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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