Design and analysis on SMT QFN silicone keypads

Chen, Xuanyou; He, Wei; Cai, Miao; Huang, Yue; Zhang, Jinyuan; Zheng, Jianna; Zhong, Zhengqi; Yang, Daoguo

doi:10.1109/icept.2015.7236753

Cited by 4 publications

(1 citation statement)

References 2 publications

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“…For example, the surface utilization percentage of printed circuit board (PCB) increases, automatic production can be performed, and the efficiency of assembly production can be greatly improved. To address the abovementioned problems of existing SREKs, a novel type of material called SMT-SREK has been developed in recent years [7]. The novel design breaks through the forms of corresponding positioning design of traditional SREKs with positioning feet.…”

Section: Introductionmentioning

confidence: 99%

Effects of Thermal Reflowing Stress on Mechanical Properties of Novel SMT-SREKs

et al. 2019

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A novel silicone rubber elastic key (SREK) is proposed in this paper for surface mounting technology (SMT) applications. Effects of thermal reflowing stress on the mechanical properties of SMT-SREKs are investigated. The manufactured SMT-SREKs, which underwent various reflowing conditions in advance, are subjected to pressing force and fatigue pressing tests. Fatigue lifetime projection model and its predicted error are then assessed systematically. The thermal degradation of silicone rubber materials is illustrated through the dynamic mechanical analysis and the Fourier transform infrared spectroscopy experiments. The mechanical finite element modeling is also conducted to simulate the pressing process. The results show that the pressing force and tactility of the SMT-SREKs are strongly affected by the reflowing condition, which contributes to the degradation of the silicone rubber materials. During the fatigue pressing test, the change rate of tactility increases with the reflowing peak temperature (T p) and is accelerated by the repeated reflowing process. Moreover, a linear model can precisely project the tactility before the fatigue pressing number of 2.0E + 6 times, and the impact rate of T p on tactility with the increasing fatigue pressing number can be predicted effectively by using a logarithm model.

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Section: Introductionmentioning

confidence: 99%