1. The chip reflow soldering curve should be close to the original welding curve with the chip. Hot air reflow oven curve can be divided into four zones: preheating zone, heating zone, reflow zone, cooling zone, four zones of temperature, time parameters can be set separately, by connecting with the computer, these programs can be stored and called at any time.
2. in the reflow soldering process to correctly select the heating temperature and time of each zone, while attention should be paid to the speed of warming. Generally in the 100 ℃ before the maximum heating speed of no more than 6 ℃ / s, 100 ℃ after the maximum heating speed of no more than 3 ℃ / s, in the cooling zone, the maximum cooling speed of no more than 6 ℃ / s. Because too high a heating speed and cooling speed may be damage to the PCB and the chip, this damage is sometimes the naked eye can not be observed. Different chips, different solder paste, should choose a different heating temperature and time. Such as CBGA chip reflow temperature should be higher than the reflow temperature of PBGA, 90Pb/10Sn should be 63Sn/37Pb solder paste selection of higher reflow temperature. For no-clean solder paste, its activity is lower than non-no-clean solder paste, therefore, the soldering temperature should not be too high, the soldering time should not be too long, in order to prevent the oxidation of solder particles.
3. Hot air reflow oven, the bottom of the PCB board must be able to heat. Heating has two purposes: to avoid warping and deformation due to the PCB board single-sided heat; so that the solder paste to shorten the dissolution time. For large size board rework BGA, the bottom of the heating is particularly important.BGA-3592-G rework equipment bottom of the heating method has two kinds, one is hot air heating, one is infrared heating. The advantage of hot air heating is that the heating is uniform, and it is generally recommended to use this kind of heating in the rework process. The disadvantage of infrared heating is that the PCB is not uniformly heated.
4. to choose a good hot air reflow nozzle. Hot air reflow nozzle belongs to the non-contact heating, heating relies on high-temperature air flow to make the BGA chip on the solder joints of the solder dissolved at the same time. The U.S. OK Group first invented this nozzle, which will be sealed BGA components to ensure that the entire reflow process has a stable temperature environment, while protecting neighboring components are not damaged by convection hot air heating.
In the production of electronic products, especially computers and communications electronics, semiconductor devices to micro-miniaturization, multi-functionality, green development, a variety of packaging technologies continue to emerge, BGA / CSP is the mainstream of today’s packaging technology. Its advantage is to further reduce the size of the package of semiconductor devices, thus improving the level of high-density mounting technology, very suitable for electronic products light, thin, short, small and functional diversification of the development direction.
Zhejiang NeoDen Technology Co., LTD., founded in 2010, is a professional manufacturer specialized in SMT pick and place machine, reflow oven, stencil printing machine, SMT production line and other SMT Products. We have our own R & D team and own factory, taking advantage of our own rich experienced R&D, well trained production, won great reputation from the world wide customers.
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Post time: Dec-15-2023