When soldering a circuit board, we often use solder paste. What details should we pay attention to when using solder paste? The following is a little knowledge shared by FASTPCBA and I hope to help you.
1 Make sure that the solder paste is used to produce the early solder paste, remove it from the refrigerator, record the removal time on the surface of the solder paste container, and place it at room temperature of 22~28 °C for 4 hours to confirm that the surface of the solder paste container is not Condensation phenomenon, open the inside and outside of the container two layers of cover, record the opening date, time and start stirring.
2 Stirring is divided into two types, one is manual stirring using a spatula, and the other is stirring using a blender.
If manual agitation is used, insert the stainless steel or plastic scraper into the solder paste. The stirring diameter is about 10~20mm. After stirring for lmin, lift the scraper. If the solder paste on the scraper slides down all the way, the stirring result is qualified and the stirring is finished. If only part of the solder paste slips, the stirring result is unqualified, and stirring must be continued; if using automatic stirring and stirring, stir for 3 minutes according to the "mixing machine operating rules".
3 After stirring, apply a certain amount of solder paste to the printer template and start using it.
4 In the production process, pay attention to the change of the amount of solder paste, add solder paste in time, add solder paste, be sure to use the scraper to stir the solder paste first.
5 The remaining solder paste in the container should be sealed with a lid (both inside and outside). When not in use, return the solder paste to the refrigerator; when using it, keep it away from light at room temperature and use it within 24 hours. If it is over 24 hours, discard it immediately.
6 Before going to work every night shift, the template should be cleaned by hand. The remaining solder paste on the template should be disposed of as waste if it has been placed for more than 24 hours. If it is not more than 24 hours, it should be packed in another container and sealed. The solder paste used is mixed to prevent contamination of the new solder paste.