Appeal No. 2006-0559 4
Application No. 10/085,527
pressure and nozzle traverse rate must be “carefully controlled” to avoid “too deep
erosion”.
In rejecting the claims over Taylor alone, the examiner has made a number of
significant observations which we find as being based upon reasonable and logical
presumptions about the knowledge and skill possessed by an engineer having ordinary
skill in the art. First, the examiner notes in her answer that the tip of a turbine blade has a
curved surface; of which the ordinary practitioner would have been well aware since it is
not a particularly subtle characteristic. Second, the examiner reasonably imputes
knowledge of basic spray jet parameters, such as blasting distance, intensity, angle and
time to the person of ordinary skill in the art; and logically suggests that such a person
would have recognized that such parameters would directly affect the amount and degree
of roughness produced at any point on a substrate surface. Third, the examiner indicates
that the engineer of ordinary skill would have recognized that it would be desirable to
achieve uniform roughness over the entire substrate surface in order to promote uniform
adherence of a subsequently applied coating over the entire surface. Fourth, since a
turbine blade tip is known to have a curved surface, one of ordinary skill would have
recognized that one way to achieve uniform roughening would be to require following the
contour line geometry of the curved surface. That is, one of ordinary skill in the art would
have recognized that uniform blasting may be achieved by maintaining a constant blasting
distance while also holding constant other critical parameters. In this regard, one of
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