4.5 Labels, Serialization, and Regulatory Technical File

A label is not merely a sticker; it is the product's legal passport. A perfectly functional device will be seized by Customs or rejected by distributors if the regulatory markings are incorrect, the serial number is unreadable, or the adhesive fails. Do not treat labeling as a graphic design task; treat it as a critical engineering sub-system that governs traceability and market access.

Label Engineering and Artwork Controls

Treat the label as a mechanical component. If the artwork is provided as a bitmap (JPG/PNG), the factory will trace it, introducing errors in logo geometry and font legibility.

1. The Source Files

• Requirement: Deliver artwork in Vector Format (AI, EPS, PDF) with all fonts converted to outlines/curves.
• Critical Dimensions: Define the minimum size of regulatory symbols (e.g., the CE mark must be ≥ 5 mm vertical height).

2. Material and Adhesion Science

The adhesive must match the surface energy of the housing. A label that sticks to a cardboard box will fall off a textured polypropylene case.

• If surface is High Energy (Metal, ABS, Polycarbonate) ⭢ Then Standard Acrylic adhesive is acceptable.
• If surface is Low Energy (PP, PE, Powder Coat) ⭢ Then specify "High-Tack" or "Aggressive" adhesive (e.g., 3M 300LSE).
• Validation: Perform the ASTM D3330 peel test or a simple 24-hour humidity soak followed by a fingernail peel attempt.

Pro-Tip: Always specify a "Keep-Out Zone" for the label on the mechanical drawing. Texture interferes with adhesion. The mold tool needs a polished patch (SPI-A or B finish) exactly where the label goes.

Serialization and Barcode Logic

Do not let the factory invent your serial number scheme. This leads to duplicates and database collisions.

1. The Syntax Rule

Define a "Smart Serial" format that encodes production data without requiring a database lookup.

• Format Example: [Model ID] [Rev] [YY] [WW] [Site Code] [Sequencer]
• Control: Providing a "Serial Number Generator" tool or a pre-issued CSV block to the factory is safer than asking them to increment a counter.

2. Barcode Symbology

• 2D Codes (Data Matrix / QR): Preferred for small electronics. High density, error-correcting.
  • Constraint: Minimum cell size must match the printer's DPI (e.g., 2 dots per cell) to prevent aliasing.
• 1D Codes (Code 128): Use only for outer cartons. Too large for products; prone to damage.

3. The Linkage:

The System Serial Number must be digitally linked to the PCBA Serial Number and the MAC Address in the shop floor manufacturing execution system (MES).

The Regulatory Technical File (The "Reg Pack")

The physical label is only valid if backed by the Technical Documentation File required by the Low Voltage Directive (LVD) and EMC Directives. Without this, you cannot legally apply the CE mark.

1. Content Requirements

For ICT/AV equipment entering the EU, the Technical File must contain:

• Test Reports: Evidence of compliance with IEC/EN 62368-1 (Safety) and EN 55032/55035 (EMC).
• Schematics & Block Diagrams: To prove the tested configuration matches the production unit.
• Risk Assessment: Documented analysis of thermal, electrical, and mechanical hazards.

2. The Declaration of Conformity (DoC)

This is the single page signed by a company officer declaring compliance.

• Requirement: A copy of the DoC (or a direct simplified URL to it) must accompany the product.
• Traceability: The DoC must reference the specific standards versions (e.g., EN IEC 62368-1:2020) used during testing.

Pro-Tip: If you change a power supply or enclosure material, the "Construction Data Form" (CDF) in your safety report is invalidated. You must update the Reg Pack before shipping the new revision.

Final Checklist

Check	Criterion	Critical Threshold / Requirement
Artwork	Vector Format?	Files are AI/EPS; Fonts converted to curves.
Markings	Symbology Check?	CE height ≥ 5mm; WEEE bin clearly visible.
Adhesion	Surface Match?	Adhesive specified for housing Surface Energy (High/Low).
Serialization	Uniqueness?	Logic defined (YYWW format); Duplicates strictly forbidden.
Scannability	Grade B or better?	Barcodes pass ISO 15415 verification.
Safety	IEC 62368-1?	Product complies with current audio/video/ICT safety standard.
Legal	DoC Signed?	Declaration of Conformity drafted and accessible to customs.
Placement	Polished Zone?	Mechanical drawing defines smooth area for label.