R&D Assembly is a subsidiary of R&D Circuits. Our facility is located in
Allentown PA. Circuits is in South Plainfield NJ. 

I can't answer your question. 

About a year ago Circuits relocated, expanding from a 10,000 sqft building
into a 26,000. I don't think they have turned on the HASL equipment since
the move. 

It isn't often they fabricate a board suited to the finish.



 

-----Original Message-----
From: James Verrette [mailto:[log in to unmask]] 
Sent: Tuesday, August 19, 2008 4:58 PM
To: [log in to unmask]
Subject: RE: [TN] Maximum HASL thickness for SMT of QFN

Guy,

Since it looks like you work for a PCB fabricator. Do you know what is your
typical target mean and std deviation for the surface thickness of SnPb HASL
process? 

Thanks,
Jim    

-----Original Message-----
From: Guy Ramsey [mailto:[log in to unmask]]
Sent: Tuesday, August 19, 2008 3:49 PM
To: 'TechNet E-Mail Forum'; James Verrette
Subject: RE: [TN] Maximum HASL thickness for SMT of QFN

I would not recommend HASL, choose one of the flat alternative finishes.


Remember type 3 paste is about 50% solder by volume. A 100 um of variation
in the HASL is more than the total applied volume of solder in the paste
deposit. This type package will not work well with 100% variation in solder
volume in the solder connection. 
You might be successful with 25 um of variation in the HASL finish. 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of James Verrette
Sent: Tuesday, August 19, 2008 1:22 PM
To: [log in to unmask]
Subject: [TN] Maximum HASL thickness for SMT of QFN

What is the maximum SnPb HASL thickness/uniformity that can be tolerated in
the SMT assembly of a .5mm pitch QFN package?  Is there anyone else out
there putting .5mm pitch parts on HASL finished boards that is willing to
share their experiences?
 
Jim
Senior Electrical Engineer
 

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