焊点

Taking a heavy truck cab as the example, a model of the spotweld space based on finite element was built to analyse the torsional stiffness of the model, and the amount and layout of the spotweld using the discrete variable topology optimization were optimized. Comparing with the original model in welding spot's number and the torsional stiffness, the optimized model has less number of welding spot, but the torsional stiffness of the two model is almost the same.

以某重型卡车驾驶室为例，在有限元模型基础上建立焊点空间模型进行扭转刚度分析，并采用离散变量拓扑优化方法对焊点的数量及空间布局进行优化，通过优化前后的对比可知，优化后在不降低扭转刚度的同时减少了焊点数目。

The influence of the size of pad and solder bump, the volume of eutectic solder and reflow temperature on the geometry of duplex SnPb solder joint with high Pb solder bump and eutectic SnPb fillet was simulated by finite element method with the software of SURFACE EVOLVER.

应用SurfaceEvolver软件，对含高铅焊料芯片凸点和共晶SnPb焊料形成的复合焊点的形态进行了有限元模拟，考察了焊盘大小、芯片凸点尺寸、焊料体积、焊接温度等焊点的设计及工艺参数对焊点形态的影响。

The simulation and experimental results verify the validity of proposed illuminator for leadless solder joint inspection,and show it can enlarge the feature distances from different classes.

仿真和实验结果表明，所设计的光源在检测无铅焊点时同样有效，并能使不同类焊点间的特征距离更大，最大为半球形光源照射下的11.88倍，从而提高了特征在无铅焊点缺陷检测的分辨能力，验证了光源设计的有效性。

According to the characteristics that SMT solder joint quality is related to its 3-D geometrical shape directly, theory of solder joint shape was put forward.

根据SMT焊点质量与焊点的三维几何形态直接相关的特点，提出了SMT 焊点形态理论。

A computer-aided system is developed to predict solder joint shape in microelectronics interconnection, and visuality of predicting and analyzing solder joint shape is realized.

提出并设计了焊点形态的剖视分析方法，以RCChip焊点为例，考察了焊点结构参数对焊点三维形态的影响规律，并进行了试验验证。

The above results are of general importance and can be used to improve the solder joint reliability of surface mount components with castellated solder fillet, the design level and the manufacturing process in SMT.

本文研究从提高SMT焊点可靠性、提高组装密度和避免焊点缺陷的角度出发，对高可靠性SMT焊点形态的设计和评价建立了四点规则，对提高有边堡钎料圆角形态表面组装元件的焊点可靠性、提高SMT工艺设计水平具有普遍意义。

The effects of electroplated Ni layer and electroless plated Ni-P layer on the diffusion behavior in Sn-Ag/Cu solder joint were studied. The results by EPMA analysis showed that the electroless plated Ni-P layer acted as a good diffusion barrier between Sn-Ag solder and Cu substrate. However, the electroplated Ni layer can not hinder the inter-diffusion and reaction between molten Sn-Ag solder and Cu substrate when reflowing, and there was a layer of IMC (Cu6Sn5) at interface of Sn-Ag/C u solder joint.

摘 要：研究了电镀Ni层和化学镀Ni-P合金层对Sn-Ag/Cu焊点扩散行为的影响，电子探针分析表明：化学镀Ni-P合金层能很好地阻止Sn-Ag/Cu焊点在焊接过程中的Cu，Sn互扩散和相互反应；而电镀Ni层则不能阻止Sn-Ag/Cu焊点在焊接过程中的Cu，Sn互扩散和相互反应，界面反应产物仍以Cu6Sn5为主。

Results show that when improving spot pitch in weld bonded joints with high elastic modulus adhesives, stresses in weld spot zone are decreased while stresses and strains at edges of overlap region are increased slightly. For the joints with low elastic modulus adhesives, both stress concentration degree at the weld spot and the shear strain at edges of overlap region are increased with the spot pitch increasing.

结果表明，高弹性模量胶粘剂胶焊接头中，增大焊点间距，焊点区应力减小而搭接区边缘胶层中的应力应变略有增大；低弹性模量胶粘剂胶焊接头中，焊点处应力集中程度和搭接区边缘胶层中的剪应变值都随焊点间距的增加而增大，增加焊点间距，两种接头的胶层断裂强度都将降低。

The influence of Pb-contamination on microstructure and shear strength of SnAg/Cu and SnSb/Cu solder joints prepared by SMT were studied by mixing eutectic SnPb solder paste into leadfree solder pastes.

与常用的Sn62Pb36Ag2焊点对比，Sn96.5Ag3.5和Sn95Sb5焊点在高温时效过程中组织结构更稳定，界面金属间化合物的生长速率和体焊料的粗化程度均低于SnPbAg焊点；同时，焊点的剪切强度较高。

The results show that the plasticity zone and dynamically quiescent layer become fine equiaxed recrystallisation under the thermo-mechanical effect, the grains in the heat-affected zone grow up because of the effect of friction heat. When the rotation speed is 2 500 r/min and the welding time is 12 s, good joint is achieved, and the tensile shear strength of the joint reaches 9.24 kN. The tensile shear strength of spot increases with increasing tool rotation speed, with increasing welding time, the strength increases first, while then reduces. The microhardness of plasticity zone is high, but is slightly lower than that of the base metal, the minimum value of microhardness is in the heat affected zone. When the energy input of joint is high, the fracture type of spot is mode Ⅰ, and the tensile shear strength is high; on the contrary, when the energy input of joint is less the fracture type of spot is mode Ⅱ, and the strength is low.

结果表明：塑性区和动态静止层的晶粒在热和力作用下发生动态再结晶形成细小的等轴晶，热影响区的晶粒在摩擦热作用下长大变粗；搅拌头旋转速度为2 500 r/min，焊接时间为12 s时，可以获得力学性能较好的焊点，焊点的剪切强度达到9.24 kN；焊点的剪切强度随搅拌头旋转速度的增大而增大，随焊接时间的延长先增大后减小；塑性区的显微硬度较高，但略小于母材，接头显微硬度的最小值分布在热影响区；焊点热输入量较多时，接头为Ⅰ型断裂，焊点的剪切强度较高；焊点热输入量较少时，接头为Ⅱ型断裂，焊点的强度较低。

In the United States, chronic alcoholism and hepatitis C are the most common ones.

在美国，慢性酒精中毒，肝炎是最常见的。

If you have any questions, you can contact me anytime.

如果有任何问题，你可以随时联系我。