Thanks Jack. I will fold this info into the other responses I received.
Phil
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson
Sent: Wednesday, January 11, 2012 11:10 AM
To: [log in to unmask]
Subject: Re: [TN] PTH hole size "standards"
I realize that this is a late reply, but I just wanted to mention that the IPC recommendations are probably related to getting good capillary action around ROUND leads, with typical hole tolerances in mind.
Using DIPS, you have PLENTY of space on the sides of the rectangle for solder to flow, and really your only consideration is insertion and hole diameter tolerance. Rather than creating a new process to keep the DIPs lifted off the surface, you will probably be okay specifying .025 MINIMUM hole size, but that means .028 +/- .003. Will that be enough of a change to improve your cleaning process? (You could probably go to .027 +/-.003)
sorry for the late reply,
Jack
.
On Mon, 19 Dec 2011 10:31:01 -0500, Phil Nutting <[log in to unmask]> wrote:
>
>We recently had a problem with flux residue under a PTH dual inline IC. The problem appears to be caused by our hole diameter of 0.035" and the tapered shape of the step in the leads allowing the device to sit closer or flush with the board causing apparent flux entrapment.
>
>I'm thinking this is more of a process issue of amount of flux, board orientation in the wash, wash time/temp or DI water quality.
>
>The responsible engineer would like to decrease the hole size to 0.025 to effectively raise the part above the board. And he wants to change all the ICs on this board and most likely all his boards going forward.
>
>So the questions comes up, what is the "standard" hole size for a dual inline IC, 0.021 wide pin, plated thru hole, 0.062 thick board, OA flux foam application and RoHS wave solder.
>
>Please add some sanity to my life.
>
>Phil Nutting
>Design for Manufacturing Engineer
>Kaiser Systems, Inc.
>126 Sohier Road
>Beverly, MA 01915
>Phone: 978-922-9300 x1310
>Fax: 978-922-8374
>e-mail: [log in to unmask]<mailto:[log in to unmask]>
>www.kaisersystems.com<http://www.kaisersystems.com>
>www.linkedin.com/in/philnutting<http://www.linkedin.com/in/philnutting>
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