Could you please advise of lead length protruding through the bottom of the
pcb on the solder side? You mention lead lengths but do not clarify the
substrate thickness (ie how much of the lead contacts the solder wave)

thanks - D. Rooke
Circo Craft

>---------------------------- Forwarded with Changes ---------------------------
>From: Kenneth R Kirby at HFCCM14
>Date: 12/1/95 8:40AM
>To: [log in to unmask] at Internet_Gateway
>Subject: Solder balls
>-------------------------------------------------------------------------------
>I am not sure if this message went out so in case it bumped into an astroid 
>while traveling through cyberspace I am resending.
>
>1. When wavesoldering with no-clean flux and nitrogen, solder balls seem 
>to be a common problem.  While solder mask is part of the problem I have 
>found that the lead length of connectors, sip's and other inline 
>componets have the greatest effect on solder ball production.  By 
>cutting the leads to .080-.085  from the standard length of .110-.120
>we can eliminate the solder balls. The problem is that you can not buy 
>connectors and other components at the storter lead length.  The 
>manufactures claim no one is asking for shorter leads.  I have not been 
>able to find any documentation that backs up my claim. If you have the 
>same requirement or have a article about lead length and solder balls 
>please let me hear from you.
>
>
>2. IPC. Do you know about this?  Have you done any testing?  I believe 
>that we need a lead length spec for the no-clean process.  Electrovert 
>knows that this is a problem and so do most of the people I have talked 
>with at the major flux companies. Can IPC help?
>
>
>