Over 90% of harness failures happen at crimps. Crimping is a "cold weld": too light means high resistance, too heavy means broken strands. Judge crimps on three levels: dimensions, pull force, cross-sections.
1. Crimp height: the first gate
Crimp height, tolerance typically ±0.02-0.05mm per terminal spec, decides everything. Oversize = under-crimped; undersize = broken strands.
2. Pull force: quantified strength
Pull tests at constant speed must meet spec minimums — roughly 30N for 22AWG, 60N for 18AWG, 100N for 14AWG. First-article plus periodic sampling catches press drift.
3. Cross-section analysis: the inside truth
Polished cross-sections should show uniformly deformed strands, tight fill, no voids, and proper insulation crimp. Compression ratio around 75-90% is the sweet spot; cross-sections are mandatory at first article.
4. Don't skip the insulation crimp
Insulation wings anchor the jacket and absorb vibration stress; skipping them loads the conductor crimp and causes hidden failures.
Final words
We run first-article cross-sections, batch pull sampling and 100% continuity. Audit visits welcome: +86 184 0755 1752 / eric@muyenda.com.