Mar27
Does PCB Solder Mask Misalignment Lead to BGA Soldering Defects?

post on March 27, 2025

Does PCB Solder Mask Misalignment Lead to BGA Soldering Defects?Recently, our company started a new project, and the R&D team has been pushing PCB layout requirements to the extreme. As PCBs size get smaller, the solder mask (S/M) design must also shrink accordingly. However, our current PCB manufacturers struggle to meet these tighter tolerances, and those who can do it demand a price increase. The moment extra cost is mentioned, everyone hesitates and sticks with the existing PCB suppliers, resulting in solder mask misalignment that extends beyond the pads.

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Design, PCB/FPC/PTF, Process, Quality, SMT, Soldering     WorkingBear    Views (1,281)     comment (0)
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Mar21
Electronic Product Burn-In and Run-In: What They Are and Their Pros & Cons

post on March 21, 2025

Electronic Product Burn-In and Run-In: What They Are and Their Pros & Cons

In the early days, when electronic component design and manufacturing were still in their infancy, burn-in (B/I) was widely used to screen out defective products. This process helped eliminate early failures before products reached customers, reducing the risk of complaints.

Statistical data shows that electronic products typically follow a bathtub curve in terms of lifespan. This means that failure rates are higher during the initial (infant mortality period or child mortality period) and end-of-life (wear-out period) phases, but once a product passes the early stage, its failure rate drops significantly and stabilizes close to zero (useful life period or normal period)—just like the shape of a bathtub.

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Process, Quality, Reliability, Test/Inspection     WorkingBear    Views (721)     comment (0)

Mar20
What is Tg (Glass Transition Temperature) and Its Role in PCBs?

post on March 20, 2025

What is Tg, Glass Transition Temperature

Glass Transition Temperature (Tg) is one of the most important properties of all plastic and epoxy resin materials. In fact, the Tg value is also an indicator of the quality of the fiberglass fabric used in PCB manufacturing. However, compared to Heat Deflection Temperature (HDT), Tg is generally considered less critical. Tg typically refers to the temperature at which the molecular chains of a plastic begin to undergo large-scale motion at the microscopic level.

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Fundamental Science, PCB/FPC/PTF, Plastic     WorkingBear    Views (2,567)     comment (0)

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

post on March 13, 2025

CTE for Train Tracks

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 – Applies to solids
  • Coefficient of Volume Thermal Expansion – Applies to gases

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Fundamental Science, PCB/FPC/PTF     WorkingBear    Views (2,030)     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 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 (1,640)     comment (0)
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