4 Layer FR4 PCB Production Record #FR4-20260505-022

This 4-layer FR-4 board measured 22 × 45.5 mm with a thin 0.8 mm thickness, TG150 material, and 1 oz copper on both sides. Produced as 120 pieces in 4×2 panels for 15 sets, the order used ENIG surface finish with 3 µin gold thickness, green solder mask on both sides, and no silkscreen layers. Minimum holes were 0.3 mm with standard 6 mil line/space. Process edges of 4 mm on the top and bottom sides supported V-cut separation. The 3-day schedule included 100% flying probe testing. Customer requirements specified sequential ID numbering on the solder-mask layer in accordance with IPC-4552 recommendations and the addition of a UL mark.

DFM review focused on marking placement constraints. The supplied data contained no silkscreen layers, so sequential ID numbers could only be applied on the solder-mask surface; the originally designated location lacked sufficient space. UL marking was requested on the bottom solder mask, which also had no available area; placement was therefore proposed on the top solder mask at an alternative position. The UL frame area itself was too small to accommodate the mark, leading to a proposed swap with the nearby LMP location to maintain legibility without reducing board clearance.

Confirmed marking locations and sequential ID application were implemented prior to production. The compact boards achieved consistent ENIG plating and clear identification markings within the accelerated timeline. Full electrical test reports and quality certificates accompanied the shipment, confirming the panels met the specified mechanical and electrical requirements.