Reflow process series#The gas is heated and then transferred to the product through a series of orifices in the orifice plate.ġ).The following equation can be used to describe the process of heat energy transfer from the airflow to the circuit board, q = heat energy transfer to the circuit board A = convective heat transfer coefficient of circuit board and components T = heating time of the circuit board A = heat transfer surface area Δ T = convection temperature difference between gas and circuit board we will move to formula one side of the circuit board related parameters, and reflow furnace parameters will be moved to the other side, can get the following formula: q = a | T | a | | T.Ģ).Double-track reflow PCB has been very popular and is becoming increasingly popular. Normally, as shown, the fan of the reflow furnace pushes the gas (air or nitrogen) through the heating coil. First, we need to understand the main factors that affect the transfer of heat from the reflow heater to the circuit board. Now, a two-track, two-speed reflow furnace with independent track speeds makes it possible to process two more widely spaced circuit boards at the same time. Currently, circuit board manufacturers are limited to handling identical or similar-weight circuit boards on each track. Working principle of double track reflow soldering:ĭouble rail reflow furnace can double the capacity of a single double rail furnace by parallel processing two circuit boards at the same time. When the PCB enters the welding zone, the temperature rises rapidly to make the solder paste melt, and the liquid solder wets, diffuses, diffuses or reflows the solder joints on the solder pads, component ends and pins of the PCB.Ĥ).PCB enters the cooling zone to solidify the solder joint The reflow soldering is completed. When PCB enters the insulation zone, make PCB and components get fully preheated, in case PCB suddenly enters the welding high temperature zone and damages PCB and components.ģ). At the same time, the flux in the solder paste will moisten the pads, component ends and pins.Ģ). When the PCB enters the heating zone, the solvent and gas in the solder paste will evaporate. Reflow welding principle is divided into several descriptions:ġ). Reflow welding depends on the action of hot gas flow to the solder joint, the colloidal flux in a certain high temperature airflow physical reaction to achieve SMD welding The reason why it is called "reflow welding" is that the gas circulates through the machine to produce high temperature for welding purposes. Reflow soldering is to weld components to PCB board, reflow soldering is to the surface of the device. Reflow soldering is to realize the soft soldering of mechanical and electrical connection between the solder end or pin of surface assembly components and the solder pad of printed board by remelting the paste soldered soft solder which is pre-distributed on the solder pad of printed board.
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