For PCBA (Printed Circuit Board Assembly) manufacturers, the factory audit is a critical moment that determines order placement. When a brand’s quality engineers arrive, they often bypass flashy presentations and dive directly into the details of the production line. Based on years of experience accompanying audits, what clients care about most is not whether you have expensive equipment, but how you manage the variables that equipment can introduce.
1、Material & Moisture-Sensitive Device (MSD) Control
How do you ensure the exposed time of components with higher MSL levels is controlled after bag opening?
This is the first step in examining a PCBA factory’s attention to detail. Clients will check the registration card after vacuum bag opening, verifying that the “floor life” has not expired, and review real-time temperature and humidity data from the humidity control cabinets.
Where are the records for solder paste thawing and stirring from refrigerator to line use?
Solder paste activity directly determines soldering quality. Clients will verify the thawing duration (typically over 4 hours) and stirring frequency to ensure condensation from temperature differences does not cause solder splatter.
2、Process Stability & Error-Proofing Mechanisms
During SMT feeder changes, what methods do you use to prevent wrong component placement?
Relying solely on manual verification is no longer sufficient. Clients expect to see a strong correlation between PDA barcode scanners and the MES (Manufacturing Execution System)—where the machine only operates after the component barcode, feeder position, and system order number are all matched.
How is the First Article Inspection (FAI) executed? Is measurement data uploaded automatically?
Clients will randomly inspect the most recent FAI report. Compared to paper records, quantified data generated by automated first-article testers is more convincing, proving that resistor and capacitor values have indeed been measured by LCR meters.
How frequently is the reflow oven temperature profile verified?
For high-precision PCBA, testing the temperature profile daily or per shift is standard practice. Clients will examine the overlap between the measured curve and the defined Solder Profile, confirming that the ΔT is within the process window.
3、Inspection Rigor & Defect Containment
If the AOI (Automated Optical Inspection) detects a defect, how do you prevent repair technicians from misjudging or missing a repair?
This is a classic closed-loop management test. Clients will check the computer screen at the repair station to confirm that defects flagged by the AOI are forced display ed, and that the board’s barcode can only proceed to the next step after the repair station confirms the fix.
For BGA packages, what is your X-Ray sampling rate and voiding acceptance criteria?
Solder joints invisible to the naked eye are potential quality hazards. Clients will request to review X-Ray images, checking the void area ratio (typically not exceeding 25%) and the system’s ability to identify Head-in-Pillow (HiP) defects.
4、ESD Protection & Traceability
How often do you test the grounding resistance of ESD wrist straps and flooring?
ESD is a red line in PCBA manufacturing. Clients may randomly select an employee for an on-the-spot demonstration of wrist strap testing and cross-check the day’s test records.
If a batch failure is found during Functional Circuit Test (FCT), how do you perform root cause traceability?
This tests the depth of your MES system. A client may provide a random finished product serial number and request that you trace back to the PCB batch, solder paste batch, and the day’s process parameters for that board—all within 5 minutes.
How is your production Stopping Rule defined?
Where is the quality red line? For example, does the system or line supervisor have the authority to forced shutdown for corrective action if three consecutive boards show the same defect?
The essence of a factory audit is building trust. If your answers are evasive or records are missing, even the most advanced equipment cannot conceal a fragile management system.
We possess a comprehensive quality management system, ensuring we can provide digital evidence for every key metric. Contact us to experience a transparent, controlled, high-first-pass-yield PCBA production floor, and let us help you smoothly introduce and scale your new product.