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IEC 60352-7: Solderless Connections — Standardized Quality Requirements for Crimp and Wire-Wrap
Why Crimp Connections Outlast Solder Joints in Aerospace and Railways
IEC 60352-7:2002 specifies solderless connection quality requirements for crimp and wire-wrap. In aerospace, space, and railway electronics, crimp connections are more reliable than solder — solder joints suffer fatigue and whisker growth under thermal cycling and vibration, while crimps are pure cold metal-to-metal bonding.
| Connection | Principle | Advantage | Application |
|---|---|---|---|
| Crimp | Terminal mechanically deforms around wire, creating gas-tight bond | Vibration-resistant, no thermal stress, automatable | Aerospace connectors, automotive harnesses |
| Wire-Wrap | Wire spirally wrapped around rectangular post, forming cold weld | Reworkable, no flux residue, extremely reliable | Telecom backplanes, prototypes |
A qualified crimp must be gas-tight — microscopic cold welding between copper wire and terminal metal prevents air and corrosive gases from entering the contact zone. IEC 60352-7 verifies gas-tightness via metallographic cross-section analysis: voids between wire and terminal must not exceed 5% of total wire cross-sectional area.
TNLab — A good crimp is more reliable than solder — it relies on metal cold welding, not a third-party material (solder) as “glue.”
