【作者】 王磊；

【导师】 吴丰顺；

【作者基本信息】 华中科技大学 ， 材料加工工程， 2004， 硕士

【摘要】 表面组装技术(Surface Mount Technology-SMT)的出现给电子工业带来巨大的变革。SMT 有更高程度的自动化,其产品电路密度更高、体积更小、成本更低。这些优势使SMT 很快地成为电子工业中的主流组装技术。焊膏是SMT 最重要的连接材料,其性能对SMT 最终产品质量有直接影响。其中,焊膏印刷性能对SMT 的影响最为重要。目前尚无用于测试焊膏印刷性能的设备和仪器。此外,国内外与焊膏印刷性能相关的标准和测试方法也存在诸多不足。针对以上情况,本课题以SMT 焊膏印刷机工作原理为基础,研制出首款焊膏印刷性能测试仪器并申请了专利。利用该仪器和确定的焊膏印刷性能评价项目,进行了焊膏印刷性能试验。焊膏印刷性能试验研究以下三个方面:焊膏印刷时所受到的阻力,焊膏焊料球试验和润湿试验。实际测试中通过检测电机电流以代替检测焊膏印刷时受到的阻力。在电机电流的研究中,利用电流变化量ΔI 和印刷距离S 之比ΔI/S 提出了电机电流变化率的概念,并根据电流变化率从焊膏印刷过程稳定性和焊膏印刷寿命两个方面对焊膏印刷性能进行评价。在焊膏印刷性能试验中的各个阶段,进行了焊膏焊料球试验和焊膏润湿试验。在焊膏焊料球试验中,根据各个阶段焊膏焊料球周围助焊剂残留物和焊球两个方面的表现对焊膏印刷性能进行评价。在焊膏润湿试验中,根据各个阶段焊料表面残留物,焊膏润湿时出现的气泡和焊膏润湿性能三个方面的表现对焊膏印刷性能进行评价。最后本文提出以焊膏印刷性能测试仪器的电机电流变化率作为焊膏印刷性能评价的主要参考,以焊膏焊料球试验和润湿试验作为焊膏印刷性能评价的辅助参考。本文还利用计算机模拟对不同印刷速度和印刷压力下的焊膏印刷性能进行了研究。研究表明:在不考虑其他焊膏印刷性能影响因素下,较高的印刷速度和印刷压力能提高焊膏印刷性能。更多还原

【Abstract】 The present of Surface Mount Technology-SMT brings great changes to electronic industry. SMT has many advances such as higher automatization, lower cost,less component volume,higher circle density, and better performance. All of these turn SMT to be the main stream of assembly technology. Solder paste is the most important connection material applied in SMT. The performances of solder paste have a direct influence to the quality of SMT products, especially the performance of solder paste printing. There are no equipments or instruments only used to testing performance of solder paste printing now. At the same time, there are some limitations in the standards and test measures of performance of solder paste printing. In this situation, the first instrument to test performance of solder paste printing was invented on the base of solder paste printer used in SMT product line in this thesis. The performance of solder paste printing was studied by the instrument and the items used to value performance of solder paste printing. The study included three aspects, which are the resistance force appearing in the solder paste printing, the solder ball test and solder paste wetting test. In the actual testing performance of solder paste printing, the current of motor was studied instead of the resistance force for convenience. The rate of current change, ?I/S, was proposed, according to the current change ?I and distance of printing S. According to the rate, the performance of solder paste printing was valued by the stability of printing process and the life of solder paste printing. Solder ball test and solder paste wetting test had been done in the every stage of experiments of solder paste printing. In the solder ball test, the performance of solder paste printing was valued on the base of observing solder flux residue and solder ball in the every stage of solder paste printing. In the solder paste wetting test, the performance of solder paste printing was valued on the base of observing solder flux residue on the surface of solder, bubbles presenting in the process of solder paste wetting and wetting ability in the every stage of solder paste printing. The principle was proposed that the result of current change rate was used as main reference and the result of the solder ball test and solder paste wetting test used as secondary reference. In this thesis, the performance of solder paste printing was simulated under the different printing velocity and printing pressure. The result of simulation indicated that higher printing velocity and printing pressure would improve the performance of solder paste printing if other factors were not considered.更多还原