Hi Alan,

From an assembly point of view, the added benefits of switching from HAL
solder to gold, may not be as strong. The major benefit is eliminating lead
and the messy HAL operation that pose air quality problems, within the PCB
fabrication plant. Additionally, the solder joints are all within IPC specs
and soldering actually occurs on the nickel layer, not on the gold.

Regards,
Lenny Kurup

On Wed, 7 Jan 1998, Alan Shaw wrote:

> We are wave soldering double sided PHT boards using  a No Clean flux.
> There is a proposal to replace the hot air levelled solder over bare
> copper(HAL ) finish with gold flash, about 5u inch thick, over 100u inch
> of nickel.
>
> The proposal would allow us to drop the carbon ink screening requirement
> used for contacts to a rubber keypad.
>
> I see no other benefits to this, only the following problems:- gold
> contamination of the solder pot and weaker solder joint strength. Does
> anyone know of any other benefits?
> Alan Shaw
>
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