SMT solder joint shape design
1. SMT solder joint shape CAD
The solder joint shape design includes the geometric parameter design of the solder joint shape, as well as the geometric size and geometric shape design of the component solder foot and PCB pad, as well as the PCB material, soldering temperature, flux and other content related to the solder joint shape and soldering reliability. Selection and design. A large number of studies have shown that the shape of solder joints is closely related to the mechanical behavior of solder joints, which directly affects the performance and reliability of solder joints. Research on the mechanical behavior of solder joints, reveal the corresponding relationship between solder joint morphology, stress distribution state and deformation, and achieve the purpose of predicting and controlling solder joint morphology and optimizing the reliability of solder joint design. For this reason, the solder joint morphology design has the generality of not only the structural geometric design, but also the mechanical and physical design.
Due to the complexity of the factors involved in the solder joint shape design, the process generally needs to be carried out with the help of computer-aided design (CAD), the basic design idea. First, according to the relevant specifications or guidelines, the relevant design parameters of the solder joint shape (such as the geometric dimensions of the solder foot and the substrate pad, material strength data, etc.) are given, and the corresponding solder joint shape is calculated using the solder joint shape prediction model. Based on the analysis method of reliability problems, the stress and strain distribution, creep and fatigue life, and interface resistance of the shape solder joint under thermal/mechanical loading conditions are investigated. If a solder joint with a certain shape does not meet the performance requirements, change the relevant parameters of the solder joint shape, repeat the above process, and finally obtain a solder joint shape that is reasonable in shape and meets the performance design requirements.