Production management of the preservation and use of solder paste requirements First, the preservation of solder paste should be stored in a sealed form in a constant temperature, constant humidity freezer, the storage temperature is 0 ° C ~ 10 ° C, such as the temperature is too high, the alloy powder in the solder paste has not chemically reacted with the flux, so that the viscosity and activity are reduced to affect its performance; If the temperature is too low, the resin in the flux will produce crystallization, which will make the form of the solder paste deteriorate. Second, when the solder paste is removed from the freezer, it should be in its sealed state, and then opened after it returns to room temperature, about 4-8 hours (500g/4H1000g/8H), if it is just taken out of the freezer, the temperature difference will make the solder paste condensation and condensation into water, which will lead to solder beads when reflowing.
Barrels that remain in their original packaging can be stored at room temperature for up to 5-7 days. Immediately after removal from the freezer, the access personnel must immediately mark each barrel with the date and time of the current time, so that it is easy to check whether the temperature return time is sufficient before use. Third, the stirring and use of solder paste should be confirmed before use, the solder paste has been fully warmed, and has not exceeded the validity period (5-7 days). After the solder paste is opened, it should be stirred with a mixer so that the components of the solder paste are fully mixed. After opening the lid, it must be used up within the time recommended by the solder paste supplier (usually 12-24 hours), the solder paste that exceeds the specified time must be scrapped four, the use of the solder paste requires that the refrigerated storage time of the unopened can be 6 months after the date of manufacture (or the expiration date recommended by the manufacturer on the tin can) The storage time under the temperature and humidity of the unopened can is ≤ 5 to 7 days The interval between the purchase of the receiving material and the time of putting it in the refrigerator≤ the time between 4 hours of warming ≥ 4 hours stirring time back to warm OK solder paste in the mixer at least 3 minutes before opening the can for the first time before the first use of the mixer, manual mixing (not recommended) 30 minutes after opening the tank once not all used up the screwing tank lid in the ambient temperature and humidity place time ≤ 12 to 24 hours (according to the recommendation of each solder paste manufacturer) on the silk screen use time ≤ 8 hours after printing the paste on the line stay time≤ 2 hours after opening the can to the time before reflux≤ 18 hours warm time + The time after opening the can to before the reflux ≤ 48 hours priority recommend the bar code system to control the solder paste FIFO batch management Different brands of solder paste are strictly prohibited from mixing