Double-sided blue oil sinking gold craftsmanship

Double-sided PCB, also known as double-sided printed circuit board, is a printed circuit board (PCB) with two-sided circuit connections. In this kind of PCB, the electronic components and circuit layout can be arranged on both sides of the PCB respectively, and the electrical connection of the circuits on both sides is achieved through vias (Vias). This structure greatly increases the functional density of the circuit board, allowing it to implement more circuit connections in a relatively small area.

Product Features:

• Through hole connection
• Component placement
• Increase the wiring space
• Improve the circuit functional density
• The cost is relatively low
• Good electrical performance
• Adapt to high integration requirements

Manufacturing process:

• Design and layout:Firstly, the PCB design is carried out through circuit design software, with wiring and component placement on both sides, and the position type of vias are planned at the same time.
• Drilling and electroplating: Drilling is carried out according to the design requirements, and electroplating is performed after drilling to form a via the circuits on both sides.
• Etching: Remove the excess copper foil to form the desired circuit pattern.
• Assembly and welding: After the components are installed, welding treatment is carried out, which can be done using surface-mount technology (SMT) or through technology (THT).

Challenges in Double-Sided Rigid PCB with Blue Solder Mask

1. Interlayer Connection (Plating)
• Plated Through-Hole (PTH) Reliability: Achieving a uniform and robust copper plating inside the small drilled holes (vias) is essential to electrically connect the top and bottom circuit layers. Poor plating quality leads to open circuits or intermittent failures.
• Registration Accuracy: Precise alignment is required between the circuit patterns on the top and bottom sides so that the drilled PTHs land perfectly on the copper pads.
2. Double-Sided Assembly Complexity
• Dual Reflow Soldering: Components on both sides necessitate the board passing through the reflow oven twice. The process must be carefully controlled to prevent components already soldered on the first side from shifting or falling off during the second pass.
• Thermal Management: Components on both sides make heat dissipation more difficult compared to a single-sided board.
3. Solder Mask Application (Blue Color Specific)
• Visual Inspection Difficulty: While not a manufacturing defect, blue solder mask can sometimes make Automated Optical Inspection (AOI) and manual visual inspection more challenging. Compared to the standard green, blue can sometimes have lower contrast against the copper traces and silkscreen, making it slightly harder to spot subtle defects like solder bridges or trace damage.
• Solder Mask Registration: Ensuring the solder mask precisely covers all copper traces while leaving the designated component pads open requires tight tolerance control to prevent "solder mask slivers" (small gaps) or "mask encroaching" (mask covering the pad).