A complete spot soldering paste system, which can use various technical methods to complete the soldering of solder joints according to the heating requirements of different products. Like other heating methods, misapplying laser energy can easily burn out parts. The laser heater makes full use of the characteristics of laser energy transmission and absorption, and creates a reflow environment according to the reflow characteristics of solder paste, which can make very difficult soldering tasks complete at a very high throughput rate.

 

It is a mature method to use samples to do reflow test to determine whether laser reflow is suitable for the product, and the process parameters that must be controlled in order to achieve the expected solder joint quality. It is one thing to study theoretically how lasers work, but quite another to apply them in practice. If laser reflow of solder paste on a product is determined to be a viable method, then it is possible to work with the solder paste and laser equipment system supplier to determine the best combination of material and equipment for the product.

 

Carbon dioxide lasers are the most powerful continuous wave lasers currently available. CO2 lasers can produce infrared light with a wavelength of about 10,600nm and 20% more power. CO2 lasers are mostly used for metal cutting and welding. Carbon dioxide lasers are made of yttrium aluminum garnet doped with neodymium metal, commonly referred to as Nd:YAG lasers. Nd:YAG lasers can generate high energy, with a wavelength of 1,064nm in the infrared spectrum. Similar to CO2 lasers, they are mainly used for cutting and welding metals, and are also used for marking metals and other materials. High power diode lasers (HDLs) mainly rely on GaAs semiconductor strips. It can provide a wavelength ranging from 790 to 980nm and an output power of 50 watts each. Over the past few years, advances in diode cooling techniques aimed at maintaining diode temperature have significantly increased diode power, lifetime, and efficiency.

 

Some users choose to use laser heating because it is the best option among many methods; while others find that because the available heating methods are very limited, laser will be the solution to the heating problems they face. The most direct reason for using laser heating is the desire for non-contact localized heating. Although the motives are different, the purpose is the same: the reflow is limited to a certain position without spreading to other areas, and it must be completed in a very short time, so as to effectively prevent other parts of the product from being transferred to more heat .

 

Solder paste is deposited on all pads prior to cable placement. Laser heating is done in one line following the spot solder paste process, and the heat applied is just enough to form the solder joints. The solder is in the molten state for no more than 3 seconds. The amount of heat conducted to the surface of the glass substrate during heating is very small, which can prevent thermal expansion and bursting. The appearance of the solder joints meets the consistency requirements. As with the previous process, solder paste is applied to each pin, and then each pin is heated with a laser. Due to heat conduction, the heating time of the first pin is longer than that of the fourth pin. Localized heating temperatures are sufficient, while total heat is safe for plastic parts