| With the progress of human civilization, people's environmental consciousness gradually. Lead the world increasingly concerned about the environmental and health hazards. Although the amount of lead in the electronics industry lead the world's total volume of only an extremely small part of the year only 10,000 tons of tin-lead alloy solder used in this area, but these have not been recovered almost solder, because most of the e-waste end up is buried in the ground, polluting the earth and water resources. So study lead-free solder paste in the electronic application package is important. This paper's actual production of lead-free solder paste and lead-free soldering process has been systematically studied. Our results for lead-free solder paste selection, evaluation and application of surface mount technology, lead-free production of a broad guide, lead-free production of electronic products has important engineering value..On the other hand, about 80% of electronics failure and solder paste-related defects and thus the performance of solder paste for SMT production is critical. However, the market of various grades, there are many different brands of solder paste, so how to choose the right solder paste, solder paste is how to evaluate the performance of all aspects of it becomes necessary. In order to adapt completely lead-free manufacturing and backward compatible with lead-free components and lead-free PCB board, we need to have a comprehensive lead-free solder paste selection and application. Through research, choose one or two lead-free solder paste.Experimental results show that lead-free solder paste in the poor mobility of steel line, resulting in deposition area, volume and height of the maximum and minimum fluctuation is obvious; use the smallest pitch of the parts (for example:IC220) on the maximum and minimum differences were significant. Lead-free solder paste from the test can be seen on the pin in the vertical direction will lead solder paste deposition area, volume and highly significant changes.Lead-free solder paste printing through the comparison of the sustainable, this was continued in the same printing process more suitable for lead-free solder paste; paste I and O have good continuity and printability of printing; after 200 printed in more than roll mixing, the paste compared to I and O, solder paste printability K and H will be a serious decline and there is great change in viscosity.Found that number for the K and H, lead-free solder paste, solder the connector SMA, there is a shortage of tin, and lead-free solder paste numbered I, SMA connector have good weldability, In these tests the PCBA's only a small tin solder. Number for the K and H, lead-free solder paste in the package parts capacitor C1206 and resistor R1206 on the tin more beads, numbered O lead-free solder paste reflow curve in the use of RSS only tin beads, and numbered I lead-free solder paste tin at least the number of beads, and the test pad on the PCB solder paste I found a very good scalability.X-RAY-ray inspection using a lead-free solder paste of voids issue, found that the size and diameter welded hollow in acceptable range. Number is the paste I use a lot of RTS reflow profile when voids, but by PCB treatment can reduce these voids. The results show that I and O solder paste reflow curve in the use of two processes, all of the welding results can be accepted; return curve using RSS, I have very little solder welding defects, and solder paste compared to H welding defects under more; and paste the welding defects K will be back with the curve will increase the use of RTS.In short, this paper studies the existing equipment and processes unchanged, to find a suitable lead-free production of the company's lead-free solder paste, thereby ensuring the production process and product reliability. |
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