When physical damage appears, typically in the form of scratched fingerprints or skins, broken corners, raised pads, or damaged plated through-holes, the PCB must be physically repaired. If desired or permitted by the customer, these repairs require the proper PCB repair tools and techniques. Techniques should be performed by subject matter experts with experience in this type of repair. Specific PCB repair tools designed to make the repair technician’s job easier and faster.
Various techniques exist, many of which were developed by the military, for use in repairing printed circuit boards. These techniques have now been assembled and are being managed by the global trade organization IPC. IPC repair procedures are detailed in IPC-7721 “Printed Circuit Board Repair”. This technical “how to” manual describes in detail the repair process, the tools required, the skill level required (good, better and better) for each of the repair processes. The PCB repair techniques in this document range from gold finger plating to solder mask repair to laminate damage repair. The specifications require customer input if a physical repair is required as described in the repair manual. Repair techniques are divided in this specification into beginner, advanced, and expert PCB repair technician levels. In some cases, there may be up to 4 different approved repair methods described in the IPC-7721, all of which will return the board to function as a PCB.
In addition to the “how to” instructions found in IPC-7721 “Printed Wiring Panel Repair”, the manual also lists the tools needed to complete the suggested repair. Each of the repair processes found in the PCB Repair Tools and Techniques manual informs the user of not only repair techniques but also PCB repair tools. In most cases, they are very generic tools that can be obtained from a variety of sources. The photographs in the standard supporting specification documentation may include a specific supplier of the tool, but in some cases, the “how to” section shows a generic sketch of the tool being used. For some procedures, very specific tools from very specific vendors are listed or referenced in the procedure being discussed.
As an example, one of the procedures found in IPC-7721 describing PCB repair tools and techniques, “Printed Wiring Board Repair” is the PCB Pad Replacement Technique. The IPC 7721 4.5.1 Ground Remediation, Epoxy Method and 4.5.2 Ground Remediation, Dry Film Method both achieve the same end result: the replacement of a ground that was typically removed after a rework process was performed. incorrectly or damage from handling. Both methods refer to the following materials: cleaner, microscope, soldering iron, tweezers and wipes. Then, in each of the methods, the specific materials specific to that method, namely adhesive, circuit frames, and cling film, are detailed in the details for each technique. Each of the process steps is listed in detail so that both PCB repair process steps and materials can be used to complete the repair.