the daily care, TPM is a maintenance initiative with a new name, and it stalls.
• Starting everywhere at once. A plant-wide launch spreads the TPM lead and the technicians thin. One model machine that clearly works convinces more people than twenty half-done ones.
• Hanging tags and not closing them. Operators stop raising tags they never see fixed. Track open tags by age and review them at the machine every week.
• Handing over tasks without training. An operator asked to check chain tension needs to be shown what correct looks like, with a limit and a one-point lesson, and checked on the skills matrix.
• Using OEE to rank crews. OEE is for finding losses on one machine. Comparing it between machines or shifts that log stops differently starts arguments about the number instead of work on the losses.
• Counting activity instead of losses. Audits done and tags hung show effort. Breakdown minutes, small stops and rejects on the loss map show results.
• Using TPM to cut maintenance headcount. If technicians expect TPM to cost them their jobs, they will not train operators. Move freed hours to planned work and improvement.
• Skipping 5S. Cleaning and inspection standards cannot hold on a machine buried in clutter, with tools and parts that have no home.