Overview
EN ISO 9455-17:2024 - "Soft soldering fluxes - Test methods - Part 17: Surface insulation resistance comb test and electrochemical migration test of flux residues" (ISO 9455-17:2024) specifies laboratory methods to evaluate deleterious effects of flux residues left after soldering or tinning test coupons. The standard covers fluxes in liquid or solid form, flux‑cored solder wire, solder preforms and solder paste, and applies to type 1 and type 2 fluxes (ISO 9454-1). It is applicable for use with both lead-containing (Sn/Pb) and lead‑free solders (for example Sn95.5Ag3Cu0.5) with testing parameters adjustable by agreement between tester and customer.
Key topics and requirements
- Purpose: Detect contamination risks from flux residues that reduce surface insulation resistance (SIR) or promote electrochemical migration.
- Main test methods:
- Surface Insulation Resistance (SIR) comb test using standardized comb-pattern test coupons.
- Electrochemical migration (ECM) test to assess ionic migration and dendritic growth from residues.
- Scope of materials: Type 1 and type 2 fluxes; solid/liquid fluxes; flux‑cored wire, preforms, paste flux.
- Sample preparation and processing: Detailed procedures for preparing flux test solutions, applying flux, soldering/tinning test patterns, cleaning, and coupon inspection.
- Measurement and assessment: Procedures for SIR measurement, verification of high‑resistance measurement systems, ECM exposure and assessment criteria.
- Test duration update: ECM exposure extended in this edition to 1 000 hours (replacing previous shorter durations).
- Test hardware alignment: Test coupon specification aligned with IPC B53 / IEC 61189‑5‑501 where applicable.
- Reporting and precision: Requirements for test reports, assessment criteria and precision information.
Applications and users
This standard is essential for:
- Flux manufacturers validating flux residue behavior and product specifications.
- PCB assemblers and OEMs assessing reliability risks from flux residues on electronic assemblies.
- Test laboratories performing standardized SIR and ECM qualification tests.
- Quality, reliability and procurement engineers who specify acceptance criteria for fluxes and soldering processes.
Practical applications include pre‑qualification of fluxes, qualification of new lead‑free process chemistries, failure analysis and comparative product testing.
Related standards
Keywords: EN ISO 9455-17:2024, soft soldering fluxes, surface insulation resistance, SIR comb test, electrochemical migration, flux residues, lead-free solder, solder paste, flux-cored solder wire.
