Darrell Wrote:

>     I am looking for some technical information/ assistance regarding 
>    component lead tinning. 
>
>  Does anyone have any experience with a tinning process causing thermal 
>    shock to integrated circuits that would cause them to separate at the 
>    lead frame bond ? What is an acceptable thermal ramp rate ? 
>    
>    The solder pot is held at 313 deg. Celsius (high temp solder), the 
>    component is suspended in type "RMA" flux for 5 seconds and then 
>    suspended in the solder pot for another 5 seconds. This process is 
>    repeated for two cycles. We are using an automated tinning machine 
>    which controls emmersion speed and depth for both the solder and flux.
>    
>    What is the typical thermal ramp rate that a component, such a DIP, is 
>    able to withstand ? This includes the cool-down (second immersion into 
>    flux prior to second tinning cycle is approximately 8 seconds).
>   

If tinning at a high temperature is a problem, why not tin using eutectic 
(lower temp) solder which will result in a solderable surface at a lower 
temperature?

Jim Marsico
AIL Systems