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Why are there bumps on the LED pins?

I notice that there is a square bump on each pin of the LED. When I insert the LED into the PCB, it cannot go low enough. Why are they there?

LED Manufacturing
November 2, 2023

Jacob Jones

Bachelor's degrees in electronic engineering. Skilled in designing LED electronic components, products, and systems, developing and testing prototypes, troubleshooting, and debugging. 8+ years of extensive experience in the electrical and electronic manufacturing industry. Reach Me Now>>

Jacob Jones

They are the residues of the manufacturing process. At the beginning, there are many pins on one single metal sheet. Then it dies, and the casings are installed on the pins. At last, these pins are cut into single ones, and this process leaves the bumps on the pins.
Besides, they are designed like this to protect the LED. If the LED flushes against the PCB when the temperature is high, the LED may split. This is because the CTE of epoxy and PCB is different, so the contact part will be under stress and thus damaged.

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