Solder paste, also known as solder paste, is gray or grayish white paste, with a specific gravity range of 7.2-8.5. It is generally packaged in 500g sealed bottles, and there are also specially customized packages, such as needle cylinder packaging or 1kg packaging. Compared with traditional solder paste, it has more metal components. It can be stored at low temperature between 0 and 10 degrees (5 to 7 degrees is the best). Recently, solder paste can also be stored at room temperature, but the effect is still not ideal.
Generally, alloy powder with 3 # powder diameter (25-45 μ m) (finer powder such as 4 # and 2.3 # coarse powder may also be used due to different needs) and 8% to 12% welding paste are used in vacuum (nitrogen protection) The uniform stirring of the environment can be classified according to the environmental protection: lead-free solder pastes such as tin lead/tin lead silver and lead-free solder pastes such as tin silver copper/tin copper/tin bismuth can be classified according to the use temperature: as high as tin copper or tin silver copper system/as often as tin silver bismuth system/as low as tin lead bismuth/tin bismuth and other solder pastes can be divided into cleaning type and free type according to whether they need to be cleaned.
1. According to the packaging form: tubular packaging; Canned packaging (250g or 500g) 2. Distinguish according to flux: no-wash (RMA or RA) and cleaning (also water and solvent washing) 3. Distinguish according to composition: lead-free solder paste (63/37) and lead-free solder paste (SnAgCu305) 4. Distinguish according to the size of tin powder particles: there are 3 # powder, 4 # powder, 5 # powder, and usually use 3 # solder paste; Lead free low temperature solder paste Sn42/Bi58 melting point 138 ℃; The working temperature demand is 150-170 ℃ (Time30-60Sec); It is the most suitable welding material at present; Due to the CPU radiator and heat dissipation module, lead-free solder paste has high resistance and high printability. It has high brightness after back welding and low surface residue, which does not need to be cleaned. It has no halogen compound residue, and meets the standards for prohibited substances for environmental protection.
Product features
1. Good printing rolling property and tin laying property, accurate printing can also be completed for pads with spacing as low as 0.3mm
2. During continuous printing, the viscosity changes very little, the operable life of the steel mesh is long, and it will not become dry after more than 8 hours, and the printing effect remains good;
3. After several hours of printing, the original shape is still maintained without collapse, and the placement elements will not be offset;
4. With excellent welding efficiency, it can show proper wettability in different parts;
5. It can meet the requirements of different grades of welding equipment. It does not need to complete welding in a nitrogen filled environment. It can still show good welding efficiency in a wide range of reflow furnace temperatures;
6. After welding, there are few residues, which are colorless and have high insulation impedance, will not corrode PCB, and can meet the requirement of no cleaning.
7. It has better ICT test efficiency, and will not cause false judgment;
8. It can be used in the Paste in hole roller coating process.
It is better to solder the circuit board with rosin, because rosin is the flux. Solder paste can only be used to weld iron parts and other articles that are difficult to tin. It is corrosive and generally only uses rosin. The role of rosin is to precipitate the oxide in solder, protect solder from oxidation, and increase the fluidity of solder. The electronic components are usually coated with good tin, which is not very impressive. If they are rusty, they should be polished first, and then they should be put on the rosin and ironed with a soldering iron before being coated with tin. After the circuit board is polished, it can be directly plugged into the tinned components and welded with rosin core solder wire. If it is a surface mounted component, how to operate it without solder paste. Remove the soldering iron before the rosin volatilizes. If the soldering tin is sticky, dip it in rosin again. Do not move the components before the soldering tin solidifies.
Hongqiao Technology Co., Ltd. is a high-tech enterprise specializing in the research, development and production of cutting fluid, electronic hardware cleaner, surface treatment agent, welding materials: solder paste, tin rod, tin wire, BGA solder ball, SMT tin, electronic flux and thinner, electronic welding equipment and accessories, electroplating anode plate (rod), semi tin ball and other products.