2.11 First Article & Golden Board

The First Article (FA) procedure is the mandatory process gate that confirms a product is ready for volume manufacturing. It is a controlled, scripted trial that validates that all inputs — CAD data, machine programs, component materials, and process settings — align to produce accurate solder prints and placements. By executing a disciplined FA, issues are caught and corrected before production begins, preventing costly scrap and rework. The output of a successful FA is the Golden Board and the Golden Recipe, which freeze the "known good" state for all subsequent production runs.

2.11.1 The FA Protocol: Proof of Process

The FA must be executed on the first panel of a new product or a product revision where major elements have changed (e.g., new PCB fabricator, different solder paste, major stencil revision).

A) Scope and Script

• Sample Size: Typically 1 to 3 full panels (or sides, if double-sided) is sufficient, provided inspection is rigorous.
• Scope: The FA validates every critical link in the SMT chain, from board support at the printer to solder wetting after reflow.
• Non-Negotiable: The process must be documented on an FA Traveler that requires sign-off from Quality, Manufacturing Engineering, and the Operator.

B) The Printer FA (The Starting Gate)

This step must be completed and passed before any component is placed.

1. Support Check: Verify that the PCB support (pins/vac tooling) provides perfect gasket seal at all risk areas (BGAs, fine pitch).
2. First Print: Run one print pass and send the board to the SPI.
3. Risk Feature Review: Review the SPI data, focusing specifically on the risk features tagged in the stencil design (Chapter 1.4). Verify that Volume C_pk and Transfer Efficiency (TE) are within the Golden Recipe limits.
4. Tuning: If necessary, adjust only one machine parameter (e.g., squeegee pressure, clean interval), reprint, and re-check the SPI data. Lock the printer recipe upon success.

2.11.2 Placement and Reflow Inspection

Once the print passes, critical placements are made and immediately inspected.

Placement FA (Witness Parts)

• Witness Parts: Place a small, representative sample (2-3 parts) of every unique package family (chips, QFN, QFP, BGA, connector) near a board edge for immediate access.
• Microscope Inspection: Using a high-magnification camera or microscope, verify the following on the witness parts:
  • Orientation/Polarity: Pin-1/A1 alignment and diode/capacitor polarity must be 100% correct.
  • X/Y Offset: Placement must be centered within machine specification (e.g., ≤ ±50 µm for fine pitch).
  • Coplanarity: Part sits flat on the paste; no visible "see-saw" or tilt on corner balls.
• Log Audit: Review the machine’s pickup and vision logs for the first 50 cycles of high-runner feeders. Near-zero miss/retry rates are mandatory.

Reflow & Final Inspection

The partially populated FA board must be run through the reflow oven using the defined profile.

• AOI Quick-Teach: Use the reflowed board to quickly teach the AOI program and confirm: zero bridges, zero tombstoning/skew on witness parts, and acceptable fillet formation on gull-wing leads.
• AXI Sample (Mandatory for BGAs): If BGAs or QFNs are present, perform an X-ray inspection to confirm BGA ball collapse (no Head-in-Pillow, HIP) and that QFN thermal pad voids are below the maximum customer/internal limit (e.g., ≤ 25%).

2.11.3 Artifacts: The Golden Board & Golden Recipe

The successful FA results are frozen into two permanent, rev-locked artifacts.

Golden Board (The Physical Reference)

The successful, reflowed FA panel must be photographed and documented.

• Photo Set: High-resolution photos (top/bottom) covering the overall assembly, specific tight features (BGAs/fine pitch), and corner references.
• Image Capture: Capture and label AOI/AXI screenshots for all critical defect zones (e.g., BGA void map, largest fillet).
• Labeling: The physical board and all associated images must be labeled with the project/revision, FA date, line ID, and the Golden Recipe ID.

Golden Recipe (The Process Reference)

This is the full parameter set that produced the Golden Board. It must be saved and locked in the Manufacturing Execution System (MES).

Process Control: All subsequent production lots must load the matching Golden Recipe ID automatically via the line control system (Hermes) to prevent running with incorrect settings.

Final Checklist: FA Gate Release