First: LED PIN forming method
1. It is necessary to 2 mm from the gel to bend the bracket.
2. Bracket forming must be done with a clamp or by a professional.
3. Bracket forming must be completed before welding.
4. Bracket forming must ensure that the pins and spacing are consistent with the board.
Second, pay attention to LED bending feet and cutting feet
Because the design requires bending and cutting the foot, when bending and cutting the LED, the position of the bending foot and the cutting foot is more than 3 mm from the bottom surface of the gel.
The bent feet should be made before welding. When using the LED plug-in lamp, the pitch of the pcb board hole corresponds to the LED pin pitch. When cutting the foot, the static vibration of the cutting machine generates a high voltage static electricity, so the machine should be grounded reliably and do anti-static work (the ion fan can be blown to eliminate static electricity).
Third, LED cleaning
Special care must be taken when cleaning the gel with chemicals, as some chemicals can damage the surface of the gel and cause fading such as trichloroethylene, acetone, and the like. It can be wiped and immersed in ethanol for less than 3 minutes at room temperature.
Fourth, LED overcurrent protection
Overcurrent protection can be used to provide LED series protection resistors to stabilize the operation.
The resistance value is calculated as: R=(VCC-VF)/IF
VCC is the power supply | voltage regulator voltage, VF is the LED driving voltage, IF is the forward current
Five, LED welding conditions
1. Soldering iron soldering: The soldering iron (up to 30W) tip temperature does not exceed 300 ° C, the soldering time does not exceed 3 seconds, and the soldering position is at least 2 mm from the colloid.
2. Wave soldering: The maximum temperature of dip soldering is 260 ° C, the dip soldering time is less than 5 seconds, and the dip soldering position is at least 2 mm from the colloid.