2.5 First Article & Golden Board

The First Article (FA) procedure is the checkpointmandatory whereprocess preparationgate becomesthat proof. Inconfirms a controlledproduct trial,is itready for volume manufacturing. It is a controlled, scripted trial that validates that all inputs — CAD data, machine programs, feeders,component materials, and boardprocess supportsettings all— align to produce accurate solder prints and placements. By placingexecuting witnessa parts,disciplined checking offsets, polarity, and coplanarity, then confirming solder performance through AOI or AXI,FA, issues are caught and corrected before theyproduction spreadbegins, intopreventing volume.costly scrap and rework. The capturedoutput of a successful FA is the Golden Board and the Golden Recipe, which freeze the "known good" state for all subsequent production runs.

2.5.1 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 (Chapter 1.6).
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.

2.5.2 Placement and Reflow Inspection

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

A) 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.

B) 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%).

2.5.3 Artifacts: The Golden Board & Golden Recipe

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

1. 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.

2. Golden Recipe then(The lockProcess Reference)

This is the full parameter set that produced the Golden Board. It must be saved and locked in the “knownManufacturing good”Execution state,System providing(MES).

a

Station	Parameter repeatableSnapshot	Purpose
Printer	Blade referenceangle/pressure/speed, forseparation/dwell, everycleaning shiftinterval, support map.	Freezes the setup that passed the SPI Cpk.
PnP	Program revision, vision versions, rotation table, feeder map, nozzle map, offset adjustments.	Ensures components are always picked and everyplaced lot.from the verified location and orientation.
2.5.1 What First Article (FA) really isOven	FAProfile isn’tname a ceremony—it’s aand gateActual Time/Temperature Plot your(thermocouple run).	Guarantees correct thermal mass handling and peak temperature exposure.
Inspection	AOI/AXI library revision, inspection thresholds used.	Ensures subsequent lot inspections match the FA baseline.

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

1. the

   Final dataChecklist: (CAD/centroid,FA orientations,Gate programs),

2. theRelease mechanics

   Requirement	Audit (support,Point	Sign-Off
   SPI	Cpk clamping,on nozzlerisk picks),features and the≥ consumables (paste, stencil, cleaning cadence)  produce known-good prints and placements1.33 after tuning.	Quality / ME
   Placement	100% correct orientation/polarity on thiswitness rev.parts.	Operator When/ FAME
   Reflow	Zero isbridges/tombstones; green,AXI youvoid takelimits photos,met.	Quality export/ settings,ME
   Lock and bless a Down	Golden Board and Golden Recipe for the build. 2.5.2 The FA run (one side, one small lot, one tight script) Scope: 1 panel (or 3 single boards) per side is enough—if you measure the right things. A) Printer FA (before a single part is placed) Support & gasket: verify support pins/vac tooling under large paste fields; confirm full stencil contact at fiducialsarchived and tight areas. First print: one pass → SPI review of the risk features you tagged in 7.4 (fine-pitch, QFN edges/thermal pads, BGA pads). Actions: adjust one knob at a time (angle/pressure/speed, separation, clean cycle), reprint, re-SPI. When TE/height/area are inside limits, freeze printer recipe. B) Placement FA (place only what you can inspect fast) Witness parts: for each package family (chips, SOT/SOIC, QFN, QFP, BGA/CSP, power pads), place 2–3 parts near a board edge. Checks at the microscope (or height camera): Orientation & polarity: Pin-1/A1, diode/cap polarity, connector keying. X/Y offset: within your machine spec (e.g., ≤±50 µm for fine pitch, ≤±100 µm for chips). Rotation: visually square; log any 90/180 traps and fix the library, not the placement. Z/height & coplanarity: part sits flat; no “see-saw” on QFN corners; BGA ball collapse expected after reflow. Pickup logs: first 20–50 picks per high-runner feeder show near-zero miss/retry; fix peel angle/feeder tension or vision/nozzle now. C) Reflow spot-check (1st pass through oven) AOI quick-teach with the FA placements; run the board and review: Chips: tombstone/skew ≤ target (ideally zero). QFN/DFN: no float/tilt; edges wetted. QFP/gull-wing: no bridges; heel fillets visible. BGA/CSP: no obvious HIP indicators (dull, non-collapsed balls). AXI sampling (if available): confirm BGA collapse/voiding trend; QFN thermal pad voids inside limit. Test smoke-check (optional now, mandatory before volume): power-safe, programming connector pinned right, boundary-scan chain enumerates. When all greens are met, complete the rest of the placements and finish the FA lot. 2.5.3 Acceptance matrix (print this on the FA traveler) Category What we check Pass (typical starting limits) If not, do this SPI TE/height/area on risk aperturesrev-locked. WithinME recipe/ limits per family (7.6) Tweak blade/clean/separation; update stencil notes if geometry is the root cause Orientation/Polarity Pin-1/A1; diode/cap; connectors 100% correct on witness parts Fix CAD library + PnP rotation table; re-import centroid if needed Placement offsets X/Y, rotation ≤±50 µm (fine); ≤±100 µm (chips); rotations at 0/90/180/270 as expected Re-teach vision; verify package/nozzle mapping Heights/flatness Sit-down/coplanarity No visible tilt; Z within spec Add board support; review paste volumes AOI after reflow Bridges, tombstones, fillet form Zero bridges/tombstones on witness set Adjust stencil apertures or reflow profile; confirm paste health AXI (spot) BGA collapse/voids; QFN voids HIP none; voids ≤ internal/customer limit Tune profile/atmosphere; consider paste change for voiding Test hooks Power on; programming; BSCAN Enumerates; current within guard; programming connects Fix connector/keying; complete DFT notes; adjust limitsManagement Accept once everything is inside band and the fix is baked into the recipe/data—not just in someone’s head. 2.5.4 The Golden Board & Golden Recipe (freeze the win) Golden Board (do not ship): One top-side photo set and one bottom-side, after reflow, covering: overall, tight features, and reference corners. AOI/AXI screenshots for critical parts (e.g., BGA collapse map, QFN thermal). Labels: project/rev/date/line, recipe IDs (printer, PnP, oven), and who signed. Golden Recipe (rev-locked with the build): Printer: blade angle/pressure/speed, separation/dwell, cleaning interval, bead policy, support map. PnP: program rev, vision versions, rotation table, feeder map (with permanent banks), nozzle map. Oven: profile name and actual time/temperature plot for this board/panel mass. AOI/AXI: library revs; tightened FA thresholds if applied. Test: fixture IDs, boundary-scan device order, smoke-check results.  Store both with the Golden Data Pack for this rev; stations load by ID, not by memory. 2.5.5 How to keep FA fast (and useful) every time Script it to 15–30 minutes of focused checks; no fishing expeditions. Put witness placements for every package family near board edges in the program—easy to inspect, zero hunting. Use check boxes, not paragraphs on the traveler; require names/time on each row. If a fix changes the outcome (e.g., new squeegee pressure), update the recipe immediately and re-run the affected check—then sign. 2.5.6 Pocket checklists FA start (printer) Support/gasket good · [ ] First print → SPI green on risk apertures · [ ] Recipe saved FA placement Witness parts placed per family · [ ] Orientation/polarity correct · [ ] Offsets & heights in band · [ ] Pickup logs clean FA reflow/AOI/AXI Zero bridges/tombstones (witness set) · [ ] BGA collapse OK · [ ] QFN voids in band Freeze & publish Golden Board photo set captured (top/bottom, AOI/AXI) Golden Recipe saved (printer/PnP/oven/AOI/test) Traveler signed; MES route released to Volume By treating FA as a disciplined gate and preserving its results, production avoids false starts and creeping drift. The line launches into volume runs with confidence—stable, consistent, and ready to sustain quality at scale. Back to top