5mm LEDs in chains - are they all manufactured this way or are these special?

[badrequest400]

Does anyone know what these weird-lookin' LED chains are (see attachment)? Is this how all LEDs are manufactured and they just haven't had those bottom bits cut off or are these specially-manufactured to be like this?

[mariush]

Resolution's a bit low, but you can see here similar leads :

[Benta]

It's for automatic pick-and-place PCB assembly.
In 99% of the cases, the LEDs have cut leads and are taped to a self adhesive band at the end of the leads and then be wound on a roll (or an "ammo-pack").
The PaP machine will unwind the roll, cut each LED and insert it into the PCB.
In this case the manufacturer opted for a simpler solution with a special leadframe instead of the tape. Cheaper? No idea.

[langwadt]

It's for automatic pick-and-place PCB assembly.
In 99% of the cases, the LEDs have cut leads and are taped to a self adhesive band at the end of the leads and then be wound on a roll (or an "ammo-pack").
The PaP machine will unwind the roll, cut each LED and insert it into the PCB.
In this case the manufacturer opted for a simpler solution with a special leadframe instead of the tape. Cheaper? No idea.

the leadframe maybe how they are produced, before being cut to be put in ammo-pack or bags

makes sense to not handle them individually when molding the plastic, and the series string might be used for a quick test

[thm_w]

Resolution's a bit low, but you can see here similar leads :

Same channel they are bonding the dies:


Good article here: https://learn.sparkfun.com/tutorials/how-leds-are-made/all

[eugene]

Seems that handling the strips could be dangerous for the LEDs. If you were to roll the strip it would put torques on the leads. Leaded LEDs seem pretty rugged, but still.

[thm_w]

Seems that handling the strips could be dangerous for the LEDs. If you were to roll the strip it would put torques on the leads. Leaded LEDs seem pretty rugged, but still.

Why would you roll the lead frame strip? Or are you talking about the paper ones.

[floobydust]

Nothing goes to waste in china, they'll sell any rejects, blemishes etc.  A few 5mm LED's I've bought are marked backwards polarity and OP's looks like the leads are uncut.
It doesn't mean they are unusable for hobby stuff.

[xrunner]

Resolution's a bit low, but you can see here similar leads :

My Gawd can you imagine doing that all day long every day?