PCB Quality Inspection: Defining Inspection and Test Requirements Before You Get Quoted | PCB168

Inspection you add after the quotation is a change order

A PCBA RFQ usually carries files and quantities. It rarely carries a defined inspection and test plan. The gap looks harmless because inspection feels like something the supplier "just does". It is not. Inspection and test consume fixtures, programs, stations, operator time and documentation effort, and each of those is priced. A check that was not in the RFQ was not in the price, so it arrives later as one of three outcomes: a cost change, a schedule change, or an argument at receiving about a criterion nobody wrote down.

PCB168's assembly page is explicit about where these items live. On /en/products/pcb-assembly/ the specification table states Inspection Plan as "Agreed per project" and Test Requirements as "Customer-defined / reviewed", and the page closes by stating that lead time, minimum order quantity, equipment or test availability, certifications, capacity and traceability deliverables are confirmed only in the written quotation or subsequent engineering response. Read that as an instruction rather than a disclaimer: the inspection plan is an input you supply, and the test requirement is something you define and we review. Send neither and engineering has nothing to price beyond a baseline it has to assume.

This page is not about how AOI or X-ray works. It is about the page of your RFQ that turns "inspected to a high standard" into line items a supplier can quote and a receiving team can enforce.

The five cells that make a requirement quotable

Every inspection or test requirement that survives into production answers five questions. Miss any one and the requirement is decorative.

Write these as five columns and your inspection page becomes reviewable in minutes. A requirement with a requester, an attribute, a criteria document, a record and an adjudicator can be priced. A requirement expressed only as an instrument name cannot, because scope, limit, basis and disposition all remain open.

Two habits make this harder than it needs to be. The first is writing instruments where attributes belong. The second is treating a standard name alone as a criterion — a standard plus a class plus an applicability statement is a criterion; the name on its own still leaves class and exclusions to be guessed.

Bare board and assembly are two different requirement sets

The two sides are governed by different documents, different requesters and often different acceptance moments. Merging them into one paragraph is the most common reason an inspection requirement becomes unenforceable.

Bare board side: the capability list is published, the applicability is not

/en/capabilities/ publishes a Quality Control block, and that is the honest starting point for what can be asked for on the fabrication side:

Note what that list settles and what it leaves open. It settles that these methods exist as capabilities. It does not settle, for your part number, whether a given check applies, against which limit, on what basis, or whether a record travels with the shipment. Those four are yours to define, and they are exactly where two quotations for the same files diverge.

The distinction matters most for the entries that sound automatic. Impedance verification is published as TDR coupon based, so the evidence is a coupon — if you want a coupon measurement report with your shipment, ask for the report, not for "impedance control". Cross-section is published as microsection for quality validation, which is destructive by nature, so whether sections come from production panels or dedicated coupons, and how often, is a definition question rather than a capability question. Ionic contamination is published as cleanliness testing per IPC standards, naming a standard family rather than a number, so your requirement must say which flow-down you are invoking and whether the numeric result belongs on record.

Impedance tolerance also shows why source pages matter. /en/capabilities/ publishes impedance as ±5% with TDR, while /en/products/heavy-copper-pcb/ publishes ±10% for that product family. Those are two page-specific figures, not one universal value. If your board is a heavy copper build with controlled-impedance nets, do not copy the tighter figure into your RFQ and assume it applies; state the tolerance you need and let engineering review confirm feasibility for your stack-up. Copying a number off the wrong page is how a requirement becomes unquotable before anyone has looked at the artwork.

The attributes buyers most often forget to define on the bare board side are the visual ones. Surface condition, edge condition and outer-layer appearance are judged by eye or by camera against a class, and "class" is the word that is usually missing. IPC-A-600 exists for exactly this, but naming it without a class, and without saying which attributes you are willing to accept at the lower class, leaves the most subjective part of the inspection undefined. If board edges matter for your assembly fixture or your enclosure fit, say so as an attribute with a criteria document; if they matter only cosmetically, say that too, because it changes what gets scrapped.

Assembly side: the page says "customer-defined" for a reason

/en/products/pcb-assembly/ lists Quotation Input as BOM plus fabrication plus placement data, Assembly Scope as confirmed by engineering review, Component Supply as defined in RFQ, Inspection Plan as agreed per project, and Test Requirements as customer-defined and reviewed. The page also notes that a typical assembly plan can include incoming-material checks, paste application, placement, soldering, visual or automated inspection, rework control and customer-defined testing, while stating that the exact sequence and available methods are not assumed and are selected and quoted by engineering for the reviewed design.

That wording is doing real work. On the assembly side there is no published pass/fail list to lean on, because acceptance depends on your component mix, your solder process, your end use and your own quality flow-down. Three definitions are therefore yours to bring:

Workmanship class and its scope. IPC-A-610 is the usual criteria document for assembly workmanship, and the class you invoke changes what is acceptable. State the class, state whether it applies to the whole assembly or only to nominated areas, and state any attribute you are deliberately relaxing. A blanket class reference with no scope statement invites a quotation built on the most permissive reading and a receiving inspection built on the strictest.

What "test" means for this product. Continuity, powered functional test, in-circuit test, boundary scan, burn-in and programming are different requirements with different fixtures and different ownership of the test program. Name the one you mean, say who supplies the test program, fixture, firmware image and golden sample, and say what the pass criteria file is. "Functional test required" with no fixture ownership is a line item nobody can price.

Which checks are conditional on the design. X-ray is published on /en/capabilities/ as BGA and via-fill verification. If your assembly has no bottom-terminated or area-array parts, asking for it as a blanket requirement adds cost for nothing; if it does, asking for it as "X-ray inspection" without saying which packages and what you want evidenced leaves scope open. The same logic applies to cleanliness testing after a no-clean process, and to any conformal coating or potting inspection you may need.

When three documents disagree, the one you named first wins

Most receiving disputes are not disagreements about facts. They are disagreements about which document was the criterion. Four documents typically carry criteria into a build, and they routinely contradict each other:

1. Your drawing or fabrication/assembly notes — part-specific, usually the most authoritative, often the least complete.
2. Your quality specification or supplier quality agreement — broad, sometimes written for a different product line, often the source of requirements nobody intended for this part.
3. The industry standard and class you invoked — well defined but general, and silent on anything your design does unusually.
4. The reviewed quotation and engineering responses — the only document that reflects what was actually agreed for this order.

Write a precedence line in the RFQ and the argument disappears before it starts. Something as short as "in case of conflict, the assembly drawing at the stated revision governs, then the quality specification, then the named standard and class; anything the engineering review changes is captured in the written quotation" is enough. What matters is that precedence is stated once, with revisions, rather than implied three times in different attachments.

Revision discipline is part of this. A criteria document without a revision is not a criterion, because both sides can be looking at different text in good faith. List each document with its revision and date, and say what happens if you revise it mid-order — which is a change-control question, and belongs in the same paragraph.

Records are a deliverable, not a byproduct

A check performed and not recorded is indistinguishable, six weeks later, from a check not performed. This is the cell buyers skip most often, and it is the cheapest one to fill.

For each requirement, say what evidence you need and how it is identified:

• Form. A pass/fail statement on the certificate of conformance, a measurement report with values, an image set, a log file export, or a signed inspection sheet. These carry very different effort, so they belong in the RFQ rather than in a request after shipment.
• Granularity. Per shipment, per lot, per panel, or per serialised unit. Serialisation in particular has to be asked for before the build, because it affects marking, handling and data capture.
• Identifier. The record must tie to something on the carton: a lot code, a work order, a date code or a serial range. A report that cannot be matched to the boards in front of you resolves nothing.
• Timing. With the shipment, before shipment for release approval, or on request within a stated window. "Before shipment for approval" is a gate that affects schedule, so it needs to be visible at quotation time.
• Retention. How long the supplier holds the underlying data, and whether you can request it later.

Note that /en/products/pcb-assembly/ groups traceability deliverables with the items confirmed in the written quotation. That is the mechanism to use: ask for the record in the RFQ, and treat the quotation's response as the binding answer.

Naming the adjudicator before you need one

Every inspection requirement implies a decision path for failure, and that path is worth one short paragraph. Three things need names:

Who is told, and how fast. A defined contact and a response window on both sides. Without them, the first hours after a finding go to locating a decision-maker.

Who can authorise rework, and under whose instruction. Rework changes thermal history, and for some assemblies that matters more than the original defect. IPC-7711/7721 is the usual reference for rework and repair procedures; naming it, and stating whether rework requires your prior written approval and whether reworked units must be identified, keeps the decision from being made silently on the floor.

Who signs a use-as-is. Some findings are real and harmless for your application. Say who on your side can accept a deviation, what record that acceptance produces, and whether accepted deviations need to be visible on the shipment paperwork. This is the clause that prevents a whole lot being scrapped over an attribute you would have waived in five minutes.

Add one more line for the boundary case: what happens when a unit fails a check the RFQ never defined. The honest answer is that it goes back to engineering review and may be a change; saying so in advance is better than discovering it during a shortage.

None of this requires a formal quality agreement to start. A named contact, a response window and a stated approval authority already remove most of the delay.

An RFQ section you can paste and adapt

The point of this page is one attachment page, not a quality manual. Adapt the following, delete what does not apply to your product, and send it with the file set.

```

INSPECTION AND TEST REQUIREMENTS — [part number] rev [x], [date]

1. CRITERIA PRECEDENCE

Assembly drawing [doc/rev] > quality specification [doc/rev] >

[standard + class] > reviewed quotation / engineering response.

Any change to the above during the order is issued as a revision

and requires re-confirmation.

1. BARE BOARD REQUIREMENTS

Attribute | Criteria doc/rev | Record required | Basis

Electrical continuity| [doc/rev] | pass/fail on CoC| [ ]

Outer-layer/visual | [std + class] | pass/fail on CoC| [ ]

Edge condition | [doc/rev] | [ ] | [ ]

Controlled impedance | [target ± tol] | coupon report | [ ]

Cross-section | [doc/rev] | report + images | [ ]

Cleanliness | [flow-down] | numeric result | [ ]

Mark "N/A" for anything not required; do not leave blanks.

1. ASSEMBLY REQUIREMENTS

Workmanship: [standard + class], applies to [whole assembly /

nominated areas listed in drawing note X]. Relaxed attributes: [ ]

Inspection: [visual / automated / X-ray on packages: ...]

Test: [continuity / ICT / functional / boundary scan / programming]

- test program supplied by: [customer / supplier]

- fixture supplied by: [customer / supplier]

- golden sample provided: [yes/no]

- pass criteria document: [doc/rev]

Conditional checks and the design feature that triggers them: [ ]

1. RECORDS

Form: [CoC statement / measurement report / image set / log export]

Granularity: [shipment / lot / panel / serialised unit]

Identifier on record: [lot code / work order / date code / serial range]

Timing: [with shipment / before shipment for release approval / on request]

Retention: [period]

1. NONCONFORMANCE

Notify: [name, email] within [n] business hours.

Rework: [permitted / permitted after written approval / not permitted

in areas ...]; reworked units identified: [yes/no].

Use-as-is authority: [name/role]; documented against the affected lot.

Findings against undefined criteria: returned to engineering review;

may be handled as a change.

1. CHANGE CONTROL

Any deviation from the above after quotation is raised in writing and

re-confirmed before it is executed.

```

Two sanity checks before you send it. First, every row has a criteria document and a record decision — the "N/A" instruction exists because blanks get filled in by assumption. Second, nothing in the block asserts a supplier capability on your behalf; feasibility, availability and schedule impact all come back in the written quotation, which is precisely what /en/products/pcb-assembly/ says.

What this does to the quotation you get back

A defined inspection page changes the reply in three visible ways. Ambiguous items come back as questions instead of assumptions, which is faster to resolve at RFQ stage than after release. Conditional and record-producing items are priced explicitly, so you can see what a coupon report or a functional test actually costs and decide whether you want it at this quantity. And the criteria precedence line means the acceptance conversation at receiving is a comparison against a named document rather than a negotiation.

If you are not sure which checks your product needs, send the files and the draft block with items marked as open questions. Engineering review is the mechanism for closing them, and /en/products/pcb-assembly/ states that available scope is confirmed from your files during that review. Submitting an incomplete but structured page is much more useful than submitting nothing and hoping the baseline matches your expectations.

Related reading on PCB168

• PCB Assembly (PCBA) — the specification table and review process this page is built around.
• Manufacturing Capabilities — the published quality control list, materials and tolerances to reference in your criteria.
• PCB Quality Inspection Methods — how the optical, X-ray, electrical and microsection methods actually work, if you need the background before choosing.
• Incoming Inspection Acceptance Plan for PCB Delivery — the receiving-side companion: attribute families, sampling and disposition after the boards arrive.
• PCB Assembly Process Guide — where inspection and test sit in the assembly flow.
• Get a Quote — submit the file set with your inspection and test page attached.

!Long production aisle lined with rows of cream-panelled enclosed machines with hinged transparent lids under daylight ceiling lamps, a worker in light clothing at the far end, and a green-topped rack of blue, yellow and cyan trays in the foreground.

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FAQ

Is inspection not included by default?

Some of it is characteristic of the process — /en/capabilities/ publishes AOI on every layer and 100% electrical testing as capabilities. What is not automatic is the applicability of the conditional checks to your part, the accept/reject criteria document, whether a record is delivered with your shipment, and the disposition path for a failure. Those four are defined in the RFQ and confirmed in the written quotation.

Where should the criteria live — my drawing or my quality specification?

Put part-specific criteria in the drawing, general criteria in the specification, and state the precedence between them in one line. The most common failure is a broad specification written for another product line pulling in requirements nobody intended for this part, with no precedence line to resolve the conflict.

Do I need to name a standard class, or is the standard name enough?

Name the class. A standard without a class leaves the most subjective attributes open, and it is the usual root cause of receiving disputes about visual and workmanship items. State the class, the scope it applies to, and any attribute you are deliberately relaxing.

Who supplies the test program and fixture for functional test?

That is a definition question, not a technical one, and it belongs in the RFQ. Say who supplies the program, fixture, firmware image and golden sample, and name the document holding the pass criteria. /en/products/pcb-assembly/ lists test requirements as customer-defined and reviewed, and states that equipment or test availability is confirmed in the written quotation.

Can I add an inspection requirement after the quotation?

You can, but treat it as a change rather than a clarification. It may affect price, schedule or feasibility, and the honest path is to raise it in writing and get it re-confirmed before the build continues. That is why the definition work is worth doing before the RFQ goes out.

What if I genuinely do not know what my acceptance criteria should be?

Send the structured page with open items flagged, along with the end use and any flow-down you are subject to. Open questions are RFQ items until both sides agree, which is exactly how /en/products/pcb-assembly/ describes the review. Sending a page with honest gaps gets you a useful conversation; sending nothing gets you a baseline you did not choose.