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Date: | Tue, 26 Apr 2011 14:58:12 +0000 |
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I'd go with the pin gauge any time. Many times I've seen the hole size be good until you got to the bottomside where the platting caused a much smaller hole size that either prevented a press pin operation or a hand insertion prior to wave solder.
The angle of the scope and other error factors and eye fatigue would not lend itself well to check hole sizes after plating.
John
----- Original Message -----
From: "Louis Hart" <[log in to unmask]>
To: [log in to unmask]
Sent: Thursday, April 21, 2011 7:24:46 PM
Subject: [TN] hole sizes
Technetters, here is a real question, to replace the spurious one I just posted by mistake.
May I have some comments on measurement of hole sizes in printed circuit boards? For many years, I have been using plug/pin gauges to check hole sizes. I recently noticed that the IPC test method 2.2.7 called for use of a microscope. My opinion is that the plug gauges are fine, and, if anything, better than a microscope, even a good 20X device. A small measurement quality study we did on some 40-100 x microscopes a while back suggested the error in using them is greater than the tolerance of a plug gage. But I don't want to get in trouble for using a non-recognized test method. Thanks for any comments.
Louis Hart
Compunetics
Monroeville, PA
USA
[log in to unmask]<mailto:[log in to unmask]>
412-858-1272
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