学术文献库

The placed electronic component can shift on the wet solder paste in pick and place (P&P) process of surface mount technology (SMT). It does not usually attract much attention, because the shift is considered to be negligibly small and the following self-alignment effect in the solder paste reflow soldering process could also make it up. However, with the decreasing size of the electronic components and the increasing demand for the low defective rate of PCB, the component shift in P&P process is becoming more and more important in quality control of SMT industries. Though a few papers are related to the component shift in P&P process, there is no earlier research using the data from the real production line. In this paper, we study two basic and important issues: the behavior of the component shift in P&P process and the contributing factors to it. Several statistical methods are used to explore the behavior component shift based on the data from a complete state-of-the-art SMT assembly line. Main effects and regression analysis are implemented to pinpoint the contributing factors. In order to investigate the issues comprehensively, six types of electronic components and multiple potential factors are considered in this work, e.g., solder paste properties (position, volume, area, height), designed position of the component, placement pressure. The results indicate that component shift cannot be ignored. Also, the position of solder paste, designed position of component and component type are the top three most important factors to study the component shifts in P&P process.