THE FLOW

From film rolls to a finished can

Put the main manufacturing steps in order.

Every step before sealing is a chance to trap a defect; every step after is a chance to catch it.

WHY CLEANLINESS

Dust at kilovolts

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A fibre or speck trapped between films

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The field concentrates around it

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Partial discharge erodes the film until it punctures

In film/foil, one trapped particle can be one dead capacitor.

CLEAN, DRY, STATIC-FREE

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Controlled rooms Winding often happens in a cleanroom or clean zone, typically far less strict than a chip fab

Humidity Kept low and steady: films and paper soak up water

Static Ionizers neutralize charge on fast-moving film

Gowning Smocks, hairnets and gloves keep people's fibres and oils off the film

5S Sort, Set in order, Shine, Standardize, Sustain: an orderly floor is a cleaner floor

Cleanliness on a capacitor line is about dust and moisture, not nanometre particles.

GAME

Trace each defect back to the step most likely to have caused it.

Knowing the process flow is what turns a failure into a fix.

INCOMING MATERIALS

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Film Thickness, breakdown strength, surface roughness and cleanliness

Metallized film Metal thickness, checked as sheet resistance in ohms per square

Foil Thickness, edge quality and surface cleanliness

Oil Moisture content, gas content and purity

Lot changes A new film lot is a classic special cause on an SPC chart

Many "process" problems turn out to be material problems, so incoming data is worth tracking.

UNIT 8 STUDY COMPLETE

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You've walked the process flow and seen how contamination, moisture, static and materials drive yield.