May02
Concept Clarification: IMC Layer Fracture Despite the Formation of Effective Solder Joints

post on May 2, 2024

Concept Clarification: IMC Layer Fracture Despite the Formation of Effective Solder Joints

In this blog, Workingbear has explored the causes and analysis of soldering cracks and electronic component detachment in several articles. It has consistently mentioned that most of the fractures occurring when electronic components detach happen at the Intermetallic Compound (IMC) layer. This indicates that the most vulnerable part of the overall structure, once the component is soldered to the PCB (Printed Circuit Board), is this IMC layer, hence the fractures occurring at this point.

However, nearly all articles also point out that it is essential to form this IMC layer between the solder paste and the component leads, as well as between the solder paste and the metal of the PCB, for effective soldering, ensuring solder joint strength.

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EDX/EDS/SEM/IMC/FTIR, Quality, Reliability, SMT, Soldering     WorkingBear    Views (2,646)     comment (0)
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Apr25
How are decisions made regarding stencil thickness, aperture, and shape? How can solder beads be prevented?

post on April 25, 2024

How are decisions made regarding stencil thickness, aperture, and shape? How can solder beads be prevented?

A user asked: “How is the thickness of the stencil determined? What considerations are there for the shape of the stencil apertures?”

The thickness of the stencil is mainly determined by the amount of solder paste needed for component soldering. Thinner stencils usually mean less solder paste deposited during printing. The amount of solder paste required for each solder joint depends on the components on the printed circuit board (PCB), especially those sensitive to solder volume, such as BGAs with the smallest ball pitch and fine-pitch components. Additionally, smaller components demand higher precision in solder paste printed. Ultimately, the decision also depends on the quality of solder joints after soldering.

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SMT, Soldering     WorkingBear    Views (4,579)     comment (0)

Apr18
Pros and Cons of Selective Soldering Machines

post on April 18, 2024

Pros and Cons of Selective Wave Soldering Machine. The image is sourced from the internet. If there's any infringement, please inform us for removal or cooperation.

Selective soldering machines are a compromise solution in modern PCB Assembly (PCBA)processes. Despite the advancements in surface mount technology (SMT), electronic components still rely on traditional Through-Hole Technology (THT) due to cost or material constraints.

Even though most components on PCBs can be assembled using SMT, some electronic parts still require THT processes. While techniques like Past-In-Hole (PIH) or Pin-In-Paste (PIP) allow through-hole components to be used in SMT assembly or use selective mask wave soldering process, limitations persist due to component technology. As a result, selective soldering machines have emerged.

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Soldering     WorkingBear    Views (2,761)     comment (0)
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Apr09
Selective Mask Wave Soldering Process: The Optimal Timing and Limitations

post on April 9, 2024

Selective Mask Wave Soldering Process: The Optimal Timing and LimitationsWorkingbear initially thought that wave soldering machines should have been relegated to museums by now! However, despite the decades-long development of Surface Mount Technology (SMT), many PCBs still undergo wave soldering processes. But nowadays, most wave soldering processes employ Selective Mask Wave Soldering, rather than the old method of immersing entire boards into solder baths.

In Selective Mask Wave Soldering, the original wave soldering machine is still used, but the PCB is placed in a wave soldering carrier. Only the pins or solder joints of components requiring wave soldering (typically through-hole components) are exposed to the solder, while other components are shielded with a mask of carrier. It’s a bit like wearing a lifebuoy in a swimming pool – the parts covered by the lifebuoy won’t get wet. Similarly, in the wave soldering process, the areas covered by the carrier won’t get soldered, eliminating the risk of re-melting solder or components falling off.

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Process, Soldering     WorkingBear    Views (2,865)     comment (0)
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Apr02
Can Surface Mount Devices Run Through the Wave Soldering Without Falling Into the Pot?

post on April 2, 2024

Can Surface Mount Devices Run Through the Wave Soldering Without Falling Into the Pot?

In previous discussions, Workingbear introduced the “wave soldering” process, which was used in early day of PCBA soldering. SMT assembly, on the other hand, emerged later. Can wave soldering be used for Surface Mount Devices (SMDs) after SMT placement? Workingbear noticed that many people still seem confused about the relationship between wave soldering and SMDs. So, this article aims to explain the key process of making SMDs  compatible with wave soldering.

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Process, SMT, Soldering     WorkingBear    Views (3,591)     comment (0)