Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


Time To Inspect

#6951

Time To Inspect | 18 June, 2001

Would comment extensively on the following?

The time is a fact for X-ray inspection. If you set the contrast, tilting angle correctly (provide you did enough cross section to know the few type of failure mode: e.g. smaller balls, shorts, missing one, etc.) you can use only few second to inspect using X-ray (if you are really good, fraction of a sec.). A lot of "leg work" has to be done prior to set up inspection in order to minimize the exposure time. (use dummy parts to figure it out first ... take few photo as bench mark example ... train the operator, etc..it is a massive undertaking)...

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Gil Zweig

#6978

Time To Inspect | 19 June, 2001

I have made reference to X-ray Ball Bond Signatures a number of times, and I cannot overstate the importance of quickly qualifying the overall ball bond pattern as either uniform in size and shape or not. Software is available that will make this qualification. If the uniformity is present then the probability is very high that the process is under control. When variations in uniformity are observed this can be due to improper temperature profiles, screening problems, physical deformation of the package. This does not imply that the bonds are defective but that a problem is creeping in. We recommend when this is observed, that an endoscopic inspection of he peripheral balls should be done. With this understanding, time to inspect should not be excessive.

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#6983

Time To Inspect | 19 June, 2001

So when xray inspection time becomes excessive, what things can happen? What are the warning signs that inspection times could be getting longer than they should be?

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Gil Zweig

#6999

Time To Inspect | 20 June, 2001

Clearly, x-ray inspection should not become a bottleneck in the production process. The concept of "signature" identification is to rapidly qualify a BGA attachment as acceptable or suspicious. If suspicious, the board is taken off line for further study. The time devoted to inspection will be subjective depending on the product and the facility.

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