Solder paste is an essential material in the process of soldering components and SMDs (Surface-Mount Devices) onto printed circuit boards (PCBs). How is this material used? Let’s explore the concept of solder paste, its proper storage after opening, and its components in this article.
What is Solder Paste?
Solder paste, also known as tin solder paste or Solder paste, is a mixture of flux and alloy particles in a specific ratio, depending on the user’s requirements, and is produced in a smooth paste form. The solder alloy powder makes up about 80% of the product’s weight.
Compared to lead bars or lead tin rolls, solder paste is more favored in factories. This is because solder paste does not need to be melted, allowing the soldering process to be quicker and simpler.
Notably, solder paste has excellent wetting properties, which help components adhere better to the PCB surface. As a result, the final product meets the desired standards.
Learn about solder paste (Photo: Internet)
Classification of Solder Paste
How is solder paste categorized? Based on its composition, solder paste can be divided into two main types: leaded solder paste and lead-free solder paste.
Leaded Solder Paste
Leaded solder paste primarily consists of Tin (Sn) and Lead (Pb) mixed in a specific percentage. Common ratios include 37% Lead, 63% Tin, or 40% Lead, 60% Tin.
Today, the use of leaded solder paste is restricted due to its lead content. Soldering with this paste produces toxic fumes, which can be harmful to human health.
Lead-Free Solder Paste
Lead-free solder paste is widely used and, as the name suggests, does not contain lead in its composition. This ensures the safety of users’ health.
The main component of lead-free solder paste is tin, with lead replaced by metals like copper and silver in a standard ratio of 0.5% Copper, 3% Silver, and 96.5% Tin.
Additionally, solder paste can also be classified according to the type of flux used:
- Rosin-based Solder Paste: Made from natural rosin extracted from pine trees. It can be cleaned if necessary using solvents like chlorofluorocarbon.
- Water-Soluble Flux Solder Paste: This type uses glycol-based and organic materials as flux. It can be cleaned using various agents after use.
- No-Clean Solder Paste: Contains resins and varying levels of residue. It does not require cleaning, but the assembly environment must be kept clean
Classification of solder paste without TAMURA TLF-204-93IVT(SH) distributed by Hapoin
Important Considerations When Using Solder Paste
To maximize the effectiveness of solder paste, consider the following tips:
- Storage Conditions: Solder paste should be stored in a cool environment, ideally between 2 to 10°C.
- Handling Between Uses: If the paste is not used for more than an hour after opening, ensure that the lid is tightly sealed during the interval and opened only when ready to use again.
- Temperature Adjustment: After removing solder paste from the freezer, let it sit at room temperature for 2 hours before stirring. Stir the paste for only 2 to 3 minutes to restore its original consistency without overmixing.
- Surface Inspection: Before stirring, if you notice small clumps forming on the surface, remove them before mixing the paste.
How to Choose the Right Solder Material
Selecting the appropriate solder material involves three critical stages:
- Composition Examination: Consider the composition of the solder paste. Key factors include the lead content, adhesion properties, melting temperature, and the diameter of the alloy particles.
- Flux Selection: The flux component in the solder paste plays a vital role in reducing surface tension and ensuring smooth, shiny solder joints. Different types of flux (R, RA, RMA, WS) have varying levels of effectiveness and limitations, so choose the flux type carefully based on the specific application requirements.
- Special Flux Characteristics: Finally, select a product with flux properties tailored to your needs, such as reducing flux residue, minimizing solder paste overflow, enhancing surface adhesion, filling capability, Halide-free properties, reverse soldering speed, or UV fluorescence…
Halogen-free solder paste is increasingly preferred by factories
Where to Buy Reliable and Quality Solder Paste?
After understanding what solder paste is, if you’re looking to purchase quality solder paste but haven’t found a reliable source yet, you can turn to Hapoin Vietnam. We specialize in providing genuine solder pastes at competitive prices. The solder paste products offered by Hapoin are imported and distributed directly from overseas, complete with full certification, ensuring customer confidence in their purchase.
You might be interested in: List of Soldering Materials
Conclusion
In this article, Hapoin has helped you explore the question, “What is solder paste?” and how to use it. We hope this article has provided valuable insights into solder paste materials. If you have any further questions, please don’t hesitate to contact us for prompt assistance.
