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为减小振动因素对产品失效的影响,改进PCBA组件的结构参数,提高PBGA(塑料球栅阵列)振动可靠性。采用有限元法,运用模态分析,得出结论:固支数目越多,焊点的振动可靠性越好。此外,利用随机振动模块,分析了板级振动条件下,焊点位置、焊点材料、PCB厚度、BGA焊点高度对可靠性的影响,并且利用焊点的疲劳寿命模型计算出关键焊点的疲劳寿命。结果表明:焊点最容易失效的位置位于焊点的顶角处;相比于Pb90Sn10、Sn63Pb37、Mix、SAC387这四种材料,SAC305的疲劳寿命最高;PCB的厚度和焊点的疲劳寿命成正比;焊点高度和焊点的疲劳寿命成反比。 相似文献
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We realized the desired spheroidizing of NiCo2O4 nanomaterials by laser irradiating NiCo2O4 suspensions with different concentrations. The results reveal that the as-prepared samples are desired spheres with the maximal average size of 568 nm and the superior dispersity, which were obtained at the energy density of 0.30 J.pulse-1?cm-2 and NiCo2O4 suspension concentration of 0.2 mg.mL-1. However, the phase segregation, which was induced by large amounts of solid redox of Co3+/Co2+ and Ni3+/Ni2+, also appears in the laser-irradiation process. 相似文献
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