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Mirtec aoi

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Mirtec aoi | 1 November, 2007

Whe have the Mirtec about 2 years now, the question is, that when you have 100 components to check he give's 20 to 30 failures that no failures are. are there people they have the same problem?

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Mirtec aoi | 1 November, 2007

If you are in the Americas, I'd contact tech support and they should square you away on that high false call rate problem. They have great WebEx training and troubleshooting.

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Mirtec aoi | 6 November, 2007

Good Morning Roger,

The Mirtec's can be adjusted to lower your false call rate. This can be done by reducing the matching percentage for each componnent but the result of this action is that the machine becomes less selective. If you lower them too much, it will incorrectly accept a defect.

The other important aspect of managing your false calls is regular program maintenance. When you inspect a board and the calls are high, exit out of the inspection results screen and go to "Preview". This will step through all of the components that failed. You can identify the windows that failed and determine the cause of the failure, (e.g. font size, color, illegible markings, etc.) You can add alternate images as needed provided that the part is actually acceptable.

Our lead inspector is certified to make changes to the library. She monitors program performance and performs maintenance as required.

We do want to see false calls to some degree. This gives us the feeling that the machine is being picky about what it is trying to match. If the machine produced no false calls, I would think it would probably accept a 74LS383 for a 74LS363.

Finding the balance between pass and fail thresholds is the key to lowering the false call rate but remember, the wider you open the window, the higher the chance that something can get through without being caught.

Good Luck


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