Ask the Experts
September 25, 2018
Rework or Repair?
We often need to strip solder splash contamination off gold edge contacts and replate them. Is this considered a repair or a rework?
Are there clear definitions for the terms repair and rework?
Expert Panel Responses
In response to the second of your two questions, are there clear definitions for the terms repair and rework?
Yes, IPC-7711/7721 Rev B section 1.4 Terms and Definitions provides clear distinction between Rework and Repair as follows:
REWORK is the act of reprocessing noncomplying articles, through the use of original or equivalent processing, in a manner that assures full compliance of the article with applicable drawings or specifications.
Whereas a REPAIR is the act of restoring the functional capability of a defective article in a manner that does not assure compliance of the article with applicable drawings or specifications.
Now in response to your first question, we would define this process a Rework. We perform this rework on a regular basis.
We are able to replate the gold fingers using an "equivalent processing" and we can measure the plating deposition thickness to "assures full compliance of the article with applicable drawings or specifications" as detailed in the IPC definition.
Circuit Technology Center
Mr. Vigneau has been a key member of the team at Circuit Technology Center since 2008. He has vast expertise, experience and understanding of complex circuit board rework, repair and modification operations. He is one of the most knowledgeable experts in this area across the globe.
Gold edge contact re-plating is considered to be a Repair, not a Rework, and is detailed as such in IPC 7711/7721 section 4.6.3 of the Repair section.
The distinctions between "Repair" and "Rework" and "Modification" are also defined in IPC 7711/7721 section 1.4:
October 2003 IPC-7711A/7721A
Because you are replating using chemicals and methods not originally on the CCA BOM, you are not returning the CCA to full print compliance, so it is considered to be a Repair. It may be fully functional, but just does not comply with the original process and/or materials. Performance of Rework is generally considered to be acceptable without customer permission, but performance of Repair methods is usually more strictly controlled and the customer may allow them outright if as done per IPC 7711/7721, or may require pre-authorization by the customer, or may not allow them.
It is important that this is defined clearly ahead of time within the contract, as agreed between User and Supplier (AABUS). Modifications are pre-approved changes documented by the customer and flowed down to the Supplier (usually) in the form of Engineering Change Notices (ECN).
You should always discuss the ground rules with your customer or supplier as the case may be, and document it as part of the Contract.
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.
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.
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.
Richard D. Stadem
Richard D. Stadem is an advanced engineer/scientist for General Dynamics and is also a consulting engineer for other companies. He has 38 years of engineering experience having worked for Honeywell, ADC, Pemstar (now Benchmark), Analog Technologies, and General Dynamics.
It is all a question of definition.
We define these activities as follows:
REWORK -- an operation that is carried out to rectify a manufacturing fault or error such as a soldering defect, a missing, incorrect or malfunctioning component. It is performed on the shop floor and usually follows the Inspection and Test procedures which reveal a defect.
REPAIR -- An operation carried out on an assembly that has passed all Inspection and QC tests, has been shipped and has subsequently failed "in the field". It is returned to the factory or a Repair Site where the repair is carried out. The actual procedures may be the same as Rework -- depending on the diagnosis of the fault -- but may also cover physical damage such as cracked PCB, broken traces, etc.
As far as the Solder Splash is concerned -- take your pick!
Harold Hyman has been involved in metallurgical aspects of the electronics industry since the 1950's, and in semiconductor development and engineering for STL, Ediswan & RCA. He later joined HTC, a pioneer of vapor phase soldering and continued industry experience Dynapert, GenRad, Teradyne, SRT and VJ Electronics.
According to IPC-7711B/7721B Rework, Modification and Repair of Electronic Assemblies, the removal of solder from a gold contact finger constitutes a repair.
The definitions of the 2 classifications are as such:
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.
Repair: The act of restoring functional capability of defective article in a manner that does not assure compliance of the article with drawings or specifications.
Director of Marketing
Matt Stevenson has over 20 years experience in the PCB industry. Serving in roles as a Chemical Lab Technician, Process Engineer, Quality Engineer, Quality Manager, and Marketing Manager. He has proven himself to be an invaluable resource.
My thoughts are:
Solder splash on contacts are caused by poor process control/design and therefore should be defined as rework as with any other defect associated with process control/design. Repair should be used for defects that have been caused by defective parts.
Global Process Manager
Mr. Ashmore is responsible for the Global Applied Process Engineering group for DEK. Clive specializes in all aspects of manufacturing engineering, with special emphasis on mass imaging technologies.
Simple definition of rework and repair.
Rework meets all applicable documentation for drawings and specifications as per contracts. Processes are not generally listed just end product.
Reworked product should not be discernible from original product in side by side analysis.
Repaired product will have same form, fit, and function as original but in side by side analysis may demonstrate a difference. i.e. spliced wire covered with shrink tube. Still works the same but is a repaired unit. Depending on product class whether rework and/or repair is acceptable without notifying end user.
Joseph Bradford, Audiosears Corporation, USA
We cover gold edge contacts on PCBs with Kapton tape at the start of the process and then remove it when all soldering processes are finished, before the boards are tested. This helps prevent any solder splashes contaminating the gold edge contacts during our processes.
The definitions of rework and repair in 7711/21B have very specific wording. But after reviewing the specific topics in Part 2 (Rework) and Part 3 (Repair) of the manual it appears the definitions can be summarized as follows:
- Remove old part
- Prepare Land/Pad/Hole
- Install new part
- Repair board conditions
- Laminate imperfections
- Repair Hole/Land/Trace
- Flexible conductors
- Splicing wires
One method of cleaning solder splash comes under Part 3 (Repair); section 4.6.3. Under OUTLINE it states "This method is used to replate edge contacts by selective swab plating. Edge contacts may require replating if they become contaminated with solder or are scratched during handling."
In Part 1 of the manual Paragraphs 1.2 and 1.2.1 state the following:
1.2 "IPC has identified the most common equipment and process in order to affect a specific repair or rework. It is possible that alternate equipment and processes can be used to make the same repair. If alternate equipment is used, it is up to the user to determine that the resultant assembly is good and undamaged."
1.2.1 "This document is intended to be used as a guide and there are no specific requirements or criteria unless separately and specifically
called out in a user's contractual or other documentation."
In short: Does it really matter if this is defined as rework or repair? Just get the assembly usable again.
Joe Lindsey, Lindsey Consulting
There is a justified reasoning for determining the difference between 'Repair' and 'Rework' if the work is being carried out under the requirements of AS9100, as there are different requirements under this standard for the two different processes.
Andy Jones, SMS Electronics Ltd., UK