DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
Claims 1-11 remain pending in the application. Claims 8-11 remain withdrawn.
Applicant’s arguments regarding the rejection of claims 1-4 and 6-7 under 35 USC 103 as unpatentable over Stratton in view of Hewitt have been fully considered, but are not persuasive. The Applicant argues that the new limitations concerning the two pre-sintered layers being sintered directly to one another prior to bonding to the blade are not disclosed. The new limitations are interpreted under product by process. The rejection is maintained.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102 of this title, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-4 and 6-7 are rejected under 35 U.S.C. 103 as being unpatentable over Stratton et al. (US2018/0311772) in view of Hewitt et al. (US2016/0069195).
PNG
media_image1.png
350
376
media_image1.png
Greyscale
Regarding claim 1, Stratton teaches an abrasive gas turbine blade tip cap preform (Fig. 2) comprising: two pre-sintered layers (130, 30) sintered directly to one another prior to bonding to a gas turbine engine blade tip, the two pre-sintered layers comprising: a bonding layer (130) and an abrasive layer (30), the bonding layer comprises a metallic layer comprising a homogenous mixture (paragraph [0072]) of a nickel braze alloy powder and a nickel base superalloy powder (see paragraph [0051] describing the matrix, and paragraph [0076] indicating the bonding layer has the same composition as the matrix but lacking embedded abrasive), and a binder in a first metal matrix, and the abrasive layer comprises a ceramic layer in a second metal matrix (see paragraph [0051] describing the matrix) comprising a cubic boron nitride (CBN) powder (42, see paragraph [0071]) and a binder in a second metal matrix, wherein the first metal matrix and the second metal matrix have a composition that is the same (see paragraph [0076] indicating the bonding layer has the same composition as the matrix but lacking embedded abrasive), and wherein the bonding layer can bond to the gas turbine blade tip under a thermal cycle that varies temperature from 1038°C to 1218°C over 250 minutes.
Stratton fails to explicitly teach the metallic layer is homogeneous.
However, Stratton teaches the metallic layer is near homogenous with discrete low melting areas that are later used to bond to a substrate (paragraph [0072]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify the abrasive gas turbine tip cap preform of Stratton and change the metallic layer to be homogenous as the non-homogenous areas are homogenized for bonding to a substrate.
Stratton fails to teach the abrasive layer having an aluminum oxide (Al203) powder.
In an analogous art, Hewitt teaches an abrasive blade tip for a turbine blade (Fig. 3a). Hewitt teaches the abrasive coating comprises aluminum oxide particles embedded in a nickel alloy matrix (paragraph [0022]) to abrade the turbine casing liner (paragraph [0050]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify the abrasive gas turbine tip cap preform of Stratton and change the abrasive layer to include aluminum oxide as taught by Hewitt to provide a material appropriate for abrading turbine casing liners.
Note that the claimed phrases “sintered directly to one another prior to bonding to a gas turbine engine blade tip” and “can bond to a gas turbine blade tip under a thermal cycle” are being treated as a product-by-process limitation; that is, that the pre-sintered layers can be sintered directly to one another prior to bonding to the blade tip and the blade tip cap can be made by thermal cycling. As set forth in MPEP 2113, product by process claims are NOT limited to the manipulations of the recited steps, only to the structure implied by the steps. Where a product by process claim is rejected over a prior art product that appears to be identical, although produced by a different process, the burden is upon the applicant to come forward with evidence establishing an unobvious difference between the two. Once a product appearing to be substantially the same or similar is found, a 35 U.S.C. 102/103 rejection may be made and the burden is shifted to applicant to show an unobvious difference. See In re Marosi, 218 USPQ 289 (Fed. Cir. 1983). Thus, even though Stratton does not explicitly teach sintering the layers prior to bonding to the blade tip and the exact thermal cycle as claimed, it appears that the product of Stratton would be the same or similar as the blade platforms claimed.
In the event that Applicant establishes an unobvious difference between the prior art product and the product by process claim, the following rejection is presented:
Stratton in view of Hewitt teach the abrasive gas turbine blade tip cap of claim 1, but fail to explicitly teach the bonding layer is configured to bond to a gas turbine blade tip under a thermal cycle that varies temperature from 1038°C to 1218°C over 250 minutes.
However, Stratton teaches bonding preforms to substrates at a temperature of 1149°C to 1260°C for an exemplary 5-10 minutes. Stratton teaches the process allows a sufficient quantity of melting point suppressant to bond and diffuse a prealloyed mixture to the substrate (see paragraph [0074]). Thus, Stratton teaches the time and temperature of the thermal cycle to be result effective variables.
Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. See MPEP 2144.05 II A. It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify the abrasive gas turbine tip cap preform of Stratton in view of Hewitt and change the bonding layer to be configured to bond to a gas turbine blade tip under a thermal cycle that varies temperature from 1038°C to 1218°C over 250 minutes to optimize a result effective variable to allow a sufficient quantity of melting point suppressant to bond and diffuse a prealloyed mixture to the substrate.
Regarding claim 2, Stratton as modified teaches the thickness of the bonding layer is 50% ± 15% of total thickness of the abrasive gas turbine blade tip cap preform (see Stratton Fig. 2 where the bonding layer is roughly half the total thickness).
Regarding claim 3, Stratton as modified teaches the bonding layer is composed of 50% ± 15% by weight of powder size particles of Ni based superalloy and 50% ± 15% by weight of powder size particles of Ni based braze alloy (see Stratton paragraphs [0051-0055] describing the matrix, and paragraph [0076] indicating the bonding layer has the same composition as the matrix but lacking embedded abrasive).
Regarding claim 4, Stratton as modified teaches the abrasive layer has 50% ± 15% by weight of a metal matrix, the metal matrix being composed of 50% + 15% by weight of Ni based superalloy and 50% ± 15% by weight of Ni based braze alloy (see paragraph [0055] and paragraph [0017] teaching the ratio of abrasive to matrix being between 1:2 and 2:1, which includes 1:1 or 50%).
Stratton as modified fails to explicitly teach the abrasive layer is composed of 25% ± 7.5% by weight of powder size particles of cubic boron nitride (CBN) and 25% ± 7.5% by weight of powder size particles of aluminum oxide (Al2O3).
However, Stratton teaches the abrasive particles constitute 50% by weight of the abrasive layer (see paragraph [0017]). Thus, It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify the abrasive gas turbine tip cap preform of Stratton as modified and change the abrasive layer to be composed of 25% ± 7.5% by weight of powder size particles of cubic boron nitride (CBN) and 25% ± 7.5% by weight of powder size particles of aluminum oxide (Al2O3) to give an even distribution of boron and aluminum oxide particles that together constitute 50% by weight of the abrasive layer.
Regarding claims 6-7, Stratton as modified teaches said nickel braze alloy is composed of: chromium 18.5- 21.5% by weight, aluminum 4.2-5.8% by weight, nickel 46.71-55.21 % by weight, other elements less than 1.1 % by weight (see paragraph [0053] and table 1), and said nickel based superalloy is composed of: cobalt 11.35-12.1% by weight, chromium 6.5-7.2% by weight, aluminum 5.9-6.6% by weight, tantalum 6.1-6.7% by weight, tungsten 4.5-5.3% by weight, hafnium 1.2-1.8% by weight, rhenium 2.5-3.1 % by weight, nickel 55.61-60.36% by weight, other elements less than 1.6% by weight (see paragraph [0052] and table 1).
Stratton as modified fails to explicitly teach the said nickel braze alloy is composed of cobalt 13.5-16.5% by weight and silicon 7.5-8.4% by weight.
Where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. See MPEP 2144.05(II)(A). In the present case, Stratton as modified teaches said nickel braze alloy is composed of cobalt 11.5-12.5% by weight, and silicon 5.7-6.3% by weight (see Stratton paragraph [0053]). Stratton as modified further teaches the composition of the nickel braze alloy is a result effective variable to control the melting point of the alloy (see Stratton paragraph [0051]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Stratton as modified and change said nickel braze alloy to be composed of cobalt 13.5-16.5% by weight and silicon 7.5-8.4% by weight to optimize a result effective variable to control the melting point of the alloy.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Stratton et al. in view of Hewitt, Schell et al. (US5952110), Brown et al. (US5359770) and Ghunakikar et al. (US10392938).
Regarding claim 5, Stratton in view of Hewitt teach the abrasive gas turbine blade tip cap preform of claim 1, but fail to teach the cubic boron nitride (CBN) particle size is in a range of 181-277 mesh in 93% wt minimum, aluminum oxide particle size is 100 mesh in 40% wt minimum, Ni based superalloy particle size is 395 mesh in 95% wt minimum and Ni based braze alloy particle size is 395 mesh in 95% wt minimum.
In an analogous art, Schell teaches an abrasive blade tip for a turbine. Schell teaches cubic boron nitride abrasive particles (16) formed in a size of 32-230 mesh (Col. 4 lines 1-26).
In an analogous art, Brown teaches an abrasive blade tip for a turbine blade. Brown teaches aluminum oxide abrasive particles formed in a size of 80-120 mesh (Col. 6 lines 9-19).
In an analogous art, Ghunakikar teaches a nickel bond coat and braze alloy for a gas turbine. Ghunakikar teaches the power particles for the bond coat powder and braze coat power have a mesh size from 10-1250.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the invention to modify Stratton in view of Hewitt and change the cubic boron nitride (CBN) particle size to be in a range of 181-277 mesh in 93% wt minimum, the aluminum oxide particle size to be 100 mesh in 40% wt minimum, the Ni based superalloy particle size to 395 mesh in 95% wt minimum and the Ni based braze alloy particle size to be 395 mesh in 95% wt minimum to form the abrasive particles and nickel alloys from appropriate mesh sizes for gas turbine applications.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to CAMERON A CORDAY whose telephone number is (571)272-0383. The examiner can normally be reached M-F 8-4 EST.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Courtney Heinle can be reached on (571) 270-3508. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/CAMERON A CORDAY/ Examiner, Art Unit 3745
/COURTNEY D HEINLE/Supervisory Patent Examiner, Art Unit 3745