Definition Servicing circuit boards - Differences between Rework and Repair

[jradford]

I am sure this is in here someplace, but after a quick search I did not find what I was looking for.

I know the difference between the two, but what are your opinions on servicing circuit boards. It follows the definition of a repair because the end result is to the original drawing/schematic, but there are a lot of things which can go wrong when removing and replacing components. Should there be a rework sheet written up every time a circuit board it touched? How do others handle this?

 

[Jim Wynne]

Re: Rework vs repair

It's not unusual for there to be a "touchup" operation after wave soldering--it's often a normal part of the process, and thus isn't considered rework. Rework happens as a result of nonconformity--a failure to meet requirements. It can involve missing or misplaced components, cold or missing solder joints, etc. Anything that causes an assembly to go backwards in the process should be considered rework.

I'm not sure what you mean by "rework sheet," but if you mean instructions specific to the job at hand, they should be provided when necessary. If a diode has been soldered in backwards and needs to be replaced, it probably doesn't warrant written instructions. On the other hand, if there's a specific procedure to follow that's not common, intuitive or is likely to be messed up without instructions, instruction should be provided.

 

[jradford]

Re: Rework vs repair

We have a rework form which gets filled out including authorization for the rework, adverse effects, work instruction doc #. Things like that.

Would it be required to take adverse effects into account with a simple solder touch up or component in backwards? Or can we get by with just defining operations we consider to be part of the manufacturing process. Still log it as non conforming and repair it. Not consider it a rework.

 

[rafrost]

Rework PCBs meet all drawing, BOM and process requirements. Replacing a component with the same original component is rework. Solder touchup, replacing a damaged component are rework , as long as the configuration is met.

Repair PCB's include work that adds or modifies the part from the original configuration. Adding jumper wires, cutting traces, etc.

The determination of rework vs repair documentation is commonly defined by the industry served.

Most of the scope of rework vs repair should be defined in your controlling documents.

 

[jradford]

Looking back at our controlling documents and SOP, we have the definitions of repair and rework backwards. The definitions were put in back in 2006. No one, including auditors, have pointed this out until I posted this thread. Ugh. Guess I had better start swapping definitions. I believe it is only in a few places so it should not be that bad. Write up an audit finding on myself (since the person who wrote the SOP is no longer with the company).

 

[rafrost]

Make certain you check your industry definition of rework vs repair. I have seen industries where the definitions are not to the common usage.
For example:
Audit and survey
Rework and repair
are two that I have encountered differing interpretations.

 

[jradford]

I barely remember back 5 years ago when we had an audit and repair/rework came up. At that time we had them combined as the same process. I believe we got dinged on it, so they were split and defined. We would have sent the changes to the NB for them to accept it. Surprised they didn't point out that we were backward from the rest of the industry.

We are a medical equipment company. Class II medical device.

 

[qusys]

I barely remember back 5 years ago when we had an audit and repair/rework came up. At that time we had them combined as the same process. I believe we got dinged on it, so they were split and defined. We would have sent the changes to the NB for them to accept it. Surprised they didn't point out that we were backward from the rest of the industry.

We are a medical equipment company. Class II medical device.

Rework is to be intended as subjected to a repeated or new production process, repair as restored to a condition compliant with the intended usage

 

[rafrost]

Rework is to be intended as subjected to a repeated or new production process, repair as restored to a condition compliant with the intended usage

I don't understand this statement. My experience does not relate either rework to the production process, only to full conformance to requirements.

Repair does not nessarily comply fully to requirements, but meets the intended usage.

Repair frequently requires customer approval. Rework typically does not.

Can you clarify?

 

[qusys]

I don't understand this statement. My experience does not relate either rework to the production process, only to full conformance to requirements.

Repair does not nessarily comply fully to requirements, but meets the intended usage.

Repair frequently requires customer approval. Rework typically does not.

Can you clarify?

It could depend upon the context. In semincondutor field it is allowed the so-called rework in the production line. It is an approved loop , for instance, to rework a lot ( to remove photoresist in case of particle on wafer where there is the printing of the mask of a level).
Repair could happen in test just in case some line of chip are not functioning and there is the opportunity to open the redudancy on the wafer ( other chips that can assure the same functionality).
The terms are common similar : rework is done to carry a non conforming product to a conforming status, while repair is usually done for restoring something, expecially on finished status.
You can customize upon the context. In some case you can have, in another not.
This is my intepretation.
According to ISO TS ,clause 8.3.2 says that there need working instruction sto do this, including the requirements for control.