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July 2001

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Subject:
From:
Edward Szpruch <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 19 Jul 2001 07:23:07 +0200
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Hi Jack,
We have very bitter experience with specs related to HASL. 
Especially, since soldering problems are nightmare of assemby people and the
easiest way is to blame the supplier of PCB.
Contrary to other para. in IPC specs,this critria is very subjective. In the
past we invested a lot of money and time in our trials to satisfy some of
our customers : we installed XRF equipment for thickness and composition
measurements and SERA equipment for soldereability measurements.
The problem was and stayed the same: QC of the customer put a  mark on
corner of SMD pad with remark :"I do not like this appearance". All our
attempts to find objective and measureable criteria end up with nothing.
The methods for evaluation of solderability are based of specimens and we
never had been able to perform non-desctrictive test of one of such "SMD pad
corners" without destroying the whole PCB.
Edward

Edward Szpruch
Eltek , Manager of Process Engineering
P.O.Box 159 ; 49101 Petah Tikva Israel
Tel  ++972 3 9395050 , Fax  ++972 3 9309581
e-mail   [log in to unmask]

> -----Original Message-----
> From: Jack Crawford [SMTP:[log in to unmask]]
> Sent: γ ιεμι 18 2001 20:29
> To:   [log in to unmask]
> Subject:      Re: [TN] HASL thickness spec
> 
> Mark, yes, there is a spec and it's in IPC-6012 Table 3-2. The applicable
> line is "Fused tin-lead or solder coat - Coverage and Solderable".  The
> lack of any specific dimension criteria doesn't make this any less a
> requirement.  There has to be complete coverage of solder on the land, and
> it must be wettable.
>  
> Many physics elements involved that affect thickness and shape (flatness)
> of the coverage. Not counting the experience-based opinions published in
> some private guidelines or technical conference papers, it has not been
> possible for your industry peers to establish any consensus standards for
> HASL coverage.
> Cordially,
> Jack
>  
> ==========================================
> APEX - the industry's premier trade show in Electronics
> Manufacturing, January 22-24, 2002, San Diego, California.
> More information on website www.goapex.org <http://www.goapex.org>
> --------
> Jack Crawford, IPC Director of Assembly Standards and Technology
> 2215 Sanders Road, Northbrook IL  60062-6135
> [log in to unmask] <mailto:[log in to unmask]> 
> 847-790-5393
> fax 847-509-9798
> 
> >>> [log in to unmask] 07/18/01 09:54AM >>>
> Is there an IPC spec regarding the thickness (or flatness) of HASL solder
> coating?  I don't see it referenced in IPC 6012 or IPC-A-600.
> 
> Thanks,
> Mark Hargreaves
> EMDS, Inc
> 

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