| Related citation: | Xingjian Yu,Run Hu,Liliang Zhou,Han Wu,Xiaobing Luo.Spreading and Curing Behaviors of a Thermosetting Droplet-Silicone on a Heated Surface[J].Journal of Harbin Institute Of Technology(New Series),2019,26(4):1-8.DOI:10.11916/j.issn.1005-9113.2019018. |
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| Author Name | Affiliation | | Xingjian Yu | School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China | | Run Hu | School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China | | Liliang Zhou | School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China | | Han Wu | School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China | | Xiaobing Luo | School of Energy and Power Engineering, Huazhong University of Science and Technology, Wuhan 430074, China |
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| Abstract: |
| Thermosetting materials are widely used as encapsulation in the electrical packaging to protect the core electronic components from external force, moisture, dust, and other factors. However, the spreading and curing behaviors of such kind of fluid on a heated surface have been rarely explored. In this study, we experimentally and numerically investigated the spreading and curing behaviors of the silicone (OE6550 A/B, which is widely used in the light-emitting diode packaging) droplet with diameter of ~2.2 mm on a heated surface with temperature ranging from 25 ℃ to 250 ℃. For the experiments, we established a setup with high-speed camera and heating unit to capture the fast spreading process of the silicone droplet on the heated surface. For the numerical simulation, we built a viscosity model of the silicone by using the Kiuna’s model and combined the viscosity model with the Volume of Fluid (VOF) model by the User Defined Function (UDF) method. The results show that the surface temperature significantly affected the spreading behaviors of the silicone droplet since it determines the temperature and viscosity distribution inside the droplet. For surface temperature varied from 25 ℃ to 250 ℃, the final contact radius changed from ~2.95 mm to ~1.78 mm and the total spreading time changed from ~511 s to ~0.15 s. By further analyzing the viscosity evolution of the droplet, we found that the decreasing of the total spreading time was caused by the decrease of the viscosity under high surface temperature at initial spreading stage, while the reduction of the final contact radius was caused by the curing of the precursor film. This study supplies a strategy to tuning the spreading and curing behavior of silicone by imposing high surface temperature, which is of great importance to the electronic packaging. |
| Key words: thermosetting material silicone surface temperature spreading and curing |
| DOI：10.11916/j.issn.1005-9113.2019018 |
| Clc Number:TN957.51 |
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| Descriptions in Chinese: |
| 热固性硅胶液滴在加热表面上的流动与固化行为研究 余兴建，胡润，周礼良，吴晗，罗小兵 (华中科技大学 能源与动力工程学院，武汉 430074) 摘要: 热固性材料作为密封剂和胶黏剂被广泛应用于电子器件封装中，以保护电子组件不受外部作用力、湿气、粉尘和其他外部因素的影响。但是热固性液滴在加热表面上的流动与固化行为却很少被研究。本文通过实验和数值方法对直径为2.2 mm的硅胶(OE6550 A/B，一种广泛应用于发光二极管封装中的胶体基质)液滴在温度为25 °C到250 °C加热基板上的流动与固化过程进行研究。实验方面搭建了以高速摄像机和温控系统为核心设备的微流体观测平台去监测硅胶液滴在加热基板上的流动成形过程。数值方面基于N. Kiuna’s 模型建立了硅胶黏度预测模型，并基于流体体积法(Volume of Fluid, VOF)结合自定义函数(User Defined Function, UDF)的方法构建了硅胶流动成形模型。结果表明，表面温度对硅胶液滴的流动成形过程影响很大。当表面温度从25 °C升到250 °C，硅胶液滴的最终接触线半径从~2.95 mm降低至~1.78 mm，并且总铺展时间从~511 s减少至~0.15 s. 通过数值模拟分析硅胶液滴在铺展过程中的黏度和温度分布发现，总铺展时间的减少是由于硅胶在铺展前期受热后黏度急剧减小造成的，而最终接触半径的减小则是由于三相接触线上前驱液膜迅速受热固化导致的。本研究提供了一种用温度调控热固性流体流动成形过程的方法，将对电子器件封装的发展带来积极推动作用。 关键词：热固性材料；硅胶；表面温度；流动与固化 |
