8.6 Cable & Harness Assembly (IPC/WHMA-A-620)

Cable assemblies are the "nervous system" of the product. Failures here are often intermittent and difficult to diagnose. IPC/WHMA-A-620 governs the quality of crimps, insulations, and soldering of wires.

8.6.1 Crimping Criteria

• Bellmouth: The flared end of the crimp terminal that prevents the metal edge from cutting the wire.
  • Requirement: Visible bellmouth required at the wire-entry end.
• Conductor Brush: The strands of wire sticking out past the crimp.
  • Target: Visible strands (flush to 1x wire diameter).
  • Defect: No strands visible (risk of partial crimp) or strands extending into the mating area.
• Insulation Crimp:
  • Target: Insulation fully supported and gripped without being pierced.

8.6.1 Strain Relief & Routing

• Cable Ties: Must be tight enough to hold but not deform the wire insulation.
  • Spacing: Every 100mm - 300mm depending on harness diameter.
  • Tail Cut: Tails must be cut flush with no sharp edges (safety hazard).
• Bend Radius: Minimum bend radius is 10x the cable diameter to prevent internal conductor fatigue.

Final Checklist