Short answer: Cosmetic and functional defect boundaries should be defined before quoting rhannau wedi'u stampio because the same scratch, burr, stain, dent, or tool mark can be harmless in one zone and rejectable in another. The RFQ should mark functional surfaces, visible surfaces, hidden surfaces, safety edges, plating zones, sample standards, packaging risk, and escalation rules.
A defect name alone does not tell a cyflenwr whether a part can ship. A burr on a hidden edge may be acceptable, while the same burr on a cyswllt edge can damage an assembly. A faint tool mark may be normal inside a bracket, but unacceptable on a visible appliance face. The boundary needs to be written before price and inspection are compared.
Use this page with the surface finish cosmetic inspection guide, burr control guide, deburring and edge break guide, and plating defect acceptance guide.
Defect boundary decisions
| Boundary | Why it matters | RFQ evidence |
|---|---|---|
| Functional zone | Small defects can affect fit, sealing, cyswllt, force, or safety. | Marked surfaces, CTQ features, test method, and zero-defect rule if needed. |
| Cosmetic zone | Visible surfaces need viewing conditions and sample standards. | Surface class, lighting, distance, photos, and limit samples. |
| Hidden zone | Over-control can add cost without improving function. | Allowed tool marks, handling marks, burr limits, and packaging rule. |
| Packaging cyswllt | Good parts can be damaged after inspection. | Tray, separator, bag, carton, rub risk, and final appearance check. |
Classify the defect by risk, not by name
Scratches, stains, dents, burrs, witness marks, oil marks, plating color variation, edge exposure, and tooling marks are not all equal. The question is where the condition appears and what it can affect. Buyers should mark surfaces as functional, cosmetic, safety, hidden, or non-critical instead of treating the whole part as one zone.
Functional surfaces may include cyswllt pads, sealing faces, datum pads, spring beams, solder areas, grounding points, sliding faces, threaded hardware seats, and edges touched by operators. Cosmetic surfaces may need lighting and viewing distance rules. Hidden surfaces often need practical workmanship limits, not premium appearance standards.
Use samples where words are weak
Terms like slight, minor, visible, clean, or acceptable are hard to enforce. Use photos, a golden sample, a limit sample, and a reject sample when judgment is involved. If the condition changes under lighting, specify the viewing angle and distance. If the condition affects a cyswllt or seal, add a functional test rather than relying only on a visual check.
Packaging can move a condition from acceptable to rejectable. A formed tab that leaves production straight can arrive bent in bulk packing. A plated surface can leave production clean and arrive scratched from part-to-part rubbing. Connect defect boundaries to the packaging and shipping guide and the packaging damage claim guide when appearance or formed features matter.
RFQ details to include
- Drawing with functional zones, cosmetic zones, hidden zones, safety edges, no-touch surfaces, datum pads, and packaging cyswllt areas.
- Defect types to control: burrs, scratches, dents, tool marks, plating stains, exposed edges, oil marks, cracks, deformation, or mixed parts.
- Acceptance rule for each zone, including measurement limit, viewing condition, limit sample, test method, or zero-defect requirement.
- Finish route, cleaning, deburring, plating, coating, handling, and packaging method that can create or hide defects.
- Inspection method, sample size, AQL or zero-acceptance rule, report format, retained samples, and escalation path for borderline findings.
- Prototype quantity, pilot run, annual volume, shipment method, and current reject history if the page supports a cyflenwr change.
How to compare cyflenwr answers
A useful answer asks which surfaces are functional, visible, hidden, and safety-related. It should not price every surface as premium unless the buyer truly needs that. A weak answer says all parts will be visually inspected without defining what inspection accepts.
Ask the cyflenwr to identify cost drivers. Strict cosmetic control may slow handling, increase scrap, require trays, or add final inspection. Strict functional control may require better tooling, deburring, plating review, gages, or tests. The quote should show which control solves which risk.
Anfon marked drawings, defect photos, surface zones, packaging needs, and acceptance samples through the cyswllt page. Use the RFQ form to define defect boundaries before the first production lot is accepted.
FAQ
What is a functional defect on a stamped part?
It is a condition that can affect fit, force, electrical cyswllt, sealing, safety, durability, assembly, or another defined function.
Are cosmetic defects always rejectable?
No. Cosmetic defects depend on visible zone, viewing condition, finish requirement, customer standard, and whether the mark affects function.
How should borderline defects be controlled?
Use marked zones, photos, limit samples, measurement limits, viewing rules, and an escalation path for buyer approval.
What should buyers send to define defect boundaries?
Anfon marked drawings, surface zones, defect photos, finish requirements, packaging method, samples, inspection rules, volume, and launch timing.