The perfect spot solder paste system can use various technical methods to complete the soldering of solder joints according to the heating requirements of different products. Similar to other heating methods, misuse of laser energy can easily burn parts. The laser heater makes full use of the characteristics of laser energy transmission and absorption, and creates a reflow environment based on the reflow characteristics of the solder paste, which can enable very difficult soldering tasks to be completed with a very high pass-through rate.
Using samples for reflow testing is already a mature method to determine whether laser pointer reflow is suitable for the product and the process parameters that must be controlled in order to complete the expected solder joint quality. Theoretical analysis and research on how lasers work is one thing, but practical applications are another. If on a product, the reflow of solder paste using laser is determined to be a feasible method, then you can cooperate with solder paste and laser equipment system suppliers to obtain the best combination of product materials and equipment.
The carbon dioxide laser is the strongest continuous wave laser currently available. The carbon dioxide laser can generate infrared light with a wavelength of about 10,600 nm and 20% power. CO2 lasers are mostly used for metal cutting and welding. Carbon dioxide lasers are made of yttrium aluminum garnet doped with neodymium metal and are usually called Nd:YAG lasers. Nd: YAG laser 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, but also for marking metals and other materials. High-power diode lasers (HDL) mainly rely on GaAs semiconductor strips. It can provide wavelengths ranging from 790nm to 980nm and output power of 50 watts each. In the past few years, advances in diode cooling technology aimed at maintaining diode temperature have significantly increased the power, life and efficiency of diodes.
Some users choose to use laser heating because it is the best option among many methods; while other users find that because the available heating methods are very limited, green laser pointer will be the solution to their heating problems. The most direct reason for using laser heating is the desire for non-contact local heating. Although the motivations are different, the purpose is the same: the return flow is limited to a certain position and will not spread to other areas, and must be completed in a very short time, thereby effectively preventing other parts of the product from being conducted more heat .
The solder paste is applied to all the pads before the cable is placed. The laser heating is completed in a line immediately after the spot solder paste process, and the added heat just forms the solder joints. The solder is in the molten state for no more than 3 seconds. The 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. The same as the previous process, the solder paste is applied to each pin, and then each pin is heated separately with a laser. Due to heat conduction, the heating time of the first pin is longer than that of the fourth pin. The local heating temperature is sufficient, and the total heat is safe for plastic parts