Andon: Stop For Improvement

After World War II, Ohno visited auto factories in Detroit. He expected to learn from the best. Instead, he found rework areas filled with broken pieces and leftover parts. Waste everywhere, hiding in plain sight.

He went back to Toyota City and did something nobody had tried before. At every station on the assembly line, he hung a rope called the Andon cord.

The instruction was simple:

If you see a defect pull the cord. The line slows or stops. Engineers, workers, and suppliers huddle up and fix it on the spot. Detroit thought he was crazy. "How can you build thousands of cars a day if you stop the line for every little scratch?"

Ohno's answer was simple:

A scratched fender is an early warning that a piece of equipment is failing. Fix the scratch today, and you prevent 500 defective fenders next week. Ignore it, and you're building rework areas just like Detroit.

That's the difference between firefighting and fire prevention.

Most operations leaders I talk to are stuck in firefighting mode. They walk past small defects every day because the line has to keep moving.

But those small defects are talking to you. They're telling you exactly where your next big quality failure will come from.

How many "minor" defects is your team walking past today that are actually early warning signs?