| On the Purpose of environment Protection, two legislations-WEEE and RoHS in Europe are set up already and that has been effective on July 1st, 2006. Lead is not permissible in the two legislations, which free-lead must be used in the electronic product. The melting point of Pb-free solder is 30℃～40℃higher than Sn-Pb eutectic solder. So the quality of lead-free solder becomes a key. Under this background and combination with the Surface Mount Technology(SMT) lead-free manufacturing of Huai'an College of Information Technology, the article includes the study of the lead-free solder paste and relative lead-free production with focus on the critical process. Multi-analysis of experiment is used and the optimizing of process parameter and ensuring of production reliability are found. The achievements as below:(1)Use solders printing comparison experiment and printing result observation numeric experiment to identify the process-optimized Parameters of screen print.(2)The wetting ability and mechanical property and high temperature application of the lead-free solder paste are analyzed . In the end, the characteristic is summarized(3)The characteristic of lead-free reflow soldering and the cooling rate of lead-free soldering that the solder quality is affected are analyzed to optimize the parameters. At the same time, the familiar questions are studied in the process of lead-free soldering. Corresponding ameliorative idea are put forward about lead-free reflow soldering.Validated the effectiveness and reasonable of the process parameters by completing lead-free products pilot run and the relative reliability testing... |
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