The fixed welding screw terminal is used in the occasions where the current is small and the heat is low. Otherwise, the overheating effect will cause the solder to melt and there is a danger of short circuit. Crimping is generally used for wire heads, but can also be used in situations where welding is impossible or not suitable for welding with relatively high heat. Reasons for the desoldering of the screw terminal: 1. The false soldering problem of your component has nothing to do with the solderability of the component pins. 2 It is because the weight of one side of the component pin and the other side are different, and the component pin is reflowed. One side is upturned to cause false soldering 3 You can try to increase the wind volume frequency of your reflow soldering, it should be improved 4. The furnace temperature is not set well, the temperature rise is too slow, and the peak value is set to more than 250 degrees 5 . The stencil opening is longer. 6. Ask the supplier whether the card socket pins are electroplated and then cut or cut and then electroplated. The tin on the later processing will be much better. 7. This question is very similar to our previous product, just relying on The jig is not enough, because your PCB board itself will be deformed to a certain extent, which will cause the feet of the parts to be raised, resulting in empty welding. On the back of your jig, use high temperature tape to fix the PCB on the jig to prevent it from lifting the part feet. At the same time, you can paste a layer of steel plate sticker near the opening position of this row of Pin feet under the steel mesh to increase the amount of tin.