军工电子产品有铅无铅混装工艺的可靠性研究
发布时间：2019-01-11 09:50
【摘要】：对于军工电子产品而言,如何在采用有铅制程的情况下焊接有铅、无铅元器件并保证其可靠性已成为军工单位迫切需要解决的问题。本文是以有色金属材料学科为理论指导,在试验的基础上,首先对有铅无铅混装工艺的军工电子产品的各个工艺流程的参数进行了控制,包括印刷参数、贴装参数,回流焊接参数等,完成了SMT有铅焊膏下有铅、无铅元器件的混装焊接;其次对试验PCB板进行了可靠性验证试验,包括温度循环试验和振动试验,最后通过使用X-Ray检测仪对焊点进行检测,用金相显微镜分别对不同焊端镀层的元器件的焊点形态及合金层进行分析,以达到生产过程的稳定、可控、可靠,使相应工艺具有可操作性、广泛性和一致性。本文在试验中发现在成分为Sn62Pb36Ag2的有铅焊膏焊接有铅元器件、镀层为纯锡、镍钯金、锡银铜等镀层的无铅元器件的条件下,在严格控制焊接温度窗口在235±5℃之间,大于有铅焊料熔点(179℃)的回流时间为80s左右,大于220℃的时间至少为4052+-秒时,能保证得到有效的Cu6Sn5合金层的厚度在4um范围内,此混装焊接可满足军用电子产品的可靠性。
[Abstract]:For military electronic products, how to weld lead, lead-free components and ensure their reliability has become an urgent problem to be solved by military industry units. Based on the theory of nonferrous metal materials, this paper controls the parameters of various technological processes of lead-free military electronic products, including printing parameters and mounting parameters, on the basis of experiments. Reflux welding parameters and so on, completed the SMT lead solder paste with lead, lead-free components mixed welding; Secondly, the reliability test of PCB plate is carried out, including temperature cycle test and vibration test. Finally, the solder joint is detected by using X-Ray detector. The solder joint morphology and alloy layer of the components deposited on different welding ends were analyzed by metallographic microscope in order to achieve the stability, controllability and reliability of the production process, and make the corresponding process operational, extensive and consistent. In this paper, it is found that under the conditions of lead-free components with lead soldering paste and pure tin, nickel, palladium, tin, silver, copper and so on, the welding temperature window is in the range of 235 卤5 鈩，
本文编号：2406991
[Abstract]:For military electronic products, how to weld lead, lead-free components and ensure their reliability has become an urgent problem to be solved by military industry units. Based on the theory of nonferrous metal materials, this paper controls the parameters of various technological processes of lead-free military electronic products, including printing parameters and mounting parameters, on the basis of experiments. Reflux welding parameters and so on, completed the SMT lead solder paste with lead, lead-free components mixed welding; Secondly, the reliability test of PCB plate is carried out, including temperature cycle test and vibration test. Finally, the solder joint is detected by using X-Ray detector. The solder joint morphology and alloy layer of the components deposited on different welding ends were analyzed by metallographic microscope in order to achieve the stability, controllability and reliability of the production process, and make the corresponding process operational, extensive and consistent. In this paper, it is found that under the conditions of lead-free components with lead soldering paste and pure tin, nickel, palladium, tin, silver, copper and so on, the welding temperature window is in the range of 235 卤5 鈩，
本文编号：2406991
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