From: Paul M Fly

Ken,

  I think IPC-2222 section 9.2.2 will give you what you want.

*********************************
          Paul Fly

Eastman Kodak Company
Engineering Technology Center
901 Elmgrove Rd.
Rochester, New York 14653-5313
Phone: (716) 726-5670
Fax: (716) 726-0275
E-mail: [log in to unmask]
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Ken Patel <[log in to unmask]> on 16/06/2000 14:01:33

Please respond to "TechNet E-Mail Forum." <[log in to unmask]>; Please respond
      to Ken Patel <[log in to unmask]>

To:   [log in to unmask]
cc:    (bcc: Paul M Fly/243609/EKC)
Subject:  [TN] component Hole dia v/s lead dia for better solder fillet




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


The boards I've seen after cleaning look acceptable. The fact that
the holes are not completely filled can also be caused by improper
PTH/component lead ratio. I suggest increasing the PTH diameter to
alleviate
the insufficient fill.
______________________________________________________
Ken Patel                       Phone:  (408) 490-6804
1708 McCarthy Blvd.             Fax:    (408) 490-6859
Milpitas, CA 95035

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