PCBA Tech - Selection of the amount of flux for pcba processing

Selection of the amount of flux for PCBA processing
In PCB processing, many engineers are trying to control the amount of flux used. However, in order to obtain good welding performance, sometimes a larger amount of flux is required. In the PCB process selective soldering process, because engineers often care about the results of the soldering, and do not pay attention to the flux residue. The following Xiaoqiancheng editor will give you a detailed explanation of the selection of the amount of flux for PCBA processing.
Most flux systems use glue dispensing devices. In order to avoid the risk of stability, the flux selected for selective soldering should be inert when it is in an inactive state-that is, in an inactive state.

Applying a large amount of flux will cause it to penetrate into the SMD area and produce a potential risk of residue. There are some important parameters in the soldering process that will affect the stability. The key is: when the flux penetrates into the SMD or other processes, the temperature is lower and the non-open part is formed. Although it may not have a bad effect on soldering during the process, when the product is in use, the combination of the part of the flux that is not turned on and the humidity will produce electromigration, making the expansion performance of the flux a key parameter.

A new development trend in the use of flux for selective soldering is to increase the solid content of the flux, so that only a smaller amount of flux can be applied to form a higher solid content solder. Usually the soldering process requires 500-2000μg/in2 of solid flux. Except that the amount of flux can be controlled by adjusting the parameters of the welding equipment, the actual situation may be complicated. Flux expansion performance is important to its stability, because the total solids of the flux after drying will affect the quality of soldering.
Do you now understand the selection of the amount of flux for PCBA processing? If you don’t know about PCBA processing, please leave a message to us, if you have any intention of PCBA processing, please contact us!
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