Lesson 1 of 10
The Six Big Losses
Ask a plant why it missed its number and you will hear about the breakdown. Ask the machine and it will tell you about five other things nobody wrote down. This lesson is the taxonomy that makes invisible loss countable — and it is the foundation of everything else in this class.
Step one
Read the material
Three ideas. The losses come in three pairs, and each pair attacks a different part of the day.
Concept one
Two losses steal time: breakdowns and setup
These are the losses everybody already counts, because they are loud. A breakdown is an unplanned stop — the machine goes down and someone gets called. A setup and adjustment loss is the time between the last good part of one run and the first good part of the next: changeover, tooling, warm-up, first-piece approval.
Both cost you availability, which is the share of your planned time the machine was actually running. And both have an honest definition worth defending: the clock starts when production stops and ends when good production resumes. Not when the technician arrives. Not when the machine turns over. When good parts come out again.
Plants that measure changeover honestly are usually shocked. The stopwatch says forty minutes; the log said twelve.
Concept two
Two losses steal speed, and nobody reports them
This is the quiet half. Small stops are the brief interruptions an operator clears without calling anyone: a jam, a misfeed, a sensor blocked by a scrap of packaging. Each one is thirty seconds. None of them is worth a form. Two hundred of them is more than an hour and a half.
Reduced speed is the machine running below its design rate — because it makes a noise at full speed, because the material is off-spec, because it was dialled back six months ago during a problem and never dialled back up. Nobody logs it, because nothing stopped.
These two are the reason TPM exists. A downtime log measures what interrupted people. Speed losses do not interrupt anybody, so they are invisible until you compare what the machine made against what it was capable of making in the same time. That comparison is the whole of lesson two.
Concept three
Two losses steal quality: startup and defects
Startup losses are the parts sacrificed while the process stabilises after a start or changeover. They are predictable, which means they are budgetable, which means they are reducible — and which also means they get accepted as normal and never attacked.
Production defects are the parts made wrong once the process is running steadily: scrap and rework.
Here is the discipline that catches people. Rework counts as a loss even though the part eventually ships. You paid for the machine time twice and the labour twice. A part that needed rescuing is not a good part; it is a defect you repaired. Count it honestly or your quality number will flatter you and you will never find the cause.
Six losses. Two on time, two on speed, two on quality. Every one of them will reappear in the next lesson as a term you can multiply.
Step two
Work it with your hands on it
One shift, eight hours. Move the six losses and watch where the day actually goes. Notice how much of it disappears without ever entering a downtime log.
Hands on it, off the screen. Stand at one machine for one hour with a notebook and a watch. Mark a tick every time it stops, however briefly, and write what it was. Do not help. Do not fix anything. Just count.
Almost nobody has ever done this at their own plant, and almost everybody who does is surprised by the tally. That single hour is the most persuasive TPM argument you will ever make to a manager.
Step three
Prove you understood it
One question per idea, new numbers every time.
All three solid.
You can name all six losses, sort them by what they steal, and count the ones that never reach a log. Lesson two turns them into a single number.
Modern Total Productive Maintenance (TPM)
Lesson one of ten. This class is taught from the Total Productive Maintenance series — the eight pillars, the six big losses, and the roadmap into AI and predictive manufacturing. Written by our founder, Dr. Gene A Constant, and donated to the Foundation.
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