Seiso (Shine)
清掃·seisō·"cleaning, sweeping"
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Seiso is the third of the 5S steps - cleaning the workplace thoroughly while inspecting for abnormalities.
Definition
Seiso, meaning "Shine" or "Sweep," is the third step of the 5S methodology. It involves thoroughly cleaning the workplace and equipment while simultaneously inspecting for abnormalities. Seiso goes beyond appearance—cleaning is also inspection. When operators clean equipment, they notice loose bolts, leaks, cracks, and wear that would otherwise go undetected. Regular seiso maintains equipment reliability, prevents contamination-related quality issues, and creates a pleasant work environment that people take pride in maintaining.
Examples
Daily seiso in a machining area includes wiping down machines, sweeping floors, and cleaning fixtures. During this cleaning, operators discovered a small hydraulic leak, a loose guard, and unusual wear on a spindle bearing—problems caught early before causing breakdown or quality issues.
Key Points
- Cleaning is inspection—seiso finds problems while cleaning
- Regular seiso prevents contamination-related quality and reliability issues
- Seiso should be assigned and scheduled, not left to chance
- A clean workplace creates pride and encourages further improvement
Common Misconceptions
Seiso is just janitorial cleaning. Seiso is performed by the people who work in the area, not cleaning staff. This is because seiso is inspection—operators know their equipment and can spot abnormalities that cleaners wouldn't recognize.
Seiso can be skipped when busy. Skipping seiso leads to equipment problems, quality issues, and degraded work environment. The time invested in seiso prevents larger problems.