Application of laser soldering in the field of connectors

　　With the development of social science and technology, electronic, electrical, and digital products are becoming increasingly mature and popular around the world, and the demand for tin welding technology for various industry parts is increasing, including automotive electronics, optical components, acoustic components, semiconductor refrigeration devices, security products, LED lighting, precision connectors, disk storage components, etc.; Large to PCB board main parts, small to crystal components, the vast majority of welding needs to be completed below 400 ° C.

　　At present, the chip level package (IC package) and the assembly of the board and card level in the electronics industry are a large number of tin-based alloy filled metal for welding, to complete the package of the device and the assembly of the card. For example, in the inverted chip process, the filler metal connects the chip directly to the substrate; In electronic assembly manufacturing, the devices are welded to the circuit board by using brazing metal.

　　Laser constant temperature tin welding is a kind of brazing method in which laser is used as heat source and molten tin makes welded parts fit tightly. Compared with the traditional soldering process, the method has the advantages of faster heating speed, less heat input and less heat influence. The welding position can be precisely controlled; The welding process can be automated; The amount of filler metal can be accurately controlled, and the solder joint consistency is good. It can greatly reduce the impact of volatiles on operators during brazing. Non-contact heating; Suitable for complex structural parts welding and other advantages.

　　Tin wire filling laser soldering applications

　　Wire feeding laser welding is a main form of Songsheng photoelectric laser soldering, wire feeding mechanism and automatic workbench supporting the use of modular control mode to achieve automatic wire feeding and light welding, with compact structure, one-time operation characteristics, automatic completion of welding, has a wide range of applicability.

　　The main application areas are PCB circuit board, optical components, acoustic components, semiconductor refrigeration components and other electronic components solder. Figure 1 is the product diagram of laser wire feeding tin welding. It can be seen that the solder joint is full and the wettability with the pad is good.

　　Figure 1: Solder joint diagram of laser wire feeding tin welding

　　Solder paste filled laser soldering applications

　　Solder paste laser welding is generally used in parts reinforcement or pre-tinning, such as the corner of the shield through solder paste melting at high temperature reinforcement, the tin melting of the magnetic head contact; It is also suitable for circuit conduction welding, and the welding effect is very good for flexible circuit boards, such as plastic antenna base, because there is no complex circuit, the solder paste welding often achieves good results. For precision micro-sized workpieces, solder paste filling welding can fully reflect its advantages.

　　Due to the heat uniformity of the solder paste is good, the equivalent diameter is relatively small, through the precision dispensing equipment can accurately control the amount of tiny point tin, the solder paste is not easy to splash, to achieve a good welding effect.

　　Based on the high concentration of laser energy, the solder paste is subjected to uneven heat burst and splash, and the sputtered tin beads are easy to cause short circuit, so the quality of the solder paste is very high, and anti-splash solder paste can be used to avoid splashing.

　　Figure 2: Solder joint diagram of laser solder paste solder welding

　　Characteristics of Songsheng photoelectric laser soldering system

　　1. Laser processing accuracy is high, spot diameter is minimum 0.1mm, can achieve micro-spacing mounting devices, Chip parts welding.

　　2. Short time of local heating, the minimum thermal impact on the substrate and peripheral components, can be implemented according to the type of components lead different heating specifications to obtain consistent welding quality.

　　3. No soldering head consumption, no need to replace the heater, to achieve high efficiency continuous operation.

　　4. Laser processing accuracy is high, laser spot can reach the micron level, processing time/power program control, processing accuracy is much higher than the traditional soldering iron. It can be welded in a space of less than 1mm.

　　5. Six kinds of optical path coaxial, CCD positioning, what you see is what you get, no need to repeatedly correct visual positioning.

　　6. Non-contact processing, no stress caused by contact welding, no static electricity.

　　7. Laser is green energy, the cleanest processing method, no consumables, simple maintenance, easy operation;

　　8. No solder joint cracks during lead-free welding.