What are the differences between leaded solder paste and lead-free solder paste?Solder pasteIt is mainly a mud-like mixture composed of solder wire powder and flux paste, and is mainly used forSMTIn the field of production and processing, resistors, capacitors,ICThe electronic components are welded by electric weldingPCBOn the board. Solder paste is further divided into leaded solder paste and lead-free solder paste. The key differences between leaded solder paste and lead-free solder paste are as follows4The differences in broad fields. In work, the common solder paste (also known as solder paste) we often see can be divided into two types. Solder paste is composed of solder alloy powder and flux/The carrier is a paste-like solid uniformly mixed in a certain proportion. There are two types: lead-free solder paste and leaded solder paste.

The color of leaded solder paste is blackish gray, and it is packed in a milky white water bottle. The lead-free solder paste is grayish-white in color and is packaged in an environmentally friendly water bottle. Solder paste with lead usually has a very strong smell. The components in lead-containing solder paste contain lead, and lead itself has a grayish-black characteristic. Lead-free solder paste is followedRoHSThe standard and conventional method in the field is to use the emerald green water bottle for storage, which is convenient for project technicians to visually distinguish when using it.
The aluminium alloy components of leaded solder paste are mainly composed of tin and lead, and their proportions are:Sn:Pb=63:37;Taking lead-free high-temperature solder paste as an example, the aluminum alloy composition is mainly composed of tin, copper and silver,Their proportion isSn:Ag:Cu=96.5:3:0.5/99:0.3:0.7.
Standard deviation of melting point of leaded solder paste183℃The standard deviation of the melting point of lead-free high-temperature solder paste is217℃-227℃Therefore The welding temperature of lead-free electric welding is higher than that of leaded electric welding. The high value of the welding temperature of lead-free electric welding should be200-205℃The highest point temperature is235℃-245℃.
The welding temperature of lead-free electric welding is higher than that of leaded welding. At a certain temperature (200-205℃High value235℃The welding effect of electric welding is relatively good.235℃The limited temperature precisely matches the maximum temperature values of electronic devices set by most electronic device manufacturers. In order to better comply with the characteristics of lead-free solder paste, the furnace temperature curve of the reflow oven is set as in the soldering method20For the section, a smoother curve graph is selected and the transportation speed is reduced to maintain a good actual welding effect.
todayJJYLet me explain to you the key points of lead-free solder paste. Let's all take a look together!The advantages of lead-free solder paste:
First, the soldering temperature is higher. The solder paste soldering temperature is also higher. As an auxiliary material throughout the soldering process, lead-free solder paste enables the entire soldering process to proceed at a higher temperature. In the solder paste, metallic tin particles exist in a state close to that between liquid and solid, and in combination with the active silver and copper metals, they can achieve a better combustion effect. Under soldering conditions, Assist the welding machinery and equipment in welding the products at a higher temperature.
Second, stronger soldering performance. Lead-free solder paste has excellent soldering performance. As an auxiliary material for soldering, the heavy metal-free solder paste adopts more scientifically researched raw materials. During the entire application process, it can assist the soldering process to proceed rapidly. The solder paste uses copper and silver metals to replace the original lead metal, achieving an environmentally friendly effect. Due to the stronger thermal conductivity of copper and silver, and their combined application with tin metal, the solder paste appears thick. During the application process, it can be evenly applied to the surface of the solder joint, giving the soldered product a more aesthetically pleasing appearance. The solder paste itself has a relatively good moisture content. Besides allowing the solder paste to fully exert its performance, it also does not require special cleaning, thereby enhancing efficiency.

To sum up, these are the key points of knowledge about the advantages of lead-free solder paste that we are sharing with you today. Shenzhen JJY Industrial Technology Co., Ltd. specializes in the soldering industry12With years of research and development and production, including the production and research of solder paste, solder wire, solder wire, solder bar, heavy metal-free solder paste and lead-containing solder paste, JJY is a reliable solder paste manufacturer.