Feb27
What is Graping Solder Defect in SMT Assembly? How to Fix it?

post on February 27, 2024

What is Graping Solder Defect in SMT Assembly? How to Fix it?

In the reflow soldering process of Surface Mount Technology (SMT) in electronic assembly, the occurrence of “Graping” solder defect refers to the situation where the solder paste does not completely melt and joint together during reflow. Instead, individual solder powders gather and stack together, resembling a cluster of grapes.

So, how does this “Graping” solder defect happen? Solder paste is essentially a mixture of tiny solder powders combined with flux. When the flux in the solder paste evaporates, it leaves behind individual solder powders.

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Process, Quality, SMT, Soldering     WorkingBear    Views (4,292)     comment (0)
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Feb20
What is IMC (Intermetallic Compound)? How does IMC relate to PCB solder joint strength? Are there IPC standards for IMC thickness?

post on February 20, 2024

What is IMC (Intermetallic Compound)? How does IMC relate to PCB solder joint strength? Are there IPC standards for IMC thickness?

In the assembly and soldering process of printed circuit boards (PCBs), we often hear engineers or lab reports mentioning the term “IMC.” But what exactly is IMC? What role does IMC play in the PCB assembly (PCBA) soldering process? Does it impact solder joint strength? People often comment on IMC being too thin or too thick, so what is a reasonable thickness for IMC?

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Soldering     WorkingBear    Views (7,478)     comment (0)
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Feb15
NWO (Non-Wet-Open) Defect in BGA Soldering: Causes and Possible Solutions

post on February 15, 2024

NWO (Non-Wet-Open) Defect in BGA Soldering: Causes and Possible Solutions

Recently, many have inquired about how to deal with Non-Wet-Open (NWO) issues when encountering BGA packaged ICs soldering. The defects associated with NWO are quite similar to those of HIP (Head-in-Pillow) and typically occur at the edges and corners of BGA packaged ICs. The root cause often lies in the substrate or PCB of the BGA, where the board material may deform due to the high temperatures during the reflow process.

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Process, Quality, SMT, Soldering     WorkingBear    Views (2,693)     comment (0)
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Feb06
Purpose of Using Lead-Free Low-Temperature Solder (LTS) SnBi, SnBiAg in Soldering

post on February 6, 2024

Purpose of Using Lead-Free Low-Temperature Solder SnBi, SnBiAg in Soldering. Tin-Bismuth alloy solder paste

The alloy composition of lead-free LTS (Low Temperature Solder) usually includes the metal “bismuth (Bi)” in addition to tin (Sn) to lower its eutectic point.

The commonly used lead-free solder SAC305 has a melting point of 217°C, while Sn64Bi35Ag1 has a melting point of only 178°C, and Sn42Bi58 has an even lower melting point of 138°C. This means that the melting temperature of solder containing “bismuth (Bi)” is significantly lower, ranging from 39°C to 79°C lower than SAC305 lead-free solder.

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Quality, Reliability, SMT, Soldering     WorkingBear    Views (1,888)     comment (0)
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Jan30
Problem Analysis and Solving: 8D report

post on January 30, 2024

Problem Analysis and Solving: 8D report

The “8D report” is a tool commonly used in the electronics assembly industry for “problem analysis and solving.” Due to its systematic and clear steps, the “8D report” is often utilized in responding to customer complaint cases.

The term “8D” refers to the “8 Disciplines process.” The person filling out the report generally follows predefined steps in sequence. This helps most quality control personnel systematically identify the causes of problems step by step. It also allows you to explain to the customer how the problem was discovered or occurred, how you analyzed the problem, found the root cause, verified if the problem was genuinely resolved, and implemented preventive measures to prevent the problem from recurring.

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Management, Quality     WorkingBear    Views (4,010)     comment (0)
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