SIST EN 2591-501:2004

Overview

SIST EN 2591-501:2004 is a European standard developed by CEN specifying test methods for verifying the soft solderability of electrical and optical connection elements used in the aerospace industry. This standard focuses on electrical male and female contacts that are soldered within connection elements, as well as contacts with self-contained solder and flux not accessible by a soldering iron.

The standard is part of the Aerospace series and is designed to be used alongside EN 2591-100, which covers general test methods for elements of electrical and optical connection.

Key Topics

• Scope and Application
  EN 2591-501 outlines methods to verify solderability of electrical contacts to ensure reliable and effective solder joints in aerospace applications, critical for electrical systems' safety and performance.

• Preparation of Specimens
  Contacts must be tested in delivery condition without contamination (e.g., grease or finger marks). Degreasing is allowed using pH neutral solvents if specified.

• Test Equipment and Materials

  • Soldering Iron: Copper bit with steel plating, heated to (350 ± 10) °C, designed for precise application on contacts.
  • Alloy and Flux: Solder wire diameter 0.8 mm with flux content between 2.5% and 3.5%, chemically specified for aerospace use. The alloy typically includes tin (59%-61%), lead as remainder, with strict limits on impurities.

• Test Methods

  • Method A (Solder Iron): Applies soldering iron and flux wire on contact barrels horizontally for 2-3 seconds. Post-test, flux residues are cleaned with solvent, and solder coverage is visually inspected under controlled lighting.
  • Method B (Heat Application): Heat is applied following installation procedures without introducing solder wire. Solder wetting and uniform film formation are inspected visually, sometimes requiring internal inspection of contact solder buckets.

• Inspection Criteria
  The solder must wet the test surface uniformly without droplets, ensuring adherence and sound electrical connections. Inspection uses EN 2591-101 visual examination guidelines with magnification up to 4x.

Applications

EN 2591-501 is essential for aerospace manufacturers, quality control teams, and certification bodies involved with:

• Aerospace Electrical Connectors
  Ensuring the solderability of male and female contact elements in aerospace connectors for aircraft, satellites, and space vehicles.

• Optical and Electrical Connection Systems
  Verifying the integrity of combined electrical and optical connectors, ensuring no solder defects compromise system reliability.

• Component Manufacturing and Assembly
  Applying standardized procedures for solderability testing during production, reducing field failures due to poor solder joints.

• Maintenance and Testing Laboratories
  Routine testing and qualification of connectors as part of preventative maintenance or post-repair verification.

Related Standards

• EN 2591-100: General test methods for aerospace elements of electrical and optical connection, used in conjunction with Part 501 for comprehensive testing protocols.

• EN 2591-101: Provides detailed visual examination procedures referenced for inspection in solderability testing.

• AECMA Prestandards: Background aerospace standards aligned with EN 2591-501, supporting harmonization of aerospace component testing.

• International Aerospace Quality Standards: Including standards from SAE and IPC, often referenced together to ensure robust soldering performance across aerospace electrical components.

Keywords: aerospace solderability testing, EN 2591-501, aerospace electrical connectors, soft solderability, solderability test methods, aerospace standards, electrical contact soldering, soldering quality assurance, aerospace optical connectors, CEN aerospace standards.