At present, SMT is the use of materials, consumables with solder paste. We analyzed the composition and related matters and role.
Know, paste.
Solder paste, solder paste) is SMT an indispensable material, it after add cooked melt, the SMT parts welded on the PCB copper foil, connecting and conducting role. Its role is similar to we often see tin wire and wave soldering tin of water, just different they are intrinsic to the state.
Solder paste is taken as a SMT pivotal material and know about its composition is very necessary, solder paste is usually consists of particles of metal powder, flux, increasing agent and some other activator composition, which plays an important role of is flux. It to remove the oxide and other surface contamination, so that the welding can be carried out smoothly paste is generally tin (SN), lead (PB) alloy, the melting point of 183 0C.
Two, the use and management of solder paste.
After the 1 solder paste supplier sent solder paste, we must carry out flow number, and put back temperature records.
2 in the use of solder paste, must be used according to the FIFO principle.
3. Solder paste before use to back to temperature 4 hours (or more than 4 hours), and the stirring action, in order to avoid due to solder paste mixing the components and caused a series of adverse effects.
The 4 solder paste on the plate residence time does not exceed 30 points (in the case of blade action).
5 in the use of the remaining paste, you must first trial, have satisfactory results under the condition of adding new paste can mix.
6 good PCB scraping board paste, not more than a store, or erase reprint paste.
7 two different types of solder paste cannot be mixed.
The 8 solder paste is corrosive, when in use to avoid splashing into the skin or eyes.
9 paste storage temperature of 2~8.
10 in the use of solder paste before completing import record, and stir before the line.
The 11 solder paste Kaifeng time more than 24H, as reported, shall not be used.
The 12 solder paste can be stored at room temperature for 30 days, can be stored at 2~8 DEG C for 120 days.
Add paste (Solder paste): in the printing machine.
The ingredients are: tin solder paste (63%), lead (37%), (5% of the total flux components).
The paste of the eutectic point of 183 DEG C, then paste paste by melting. The cold into the solid body.
It is the role of the heating medium is abnormal, PCB parts and PAD welding.