Visual and Cosmetic Acceptance Standards

What is inherent to forming

Some marks are the physical signature of the process and will appear on every part made by it: light draw marks in the direction of material flow, slight lamination or orange-peel texture where the material stretches, earing at the flange edge, and polish or tool marks transferred from the die. None of these affect function, and most are invisible once the part is plated or assembled.

What counts as a defect

Rejectable conditions are different in kind, not degree: through-thickness cracks, wrinkles or buckling, galling or material pick-up that removes metal, deep scratches that breach the intended surface, burrs on a functional edge, rust or corrosion, and earing severe enough to interfere with a mating part. These are detected by the process control and the inspection plan, not by a subjective look at the end of the line.

How acceptance is defined

There are three workable ways to define cosmetic acceptance, and we recommend agreeing on one before serial production starts:

• Boundary sample. A physical part, signed and retained by both sides, that represents the worst acceptable appearance.
• Criteria table. A written list of conditions with limits — for example, draw marks permitted but not feelable with a fingernail; no cracks at any magnification.
• Reference photographs. Useful where the customer's own quality team is remote, but always paired with a boundary sample or a written limit, because lighting changes appearance.

Inspection lighting and viewing distance should be specified alongside the criteria, otherwise the same part passes in one plant and fails in another.

How finishing changes the picture

Plating and coating hide light draw marks and tool polish but cannot repair a crack or a deep scratch — and they can introduce their own appearance variables such as brightness variation between batches. Passivation and electropolishing change surface appearance rather than covering it. Where a part will be visible to an end user, it is worth telling us at quotation stage so the process route, not just the drawing, can be chosen accordingly.

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