RAYPCB ยท ENGINEERING GUIDE
PCB Testing Laboratories: Evaluate Scope, Methods and Reports
A PCB testing laboratory should be selected for the specific question it can answer and the evidence it can provide. Equipment photographs and a broad quality statement are insufficient to establish competence for a particular method. The request should define the specimen, measurement, decision and reporting needs before samples are shipped.
This page is a laboratory-evaluation guide, not a claim that RAYPCB holds a particular accreditation or performs every listed method in-house. Availability and any subcontracted scope need project-specific confirmation.
Translate the concern into a test objective
Different questions require different methods. A suspected interconnect crack, ionic residue, coating adhesion problem or electrical intermittent cannot all be resolved by a generic PCB test. Describe the symptom, conditions and engineering decision that the result must support.
Ask the laboratory to explain what the proposed method can reveal and what remains uncertain. The failure-analysis guide helps preserve evidence when the cause is unknown; a routine conformity test may not be the right first step.
Verify accreditation by scope
ISO/IEC 17025 addresses the competence, impartiality and consistent operation of testing and calibration laboratories. Accreditation applies to a defined organization, location and scope. Check the issuing body's records and the specific methods or ranges relevant to the work.
Do not treat an unrelated accredited method as evidence that all services are accredited. Ask whether the proposed report will be issued within the accredited scope and identify any subcontracted activities. The online worksheet records what you have reviewed; it does not validate certificates.
| Review item | What to establish |
|---|---|
| Scope | Verify method and location against current accreditation records. |
| Specimen | Record identity, conditioning and preparation. |
| Decision | Agree limits, uncertainty treatment and report wording. |
| Custody | Define destructive work, retention and raw-data access. |
Agree the method and specimen preparation
Identify the method revision, relevant deviations, sample dimensions, conditioning and the number of specimens. Preparation can influence the result, particularly for destructive analysis or contamination studies. Decide who approves changes if the sample is unsuitable.
For test coupons, preserve the link to the production panel and construction. For assemblies, record fitted options, prior rework, coating and service history. Missing history should be stated as a limitation rather than silently assumed away.
Ask how measurements support decisions
Where a result is compared with a limit, define the decision rule and the treatment of measurement uncertainty as applicable. A displayed number with many decimal places is not evidence of equivalent accuracy. Calibration, method capability and sample variation are separate considerations.
The report should distinguish observations from interpretations and conclusions. If the laboratory provides a root-cause opinion, ask which evidence supports it and which alternatives remain plausible.
Laboratory evidence review
Laboratory evidence review
Use the current inputs and keep the assumptions
Choose the engineering question before entering numbers. Fields begin blank. Load example fills teaching values so you can understand the model; those values are not recommended dimensions, process settings or market prices. The example label remains visible after edits. Reset before preparing a record based entirely on your own project data.
Use the displayed units and keep a reference for each input. Counts must describe the same scope, and measurements must share the declared conditions. A threshold entered by you remains your supplied review condition. The website does not turn it into an IPC limit or an approved product requirement. If the necessary value is unknown, obtain the evidence rather than replacing it with an attractive assumption.
Read the result and its limitations together. An access fraction is not fault coverage, a cost allowance is not a quotation, and a completed evidence checklist is not a safety or quality approval. Negative margins remain visible where the model permits them. They identify a conflict in the entered scenario rather than silently adjusting the result.
Changing an input invalidates the result and disables its download until you run the tool again. The text record contains the inputs, result and limitations. Processing stays in your browser; no CAD files, instruments or certificates are read. No data is automatically transferred to the enquiry form. Download and attach the record manually if useful, or contact RAYPCB directly without completing the tool.
| Input | What to establish before using it |
|---|---|
| Review reference | Use a nonconfidential revision or scope reference. |
| Current accreditation / method scope reviewed | Self-reported status; retain the actual evidence or N/A rationale. |
| Exact method and revision agreed | Self-reported status; retain the actual evidence or N/A rationale. |
| Sample preparation and identity defined | Self-reported status; retain the actual evidence or N/A rationale. |
| Report and decision rule agreed | Self-reported status; retain the actual evidence or N/A rationale. |
| Subcontracting / retention / raw-data terms | Self-reported status; retain the actual evidence or N/A rationale. |
| Next action / record reference | Use a nonconfidential reference; this tool does not verify the record. |
Plan traceability and sample disposition
Use unique sample identifiers and a receipt record. Photograph the incoming state when relevant and preserve packaging or contamination evidence. Agree which samples can be consumed and which should remain available for follow-up.
Define retention, return, confidentiality and access to raw data before testing. A low quotation that excludes useful images, detailed measurements or retained samples may not support the intended engineering decision.
Example: a chamber is not a qualification program
An environmental chamber photograph demonstrates an equipment category, not a released product qualification. The program still needs specimens, stress conditions, monitoring, duration, criteria and a method for investigating failures.
Similarly, a microscopy image without scale, location and specimen identity is difficult to use. Ask for a representative report format before commissioning the work so that the final evidence is usable by design, quality and purchasing teams.
Build a laboratory request that can be quoted
Send the question, specimen description, available history, applicable requirements, sample count, deadline and required report detail. Identify whether you need a conformity statement, comparative study or exploratory analysis. State any required accreditation scope explicitly.
For the manufacturing relationship, use RAYPCB quality information and a direct project enquiry. Laboratory evidence should support a defined release decision, while unresolved items remain visible in the circuit-card test plan.
Questions to resolve before the next build
Does a calibration certificate prove a laboratory test is valid? It supports the identified instrument's calibration relationship under stated conditions. The method, specimen preparation, operator competence, fixture and decision rule still matter. Review the complete proposed work and its relevant accreditation scope when required. A collection of calibrated instruments is not the same thing as a verified method for the particular PCB question.
What should a sample report show? Look for specimen identity, method and revision, preparation, result units, relevant conditions, deviations and the basis of the conclusion. Images need location and scale where appropriate. Ask whether raw data or retained samples are available when the decision needs follow-up. Requesting a representative report before ordering is often more useful than asking only how many instruments the laboratory owns.
Evaluate the record as well as the equipment
Begin with a requirement-to-record map. Each important decision should identify the object being evaluated, the method, the responsible owner and the evidence expected. This makes gaps visible before a supplier quotation or production program turns assumptions into routine practice. Keep mandatory requirements separate from useful supplementary observations.
Control document identity at the level needed for the task. A drawing, standard, firmware image, test program and fixture may each have its own revision. Record the compatible combination rather than assuming that the newest file in every category belongs together. Resolve conflicts between the purchase requirement and the implementation before work begins.
Ask whether another qualified reviewer can reproduce the interpretation. The record should identify units, locations, conditions, limits and any decision rule. A pass statement without scope can be misleading; a long report without specimen identity can be equally unhelpful. More data is valuable only when it answers the question and remains traceable.
Separate evidence availability from evidence verification. A box marked recorded means that someone reports having a document, not that the document is current, applicable or correct. Review the actual material and retain a reference to the approved version. The online worksheets intentionally avoid a compliance percentage because incomplete evidence does not become acceptable through averaging.
Define the handling of exceptions. Missing information, an invalid run, an unavailable station and a confirmed product failure need different actions. Record who can approve a deviation and which requirements remain binding. A supplier acknowledgment should not be mistaken for technical approval, and a successful software run should not substitute for method validation.
For external work, confirm scope and responsibility. Identify any subcontracted activity, the method used, the report issuer and the records that will be returned. Where accreditation is relevant, verify the applicable scope rather than relying on a broad logo. Where the work is outside that scope, describe it accurately instead of implying a status that has not been established.
Use the handoff to support the next person in the process. A buyer needs comparable scope, an engineer needs interpretable evidence and a production team needs executable instructions. A concise controlled package can serve all three when the task, version, result and open points are clear. Keep confidential design and customer information in the agreed project channel rather than in public comments or analytics.
Standards, source context and limits
Use each reference for its stated scope. Equipment and material documentation applies to the identified product and conditions. A published study describes its own specimens and methods; its settings are not universal production limits. Public standard summaries and revision tables do not replace the controlled normative document.
Agree the applicable standards, revisions, product class where relevant, measurement methods and exceptions before production. Distinguish printed-board requirements, assembly workmanship, laboratory competence and finished-product certification. A method name or photograph does not establish that a supplier holds an accreditation or that a particular test is included in an order.
Archive photographs illustrate relevant boards, equipment or operations from the existing RAYPCB website. They are not evidence of current equipment ownership or results from your project. Original diagrams explain concepts and measurement boundaries; they are not inspection records or released manufacturing drawings. Confirm the actual service and reporting scope in the project review.
