I feel a need to jump in here so we don't end up with more confusion than is necessary.
IPC's previous rework/repair support guideline was IPC-R-700. I suspect that the "R" is just stuck in some folks minds; it's no longer part of the title. When that document was finally updated, it was published in Feb 98 as two separate documents, as noted below. They are now full-color documents provided in a three-ring binder so that additional procedures can be inserted as they are published by IPC, or perhaps even more importantly, so that company unique procedures can be inserted into the binder also. They were originally marketed to include two years of a free updating (subscription) service, but that has been changed for new purchasers. Everyone who purchased under previous agreements will still get their two years of updating, but in the future all updates will be published for free download from the IPC website, and hard copies will be available for purchase. Curious minds can go www.ipc.org and select the "On-Line Resources" link, then the "IPC Documents Available for Download" link. You'll see a 7721 update that you can download.
The terms rework and repair have some muddled meanings within industry. IPC-T-50 Terms and Definitions for Interconnecting and Packaging Electronic Circuits is a mini-dictionary, title self-explanatory, that provides definitions based on industry consensus. It matches an international document published by IEC. I'm quoting the definitions for rework and repair below. You'll see that rework isn't restricted to just "touch-up"--it is essentially any and all actions that you accomplish to make the assembly align to drawings. Removing and replacing a defective component during the manufacturing process, or even doing that same action when a component has failed in fielded equipment, for example, is a rework. The assembly should then look like and act like it was intended by original drawing.
Repair, on the other hand, would include actions to a work piece that will cause it to function like it was intended, but it will no longer match the drawings. Maybe using a different part number component that functions acceptably but doesn't match drawing, or running jumper wire to bypass an internal conductor open, for example.
Modification is pretty self explanatory. Doesn't match drawing, changed to make it function in some new way.
There are, by design, NO restrictions on number of reworks or repairs or modifications in either of the IPC documents.
"Rework
The act of reprocessing noncomplying articles, through the use of original or alternate equivalent processing, in a manner that assures compliance of the article with applicable drawings or specifications."
"Repair(ing)
The act of restoring the functional capability of a defective article in a manner that recludes compliance of the article with applicable drawings or specifications."
IPC-7711 Rework of Electronic Assemblies
IPC-7721 Repair and Modifcation of Pringed Boards and Electronic Assemblies
An effort was made in both documents to provide several suggested methods so that users could fit "tools on hand" into the process and not be restricted to procure some specific tools as the only way to do a job. Of course, there are limitations driven by market/technology on this. Sometimes only one kind of tool is available.
I hope this helps some, and anyone is welcome to contact me off-net if you have more questions. Jack
==========================================
APEX - the industry's premier trade show in Electronics
Manufacturing, January 16-18, 2001, San Diego, California.
More information on website www.apex2001.org
--------
Jack Crawford, IPC Director of Assembly Standards and Technology
2215 Sanders Road, Northbrook IL 60062-6135
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847-790-5393
fax 847-509-9798
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