EN 3475-706:2005

Overview

EN 3475-706:2005 is a European standard developed by CEN that specifies the test method to assess the ultraviolet (UV) laser markability of aerospace electrical wires and cables. It focuses on establishing the performance criteria for laser marking when using UV laser wire marking systems, ensuring consistent, high-quality identification on aircraft wiring.

This standard supports the aerospace industry in maintaining reliable wire and cable identification, critical for safety and maintenance, aligning with the procedures defined in TR 4543 for UV laser marking systems and EN 3475-100 for general aerospace cable test methods.

Key Topics

• Laser Marking System Requirements
  The standard recommends using pulsed UV lasers such as:

  • Frequency tripled Q-switched Nd:YAG laser (wavelength 355 nm, pulse length 4–20 ns)
  • Xenon chloride (XeCl) excimer gas laser (wavelength 308 nm, pulse length 10–30 ns)

• Laser Marking Fluence
  A marking fluence of (0.9 ± 0.1) J/cm² is typically used to achieve optimum contrast without damaging the wire insulation. This ensures permanent, legible marks without degrading mechanical or electrical properties.

• Sample Preparation and Marking Process
  Wire surfaces must be clean and dry-contaminants like dust or oil should be removed using a dry cloth or isopropyl alcohol if necessary. Samples are marked with a laser beam shaped by a mask (commonly square or rectangular with minimum mark dimensions of 1 x 1 mm).

• Contrast Measurement
  Laser mark contrast is quantified following EN 3475-705, measuring the contrast between marked and unmarked insulation areas using defined measurement zones around the wire’s central axis. This ensures the marking is legible and consistent.

• Laser Beam Profile and Intensity Uniformity
  The laser beam intensity must be uniform to ±10% across the marking area to prevent contrast variations, maintaining high-quality marking performance.

• Terminology and Laser Types
  The standard defines key terms such as UV laser, pulse length, fluence, harmonic generation, and types of lasers (Nd:YAG, excimer).

Applications

• Aircraft Wire and Cable Identification
  UV laser marking compliant with EN 3475-706 enables permanent, non-aggressive coding of aircraft electrical wire and cable insulation, essential for maintenance, traceability, and safety.

• Aerospace Manufacturing and Quality Control
  Manufacturers use this test method during production to verify that wire batches meet required laser markability standards before installation in aircraft systems.

• Ensuring Wire Insulation Integrity
  The method safeguards against marking-induced damage, preserving insulation mechanical and electrical properties while achieving optimal mark contrast.

• Compatibility with UV Laser Marking Systems
  EN 3475-706 complements TR 4543 guidance on UV laser marking hardware and EN 3475-100 for general test procedures, creating a comprehensive framework for aerospace wire marking.

Related Standards

• EN 3475-100 – Aerospace series cables test methods, Part 100: General
  Provides overarching test procedures and general requirements for aerospace electrical cables.

• EN 3475-705 – Aerospace series cables test methods, Part 705: Contrast measurement
  Defines the method for measuring laser mark contrast on wire insulation, used for evaluating marking legibility.

• EN 3838 – Aerospace series requirements and tests on user-applied markings
  Sets performance criteria for markings on aircraft electrical cables, including durability and legibility.

• TR 4543 – UV laser wire marking systems for aircraft wire and cable identification
  Details the hardware and operational guidance for UV laser marking systems applied in aerospace wire identification.

EN 3475-706:2005 is essential for aerospace manufacturers and quality assurance professionals focused on achieving reliable, permanent laser marking of aircraft wiring. Its application ensures compliance with industry best practices for wire identification, supporting safety, traceability, and maintenance efficiency across aerospace electrical installations.