The ultrasonic inspectability of a supplied part out of which a final component is to be machined is determined by following a set of inspection rules for ultrasonic inspection of the supplied part. The rules determine which parts of the polygon cannot be inspected by a scan at a given ultrasound beam angle (typical beam angles are 0°, +20° and −20° relative to the perpendicular direction to the edge) along a given edge of the polygon.