In a message dated 06/16/2000 1:01:25 PM Central Daylight Time,
[log in to unmask] writes:

<< Guys,
 It was told to us by our assembly house that PTH/component lead ratio is too
 tight for good solder fillet and to avoid solder depression (hole is not
 being completely filled up). I can see there is no de-wetting either on wall
 or the pin after cross-section.

 I want to know what that magic number should be. I believe that clearance or
 the gap between pin and hole - what is the minimum clearance recommenced and
 what should be maximum clearance for better solder fillet.

 Is this information available on any IPC document? I have read it but can't
 remember now.

 re,
 ken patel >>

Hi Ken!

The rule of the thumb that I've always used is the finished hole size should
be
.015 - .020" larger than the lead diameter. That takes autoinsertion into
account
as well...

-Steve Gregory-

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