Category Archives: PCB/FPC/PTF


Mar13
What is CTE (Coefficient of Thermal Expansion)? What is α2-CTE? How Does CTE Affect PCB Quality?

post on March 13, 2025

CTE (Coefficient of Thermal Expansion) refers to how a material’s geometric properties change as its temperature rises or falls due to thermal expansion and contraction. In practical applications, CTE is divided into two main categories: Coefficient of Linear Thermal Expansion … Continue reading →

Fundamental Science, PCB/FPC/PTF     WorkingBear    Views (2,993)     comment (0)
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Mar06
What is the Popcorn Effect in PCBs and Electronic Components?

post on March 6, 2025

The Popcorn Effect in PCB and electronic components refers to the delamination (board cracking) or formation of bubbles when exposed to high temperatures during soldering. This phenomenon is similar to how popcorn pops—it happens because of trapped moisture inside. When … Continue reading →

Moisture Sensitive, PCB/FPC/PTF, Process, Quality, Reliability     WorkingBear    Views (2,364)     comment (0)
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Feb27
What Is Solder Mask (S/M)? What Is Its Purpose on a PCB? Why Is It Usually Green?

post on February 27, 2025

In discussions about printed circuit boards (PCBs), you’ll often hear the term Solder Mask (S/M). But what exactly is a solder mask, and what role does it play in a PCB? Some also refer to it as solder resist. What … Continue reading →

Design, PCB/FPC/PTF, SMT, Soldering     WorkingBear    Views (2,577)     comment (0)

Feb20
PCB Popcorn Effect: Why it Happens and How to Stop It

post on February 20, 2025

The main reasons for PCB delamination or “popcorning” are primarily (1) moisture absorption and (2) excessive α2/Z-axis CTE (Coefficient of Thermal Expansion). Among these, moisture absorption is responsible for about 70% of delamination issues. Other factors, such as uneven thermal … Continue reading →

PCB/FPC/PTF, Quality, SMT     WorkingBear    Views (2,292)     comment (0)
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Jan24
Top ENIG PCB Issues: Black Pad and Phosphorus-Rich Layers Explained with Prevention Tips

post on January 24, 2025

With the rapid adoption of smartphones, the trend toward miniaturized electronic products, and the EU’s requirements for lead-free manufacturing, Electroless Nickel Immersion Gold (ENIG) surface treatment PCB has become a popular choice for many electronic products. This is largely due … Continue reading →

EDX/EDS/SEM/IMC/FTIR, PCB/FPC/PTF, Process, Quality, Reliability, SMT, Soldering     WorkingBear    Views (3,971)     comment (0)
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