Select welding paste butt welding for welding process The quality of the point, the long-term reliability and the overall performance of the selective soldering are very large, but this problem is often overlooked. This article briefly describes the key factors of solder paste commonly used in soldering, and the impact of these solder pastes on solder joint quality and reliability and on device performance.

The solder paste can basically be divided into three main types:

·  Low solid content no-clean solder paste

·  Rosin solder paste (all solid rosin / high solid content rosin)

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·  Water-Soluble Solder Paste

 When discussing the solder paste used in the soldering process, we usually Refers to low solids no-clean solder paste, which is a commonly used solder paste in selective soldering.

 If a company uses a full rosin solder paste or water soluble solder paste in their selective soldering process, they will usually follow the customer’s requirements. Or industry regulations use such solder pastes, and they generally produce conventional products in accordance with conventional reliability standards. Since the solderability of these two types of solder pastes is very good, their soldering results are rarely evaluated. However, most companies avoid using these two types of solder paste as much as possible when performing selective soldering because they require expensive cleaning processes. In any case, one of the benefits of selective soldering is the ability to select a solder paste to eliminate the cleaning process.

It’s important to note that if you need to use rosin solder paste or water-soluble solder paste in your choice soldering process, you should consult with you. The device manufacturer determines if you have the right choice of type or material to use when handling these types of solder paste.

Low-solids no-clean solder paste is subdivided into the following categories:

·   Alcohol-based solder paste containing rosin or resin

·  Alcohol-based solder paste, no rosin or resin

·  Water-based solder paste, no rosin or resin (no volatile organic compounds); in rare cases, rosin or resin

 According to this classification, there are many manufacturers and more solder pastes to choose from. So how do you make a decision? Even if your customer, company management, or your existing manufacturing process requires you to use some kind of solder paste, in this case, it's important to figure out if you use this solder paste, it Whether it is beneficial or unfavorable for your selective welding process.

Generally speaking, the low-solids no-clean solder paste has less active chemical components than rosin solder paste or water-soluble solder paste. It is more challenging for welding. Some solder pastes are used to solve some special problems. They may be problems you have not encountered. However, these solder pastes may have disadvantages in solving other problems, which is another problem. It is often the case that the type of product you produce may affect the solder paste that is right for your process. Or, to put it more directly, you have a very wide variety of products, which may affect your choice of solder paste. Even different products may require different solder pastes. One of the problems with

is that many of the solder pastes that were originally used for wave soldering are now used in selective soldering. For the entire electronics industry, wave soldering processes are better suited to these different types of solder pastes, both in terms of products and applications. Until recently, some solder paste manufacturers have truly realized the difference between the selective soldering process and the wave soldering process, and began to produce solder paste specifically for selective soldering.

However, in various optional solder pastes, rosin/resin, alcohol-based, low-solids no-clean solder pastes are usually soldered. A good choice for craftsmanship. They perform well on a variety of different surfaces, have a relatively wide process window, and have a longer processing time at elevated temperatures. They can be used in lead-containing solders and lead-free solders, all burned off, leaving residues usually safer.