Laser Welding for PCB

With the improvement of IC chip design level and packaging technology, SMT is developing towards the miniaturization direction of high stability and high integration, and the traditional soldering iron welding can no longer meet its production technology requirements. The number of pins of single components continues to increase, and the pin pitch of integrated circuit QFP components is also continuously reduced, and is developing in a more precise direction. As a new welding process to make up for the shortcomings of traditional welding methods, non-contact laser soldering technology is gradually replacing traditional soldering iron welding with its advantages of high precision, high efficiency and high reliability, and has become an irreversible trend.



The laser light source for laser welding is mainly a semiconductor light source (915nm). The semiconductor light source belongs to the near-infrared band, has good thermal effect, and its uniformity of beam and the continuity of laser energy have a significant effect on the uniform heating and rapid heating of the pad, and the welding efficiency is high.


The difference between laser welding and soldering iron welding

1. Differences in contact methods

Soldering iron welding generally adopts contact welding, which is likely to cause scratches on the surface of the product. During welding, the soldering iron tip will bring a certain amount of pressure to the welded workpiece, resulting in sharp solder joints, and there is a risk of transmission. In contrast, laser welding adopts non-contact laser welding, which can better avoid these risks, neither causing mechanical damage to the product, nor exerting pressure on the welding components.


2. Differences in adaptability

When welding some workpieces with complex surfaces, soldering iron welding takes up a lot of space due to the soldering iron tip and wire feeding device, and the components on the surface of the workpiece are very likely to interfere with it. The laser welding wire feeding device takes up less space and is less prone to interference. In addition, the spot size of laser welding can be automatically adjusted, which can adapt to various types of solder joints and meet the needs of more products, while the traditional soldering machine needs to replace or redesign the soldering iron head. Therefore, the adaptability of laser welding is higher.


3. Differences in the influence of welding components

Soldering iron welding generally uses the whole board to heat, which will undoubtedly have a negative impact on some of the existing heat-sensitive components, while in the laser welding process, the laser only heats the part irradiated by the spot, and the local temperature rises quickly, and can effectively reduce the impact on devices around the solder joint.


4. Differences in energy consumption materials

From the aspect of material saving: in the soldering iron welding process mostly use the iron tip to provide the required energy, but with the aging of the iron tip, wear and tear, etc. makes the temperature does not meet the welding requirements, while contact welding method caused by the iron tip wear serious, making the iron tip need frequent cleaning, replacement, increased welding costs.

From the perspective of energy saving: Since the heating method of the traditional soldering iron welding process is the whole board heating, it will cause more meaningless loss of heat and increase the loss of electric energy.


5. Differences in processing precision

Due to the limitation of the traditional soldering iron welding process and the restriction of the control method, the wire feeding and welding accuracy are limited; the laser welding technology has the characteristics of rapid heating and rapid cooling, which can make the metal compound produced more uniform and finer during welding, and the mechanical properties of the solder joints are better. Local heating is more conducive to soldering heated components and heat-sensitive components on circuit boards with dense components and solder joints, and can reduce the bridging between solder joints after soldering.


6. Differences in safety performance

The non-contact laser welding method reduces the use of rosin and the residue of combustion aids, and reduces the generation of harmful smoke and wast. It has been able to accurately control the temperature of solder joints in real time, prevent burning boards, and greatly reduce the difficulty of debugging the welding process , reducing the injury to the operator.


About HGTECH: HGTECH is the pioneer and leader of laser industrial application in China, and the authoritative provider of global laser processing solutions. We have comprehensively arranged laser intelligent machine, measurement and automation production lines, and smart factory construction to provide overall solutions for intelligent manufacturing.