GrandSeed

400-0599-111
CN

News

Forge ahead to meet the new era

Key points of temperature setting for lead free reflow soldering

2021-01-28 Classify: Products Information Author: GrandSeed Browse: 400

Lead free reflow soldering process has become the main process of electronic products manufacturing and welding. The design of lead-free reflow soldering equipment must be changed to meet the requirements of lead-free. The heat sensitive parts of the machine must be modified or measures should be taken to prevent heat transfer to these parts.

Lead free reflow soldering process has become the main process of electronic products manufacturing and welding. The design of lead-free reflow soldering equipment must be changed to meet the requirements of lead-free. The heat sensitive parts of the machine must be modified or measures should be taken to prevent heat transfer to these parts. So the lead-free reflow soldering temperature setting is very important, guangshengde reflow soldering here to share with you the key points of lead-free reflow soldering temperature setting.


The melting point temperature of lead-free reflow soldering is about 30 degrees higher than that of lead-free reflow soldering. In lead-free reflow soldering process, the melting point of lead-free reflow soldering varies according to different lead-free solder paste. The melting point of tin copper alloy solder paste is 227 degrees, and that of tin silver copper alloy is 217 degrees. Below this temperature, the solder paste will not melt, Here we should also pay special attention to the fact that if the equipment made by the lead-free reflow soldering manufacturer has poor thermal insulation, the difference between the test temperature and the actual temperature of the solder paste in the lead-free reflow soldering furnace should be about 10 degrees.


无铅回流焊温度曲线


Temperature curve of lead free reflow soldering


Lead free reflow soldering process temperature curve is divided into the following sections: preheating, heat preservation and drying, welding. Preheating is to minimize the thermal impact of components during welding. Generally, the temperature change rate of components is less than 4 ℃ / sec, so the heating rate of preheating stage is generally controlled at 1 ℃ / sec ~ 3 ℃ / sec, and too fast temperature rise will cause solder splashing.


The heat preservation and drying of lead-free reflow soldering process is to ensure that the solder flux is completely dry, and at the same time, the flux can activate the oxide removal on the bonding surface. In the reflow soldering area of guangshengde, the solder paste begins to melt and flow. Generally, the soldering quality can only be guaranteed when the melting point temperature exceeds 20 ℃. In order to ensure that the solder in flowing state can wet the whole pad and the lead out end of components, it is required that the time of solder in melting state is 40-90 seconds, which is also an important factor to determine whether there is false soldering and false soldering.


Backtrack
<Control of main process parameters of reflow soldering Function of wave soldering machine>