Application and future development trend of laser welding machine
With the development of science and technology, electronic, electrical and digital products are becoming more and more mature and popular in the world. From the main point of view, from PCB to crystal oscillator, any component in the products covered by this field may involve the welding process. For components, most welding needs to be carried out below 300 ° C.
Today, the electronic industry's chip-level packaging (IC packaging) and board assembly mainly use tin-based alloy filler metal welding to complete equipment packaging and card assembly. For example, in the process of inverting the chip, the welding material directly connects the chip to the substrate. In electronic assembly and manufacturing, welding materials are used to weld the equipment to the circuit substrate.
The welding process includes peak welding and reflow welding. Peak welding uses the peak surface cycle of molten solder to make it contact with the PCB welding surface connected to the component to complete the welding process. Reflow welding is a welding process. After putting the solder paste or solder pad together in advance and heating the PCB, the melting of the solder paste or solder pad will connect the components to the PCB between the solder pads.
Laser welding is a brazing method, which uses laser as a heat source to melt tin and make the weldment fit closely. Compared with the traditional welding process, this method has the advantages of fast heating speed, less heat input and large heat impact. The welding position can be controlled accurately, the welding process is automatic, the welding quantity is controlled accurately, and the welding point is consistent. It can greatly reduce the impact of volatiles on operators during welding, and non-contact heating is suitable for welding complex structural components.
According to the state of tin material, it can be divided into three main forms: tin wire filling, solder paste filling and solder ball filling.
01: tin line filling laser soldering application
Laser welding is the main form of laser welding. The wire feeding mechanism is used in conjunction with the automatic workbench, and the automatic wire feeding and light output are realized through modular control. Welding has the characteristics of compact structure and one-time operation. Compared with other welding methods, its obvious advantages are one-time clamping of materials and automatic welding, with wide applicability.
The main application fields are PCB soldered circuit boards, optical components, acoustic components, semiconductor refrigeration components and other electronic components. The solder joint is full and the pad wettability is good.
02: Application of solder paste filled laser soldering
Solder paste laser welding is usually used for parts reinforcement or pre-tinning, such as the four corners of the shielding cover strengthened by high temperature melting, and the magnetic head contacts the tin for melting; It is also suitable for circuit conduction welding. For flexible circuit boards (such as plastic antenna mounting base), the welding effect is very good. Because there is no complex circuit, solder paste welding usually achieves good results. For precision and micro workpieces, solder paste filling welding can fully reflect its advantages.
Because the solder paste has good thermal uniformity and relatively small equivalent diameter, the number of tin spots can be accurately controlled by precise distribution equipment. The solder paste is not easy to splash, and the welding effect is good.
Due to the high concentration of laser energy, uneven heating of solder paste, cracking and splashing, the splashing solder ball is easy to cause short circuit. Therefore, the quality of solder paste is very high, and anti-splash solder paste can be used to avoid splashing.
03: Solder ball filling laser soldering application
Laser solder ball welding is a welding method in which the solder ball is put into the solder ball nozzle, melted by the laser, and then dropped onto the pad, and then wetted by the pad.
Tin balls are small particles of pure tin and are not dispersed. Laser heating and melting will not cause splash. It will become full and smooth after curing. There is no other process, such as subsequent cleaning or surface treatment of the gasket.
Through this welding method, the welding of small pad and enameled wire can achieve good welding effect.
04: The application of laser soldering technology is difficult
Traditional welding, including peak welding, reflow welding and manual welding, can solve problems in the welding process. Laser welding can be replaced gradually, but like patch welding (mainly used for reflow welding), the current laser welding process is not applicable. Due to some characteristics of laser, the laser welding process is more complex, which can be summarized as follows:
1) For precise and precise welding, it is difficult to find and clamp the workpiece;
2) For flexible wires, the consistency of clamping and positioning is not good, and the fullness and appearance of welding samples vary greatly;
05: Overview of laser soldering market demand
After years of development, the market demand for laser soldering at home and abroad has been constantly changing. Under the guidance of welding process requirements for electronic and digital products, not only the number of vertical increases, but also the horizontal application fields are expanding.
It covers the welding process requirements of other components in various industries, including automotive electronics, optical components, acoustic components, semiconductor refrigeration equipment, safety products, LED lighting, precision connectors, disk storage components, etc.; In terms of customer base, the company has been looking for laser welding process solutions, mainly the relevant welding process requirements derived from the relevant components of Apple's customer products (including the upstream industrial chain). Generally speaking, laser welding will last for a long time. There will be an explosive growth and relatively large market volume.
In the current weak global economy, Apple is booming. Its huge market share in digital electronic products and global large-scale procurement have driven the business growth of many companies. The main products of these companies are electronic components and welding. This is an indispensable part of its production process.
06: Process breakthrough requirements
The products produced by companies including Apple and its suppliers are the latest and most high-end designs. There will be difficult technological problems in the process of mass production, which need to be improved and improved.
A very typical area is the storage component industry. Magnetic head is a storage component with high precision and high technical requirements. The data line of the magnetic head is usually a flexible PCB attached to one end of the steel structure. The small spots in the array layout need to be tinned in advance, and the trace tin can only be completed under the microscope, and the welding effect is extremely strict.
The traditional welding method is manual welding, which requires operators to have a high level of welding. The scarcity and mobility of labor resources have brought great uncertainty to production. In addition, it is impossible to quantify the process standard (there is no process parameter, which depends entirely on human feeling to judge the effect after welding), so laser welding process is needed to overcome the technical obstacles.
07: Process upgrade extension requirements
Laser soldering can stimulate process parameters, improve output, reduce costs and ensure standardization of production operation.
