Conventional surface mount type connector according to SMT part shape and use, the more common lead structure gulls type, J type peace line and so on. Every lead structure has its unique nature, characteristics and applications. The SMT connector wire structure, the type is the most common type of lead tectonic . J type lead can provide better welding thickness and interface, but manufacturing J type lead tend to use more complicated and costly forging bed can be completed. The finished product, but not to provide any technical skill and technique advantage. Parallel wire structure will find the missing wire and welding pad contact due to surface area. However, whether can provide good wire and welding the contact is SMT users are most concerned about the practical problems. Practice has proved, parallel wire in welding can provide tensile strength less than the type or J type lead half. Lead dislocation can lead to lead off board tin pad thereby produced during welding Xuhan and bridging. Every tiny lead error often combined into a not to be ignored in the serious amlposition, even can lead to a high of 50% wire can not be placed in the solder pad . seagulls type lead is bent into a vertical straight lead angle of 90. The common problem is the lead molding and molded on the bending angle error control and maintain.

At present, the industry of angular error allowed value is 0 and 7 ( i.e.: lead angle of not more than 90, not less than 83 ). Any incorrect operation and transport may lead to lead change shape. In order to ensure that the quality demands of the users, Shen Tai Company took data statistical monitoring methods ( SP ) to control the production process, in order to discover in time and solve any possible quality problem. 2.2.PLCC ( Plastic Leaded Chip Carrier ) vector and a is used in PLCC32 sealing mode, from the shape of a square, surrounded by pins, size is much smaller than the DIP package. PLCC package for SMT surface installation technology on PCB wiring installation, having the advantages of small size, high reliability. 2.3.BGA ( Ball Grid Array ) BGA package BGA package as the bottom surface leads to fine needle form, with the controlled collapse chip welding ( referred to as C4 welding ). With BGA packaging not only has smaller volume, but also thinner ( package height less than 0.8mm ). Then, BGA will have a higher heat transfer efficiency, is very suitable for a long time operation of the system, excellent stability . BGA sealing device I / O pins while increasing, but the pins are spaced far More than QFP, so as to improve the assembly yield. Although its power increased, but BGA can use a controlled collapse chip welding method, referred to as C4 welding, which can improve the electric performance. It has a signal propagation delay is small, frequency of use is greatly improved; assembly usable coplanar welding, high reliability advantages, disadvantage is that BGA package still with QFP, PGA, accounting for a large area substrate.