Quality Control at HUAYU

Stage 1 — Raw Material Inspection

All incoming materials — anode foil, cathode foil, electrolyte, separator paper, rubber seals, aluminum cases, and terminals — are tested against strict incoming quality specifications before entering the production line. We maintain relationships with qualified, audited suppliers and conduct periodic supplier quality assessments.

Key checks include: foil thickness and purity, electrolyte conductivity and flash point, rubber compound hardness and seal integrity.

Stage 2 — In-Process Control

Automated monitoring at every critical production stage. Winding tension, electrolyte impregnation pressure and temperature, assembly alignment, and crimping force are continuously measured and recorded. Any deviation from process parameters triggers an immediate alert and production hold.

Statistical process control (SPC) charts are maintained for key process parameters to detect trends before they reach specification limits.

Stage 3 — Aging & Screening

All capacitors undergo an accelerated aging process at elevated temperature and rated voltage. This burn-in step stabilizes the dielectric oxide layer, reforms any defects in the anode foil, and screens out early-life failures (infant mortality). Aging parameters are specific to each product series and voltage rating.

Post-aging, each capacitor is discharged and undergoes a stabilization rest period before final testing.

Stage 4 — 100% Final Testing

Every single capacitor is individually tested for:

• Capacitance — measured at 100Hz or 120Hz, within specified tolerance
• ESR (Equivalent Series Resistance) — at 100kHz or specified frequency
• Leakage Current (DCL) — after 2–5 minute rated voltage application
• Impedance — at specified frequency
• Visual inspection — sleeve alignment, case marking readability, terminal integrity

Test data for each capacitor is recorded and linked to its batch traceability code.

Stage 5 — Batch Traceability

Every production batch is assigned a unique traceability code printed on each capacitor sleeve or case. This code links back to:

• Raw material lot numbers (foil, electrolyte, separator, rubber, case)
• Production date and shift
• Process parameter records
• Aging and test results
• Inspector identification

In the unlikely event of a quality issue, we can trace the affected batch, identify root cause, and implement corrective action with precision.