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Solder bar and solder wire defect analysis ------ pinholes and pores

2018-04-29 09:36:09

On the surface, the difference between the pinhole and the porosity is that the diameter of the pinhole is smaller, and the bottom can be seen on the surface. Pinholes and pores represent that there are bubbles in the solder joint, but it is still extended to the surface, most of which occur at the bottom of the substrate, when the bottom of the bubble is fully diffused and the money has been condensed, that is, pinholes or pores are formed. The reasons are as follows:


Organic contaminants on substrate or part molding. Such unmanned materials come from factors such as automatic insertion machines, parts forming machines and poor storage. Such contaminants can be easily removed with common solvents, but it is more difficult in the case of silicone oils and similar silicon-containing products. If the problem is found to be caused by silicone oil, it is necessary to consider changing the source of lubricating oil or release agent.


When the substrate contains wood gas produced by electroplating solutions and similar materials, if the substrate uses a cheaper material, it is possible to inhale this moisture gas and generate enough heat during soldering to vaporize the solution and thus create pores. Baking the substrate in an oven before assembly can ameliorate this problem.


The substrate stores too much goods improperly packaged and absorbs moisture from the nearby environment, so it needs to be baked before assembly.


The flux tank contains water. The flux should be replaced regularly.


Blowing agent air to compressed air contains too much water, need to install a water filter, and regular exhaust.


The preheating temperature is too low to evaporate water vapor or solvents once the substrate enters the tin furnace. Instant contact with high temperatures. And produce burst, so the need for a high preheating temperature.