The 5 Whys Only Work If You Answer Honestly

The first answer is usually the event. The bearing failed. The line stopped. Everybody nods, and the meeting orders a spare.

The spare goes in. A few weeks later the same bearing fails again, and the same meeting orders another spare. That is not a fix. That is a subscription.

Five whys is a way to keep asking past the event until you reach something you can change. Here is a chain worked all the way down. Say a conveyor keeps stopping.

Why did the conveyor stop? The bearing seized. Why did it seize? It ran dry. Why did it run dry? It missed grease on the last two checks. Why did it miss grease? The grease point sits behind a guard, and the check is scheduled in a short window between runs. Pulling the guard does not fit in the window. Why is the grease point behind the guard? The guard was added later, and nobody moved the grease point.

Now you have a cause with a handle on it. Have qualified maintenance review a lubrication point that can be serviced safely without bypassing the guard. Any work on the machine follows the site’s energy-control procedure. Name who owns the review and by when. That is the action. The spare bearing was never the answer, because the bearing was never the problem.

Two rules keep the chain honest. First, every answer has to be something you can check at the machine, not something you suspect. If you cannot go look, you are guessing, and a guess at step two sends the next three steps down the wrong road. Second, stop when the next answer is an action with a name on it, not when you reach five. Sometimes it takes three. Sometimes seven. A chain that ends in “people need to care more” is not a chain. It is a complaint, and it lets the setup that caused the failure off the hook.

This week, take one failure that keeps coming back. Write the whys. Check each answer at the machine. Stop at the action, put a name on it, and watch whether the failure returns.

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