Sigh, I don't know how many times the definitions between Rework and Repair have had to be clarified here, so all 8 people in the room understand the difference.
Please read IPC 7711/7721. It is defined in there.
1.4 Controls
Although modification, rework and repair
procedures may be very similar, the control of such procedures
may not be the same, due to the conditions and
objectives involved.
1. Modification
The revision of the functional capability of a product
in order to satisfy new acceptance criteria.
Modifications are usually required to incorporate
design changes which can be controlled by drawings,
change orders, etc. Modifications should only be performed
when specifically authorized and described in
detail on controlled documentation.
2. Rework
The act of reprocessing non-complying articles,
through the use of original or equivalent processing, in
a manner that assures full compliance of the article
with applicable drawings or specifications.
3. Repair
The act of restoring the functional capability of a
defective article in a manner that precludes compliance
of the article with applicable drawings or specifications.
Repairs are generally changes to an unacceptable end
product to make it acceptable in accordance with original
functional requirements. The control of repaired
products should be by means of Material Review
Board (MRB), or its equivalent, which may consist of
Design Engineering, Quality Assurance, and User representatives.
The MRB, with technical support, should
define the mutually acceptable repair method to be
used and take the action necessary to ensure that all
applicable procedures are adhered to.
Repair of a failure in the field seldom includes an
MRB, and typically is done in accordance with a contract,
repair/service order or the user-activity maintenance
program requirements. The maximum number
of repairs per printed wiring board assembly should be
determined by the using activity or agency.
Per the above, Rework brings the CCA back to full conformance to all specifications, ie, the solder joints meet all specifications in IPC-610 or J-STD-001, the polarity is per the assembly drawing, etc. without having to add anything not on the original BOM or drawing. So, for example, a solder bridge is removed, insufficient solder defect is re-soldered, etc., to bring the CCA into full compliance.
Repair brings back the full functionality, form, fit and reliability, but in order to do so you need to add something NOT on the BOM or assembly drawing. For repair of a lifted pad, for example, you must add epoxy not on the BOM or at least not specified to be added to that location. To repair a lifted trace, you need to add a jumper wire plus epoxy, also not on the BOM. So the Repaired CCA meets full fit, functionality and reliability, but does NOT conform to the BOM/assembly drawing.
Whether Rework or Repair is done in the field, in the factory, or in your Aunt Mabel's garage makes absolutely no difference in the interpretation. Neither does it matter whether it was done with or without MRB action, as that is AABUS and does not fit into the classification either.
Some customers do not provide MRB approval for standard repairs. That is their prerogative. They need to understand though, that most repairs, if performed per IPC 7711/7721 are actually MORE reliable than equivalent undamaged product, and by not allowing repairs they are driving up the cost of the product to themselves. However, it could be a smart business decision if the product is low-cost high volume low-reliability product. It is a different story if the product is a high-rel military avionics CCA where each and every component first has to go through full functional testing before ever being assembled to the CCA. For those types of CCAs, even a relatively simple small CCA with a connector and 10 parts on it represents a 6-month lead time for replacement.
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Blair Hogg
Sent: Thursday, May 16, 2013 7:14 AM
To: [log in to unmask]
Subject: Re: [TN] Trend Analysis of Repair Usage
From my old Mil-Q-9858 and Mil-Std-1520 days I remember that the defeinitions we used were that rework would leave the item indiscernible from original manufacture, while repair would bring the item to a usable state, however, one could tell upon inspection that it wasn't originally intended to be manufactured in that manner. Repairs were normally actions that had to be approved via a Materials Review Board, which was typically representatives from Engineering, Quality, Manufacturing Engineering, and, in many cases, a customer represntative. MRB actions had to include a corrective action statement as to why the defect occurred and what actions would be taken to minize recurrence.
If a MRB repair process was defined well it could be approved as a Standard Repair process and allowed to be used repeatedly without MRB approval.
I suppose that if you get 6 people in a room you might get 8 different opinions as to how repair could be defined.
Blair
On Wed, 15 May 2013 17:32:46 -0400, Bob Landman <[log in to unmask]> wrote:
>Exactly my thoughts.
>
>Having just spent considerable time at our assembler dealing with boards that did not test ok due to a variety of pick & place and solder paste problems,....
>
>To me they required rework, not repair.
>
>Repair, to me, implies that at a point in time the assembly did power up and test ok.
>
>Rework covers a multitude of sins in assembly.
>
>Bob
>
>Sent from my iPhone
>
>On May 15, 2013, at 4:32 PM, Ahne Oosterhof <[log in to unmask]> wrote:
>
>> A repair is due to damage. Rework is due to assembly error.
>> A thought from Mike Bogden, Engineer
>>
>> My follow up on that thought: "Rework" is "Repair waiting to be needed".
>> ===
>>
>> Why wait for a "standard" to do tracking of rework and repair? The
>> requirement exists in-house.
>> The better you track both of these, the better and quicker you can
>> fix these problems in order to improve quality and bottom line.
>> It helps if you determine the cost of each individual of these
>> problems so that you can tackle the most costly ones first. And cost
>> should include time to analyze cause of the problem, determining
>> frequency of problem, cost of component involved, cost of time lost,
>> maybe even the cost impact of field failures (hard to put a number on).
>>
>> Ahne.
>>
>> PS: I have stated before: some people are very proud of their rework
>> department, but should not be of the fact they need one.
>>
>>
>>
>> -----Original Message-----
>> From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
>> Sent: 15 May, 2013 06:53
>> To: [log in to unmask]
>> Subject: [TN] Trend Analysis of Repair Usage
>>
>> I am trying to find out if there is an industry requirement or
>> recommendation that usage of Repair Procedures be tracked and
>> monitored? I could not find any information on this in IPC-7711/7721.
>> In previous lives the number of repair usages was tracked, and pareto
>> was published quarterly (number of repairs used versus number of
>> total CCAs built, number of repairs used by a given CCA part number,
>> number of repairs associated with a given component part number, etc.) .
>> Because repairs are infrequent, it is not easy to detect any trend in
>> their usage, but over time the trend analysis can provide good data
>> to detect root causes.
>> I just want to know if there is any industry standard that covers this.
>> I am talking about repairs, not rework. If you don't know the
>> difference please do not respond.
>> Thanks
>> dean
>>
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