Appeal No. 2001-0786
Application No. 09/089,575
claimed invention). Kragle discloses the economic benefit as
follows (col. 7, lines 58-63):
The array of openings in each of the thin plates
used to construct the transition section of the die may
be formed by conventional machining processes, but more
suitably are made by photo-chemical machining methods.
These well established, mature processes can produce
etched orifice plates in a flexible and economical
manner.
Kragle also discloses that forming the compound feed section
in a multilayer structure avoids some of the problems encountered
with conventional fabrication methods. Specifically, in
conventional methods, feedholes are drilled into one face of a
metal die body and discharge slots are cut into the opposite
face. Since the region of feedhole/slot overlap is created
within the inaccessible interior of the dies, an efficient flow
path is rarely formed. See col. 2, lines 7-50. In contrast, the
multilayer structure disclosed in Kragle is formed by drilling
openings into individual plates in desired sizes and shapes
enabling the selection of a particular flow path to fairly exact
specifications. See col. 7, lines 41-57. Thus, one of ordinary
skill in the art would have been motivated to modify the compound
feed section of Duerr with the multilayer structure of Kragle to
take advantage of these improvements in prior art fabrication
methods as well.
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