8.7 Box Build & Mechanical Assembly (IPC-A-630)

IPC-A-630 covers the "Box Build"—the integration of PCBAs into chassis.

8.7.1 Hardware Installation

• Torque Verification: All structural screws must be torqued to specified values.
  • Torque Striping: A line of "tamper paint" (Torque Seal) applied across the screw head and chassis. A broken line indicates loosening.
• Thread Engagement: For screws into nuts, the screw must protrude at least 1.5 threads past the nut body.
• Washers: Correct stack-up (Split washer -> Flat washer) is mandatory to prevent damage to the surface and ensure locking.

8.7.2 Chassis Cleanliness (FOD)

• Foreign Object Debris (FOD): Any loose material (wire clippings, solder balls, washers) inside the enclosure is a critical defect.
• Shake Test: A mandatory audible check ("The Rattle Test") for loose hardware before closing the box.

Final Checklist