PCB Assembly Rework, Repair and Modification: Who Authorizes What in the PO

Three words that are not interchangeable

• Most PCB assembly POs say "rework allowed per IPC" and stop there. That line treats three different actions as one.
• Rework brings a nonconforming assembly back into full conformance with the original drawing and spec. Example: reflowing a bridged joint, replacing a misaligned part with the same part number.
• Repair restores function but does not make the board fully conform to the original documentation. Example: a lifted pad rebuilt with a bonded replacement, a cut trace bridged with wire.
• Modification changes the design itself. Example: an added jumper wire, a part changed to a different value, a trace cut on purpose. It comes from a design change, not from a defect.
• IPC-A-610 uses this split. IPC-7711/7721 describes the methods. Your PO has to say which class needs whose approval.

Why the split matters to the buyer

• Rework is usually routine. Repair and modification change what you receive. That is why they need your decision, not the assembler's.

The authorization matrix

State one named decider per row. Adapt the rows to your program.

• "Notify the buyer" without a time window is not a decision point. Give a response window your side can meet.
• A request that arrives after the work is done is a report, not an approval.

Allowed methods

• Cite IPC-7711/7721 by name as the method reference, and IPC-A-610 at your chosen class for acceptance after the action.
• For repair, list the repairs you accept in advance (for example, pad or trace repair on non-critical nets). Anything outside the list needs case approval.
• Name the nets or areas where repair is never allowed: high-voltage gaps, controlled impedance lines, RF sections, safety-critical circuits.
• For modification, state that wire type, routing, fixing and coating over the wire follow your drawing or change notice, not the assembler's habit.

Limits: write the rule, agree the number

• Set a maximum number of rework cycles per location and per component. State what happens when it is reached: scrap, or escalate to you.
• Do not copy a number from an article. The right limit depends on the part, the board, the finish and the thermal profile. Agree it in the engineering review and write the agreed value into the PO or quality agreement.
• Set a limit on the number of repairs per board, or state that any board needing more than the agreed count is scrapped.
• Moisture-sensitive parts removed during rework are not reused unless your spec says so.

Re-inspection after the action

• Every reworked, repaired or modified location is re-inspected to the same criteria as a first-pass board, plus any test that covers it.
• State the scope: only the touched joints, the whole unit, or the whole lot. Each is a different cost.
• If the original defect was found by electrical or functional test, the board goes back through that test. Visual re-inspection alone does not close it.
• For parts under X-ray criteria, re-run X-ray on the reworked part. See BGA X-ray void criteria in the PO.

Records the assembler keeps and sends

• Serial or lot, board location (reference designator), defect found, action class (rework / repair / modification), method reference, operator, date, re-inspection result.
• For repair and modification: the approval reference (your email, deviation or change number).
• Cycle count per location, so the limit can be checked.
• Ask for a summary on the certificate of conformance and the full log on request. See shipment documents and lot traceability.

Marking at shipment

• Decide whether reworked units must be identifiable on arrival: by serial list, by a mark on the board, or by a separate packing sub-lot.
• Repaired boards should always be identifiable. They differ from your released data.
• Modified boards carry the new revision or deviation number on the board or label, as your change notice requires.
• State where a physical mark may go. A mark on a test pad or a label over a vent is a new problem.

How this goes wrong

• The PO says "rework allowed". A jumper wire is added to fix a layout error and the lot ships as the old revision.
• A BGA is reworked three times. Each cycle passed visual. Nothing in the records shows the count.
• A lifted pad is repaired on a high-voltage net. Nobody had said that net was off limits.
• Approval is asked by phone, given verbally, and nothing exists when a field return arrives.

PO clause block you can adapt

• "Rework, repair and modification have the meanings used in IPC-A-610. Methods shall follow IPC-7711/7721. Acceptance after any action shall be to IPC-A-610 Class [ ] for this assembly."
• "Repair and modification require Buyer written approval before work starts. Rework on parts listed in Annex [ ] requires Buyer approval of the method."
• "The maximum rework cycles per location are as agreed in the engineering review and recorded in Annex [ ]. Units that reach the limit shall be scrapped or held for Buyer decision."
• "No repair is allowed on nets or areas listed in Annex [ ]."
• "Each touched unit shall be re-inspected and re-tested as listed in Annex [ ]. Records per Annex [ ] shall be kept and a summary sent with each lot."
• "Repaired and modified units shall be identified on shipment as stated in Annex [ ]."

PO checklist

• [ ] Rework / repair / modification defined by IPC-A-610 terms
• [ ] Authorization matrix with one decider per row and a response window
• [ ] Method reference and pre-approved repair list
• [ ] No-repair nets and areas
• [ ] Cycle limit rule and agreed value
• [ ] Re-inspection and re-test scope
• [ ] Records, CoC summary and approval references
• [ ] Shipment marking for reworked, repaired and modified units

FAQ

What is the difference between rework and repair on a PCB assembly?

Rework returns the board to full conformance with the original drawing. Repair restores function but leaves the board different from the drawing, so it needs buyer approval.

Is adding a jumper wire a repair or a modification?

If it corrects a defect on the board, it is a repair. If it implements a design change, it is a modification and needs a change notice and a new revision or deviation number.

How many rework cycles should the PO allow?

There is no single number. Agree it per part type in the engineering review with your assembler, then write the agreed value into the PO or quality agreement.

Can the assembler rework without telling the buyer?

Routine rework under a documented procedure can proceed if it is recorded. Repeat cycles, area-array parts, repair and modification should need your approval first.

Do reworked boards need to be marked?

Repaired and modified boards should always be identifiable. For reworked boards, decide in the PO whether a serial list is enough or a physical mark is needed.

Related links

• Assembled PCB panel with breakaway rails, representing boards that may be reworked, repaired or modified before shipment
• PCB assembly service
• Solder joint acceptance class and defect disposition
• First article inspection report and release terms
• Shipment documents and lot traceability
• Request a quote