What’s the Difference Between PCB and PCBA?
A PCB is a bare printed circuit board without any components. A PCBA is a fully assembled board with all components mounted via SMT or DIP.
Note: In many cases, “PCB” refers to PCBA in everyday use!
Surface Finishing Techniques
Surface finish prevents oxidation and ensures solderability during assembly.
| Finish Type | Features | Applications |
| ENIG | Flat, reliable, excellent solderability | High-end products, smartphones, servers |
| OSP | Eco-friendly, low-cost | Short-term assembly products |
| HASL | Inexpensive, uneven surface | Traditional through-hole production |
Types of Vias in PCBs
PTH (Plated Through Hole): Full layer connection, used for power or signals.
Blind Via: Connects outer and inner layers only, space-efficient.
Buried Via: Located between internal layers only, increases density without affecting surface routing.
SMT Assembly Process
Standard SMT Process:
Functional testing and packaging
Solder paste printing
SPI (Solder Paste Inspection)
Pick and place components
Reflow soldering
AOI (Automated Optical Inspection)
Panelization Tips for Cost Saving
Mixed layout (Yin-Yang design): Combine different sides/components in one panel.
V-cuts / breakaway holes: Easier depanelization.
Edge rails: Add space for testing and handling, improving yield.
PCB Material & Copper Thickness
Common materials: FR4, Rogers, PI (for flex circuits)
Typical board thickness: 0.8mm, 1.0mm, 1.6mm
Copper thickness: 1oz standard, 2–3oz for high current designs
Choosing the right material impacts both cost and long-term reliability!