PCBA Tech - PCBA processing reflow soldering is diversified

PCB factory reflow soldering is a widely used surface component soldering method in the industry. Many people also call it reflow soldering process. Its principle is to print or inject proper amount of solder paste on the PCB board and PCBA board pad and mount it. Corresponding SMT chip processing components, and then use the hot air convection heating effect of the reflow oven to melt the solder paste and form reliable solder joints through cooling. Connect the components to the PCB board and PCBA board pads for mechanical and electrical connection effect.

Preheating zone: It is the segment of the product's heating stage smt paste. Its purpose is to make the product heat up quickly at room temperature to activate the solder paste flux, and it is also to avoid the high temperature and rapid heating during the subsequent immersion of tin. A heating method necessary for poor thermal damage of components.

Therefore, the heating rate is very important to the product, and it must be controlled within a reasonable range. If it is too fast, thermal shock will occur, and the PCB and components will be subjected to thermal stress and cause damage. At the same time, the solvent in the solder paste will be heated rapidly, which will cause PCB processing. Rapid volatilization causes splashing and formation of tin beads. Too slow will cause the solder paste solvent to not fully volatilize, which will affect the quality of soldering.

Constant temperature zone: The purpose is to stabilize the temperature of each component on the PCB board and PCBA circuit board, and reach agreement as much as possible to reduce the temperature difference between the components. At this stage, the heating time of each component is relatively long. The reason is that small components will first reach equilibrium due to less heat absorption, and large components will absorb more heat, so it takes enough time to catch up with small components and ensure that the flux in the tin smt patch paste is fully volatilized At this stage, under the action of the flux, the oxide on the pads, solder balls and component pins will be removed. At the same time, the flux will also remove the grease on the surface of the components and pads, increase the soldering area, and prevent the components from being oxidized again., After this stage is over, the components should be kept at the same or similar temperature, otherwise, the temperature difference may be too large, resulting in poor welding.

PCBA capacitors are one of the most commonly used components in electrical remote control of mobile communication equipment, computer board cards and chip processing manufacturers. In order to meet the trend of miniaturization, large capacity, high reliability and low cost of electronic equipment Due to the needs of development, smt chip capacitors themselves are also developing rapidly. Its types are constantly increasing, its size is constantly shrinking, its performance is continuously improving, smt technology is continuously improving, materials are constantly being updated, and the light, thin, short and small series of products have become standardized and generalized. Its application is gradually infiltrating and developing from consumer equipment to investment equipment, and is developing in the direction of diversified smt patch foundries.

(1) In order to meet the needs of portable communication tools, PCBA capacitors are developing towards low voltage, large capacity, ultra-small and ultra-thin.

(2) In order to adapt to the development of certain electronic complete machines (such as communication equipment), high withstand voltage, high current, high power, ultra-high value, low ESR type medium and high voltage chip capacitors are also an important development direction at present.

(3) In order to meet the requirements of highly integrated circuits, develop towards a multi-functional complex.