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Subject:
From:
"Howieson, Rick" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Wed, 31 May 2000 17:08:32 -0600
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text/plain (147 lines)
Jerry,
Thanks for your FIRST sentence, opinion. We use x-ray and as far as
troubleshooting and improving our process it has been one of the best
investments made.
Rick Howieson
General Technology Corp.

>-----Original Message-----
>From:  Jerry Cupples [SMTP:[log in to unmask]]
>Sent:  Tuesday, May 30, 2000 4:12 PM
>To:    [log in to unmask]
>Subject:       Re: [TN] To X-ray or Not to X-ray.
>
>At 02:53 PM 5/30/00 -0600, you wrote:
>
>>Help,
>>
>>My company is asking for information leading to the possible purchase of an
>>X-ray machine for BGA s.
>>
>>We are placing some with metal tops such as the ALTERA.  ANY info on who,
>>what, where, etc. etc. etc.
>>
>>Would be kindly appreciated.
>
>I have an opinion here, and it's just an opinion...
>
>Buying an X-Ray machine "for BGA's" is pretty common, as of course you can't
>"see" the joints much otherwise.
>
>But you wouldn't buy an X-Ray machine just to check your lungs every 6
>months, would you? Not even if you were doing it for every employee, you
>wouldn't.
>
>My brother is a radiologist. He can look at images which look like clouds,
>and pick out the "Roentgen signs" that indicate disease and abnormalities.
>When I look at them, they look like clouds. It took him years of internship
>and residency to develop the skill analyze the images, plus a photographic
>knowledge of human anatomy achieved along the way. He needs to know what
>every section of a body SHOULD look like, and indicators for many
>abnormalities in males, females, adults, juveniles.
>
>If you do buy one, you should plan to dedicate a technician who will learn
>how to operate the equipment, process the images, and interpret what is found
>- and the time and cost of this manpower is probably greater than the cost of
>the equipment. You can expect it to be a long process to get much useful
>information. There are many types of packages, and they are mounted on
>different boards with different pads. This will change every six months or so
>with some regularity.
>
>Some  people think the process of interpreting the image ought to be simple,
>like looking at the x-ray of a broken arm, and seeing the crack, and saying,
>"yes, it's broken". The reality is that you see cloudy images and have to
>adjust the contrast and use a lot of your training and experience to
>determine what the image means.
>
>Having an X-Ray machine just to find shorts on BGA's after soldering is
>overkill. What you may want is the ability to make judgements about the
>amount of solder, the voids, and the wetting. This requires laminography,
>sophisticated image processing, a trained technician, and then you have
>indications which can be used to make logical inferences, not necessarily
>clear cut process measurements. (I've seen my brother arguing with other
>radiologists about the meaning of images, and he wrote a chapter in one of
>the medical texts...)Your mileage may vary, etc.
>
>
>cheers,
>
>
>Jerry Cupples
>Interphase Corporation
><html>
>At 02:53 PM 5/30/00 -0600, you wrote:<br>
><br>
><blockquote type=cite cite><font face="arial" size=2>Help, <br>
></font><br>
><font face="arial" size=2>My company is asking for information leading to
>the possible purchase of an X-ray machine for BGA s.<br>
></font><br>
><font face="arial" size=2>We are placing some with metal tops such as the
>ALTERA.&nbsp; ANY info on who, what, where, etc. etc. etc.<br>
></font><br>
><font face="arial" size=2>Would be kindly appreciated.<br>
></font></blockquote><font face="arial" size=2><br>
></font>I have an opinion here, and it's just an opinion...<br>
><br>
>Buying an X-Ray machine &quot;for BGA's&quot; is pretty common, as of
>course you can't &quot;see&quot; the joints much otherwise.<br>
><br>
>But you wouldn't buy an X-Ray machine just to check your lungs every 6
>months, would you? Not even if you were doing it for every employee, you
>wouldn't.<br>
><br>
>My brother is a radiologist. He can look at images which look like
>clouds, and pick out the &quot;Roentgen signs&quot; that indicate disease
>and abnormalities. When I look at them, they look like clouds. It took
>him years of internship and residency to develop the skill analyze the
>images, plus a photographic knowledge of human anatomy achieved along the
>way. He needs to know what every section of a body SHOULD look like, and
>indicators for many abnormalities in males, females, adults,
>juveniles.<br>
><br>
>If you do buy one, you should plan to dedicate a technician who will
>learn how to operate the equipment, process the images, and interpret
>what is found - and the time and cost of this manpower is probably
>greater than the cost of the equipment. You can expect it to be a long
>process to get much useful information. There are many types of packages,
>and they are mounted on different boards with different pads. This will
>change every six months or so with some regularity.<br>
><br>
>Some&nbsp; people think the process of interpreting the image ought to be
>simple, like looking at the x-ray of a broken arm, and seeing the crack,
>and saying, &quot;yes, it's broken&quot;. The reality is that you see
>cloudy images and have to adjust the contrast and use a lot of your
>training and experience to determine what the image means.<br>
><br>
>Having an X-Ray machine just to find shorts on BGA's after soldering is
>overkill. What you may want is the ability to make judgements about the
>amount of solder, the voids, and the wetting. This requires laminography,
>sophisticated image processing, a trained technician, and then you have
>indications which can be used to make logical inferences, not necessarily
>clear cut process measurements. (I've seen my brother arguing with other
>radiologists about the meaning of images, and he wrote a chapter in one
>of the medical texts...)Your mileage may vary, etc.<br>
><br>
><br>
>cheers,<br>
><br>
><br>
>Jerry Cupples<br>
>Interphase Corporation</html>
>

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