Rob,
    To answer your first question and I'm not meaning to sound like an Arkansas
lawyer - yes and no.  We have ran more visible light LEDs through the wave
solder with no problems than I can count.  We processed  numerous LEDs on one
assembly that were mounted on a stand-off that held the base off a double sided
PWB less than .1" with no problems.

    On the other hand infrared LEDs seem to be a different breed.  Overtime we
have tried to wave solder the IR type we have experienced high fallout rates.
The failure mechanism does not always produce an immediate failure.  Latent
failures show up after burn-in, which unfortunately is also after potting,
resulting in the entire sensor being scrapped.  Failure analysis has indicated
a fracture of the wire bond on the cathode lead.  Temperature profiling on the
component lead during wave soldering indicates no violation of the manufacturer
soldering specifications.  Hand soldering can also lead to the same failure.
Heat sinking the legs of the LED during hand soldering is necessary to avoid
this problem.

    Unfortunately, we have not been able too further pursue this issue.  I am
sorry I have no other remedy to offer.  I would certainly do not want to heat
sink these devices forever because wave soldering is more cost effective.
Perhaps somebody else on Technet could shed some light on this LED problem.

[log in to unmask] wrote:

> Has anyone experienced LED failures while running product through a wave
> solder?  I am having some fallout on some LED's.  The component spec.
> states that it can handle solder temperature of 260
>
>   ------------------------------------------------------------------------
>
> °C for 5 seconds.  My
> solder pot is only at 250°C and a dwell time of 2 seconds.  Can anyone shed
> some light on this subject for me?
>
> Rob
> [log in to unmask]

################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe:   SUBSCRIBE TechNet <your full name>
To unsubscribe:   SIGNOFF TechNet 
################################################################
Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information.
For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312
################################################################