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Lite-On side looking LED assembly problems

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Lite-On side looking LED assembly problems | 29 May, 2014

On one of our designs, we use LEDs Lite-On/LTST-S110TB (SMD). PCB footprint was designed according to manufacturer's recommendations. However, our vendor has problems with assembling these parts. Some parts are tilted, other have bad solder joints or insufficient solder on the pads. The part has rather unusually shaped terminals. Do anybody experience the similar problems with assembling this part? Any suggestions how to fix the problems?

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Lite-On side looking LED assembly problems | 30 May, 2014

Starting with the manufacturers layout is a good start. Tilted parts, bad solder joints, sounds like a wetting issue and the board or the parts. Insufficient solder sounds like the printing process needs some attention.

We have used this part in the past. The pads are unusual, but we have had no issues of this nature. Fix? Verify Print Process is robust Verify Oven profile is correct for conditions and requirements Change to a different date code of parts, to see if a wetting issue can be ruled out. Good luck, let us know how this turns out! 'hege

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Lite-On side looking LED assembly problems | 4 June, 2014

This style gave me grief as well. The problem is the way the part is manufactured leading to an unusual pad configuration. When the part is placed on the PCB there is no pad wrap under the part, the pad is 90 degrees to the board. The datasheet shows a fillet on the corners, which may help some. The LEDs I was using did not have the fillets. I was able to get slightly better results by minimizing paste and pad under the part so that the part would not float as readily on the melted solder. I haven't had to run these for quite some time, and now avoid using them in my designs.

Keep us informed if you find a good solution.

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