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BIG Daddy's Xray Machines

#6985

BIG Daddy's Xray Machines | 19 June, 2001

In the newspaper, I read about "BIG Daddy" ice cream by DeConna Ice Cream Co. of Orange Lake, FL. According to the packaging label, a 12 oz serving "BIG Daddy" has 100 calories and 2 grams of fat. At only 2 Weight Watchers points, the stuff is virtually flying out the super market doors from Florida to Virginia. Long story short, "BIG Daddy" uses consumer labeling that is [How shall we put it?], um, less than representative of the result of tests done by independent test labs.

I am not accusing or suggesting that any xray machine supplier of pulling a "BIG Daddy". Nor do I think for one single moment that anyone in that business would ever consider doing anything less than what was right and proper, but we all know there are moments in the heat of battle that we all wished we had a just a little more zip in our douda. [I do that more often than I�d like to think.]

What are some of the sneaky little tricks that a "BIG Daddy" of xray machines might "try to pull" to make their machine appear a little more attractive than it might otherwise appear. Please talk about both specmanship and operating tricks.

What is the standard, ANSI or something like that, test of the operation of and xray machine? Is there a standard object, er structure, that xray-types use to compare, assess machines?

Each of us use certain machines everyday and are more intimately familiar with that type of machine than others. On the machine that we are intimate with, we could do a pretty good job of wringing-out another similar machine, maybe made by another supplier, to understand the "ins & outs" of its operation. What are the steps of a process used to assess a xray inspection machine?

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Gil Zweig

#6990

BIG Daddy's Xray Machines | 20 June, 2001

Dave: Your question is very astute. First let me make the observation that x-ray imaging is a technology that not many people in electronic fabrication are familiar with (but some think they are); consequently they are gullable acceptors of sales distortions. Despite the arcane-ness of x-ray technolgy, it is very easy to get into the business. All one need do is purchase an x-ray source from the more popular suppliers and purchase an "off the shelf" CsI image intrensifier from the more popular suppliers, add some image processsing and encase it in a shielded cabinet and you are in business. A number of present equipment suppliers do just that.

Since CsI image intensifiers have intrinsicly lower resolution ,in the range of 3 to 5 line pairs per millimeter (lp/mm) the system design is forced to employ smaller focal spot x-ray sources to obtain any reasonable magnification of the image. (Caused by penumbra blurring) Because the basic design of these image intensifiers reqire greater kV to activate them, the design is forced to go to a higher kV source. Increasing the cost of the system significantly. In the specsmanship phase, these design necessities may be then described as "unique features" Also bear in mind that any image processing features is a plug-in addition to the basic x-ray system and not an integral part of it.

There are a number Design Safety Standards for X-ray inspection systems such as ANS N537 and CFR21 but they do not address imaging performance. The best criteria to judge an x-ray inspection system is image quality, cost and the reputation of the supplier.

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PCB X-Ray Inspection

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