The Importance of Microsectioning in PCB Quality Control

Microsectioning plays a vital role in assessing the quality of circuit boards, troubleshooting issues, and improving processes. It is a critical step in ensuring accuracy and making well-informed decisions. While standard quality monitoring procedures are used in production lines, a rushed or inexperienced approach may only reveal a portion of the truth, typically around 60-70%. To achieve comprehensive problem-solving and quality control, precise and non-destructive microsectioning is indispensable.

Types of Microsectioning:

• General Slicing (Microslicing): Cutting vertical or horizontal sections in the through-hole area.
• Cut Holes: Creating openings to observe the original surface condition of half of the hole wall.
• Oblique Section: Making angled cuts (45° or 30°) for inspecting multi-layer board surfaces or through hole areas.

Production Techniques:

• Utilize a special cutting die or shearing machine to extract samples from any part of the board.
• Avoid deforming through holes due to tension and steer clear of the hole edges.
• Use a diamond saw blade for precise sample cutting to minimize mechanical stress.

Sealing Methods:

• Fill the through hole with a sealant to secure and stabilize the wall for observation.
• Select a sealant with excellent transparency, high hardness, and minimal air bubbles.
• One formal approach involves using a rolling spring clamp and pouring sealant into a cylindrical blue rubber mold for easy demolding.
• Other methods include using mold release agents, rubber powder in hot pressing molds, the Nelson-Zimmer technique, ready-made acrylic molds, applying colloid on PE paper, and direct glue filling with bamboo sticks at the hole.

Conclusion:

Thorough and careful microsectioning is crucial for effective quality control and problem-solving in PCB manufacturing. It demands precision in sampling and sealing techniques to achieve clear and visible micro-slices without causing any damage or misinterpretation.