In the process of using solder paste, have you also discovered the problem of tin beads? The following is our test of different solder pastes, hope to help you.
Four solder pastes were used in the test. Solder paste is temporarily replaced with letters. Tin Paste A: The solder paste used by the company has always been tin beads. Solder paste B, C, d … three solder pastes from the solder paste manufacturer.
Test step 1: Take out 3 cans of solder paste A. After standing for 4 hours at room temperature, stir the machine for 0 minutes (ie without stirring), 3 minutes, 5 minutes. Then, the same print setting and temperature setting were used to make ten plates. Check the number of tin beads by the quality department. Result: The solder paste A was stirred for 5 minutes, and the solder beads were the least after the furnace was discharged. Therefore, it was decided to use normal temperature for four hours and stir for 5 minutes.
Test step 2: Take out the solder paste B, C, d for 4 hours at room temperature, and stir for 5 minutes. Then, the same print setting and temperature setting were used to make ten plates. Check the number of tin beads by the quality department. As a result, solder paste B tin beads a lot. Solder paste C: a tin bead (0.15mm or less). Solder paste D: two tin beads. From the effect point of view, solder paste C seems to be the best choice, but considering in the price direction, solder paste D is much cheaper. So I decided to use solder paste D.

Test step three:take out the solder paste D. After standing for four hours at room temperature, stir for 5 minutes. Then the same print setting, temperature setting, and different time, using baked and unbaked materials, respectively, make ten pieces board. Check the number of tin beads by the quality department.Result: The baked material did not have tin beads after the plate came out.
Finally decided to use solder paste D, placed at room temperature for four hours, the machine is stirred for 5 minutes after use. The PCB board must be baked. Of course, this time is only a test, can not say that there is no tin beads at all, it is impossible. Only now, tin beads have been controlled to a minimum.
Observe the solder paste B, C, D. The metal particles of solder paste D are 28-45um, which is larger than the particles of the solder paste we used before, and should be stronger in terms of anti-collapse.
The above is a test of different degrees of tin paste on different solder pastes, for reference only.

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