Bare PCB Cosmetic Defects and Repair Disclosure: A Three-Tier Acceptance Framework | PCB168

1. Why the word "cosmetic" starts leaking the moment it enters a contract

Incoming acceptance disputes follow a stable distribution. Electrical issues are almost never argued. Dimensional issues are argued, but briefly. Cosmetic issues are argued without an endpoint.

The cause is not attitude. It is the datum. Electrical testing has a netlist. Dimensions have drawing callouts and tolerances. Both reduce "conforming" to a repeatable measurement. Only a small subset of visual attributes has that property: board edges, depaneled faces, hole mouths — places with a physical boundary.

Everything else behaves differently. Surface scratches, solder mask colour variation, legend offset, thin mask coverage, copper impressions, uneven surface finish: their shared trait is that the conditions of observation were never agreed. Change the light angle, the background, or the viewing distance, and the same board moves from acceptable to obviously defective.

So neither party is lying. The buyer sees a scratch running across the panel under raking light. The supplier sees a conforming board under diffuse light from directly above. The contract says "good appearance, no obvious defects", and at the moment of dispute that sentence supplies no criterion at all.

More importantly, the word "cosmetic" creates an illusion: it sounds negotiable. Nobody expects to negotiate a dimensional overrun, but both sides will try to talk through a cosmetic one. If it can be talked through, there was no predetermined rule. Without a rule, consensus has to be rebuilt every single time, and the cost of rebuilding consensus lands entirely on the schedule.

2. Which visual attributes are actually precursors to functional ones

Treating all cosmetic items as "does not affect use" is the most common misjudgement. One class of visual findings matters not for itself but for what it indicates. A buyer should at minimum be able to recognise these, because they decide whether a board goes to concession acceptance or rejection:

Solder mask. Thin mask, mask lifting, mask in holes. These look like questions of colour and coverage. What they correspond to is insulation continuity and mask resistance during subsequent soldering. On a board where mask has receded at the pad edge, the effective pad size at assembly is no longer the one on the drawing.

Surface finish. Yellowed or whitened pads, localised non-coverage, fingerprint-like marks. These look like appearance. What they correspond to is solderability. The hard part is this: the same condition reads as cosmetic at bare board acceptance and as a defect rate at assembly — and those two stages are usually owned by different people judging against different standards. By the time SMT reports a problem, the bare boards were signed off and stocked long ago.

Mechanical surface damage. Scratches, dents, pits. These look cosmetic. There is only one question that matters: does it reach the copper. Damage to the substrate is a cosmetic item; damage to a trace is an electrical one — and the depth of many scratches is only visible at a particular angle.

Copper oxidation and contamination. This may be nothing more than a function of storage time, or it may be the result of incomplete cleaning. The first is treatable; the second will keep developing through downstream processes.

What these four share: their severity at the bare board stage cannot be determined from appearance alone, yet the disposition decision has to be made at that stage. That is exactly why they cannot be left to "we will look at it when it arrives". They have to be filed into a disposition tier before the order is placed.

3. Board edges and depaneled faces: the one class with a physical datum

Among all visual attributes, board edges are the exception, and worth separating out, because they can be measured.

Edge and depanel condition has a concrete physical carrier: whether the profile sits within tolerance, how much V-cut web thickness remains, whether the routed face shows delamination, whether hole mouths are rolled over, whether burr height exceeds what the mating surface allows. All of these resolve to numbers, can be re-verified, and can be reconstructed during a dispute.

The article pcb-board-edge-depaneling-acceptance-criteria already covers those criteria themselves — which quantities to measure and how to express V-cut web thickness and routing burrs. This article does not repeat them.

Edges are cited here for contrast. Edges generate the fewest disputes not because they matter least, but precisely because they have a datum. Once a datum exists, acceptance degrades from negotiation into measurement, and the space for disagreement collapses on its own.

That contrast gives the method for everything else: for visual attributes with no physical datum, do not try to invent a datum. Create a disposition rule instead. Rather than writing an unenforceable "scratch depth shall not exceed X" into a contract, write out which tier surface scratches belong to, what that tier entitles, and who holds authority to grant concession acceptance. The former is a fake criterion. The latter is a real process.

4. Three types of repair, and the disclosure granularity each requires

Now the half that contracts miss entirely: repaired boards.

When a localised defect appears during fabrication, the board is not always scrapped. Some defects can be repaired, and a repaired board passes electrical test completely. That is the source of the problem. It passes every test you would run, so you will not find it unless the supplier tells you. And the clause that obliges the supplier to tell you does not exist in most POs and engineering annexes.

By impact on downstream reliability, repairs fall into roughly three classes, and disclosure granularity should differ:

Class 1: in-process correction. Localised mask touch-up, legend reprinting, re-treatment of light oxidation. These do not alter conductor structure and are generally treated as rework within normal process latitude. A reasonable granularity is lot level — this lot contained such handling, with no need for per-board identification.

Class 2: conductor repair. Repair of an open, compensation of a localised width reduction. These alter the conductor itself, and the long-term reliability of the repair site under thermal cycling, mechanical stress or a corrosive environment is not equivalent to native copper. A reasonable granularity is per board, with location — which board, which coordinate, which treatment. Only then can the buyer decide whether that board suits the application. For aerospace, automotive or medical use, the buyer may simply decline, and must have the opportunity to make that call.

Class 3: jumper wires. Wire added to establish continuity. Electrically the board conducts. Mechanically, in assembly, in insulation and in appearance it is an entirely different object. A reasonable granularity is per-board declaration with prior written approval — not notification after the fact, but permission before it.

These three lines are not a technical argument. They are a division of information obligation. The IPC framework classifies and identifies repair and modification, and a buyer can cite it by name, but citing a standard does not by itself create a disclosure duty: the standard describes how it is done; only the contract decides whether you are told.

The real disagreement was never "is repair acceptable". Repair is often reasonable, economical, and better for both parties. The disagreement is whether it must be disclosed. A supplier who repairs without disclosing and a supplier who repairs and declares it honestly look identical in your inspection data, while carrying entirely different risk. The only instrument that distinguishes them is the disclosure clause you wrote before placing the order.

5. Write it as three tiers, not as "good appearance"

The structure below can drop straight into an engineering annex. Its purpose is not to raise the standard. It is to eliminate the category that requires discussion on the spot.

Tier 1: allowed, no separate disclosure.

What belongs here is what you have confirmed does not affect function, does not affect downstream processes, and does not alter conductor structure. Typically: mask colour variation, slight legend offset, light surface marks not reaching copper, in-process mask touch-up. The value of this tier is that it explicitly surrenders your right to pursue these items, and buys enforceability for the other two tiers. A contract that puts nothing in Tier 1 has agreed to nothing, because the supplier will attempt to negotiate every single item.

Tier 2: allowed, but must be disclosed and identified with the shipment.

Conductor repair, surface finish anomalies in pad areas, lots that required re-treatment. This tier must state three things together: the granularity of disclosure (lot / per board / with coordinates), the carrier of disclosure (which shipping document), and the timing (before shipment or on arrival). Missing any one of them, this tier collapses back into Tier 1 during execution.

Tier 3: not accepted, or prior written approval required.

Jumper wires, any repair touching nets you have designated as critical, and anything you require in native condition. "Not accepted" and "prior written approval" carry different force in a contract, and which you choose depends on your schedule tolerance. Writing an outright rejection turns the event, when it happens, into a delivery incident. Writing prior approval preserves your ability to make a trade-off.

One practical point when writing the tiers: fill Tier 1 as fully as you can, and keep Tier 3 as narrow as you can. A broad Tier 1 gives the supplier room to report what genuinely needs reporting. A narrow Tier 3 is the only version that gets treated as a real red line. Invert it — an empty Tier 1 and an overloaded Tier 3 — and all three tiers fail together.

The tiers also need one ownership sentence: who holds authority to grant concession acceptance. Procurement, your quality function, or the end customer. Without it, every disclosure under Tier 2 stalls, because nobody is willing to sign. A process with unassigned authority executes exactly like no process at all.

6. After an undisclosed repair is found: the escalation path

Everything above happens before the order. This section handles the event itself: you have found an undeclared repaired board.

The usual mistake here is jumping straight to a commercial conclusion — return, claim, change supplier — and skipping fact fixing. A workable escalation runs as follows:

Step 1: fix the evidence and the scope. The board identifier, the repair location and class, which lot it belongs to, which PO. Scope matters far more than the single board: one board is an execution lapse, one lot is a process gap, several consecutive lots mean information asymmetry has become the normal state. The three call for completely different follow-up, and you have to know which one you have.

Step 2: determine which tier it violated. If your annex has no tiers at all, acknowledge that honestly — the real origin of this dispute is a missing clause, the room for assigning blame is limited, and the first action is to add the clause rather than to pursue liability. If tiers do exist, check against Tier 2 or Tier 3; the path is already defined and does not need renegotiating.

Step 3: dispose of work in progress and in transit. Unshipped units from the same lot, units in transit, units received but unused, units already on the line: the handling cost of these four states differs by orders of magnitude. Freeze the last two first, then negotiate the first two.

Step 4: corrective action and how it will be verified. What you need from the supplier is not "we will be more careful". It is which step in their process produces the disclosure. If the answer is "the operator judges whether a report is needed", the problem will recur. If the answer is a mandatory step with a record carrier, verification becomes possible.

Step 5: the commercial conclusion. Last, because the previous four steps define its reasonable range. Discussing compensation before them is discussing emotion rather than fact.

The value of this path is that it downgrades "undisclosed" from a collapse of trust to a process defect. The former leaves you only with changing supplier. The latter can be repaired — and changing supplier usually costs far more than adding a tiering clause.

7. FAQ

Q1: Is a cosmetic defect a legitimate basis for rejection?

It depends on whether you filed it in advance. With no tiering, the word "cosmetic" carries almost no force in a dispute, because the conditions of observation were never agreed. With tiering in place, an undisclosed Tier 2 item and any Tier 3 violation are both clear grounds for rejection or claim. The right to reject comes from prior tiering, not from the severity of the appearance itself.

Q2: Can edge burrs and surface scratches be judged with the same logic?

No, and that distinction is the core of this article. Edges have a physical datum: they can be measured, reproduced and written as criteria. Surface scratches in most cases have no agreeable observation condition, and can only be handled through tiers plus disposition rules. Write criteria for the first and process for the second. Writing them together weakens the first and still leaves the second unenforceable.

Q3: The supplier repaired a board and it passed electrical test. Am I entitled to know?

Only if you wrote a disclosure clause. This is a contract question, not an ethics question: a repaired board passes every test you would run, so no technical means substitutes for the disclosure duty. If you want to know, state before ordering which repair classes must be declared, at what granularity, and in which document.

Q4: Is "no repairs of any kind accepted" the safest thing to put in a PO?

Usually not. It converts situations that could have been declared and judged by you into a binary of concealment or scrap-and-rebuild, which returns to you as schedule and price. The more durable approach is a fully populated Tier 1, a Tier 2 with explicit granularity and carrier, and a Tier 3 limited to what is genuinely non-negotiable.

Q5: Does this go into the RFQ, the PO, or the engineering annex?

Tiering and disclosure obligations belong in the engineering annex (technical agreement), because they need version control. The PO body references that annex by version. The three tiers should go out with the RFQ itself, so that quotations include the cost of meeting them. Requirements introduced after the RFQ give the supplier legitimate grounds to requote.

Q6: Can IPC standards replace this tiering outright?

Not entirely. IPC provides a classification and identification framework for defects and for repair and modification, and it is a good shared language — citing it by name reduces definitional disputes. But the standard describes how work is done and how it is marked. Whether you are told, when you are told, and who may approve it are contractual matters, and the two parties have to write them.

8. Sources and basis

• Published PCB168 content: board edge and depaneling acceptance criteria, incoming sampling and inspection plan, PCB quality inspection methods. The division of scope against all three is stated in the header.
• Google Search Console (sc-domain:pcb168.com, trailing 90 days, data through 2026-10-09): pcb edge quality inspection 13 impressions / 0 clicks / average position 64.2. This is the demand evidence for the topic.
• The IPC framework for bare board acceptability and for repair/modification classification and identification: cited by name only, used to mark the boundary between "the standard supplies language" and "the contract supplies obligation". No clause numbers or figures are quoted.
• All statements here concern responsibility, declaration order and process. No PCB168 inspection equipment, scrap rate, yield, lead time, certification or customer case is claimed or relied upon.

9. Putting the three tiers to work

Tiering and disclosure duties need version control, which is why they belong in the engineering annex; and they need to reach the supplier with the enquiry, so that quotations price them in. Send your cosmetic tiers and repair disclosure requirements through the quote request and the review will address those clauses directly. The products overview covers construction options by board type, and the capabilities and quality entry covers the process window acceptance sits inside.

Three areas deliberately left out of this article are covered elsewhere: board edge and depaneling acceptance criteria handles the one class with a physical datum, used here only for contrast; incoming sampling and inspection plan handles how the plan itself is written, assumed here to exist; and PCB quality inspection methods handles inspection technique, while this article handles the half technique cannot reach — disclosure duty and the escalation path.

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