PCB PCBA Assembly Full Process Disassembly

　　1. Preliminary Preparation: Ensuring "Material and Process Matching"

　　Two key preparations must be completed before assembly to avoid process adaptation issues:

　　Material Verification and Pretreatment

　　Bill of Materials (BOM) Verification: Confirm that component models, packages (e.g., 0402 resistors, QFP chips), and parameters (e.g., capacitor values, chip voltages) are consistent with the PCB design to avoid incorrect materials.

　　Component Pretreatment: Bake damp components (e.g., ICs, BGAs) at 85°C for 12 hours to remove moisture and prevent "popcorning" (component cracking) during soldering. Pretreat the pins of plug-in components (e.g., connectors) to remove oxide layers.

　　Process File Development

　　Core Process File Output:

　　Stencil File (Gerber Format): Defines the solder paste printing area and thickness (e.g., 0.12mm thick stencil for 0402 package, 0.15mm for QFP);

　　Reflow Oven Temperature Profile: Defines the heating zones (preheating zone, constant temperature zone, reflow zone, and cooling zone) based on the solder paste type (e.g., Sn63Pb37, lead-free SnAgCu). For example, the peak temperature in the reflow zone for lead-free solder paste must be controlled at 240°C ± 5°C;

　　Placement Coordinate File: Defines the X/Y/Z coordinates and placement angles of each component on the PCB to ensure accurate placement by the placement machine.