Illustrative inspection checklist

Balance

Whether the frame stays put when the head is tipped forward

Temple pressure

Measured, because pressure is what holds a sport frame on

Lens edge

Finished, because a rimless lens carries load at the edge

Fixing torque

On rimless mounts, because the fixing loads the lens

Base curve

Checked against the drawing, because it limits the prescription

Coating

Adhesion and evenness, assessed after the lens is edged

Grip ageing

Rubber tested wet and after exposure

Marking

Batch identifier legible on the temple or its packaging

An illustrative checklist for a fictional range. A real programme defines the tolerance, the sampling method, the inspection window and the remedy if a batch fails.

The four things a programme needs in writing.

The tolerance, the sampling method, the window in which inspection happens, and what happens if the batch fails. Without all four, a failed delivery becomes an argument rather than a process.

Why balance is checked rather than measured.

Because it is a behaviour rather than a dimension. Two frames of the same weight can differ in where the mass sits, and it is the position rather than the total that decides whether the frame moves.