PCB Baking Protocol: Why and How KingSheng PCBA Handles Moisture Absorption

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At KingSheng PCBA, precision and reliability are at the core of our production philosophy. One critical process that ensures the highest quality of our assemblies is the PCB baking protocol. Moisture absorption is a silent killer in electronics manufacturing, and understanding how to handle it is essential for any successful project.

Ⅰ.Why Do PCBs Need Baking?

Printed Circuit Boards (PCBs) are made of epoxy-based materials (like FR-4) which are hygroscopic, meaning they naturally absorb moisture from the air. When a PCB is exposed to humidity, moisture seeps into the laminate. If a moisture-laden board goes through the reflow soldering process (where temperatures exceed 250°C), that trapped water rapidly turns to steam. The sudden expansion can cause internal delamination, blistering, or even catastrophic cracking of the board—a defect commonly known as the "popcorn effect." This can ruin the board entirely or create latent defects that fail in the field.

Ⅱ.KingSheng PCBA’s Baking Standards

• At Kingsun PCBA, we strictly adhere to IPC standards to mitigate these risks. Whether you are using standard FR-4 or high-temperature boards, our rule of thumb is simple: If the boards have been stored in a humid environment or the vacuum packaging is compromised, they must be baked.
• Generally, our standard baking procedure is as follows:
• Temperature: 120°C ± 5°C (248°F)
• Duration: 4 to 6 hours for standard thickness boards.
• For thicker boards: (e.g., 2.0mm or multi-layer heavy copper boards) we may extend the duration to 8-12 hours to ensure the inner layers are completely dry.

Baking Orientation: Boards are placed vertically to ensure even airflow and prevent warpage.

Ⅲ.What Happens If You Skip Baking?

Skipping the baking process can be a costly mistake. When moisture-laden boards are processed:

• Delamination: The intense heat separates the layers of the PCB, destroying its structural integrity.
• Via Damage: The expansion can crack the copper plating inside the vias, leading to open circuits.
• Solder Mask Pop-off: Moisture can cause the solder mask to chip or peel away from the substrate.
• Outgassing: During assembly, trapped moisture can cause solder splatter or voids in BGA (Ball Grid Array) solder joints, leading to poor connectivity.

Ⅳ.How KingSheng PCBA Protects Your Boards

Our facility is equipped with programmable industrial ovens that provide precise temperature control to prevent thermal shock. Once the baking cycle is complete, we move the boards to our dry storage cabinets or directly to the SMT line to prevent re-absorption before soldering.

For high-reliability or quick-turn prototypes, trusting your manufacturer to handle moisture properly is vital. At KingSheng PCBA, we don't just assemble boards; we safeguard your electronics from the inside out.
Need a partner who understands the science behind the solder? Contact KingSheng PCBA today to ensure your next project is built to last.

With 16 years of expertise in PCBA design, manufacturing, and service, KingshengPCBA is ready to help turn your ideas into reality. Feel free to contact us anytime to discuss your requirements and get a professional quotation.