Technetters,

     I know that this information was already circulated, but I am in dire
     need of some type of help.  I would not normally create redundant
     information knowing that everyone is already extremely busy, but you
     guys are my hero and savior, and I really need some help right now.
     If pictures would help let me know and I will get some together.  I
     would greatly appreciate some advice or opinion on this matter.

     We have a problem with a defect that has occurred in two (2) of our
     customer's assemblies from the post assembly manufacturing process.

     The dilemma is as follows:  Is the defect caused by an improper solder
     fillet, or is the defect inherent in the design/application?

     The processes are as followed:

     Process #1:

     We have an assembly that is a "single-sided" CEM-1, Electroless,
     Nickel-Gold PCB, w/ a round pin "non-supportive" five (5) pin flat
     cable installed perpendicular to the PCB, then wave soldered w/ a
     no-clean process.  After post wave, the flat ribbon is then packaged
     without any stress on the solder fillet.

     Problem #1:

     The customer's process then requires that the flat cable be flexed
     around and under the board in order for the assembly to be connected
     to another assembly.

     Question #1:

     Does anyone out there have any documentation on how much mechanical
     force can be applied to a solder fillet of an "unsupported" hole
     without causing premature failure?  This information would allow us to
     go to the customer for a possible design change.

     Process #2:

     We also have a "single-sided" CEM-1, Electroless, Nickel-Gold PCB, w/
     a right angle square post "non-supportive" five pin header installed,
     then wave soldered w/ a no-clean process.  After post wave, the header
     is then slipped into a plastic housing that supports the square post
     and works as the female part of a connector.

     Problem #2:

     If the unsupported pins (5) are slightly skewed, and if the assemblers
     adjust the pins so that they are perpendicular to the edge of the PCB,
     over a period of time (3-months) we have experienced a concentric
     fracture of the solder fillet.

     Question #2:

     Does anyone out there have any ideas on alleviating this condition?
     This parallels Question #1...is there any information on unsupported
     holes in terms of mechanical force being applied to solder fillets?

     I greatly appreciate your response in advance,


     Ron Waugh
     Process Engineer
     Email:  [log in to unmask]

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