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 heated, the internal moisture turns into steam, and as the temperature increases, the pressure from the steam rises. If this pressure exceeds the bonding strength of the component, PCB, or IC package, it causes a sudden expansion—just like a kernel turning into fluffy popcorn.

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Moisture Sensitive, PCB/FPC/PTF, Process, Quality, Reliability     WorkingBear    Views (3,093)     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

What Is Solder Mask (S/M)? What Is Its Purpose on a PCB? Why Is It Usually Green?

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 Is a Solder Mask?

As the name suggests, a solder mask is used to prevent solder from accidentally adhering to areas that shouldn’t be soldered during assembly. The color you see on a PCB is actually the printed solder mask layer, not the natural color of the PCB material.

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Design, PCB/FPC/PTF, SMT, Soldering     WorkingBear    Views (3,421)     comment (0)
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Feb20
PCB Popcorn Effect: Why it Happens and How to Stop It

post on February 20, 2025

The Relationship Diagram Between Temperature and Vapor Pressure

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 expansion, inconsistent cooling and heating, mechanical damage during processing, or poor oxidation treatment, can also contribute—but their impact is generally much lower.

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PCB/FPC/PTF, Quality, SMT     WorkingBear    Views (3,065)     comment (0)
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Feb06
Causes of Solder Empty and Tombstoning in Small Chip of Resistors and Capacitors

post on February 6, 2025

small chip tombstoneRecently, some people have asked about issues with solder empty in small chip SMD components like resistors and capacitors. Even after thoroughly checking the reflow oven profile settings and confirming everything is correct, solder empty still frequently occur with these components, often in fixed positions. Observations of the solder also don’t show any signs of non-wetting or de-wetting, leaving many puzzled.

In reality, the cause of solder empty in these components isn’t that hard to understand! It’s essentially the same reason tombstoning occurs. To put it simply, it all comes down to this: “The solder paste on the two terminal ends of the component melts at different times, resulting in uneven forces and causing one side to lift.”

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Process, Quality, SMT, Soldering     WorkingBear    Views (3,111)     comment (0)

Jan24
Top ENIG PCB Issues: Black Pad and Phosphorus-Rich Layers Explained with Prevention Tips

post on January 24, 2025

Two Major Potential Issues with ENIG Surface PCB Pads (Black Nickel and Phosphorus-Rich Layers) and How to Prevent Them

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 to its simplicity and lower cost compared to other surface treatments, as well as its numerous advantages, including:

  1. Excellent reworkability: ENIG allows for multiple soldering processes without compromising quality.
  2. Superior flatness: Perfect for fine-pitch components.
  3. Strong resistance to oxidation: Suitable for long-term storage.
  4. Versatility: Can be used for contact circuits like keypads.

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EDX/EDS/SEM/IMC/FTIR, PCB/FPC/PTF, Process, Quality, Reliability, SMT, Soldering     WorkingBear    Views (4,925)     comment (0)
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