How to select lead-free and lead-free tin spraying for PCB? 2021-11-16

Tin spraying is the form of pad coating , Is one of the most common PCB Plate treatment method . Tin spraying can be divided into lead tin spraying and lead-free tin spraying , The standard for tin spraying thickness in the industry is 20uM. Some customers do not understand the difference between lead and lead-free tin spraying , that pcb Which is better, lead spray tin or lead-free spray tin ？ Today, jettoban PCB Xiaobian will tell you about lead spraying tin and lead-free spraying tin .

• We can know from the literal meaning , Lead free tin spraying belongs to environmental protection type , Tin spraying with lead is not environmentally friendly . Lead free does not contain more than 5, And the lead content of lead has reached 37, It is more than seven times the lead content of lead-free .
• It is also possible to distinguish between lead-free and lead-free tin spraying by the appearance color , Generally, the pad with lead paint treatment should be brighter , Lead free tin sprayed pads are darker . The wettability of lead sprayed tin is better than that of lead-free tin , Some tin spray is more cost-effective than lead-free , It is more cost-effective to choose lead only in terms of price . For those who have higher requirements on environmental protection, it is better to choose lead-free tin spraying .
• The melting point of lead is 183℃ about , This requires that the temperature of the tin spraying furnace be controlled at 245℃-260℃, The temperature of the wave crest shall be controlled at 250℃, The reflux temperature is controlled at 245℃-255℃.
• The melting point of lead-free is 218℃, It is necessary to control the temperature of tin spraying tin furnace at 280℃-300℃, The temperature of the wave crest shall be controlled at 260℃, Reflux temperature control 260℃-270℃.

Because lead will improve the activity of tin in the welding process , Therefore, lead tin wire is better than lead-free tin wire ; But the melting point of lead-free tin spray is higher than that of lead tin spray , Therefore, the lead-free solder joint is much stronger than the solder joint with lead spray .

The above is jettoban PCB Shared by Xiaobian pcb Knowledge of lead tin spraying and lead-free tin spraying , I hope it helped you ！

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