Stuffing boards with pulled QFP chips

[Jon Elson]

On 03/31/2017 06:32 AM, David Griffith via cctalk wrote:
>
> I'm down to the last few P112 boards for sale and am 
> pondering another run of them because demand is steady.  
> One of the biggest challenges for the last run was getting 
> the QFP-packaged 100-pin chips[1] in a state such that the 
> pick-and-place robot wouldn't throw a fit about slight 
> differences in lead position.  The stuffing house insisted 
> that I send them new chips.  Pulls, though they looked 
> perfectly okay to me, were not acceptable.  Does anyone 
> here know anything about pick-and-place robots using 
> pulled 100-pin QFPs, particularly a stuffing house that 
> can work with such chips and not screw up?
>
> [1] The now-obsolete super-io chips
>
>
There USED to be outfits that recycled chips.  They had some 
system to clean and replate/reflow the leads and align 
them.  The good ones could counterfeit them for new, you 
absolutely could NOT TELL they were not new from the 
factory.  I have no idea if any of these outfits still 
exist.  Probably they do, in China!

My P&P would have no problem, it uses mechanical alignment 
jaws.  But, modern P&P use vision to locate the solder area 
of the leads and then position using those coordinates.  So, 
anything that changes the reflection of the leads or causes 
slight misalignment would cause an alignment failure.

Jon