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 .
Specification
The disclosure is objected to because of the following informalities:
Paragraph [0017], “IN” should be “In”;
Paragraph [0073], “PCD material 704” should be “PCD material 804” as written both earlier and later in paragraph [0073] because paragraph [0073] describes Fig. 13 not Fig. 12;
Paragraph [0084], “Fig. 16 is a block diagram” should be “Fig. 17 is a block diagram”;
Paragraph [0092], “a single database 1006 in Fig. 10” should be “a single database 1006 in Fig. 17”
Paragraph [0093], “single memory 1007 in Fig. 10” should be “single memory 1007 in Fig. 17”;
Paragraph [0093], “memory 907” should be “memory 1007”.
Appropriate correction is required.
Claim Rejections - 35 USC § 112
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 22-25 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Regarding claims 22 and 25, claim 22 recites the limitation "the carbide substrate" in the second line of the claim. Claim 25 recites the limitation "the carbide substrate" in the second line of the claim. There is insufficient antecedent basis for this limitation in the claims. Claim 21, on which claims 22 and 25 depend, introduces a substrate, but a substrate is not necessarily a carbide substrate.
The term “generally cylindrical” in the second line of claim 23 is a relative term which renders the claim indefinite. The term “generally cylindrical” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. It is not clear from the specification as filed, the extent to which a PCD may differ from a cylindrical shape and still be considered “generally cylindrical”.
Claim 24 is rejected under 35 USC 112(b) because it depends on claim 23.
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 (i.e., changing from AIA to pre-AIA ) 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, 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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 21, 23-24, 26-27, 29-30, 32-36, and 39-40 is/are rejected under 35 U.S.C. 103 as being unpatentable over Belnap (US20120125696). Belnap is cited in the IDS filed October 9, 2024.
Regarding claim 21, Belnap discloses a downhole drill bit comprising: a body; and a plurality of cutters (Figs. 6-7, 9, [0002], [0004], [0025-28], [0098]). Belnap discloses that each cutter comprises a single phase, substantially catalyst-free synthesized polycrystalline diamond (PCD) (“the entire PCD material may be treated to remove the catalyst material therefrom, leaving a diamond-bonded body that is substantially free of the catalyst material” [0090], “PCD bodies of this invention may be constructed having a single homogeneous PCD phase” [0096]). As Belnap discloses treating the entire PCD body to remove the catalyst [0090], Belnap suggests that the substantially catalyst free PCD body approaches a catalyst-free body. Belnap discloses that the PCD is synthesized from diamond powders having an average diameter grain size in the range of from submicrometer in size to 100 micrometers, and more preferably in the range of from about 1 to 80 micrometers, and Belnap discloses that in an example embodiment, the diamond powder has an average particle grain size of approximately 20 micrometers [0035]. Both the broad submicron to 100 micrometers and the preferred 1 to 80 micrometers disclosed by Belnap [0035], overlap the claimed range of 0.5 μm to 50 µm, and 20 micrometers lies in the claimed range of 0.5 µm to 50 µm (µm is the metric abbreviation for micrometer). When claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. See MPEP 2144.05(I). Belnap discloses that the PCD is attached to a substrate [0012], [0017].
The limitation “wherein the single phase catalyst-free synthesized PCD is formed without leaching” is a product-by-process limitation for which the determination of patentability is based on the structure implied by the steps and not by manipulation of the steps (MPEP 2113(I)). The structure implied by downhole drill bit comprising: a body; and a plurality of cutters, each cutter comprising a single phase catalyst-free synthesized polycrystalline diamond (PCD), wherein the single phase catalyst-free synthesized PCD is formed without leaching is a downhole drill bit comprising: a body; and a plurality of cutters, each cutter comprising a single phase catalyst-free synthesized polycrystalline diamond (PCD). The specification does not disclose or suggest how a catalyst-free PCD formed without leaching is different from a catalyst-free PCD from which all catalyst has been leached. Rather, the specification indicates that a PCD comprising catalyst is structurally different from a PCD which does not comprise catalyst. As Belnap discloses treating the entire PCD body to remove the catalyst [0090], Belnap suggests that the substantially catalyst free PCD body disclosed by Belnap [0090], [0096] structurally meets or approaches the structure of a catalyst-free body, wherein the single phase catalyst-free synthesized PCD is formed without leaching, thereby meeting or approaching the structure implied by the product-by-process limitation recited in claim 21.
Regarding claims 23, Belnap shows that the catalyst-free synthesized PCD is a generally cylindrical catalyst-free synthesized PCD with a non-planar end surface (Figs. 2, 4, 5, [0099]).
Regarding claim 24, the limitation “a laser-formed non-planar end surface” is a product-by-process limitation, for which the patentability is determined by the structure implied by the process and not by manipulation of the recited steps (MPEP 2113(I)). The structure implied by the claimed laser cutting step is a PCD cut into a desired shape. Belnap discloses machining the PCD into a desired shape [0099], thereby meeting the structure implied by the product-by-process step recited in claim 24.
Regarding claim 26, Belnap discloses that the PCD is attached to the substrate by placing the single phase catalyst-free synthesized PCD in contact with a powder form (powdered) of the substrate [0037].
Regarding claim 27, Belnap discloses that the substrate is a WC-Co substrate comprising a Co content within a range of one percent to 20 percent by weight [0051]. As Belnap discloses providing the substrate as a powder [0037] and that the substrate is WC-Co with a cobalt concentration of one percent to 20 percent by weight [0051], it would have been obvious for one of ordinary skill in the art, at the time of filing, in view of Belnap to provide the substrate as a powder form of the substrate which comprises a WC-Co powder having a Co content within a range of one percent to 20 percent by weight.
Regarding claim 29, Belnap discloses that the catalyst-free synthesized PCD to the substrate comprises attaching the PCD to the substrate by high pressure high temperature (HPHT) bonding [0013], [0037], [0044].
Regarding claim 30, the recitation “the single phase catalyst-free synthesized PCD is attached to the substrate by vacuum diffusion bonding in a vacuum chamber with 1.0×10−2 Pa to 1×10−5 Pa pressure” is a product-by-process limitation for which the patentability is determined by the structure implied by the steps and not by manipulation of the recited steps (MPEP 2113(I)). Within the present disclosure, the structure implied by the process steps recited in the product-by-process limitation(s) of claim 30 is a PCD attached to a substrate. As Belnap discloses that the PCD is attached to the substrate [0012-13], [0017], [0037], [0044], Belnap appears to meet the structure implied by the product-by-process limitations recited in claim 30.
Regarding claims 32-35, the limitations “wherein the single phase catalyst-free synthesized PCD is attached to the substrate by spark plasma sintering” recited in claim 32 and the spark plasma sintering parameters of claims 33-35 are product-by-process limitations for which the patentability is determined by the structure implied by the steps and not by manipulation of the recited steps (MPEP 2113). Within the present disclosure, the structure implied by the process steps recited in the product-by-process limitation(s) of claims 32-35 is a PCD attached to a substrate. As Belnap discloses that the PCD is attached to the substrate [0012-13], [0017], [0037], [0044], Belnap appears to meet the structure implied by the product-by-process limitations recited in claim 32-35.
Regarding claim 36, Belnap discloses that attaching the PCD to the substrate comprises applying a pressure of 5 GPa (5,000 MPa) or greater and a temperature of from about 1,350
°
C. to 1,500
°
C [0044]. The pressure range disclosed by Belnap overlaps that recited in claim 36, and the temperature range disclosed by Belnap [0044], lies within that claimed in claim 36. Belnap further discloses a narrower pressure range of about 5 GPa to about 6.2 GPa (about 5,000 to 6,200 MPa) [0045] which lies entirely within the pressure range recited in claim 36. Considering the extent to which the temperature and pressure conditions disclosed by Belnap [0044-45] overlap those recited in the product-by-process limitations of claim 36, one of ordinary skill in the art would expect the cutter disclosed by Belnap, applied above, to meet the structure of the cutter implied by product-by-process steps of claim 36. Further, when claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. See MPEP 2144.05(I).
Regarding claims 39 and 40, the synthesized PCD disclosed by Belnap [0090], [0096] must have some hardness and fracture toughness by virtue of being a material. Belnap discloses that the amount of catalyst material used to form PCD materials represents a compromise between desired properties of toughness and hardness/wear resistance in the resulting sintered diamond body [0007]; Belnap discloses that the disclosed materials do not sacrifice toughness [0018], and that the disclosed PCD displayed an optimized combination of properties including fracture toughness [0031]. Belnap is silent on the fracture toughness and Vickers hardness of the synthesized PCD. fracture toughness and Vickers hardness are material that are inseparable from the chemical composition of the material. See MPEP2112.01(II). When the claimed and prior art products are substantially identical in structure or composition, or are produced by substantially identical processes, a prima facie case of obviousness has been established. See MPEP.2112.01(I). The discovery of a previously unappreciated property of a prior art composition, or of a scientific explanation for the prior art’s functioning, does not render the old composition patentably new to the discoverer See MPEP2112(I). Considering Belnap discloses providing a substantially single phase [0096], substantially removing all catalyst from the PCD [0090]; Belnap weighs effects of material additives and processing on fracture toughness and hardness to achieve a property balance [0007], [0018], [0031], and considering the size of the diamond particles which Belnap discloses to form the PCD [0035], Belnap establishes a sound basis for believing that the PCD disclosed by Belnap would necessarily have the same material properties as a synthesized single-phase catalyst-free PCD, including the claimed properties of fracture toughness and Vickers hardness. The present disclosure establishes that the fracture toughness and Vickers hardness of single-phase catalyst-free PCD are 18.7
MPa
m
and 120 GPa respectively; therefore, the synthesized PCD disclosed by Belnap [0090], [0096] would be expected to have a fracture toughness of 18.7
MPa
m
and a Vickers hardness of 120 GPa.
Claim(s) 22, 24-25, and 31 is/are rejected under 35 U.S.C. 103 as being unpatentable over Belnap (US20120125696) as applied to claims 21, 23, and 29 above, and further in view of Bertagnolli (US9254554). Bertagnolli is cited in the office action filed October 9, 2024.
Regarding claim 22, 25, and 31, Belnap does not disclose that the cutter comprises a filler metal is placed between the catalyst-free synthesized PCD and the substrate before pressure is applied.
Bertagnolli teaches a method of forming a cutter for a downhole drill bit (abstract, column 1 lines 9-22, column 17 lines 5-13, Figs. 9-10). Bertagnolli teaches providing a substantially single phase (the sintered substantially single-phase PCD body column 4 lines 21-30) substantially/essentially catalyst free (essentially/substantially with complete absence of catalyst column 4 lines 21-30) synthesized (preformed) polycrystalline diamond (PCD) (column 7 line 47 to column 8 line 11; column 8 lines 42-50). Bertagnolli teaches providing a substrate (column 8 lines 42-50, Figs. 5A-5B) and attaching the substantially single phase catalyst-free synthesized PCD to the substrate (column 4 lines 21-30; column 8 lines 42-50). Bertagnolli teaches that attaching the synthesized PCD to the substrate comprises attaching the synthesized PCD to the substrate by high-pressure, high temperature (HPHT) bonding (column 8 lines 42-50), and Bertagnolli teaches embodiments in which a filler braze metal is placed between the synthesized PCD and the substrate before pressure is applied (HPHT) (column 8 lines 53-58, column 13 line 49 to column 14 line 26). Bertagnolli teaches that the filler material provides a strong metallurgical bond between the sintered substantially single-phase PCD body and the substrate (column 13 lines 55-58). Bertagnolli teaches a WC-Co (cobalt tungsten carbide) substrate (column 4 lines 14-20, column 16 lines 15-20).
Both Belnap and Bertagnolli teach substantially similar process for producing a cutter for a drill bit comprising a step of providing a substantially catalyst-free PCD. Belnap identifies material mismatch at the PCD substrate interface as a source of difficulty in producing PCD materials attached to a WC-Co substrate [0007], [0041].
It would have been obvious for one of ordinary skill in the art to place a braze filler metal between the catalyst-free synthesized PCD and the substrate before pressure is applied in the process disclosed by Belnap as applied above because Bertagnolli teaches (and thereby predicts) forming a strong metallurgical bond between a sintered substantially single-phase PCD body and a WC-Co (column 13 lines 55-58) in embodiments wherein a filler metal (braze material) is placed between the synthesized PCD and the substrate before pressure is applied (HPHT) (column 8 lines 53-58, column 13 line 49 to column 14 line 26). A braze-filler material in between the PCD and substrate in the cutter disclosed by Belnap meets both the structure directly recited in claims 22 and 31, and the structure implied by the product-by-process limitations recited in claim 25.
Regarding claim 24, in the event that laser forming implies a structure beyond the desired machining disclosed by Belnap [0099], Belnap does not disclose laser forming. Bertagnolli teaches that the cutters comprise a cylindrical shape with a non-planer end (Figs. 1-2, 5). Bertagnolli teaches forming the non-planer surface by laser forming (column 8 lines 36-58, column 11 line 58 to column 12 line 23, column 16 lines 28-36). The general machining and lack of more specific machining disclosed by Belnap [0099] would necessitate and motivate one of ordinary skill in the art to apply machining techniques known in the art to form surfaces for PCD cutters. In view of Bertagnolli (column 8 lines 36-58, column 11 line 58 to column 12 line 23, column 16 lines 28-36) it would have been obvious for one of ordinary skill in the art, at the time of filing to laser form the non-planar surface of the PCD cutter disclosed by Belnap, applied above by laser forming in order to predictably form an end surface of a PCD cutter.
Claim(s) 28 and 37-38 is/are rejected under 35 U.S.C. 103 as being unpatentable over Belnap (US20120125696) as applied to claims 21, and 26-27 above, and further in view of Moriguchi (US5889219). Moriguchi is cited in the IDS filed October 9, 2024.
Regarding claim 28, the WC-Co powder suggested by Belnap as applied above must have some average particle size, but Belnap is silent on the average size of the WC-Co powder.
Moriguchi teaches forming a cutter for a drill bit (column 7 lines 32-49). Moriguchi teaches that commercially available WC powder and Co powder a mean powder grain size of 2 µm (column 9 line 66 to column 10 line 1). Moriguchi teaches sintering the WC, Co, and diamond powders (column 9 line 66 to column 10 line 26). Moriguchi teaches that the sintering process produces diamond and cemented carbide composite material (column 2 lines 9-19, column 4 lines 29-36).
Both Moriguchi and Belnap as applied above teach forming a cutter for a drill bit comprising diamond and WC-Co.
Belnap as applied above, renders obvious all limitations of present claim 28 but Belnap is silent on a size of WC-Co powder. It would have been necessary for the WC-Co powder rendered obvious by Belnap [0037] to have some particle size. In view of Moriguchi, a WC-Co mean size of 2 µm was known to one of ordinary skill in the art for forming a WC-Co substrate material through a sintering process (column 9 line 66 to column 10 line 26). It would have been obvious for one of ordinary skill in the art to supply a WC and Co powder with a mean size of 2 µm as taught by Moriguchi (column 9 line 66 to column 10 line 26) to yield the predictable result of a WC-Co substrate formed from commercially available powder known to produce similar cutter materials, which meets the selection criterion disclosed by Belnap [0037], [0051].
Regarding claims 37 and 38, Belnap shows that the PCD is a cylindrical layer on the substrate (Figs. 1-2, 4-5); therefore, the PCD disclosed by Belnap [0090], [0096] must have some diameter and thickness, but Belnap is silent on the diameter and thickness of the PCD or portions of the cutter formed therefrom. Examples of Moriguchi have dimensions of: 20 mm in diameter and 5 mm in thickness (column 10 lines 27-28, 58-59) and 50 mm in diameter and 20 mm in thickness (column 14 lines 31-33) and Moriguchi teaches that the portion of the cutter comprising the diamond has a thickness of 5 mm (Table 7). It would have been necessary for one of ordinary skill in the art to size the cutter disclosed by Belnap [0002], [0004], [0017], [0098] appropriately; therefore, it would have been obvious for one of ordinary skill in the art to size the PCD disclosed by Belnap to attain dimensions which Moriguchi teaches as appropriate for a cutter (column 10 lines 27-28, 58-59; column 14 lines 31-33; Table 7). As a diameter and thickness are both some characteristic cross-sectional dimension of the PCD, in sizing the PCD, one of ordinary skill in the art would arrive at some dimension greater than both 1 mm and greater than 8 mm, thereby meeting the additional imitations of claims 37 and 38.
Claim(s) 32-35 is/are rejected under 35 U.S.C. 103 as being unpatentable over Belnap (US20120125696) as applied to claims 21, and 26-27 above, and further in view of Liang (US20180208511). Liang is cited in the IDS filed October 9, 2024.
Regarding claim 32, in the event that the product-by-process limitations of claim 30 imply a structure beyond attachment, Belnap discloses that attaching the synthesized PCD to the substrate comprises attaching the synthesized PCD to the substrate by high-pressure, high temperature (HPHT) bonding [0013], [0037], [0077]. Belnap does not disclose attaching the PCD by spark plasma sintering.
Liang teaches a method of forming a cutter [0015] for a downhole drill bit (Fig. 5, [0041]). Liang teaches providing a catalyst-free synthesized polycrystalline diamond (PCD) (“polycrystalline diamond is leached polycrystalline diamond, including thermally stable polycrystalline diamond” [0015] “fully leached polycrystalline diamond of FIG. 1B” [0016], “polycrystalline diamond 30 with pores, such as leached or thermally stable polycrystalline diamond, is placed in a spark plasma sintering assembly” [0025], “the entire polycrystalline diamond was leached” [0036]). Liang teaches providing a substrate ([0025-26], [0035-36], Fig. 2); and attaching the PCD to the substrate [0035-36], [0045] to form the cutter [0036], [0041], [0045]. Liang teaches that attaching the PCD to the substrate comprises attaching the catalyst- free synthesized PCD to the substrate by spark plasma sintering [0015-16], [0025], [0030], [0034], [0036], [0043]. Liang appears to present the spark plasma sintering as an alternative to high-temperature high-pressure attachment [0002], [0015] for the Liang teaches spark plasma sintering yields favorable PCD properties [0015].
Both Belnap and Liang teach attaching a substantially catalyst-free PCD to a substrate for a cutter for a downhole drill bit.
It would have been obvious for one of ordinary skill in the art, at the time of filing to attach the PCD to the substrate disclosed by Belnap, applied above by spark plasma sintering, thereby achieving the structure implied by product-by-process limitations recited in claim 32, because Belnap discloses attachment by high temperature high pressure processing [0044-45], and Liang suggests spark plasma sintering as an alternative to high temperature high pressure PCD and substrate attachment which yields favorable results [0002], [0015].
Regarding claims 33-35, in attaching by spark plasma sintering as disclosed by Belnap in view of Liang, applied to claim 32 above, it would have been obvious to one of ordinary skill in the art at the time of filing to perform the spark plasma sintering at parameters which Liang teaches for effective attachment. Liang teaches that the spark plasma sintering comprises heating at a range of 300° C. and 1500° C within a vacuum [0030-31], which encompasses the temperature range recited in claim 33. Liang teaches the spark plasma sintering comprises heating the PCD and the substrate by passing a pulsed or a direct electric current of 600 amps (A) to 6000 A through the PCD and the substrate [0032], which encompasses the range recited in claim 34. Liang discloses heating stepwise (may also be pre-heated or jointly heated) to a desired temperature [0031], [0033-34] at which the joining occurs [0035-36], [0045]. Liang does not disclose a heating start temperature of room temperature; however, as active heating or cooling must be required in order for feed material to attain a temperature other than room temperature, given Liang’s silence on active heating or cooling prior to the heating relied upon above [0031], [0033-34], it would have been obvious to one of ordinary skill in the art that the heating disclosed by Liang [0031], ,[0033-34] has a start temperature of ambient room temperature. The parameter ranges taught or rendered by Liang [0031-34], encompass or overlap values recited in claims 33-34; therefore, application of parameters taught by Liang would predictably result in the structure implied by the product-by-process steps recited in claims 33-35. Further, when claimed ranges overlap or lie inside ranges disclosed by the prior art a prima facie case of obviousness exists. See MPEP 2144.05(I).
Claim(s) 30 is/are rejected under 35 U.S.C. 103 as being unpatentable over Belnap (US20120125696) and Liang (US20180208511) as applied to claims 1 and 29-30 above, and further in view of Moriguchi (US5889219) and Terasaki (US20210238102). Terasaki is cited in the IDS filed October 9, 2024.
Regarding claim 30, in the event that the product-by-process limitations of claim 30 imply a structure beyond attachment, Belnap discloses that attaching the synthesized PCD to the substrate comprises attaching the synthesized PCD to the substrate by high-pressure, high temperature (HPHT) bonding [0013], [0037], [0077]. Belnap does not disclose attaching the PCD by vacuum diffusion bonding.
Liang teaches that the spark plasma sintering comprises heating a range of 300° C. and 1500° C within a vacuum [0030-31], which is a high temperature process under vacuum. In performing the spark plasma sintering process taught by Liang as applied to Belnap in view of Liang, applied above, it would have been obvious for one of ordinary skill in the art to apply the parameters which Liang teaches for such spark plasma sintering. Liang is silent on the pressure of the vacuum atmosphere.
Moriguchi teaches forming a cutter for a drill bit (column 7 lines 32-49). Moriguchi teaches accelerating the process through spark plasma sintering (it is also possible to accelerate the sintering by generating plasma between the grains through a pulse current column 2 lines 37-39). Moriguchi teaches providing diamond, tungsten carbide (WC) and cobalt (Co) powder to a mold, pressure of 20 MPa from above and below in a vacuum of not more than about 0.01 Torr (
10
-
2
Torr), and kept at a temperature of 1150
°
C to sinter the supplied powder (column 9 line 66 to column 10 line 26). In an example of sintering powder comprising diamond, WC, and Co Moriguchi teaches feeding a current to a graphite mold in a vacuum of 0.005 Torr (
5
×
10
-
3
Torr) under 40 MPa pressure and sintering at 1,150
°
C (column 17 lines 22-40). Moriguchi teaches that the sintering process produces diamond and cemented carbide composite material (column 2 lines 9-19).
Both Moriguchi and Belnap in view of Liang teach methods of forming a cutter for a drill bit comprising spark plasma sintering at elevated temperatures. Liang teaches that the spark plasma sintering step which attaches the PCD to the substrate comprises directly applying pressure up to 100 MPa [0030].
The vacuum applied by Liang [0030-31] must occur at some degree of vacuum. Given Liang’s silence on the degree of vacuum, it would have been necessary and obvious for one of ordinary skill in the art to look to the art for exemplary degrees of vacuum for forming diamond composites by spark plasma sintering. In looking to the art, it would have been obvious for one of ordinary skill in the art to apply a degree of vacuum of 0.01 Torr (
10
-
2
Torr) or 0.005 Torr (
5
×
10
-
3
Torr) either of which Moriguchi teaches as effective degree of vacuum for sintering diamond composite material to form a cutter comprising diamond and a cemented carbide. As Belnap in view of Liang and Moriguchi as applied above directly applies a pressure, in a vacuum atmosphere, at an increased temperature, some degree of vacuum diffusion bonding would occur in the vacuum chamber taught by Liang [0030], to form the drill bit disclosed by Belnap in view of Liang and Moriguchi as applied above.
Terasaki teaches a process of bonding chemically dissimilar materials [0001]. Terasaki teaches adjusting vacuum conditions to remove residue from the bonding interface [0028], [0036], thereby establishing the degree of vacuum as a variable which affects the result of the quality of the bond. Terasaki directly applies a pressure at elevated temperature to the material to be joined [0032], [0068-69]. Terasaki teaches degree of vacuum in the bonding step is preferably in a range of
1
×
10
-
6
Pa or more and
5
×
10
-
2
Pa or less [0070].
Both Terasaki and Belnap in view of Liang and Moriguchi teach bonding dissimilar material under vacuum while applying pressure at elevated temperature. Liang teaches that one purpose of the vacuum is to clear the PCD prior to sintering [0027]. Though Moriguchi teaches degrees of vacuum, Moriguchi does not teach a limited range or any results from the degree of vacuum, and Liang is silent on the degree of vacuum in the vacuum chamber [0029-31].
It would have been obvious for one of ordinary skill in the art, at the time of filing, to perform the spark plasma sintering steps disclosed by Belnap in view of Liang, applied above, in a vacuum chamber [0029-31] at a degree of vacuum of
1
×
10
-
6
Pa or more and
5
×
10
-
2
Pa or less. One of ordinary skill in the art would have arrived at this degree of vacuum as the result of routine optimization of known parameters for bonding dissimilar material under vacuum because Terasaki specifically teaches
1
×
10
-
6
Pa or more and
5
×
10
-
2
Pa or less for the purpose of joining dissimilar inorganic components [0070], because Terasaki teaches that the degree of vacuum can be adjusted to remove residue from the bonding interface [0028], [0036], and neither Liang nor Moriguchi teaches a specific, preferred degree of vacuum. Generally, differences in a parameter will not support the patentability of subject matter encompassed by the prior art unless there is evidence indicating such parameter is critical. See MPEP 2144.05(II)(A-B).
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to SEAN P O'KEEFE whose telephone number is (571)272-7647. The examiner can normally be reached MR 8:00-6:30.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Sally Merkling can be reached at (571) 272-6297. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/SEAN P. O'KEEFE/ Examiner, Art Unit 1738
/SALLY A MERKLING/ SPE, Art Unit 1738
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