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How many repairs for SMT component ?

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#62450

How many repairs for SMT component ? | 17 August, 2010

Our customer ask us how many repair (component removal, change and soldering) we guaranty for SMT components on our printed wiring board. We all have the number "3" in mind but we can't justify it by a standard. We can't reply "state of the art". Does someone know a standard which precise the maximum number of repairs: american standard or european one? Even if it's a very old one (that could explain why we don't remember the origin). No precise number is stated in IPC 7711/7721. Thanks a lot.

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#62458

How many repairs for SMT component ? | 17 August, 2010

IPC-7711/7721 states under Scope section: "This document does not limit the maximum number of rework, modification or repair actions to a Printed Circuit Assembly". This is from Rev B of this standard. There are many factors that play a role in the decision to rework or not a certain component. In my experience, in an environment where High reliability products are built, we rework one component/ location once. I'm referring to BGA, QFN packages and always use new components.

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#62460

How many repairs for SMT component ? | 17 August, 2010

In the fine SMTnet Archives, search => heat cycl*

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#62461

How many repairs for SMT component ? | 17 August, 2010

Latest and greatest after discussing w colleagues w experience in commercial electronics. According to the 'Printed Circuits Handbook' by Clyde F Coombs JR, the number of "SMT solder rework cycles per component per board is kept to two-three. Beyond that the board should be scrapped to avoid reliability problems".This is a quote from Soldering repair and rework chapter.

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