Issue link: https://iconnect007.uberflip.com/i/1535414
38 PCB007 MAGAZINE I MAY 2025 best? e decision must take several factors into account, including: • e code must withstand subsequent pro- cesses, such as scrubbing and plating • It must remain readable at later stages (e.g., direct imaging) • If each drilling station reads codes indi- vidually, the manufacturer must equip ever y station with a scanner and ensure it operates independently, which signifi- cantly raises the cost. In that case, stack drilling would not be possible, affect- ing productivity for boards that do not require optical alignment Unique Serialization Path If unique serialization is required, the most stable method is to drill the data-matrix code during the X-ray stage. However, this affects throughput. Code drilling slows the X-ray pro- cess as it needs additional time for the code drilling and can create a production bottleneck. Alternative: Job-based Traceability Another option is using job-level traceabil- ity rather than full serialization. In this model, the sequence is: • A laser marker at the X-ray stage creates a code without slowing down processing • e code is read at station 1 of the drilling machine to load the job • All stations then drill into each board: › A job-specific data-matrix code › Date and time of drilling › Machine number › Station number (1–6) › Operator ID While this approach doesn't provide full traceability, it strikes a balance between cost and process visibility. It provides some infor- mation to track production history without creating a bottleneck at the X-ray stage, since we drill the job code at the drilling machine. Which approach is right for you? It depends on your vision of the factory and desired level of traceability. Outer Layer and Solder Mask Exposure Once a drilled data-matrix code exists, be it a unique identifier or a job code, it will probably survive subsequent processes. is makes it easily readable by the direct imaging system at the outer layer or solder mask exposure stage. Summary Full traceability with unique serialization in PCB production is possible, but is it always practical or necessary? e answer depends on the specific needs, cost considerations, and production volume of each factory. PCB007 Kurt Palmer is president of Schmoll America. To read past columns, click here.