What should be paid attention to when using lead-free high t

Friends who have used lead-free solder know that there are high and low temperature lead-free solder pastes. As the name suggests, lead-free high-temperature solder pastes are used in high-temperature environments. The difference between high-temperature lead-free solder paste and low-temperature lead-free solder paste is that the melting point is different. High-temperature lead-free solder paste is composed of tin, silver and copper, low temperature is tin-bismuth, low temperature is 138, and high temperature is 217-227, so If you want to distinguish between these two furnace temperatures, you might as well put both solder pastes through the furnace, and set the reflow soldering temperature profile to low-temperature solder paste. If there is one that will drop badly or not stick after the furnace is over If it goes up, it is a high-temperature lead-free solder paste, because the melting point of the high-temperature lead-free solder paste is 217 and the maximum temperature of the low-temperature solder paste may just reach the high-temperature melting point of 220, so the inability to melt the tin will cause dropouts. So, what should be paid attention to when using lead-free high temperature solder paste?

 

Solder paste

 

Lead-free high temperature solder paste will be affected by humidity and temperature, so it is recommended that the working environment be at room temperature between 23 to 25 degrees, with a humidity of 60%, and the viscosity of the solder paste is between 23 and 25 degrees. The viscosity is adjusted appropriately, so the temperature is too high will cause the viscosity to be too low, the temperature is too low, the viscosity is too high, and the perfect effect cannot be achieved after printing. Due to the moisture absorption of the solder paste, the solder paste will absorb in a high temperature and humid environment. Moisture in the air causes solder balls and splashes.