Overview
EN ISO 22553-6:2020 (ISO 22553-6:2019) defines a laboratory test method to identify and evaluate entry marks (immersion marks or streaks) that can occur during electro-deposition coatings (e-coat). Entry marks typically appear parallel to the bath surface when a workpiece (anode or cathode) is immersed under applied electric potential. The standard is applicable to automotive and other industrial e-coating applications (chillers, radiators, consumer products, aerospace, agriculture).
Key topics and technical requirements
- Test principle: Wet one half of a conductive test panel with demineralized water, mount vertically, energize, and immediately immerse under specified deposition conditions. After coating, rinse and cure per product specification, then evaluate visually and by film‑thickness measurement.
- Apparatus: Laboratory deposition system with tank recirculation and DC voltage supply, conveyor/immersion unit, film-thickness gauge (≤0.1 µm error), thermometer, oven, demineralized water.
- Test panels: Electrically conductive panels with pretreatment per ISO 1514; dimensions approx. 190 × 105 × 0.75 mm.
- Number of determinations: Duplicate tests are required.
- Typical deposition parameters (as specified in the standard):
- Anode/cathode area relation: 1:4
- Anode/cathode distance: 10 cm
- Tank temperature: 29 °C to 35 °C
- Immersion voltage: 40 V below the breakaway voltage
- Stirrer speed: 500 min⁻¹
- Immersion angle: 90°, speed 1 cm/s, depth 14 cm
- Coating duration: 2 min
- Evaluation:
- Visual scoring (0–5) for marks (0 = no visible marks; 5 = severe plastic marks). Assessment covers plastic marks and hashmarks on both wetted and dry halves.
- Dry-film thickness measured in the middle of the dry and wetted halves (reference ISO 2808).
Applications and users
This standard is intended for:
- E-coat process engineers and production staff in the automotive and general industrial sectors
- Quality control and laboratory technicians performing coating defect analysis
- Coating suppliers, R&D teams and surface-finish inspectors who need to reproduce and quantify immersion-related defects
- Contract testing laboratories and standards bodies establishing acceptance, troubleshooting and preventive measures for immersion marks in e-coating lines
Using EN ISO 22553-6 supports consistent, reproducible evaluation of entry marks, helps identify process limits (e.g., breakaway voltage effects), and informs corrective actions to improve coating uniformity and cosmetic quality.
Related standards
- ISO 1514 - Standard panels for testing
- ISO 2808 - Determination of film thickness
- ISO 4618 - Terms and definitions (paints and varnishes)
- ISO 22553-1 - Electro-deposition coatings - Vocabulary
- ISO 23321 - Demineralized water for industrial applications
Keywords: EN ISO 22553-6:2020, ISO 22553-6, electro-deposition coatings, e-coat, entry marks, immersion marks, paints and varnishes, film thickness, visual evaluation.