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 .
Information Disclosure Statement
The information disclosure statement(s) (IDS) submitted on 3/27/24 has been considered by the examiner.
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.
Language from the reference(s) is shown in quotations. Limitations from the claims are shown in quotations within parentheses. Examiner explanations are shown in italics.
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.
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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
Claims 1-4, 12, 14, 18, 23-24, and 27 are rejected under 35 U.S.C. 103 as being unpatentable over Black et al. (US 20230166328 A1) in view of Sun et al., Phase Transformations and Formation of Ultra-Fine Microstructure During Hydrogen Sintering and Phase Transformation (HSPT) Processing of Ti-6Al-4V. Metall Mater Trans A 46, 5546–5560 (2015). https://doi.org/10.1007/s11661-015-3141-8.
Regarding claims 1-2, Black teaches that “embodiments of the present disclosure relate to additive manufacturing, also known as 3D printing, and in particular to binder jetting, components used in binder jetting, and resultant products which contain metals or alloys” (which reads upon “a method of making [an] article comprising”, as recited in the instant claim; paragraph [0002]). Black teaches “(i) providing a layer of a powder bed which comprises a compound of a first metal, and optionally also said first metal in elemental form and/or optionally other elemental metal(s) which are suitable for alloying with said first metal” (which reads upon “forming a powder bed of a titanium feedstock”, as recited in the instant claim; paragraph [0024]). Black teaches that “to produce pure titanium products, the compound of a first metal used in the powder bed is a titanium compound, for example titanium hydride, and the functional binder in the ink is a titanium-containing binder” (which reads upon “a densified sintered titanium article, forming a powder bed of a titanium feedstock”, as recited in the instant claim; which reads upon claim 2; paragraph [0039]). Black teaches “jetting a functional binder onto selected parts of said layer, wherein said functional binder infiltrates into pores in the powder bed” (which reads upon “applying a binder to a portion of the powder bed to bind the titanium feedstock together”, as recited in the instant claim; paragraph [0024]). Black teaches that “the infiltrated material may optionally comprise up to 20% by volume of reactive binder (e.g. ROM) with the balance being comprised of particles, other components and carrier, and that together these components act as an infiltrating metallic binder to hold the 3D part in a green state until it can be subsequently consolidated by heat treatment” (which reads upon “thereby forming a green body”, as recited in the instant claim; paragraph [0085]). Black teaches that “the titanium precursor and other materials used in the functional binder are typically dissolved or suspended in a solvent, for example toluene” (paragraph [0072]). Black teaches that “the product may be heat-treated to consolidate and further strengthen, e.g. fuse, the structure” (which reads upon “debinding the green body to remove at least a portion of the binder to form a debinded titanium article; sintering the debinded titanium article at a sintering temperature to produce a sintered titanium article”, as recited in the instant claim; paragraph [0061]; fuse reads on sintering; the toluene will evaporate before the titanium fuses). Black teaches that “this produces a fully-dense-high-strength “green” part, which can then be heat treated to create the correct final microstructure for functional use” (which reads upon “holding the sintered titanium article at a phase transformation temperature to form a microstructure-controlled titanium article”, as recited in the instant claim; paragraph [0106]).
Black is silent regarding sintering the debinded titanium article at a sintering temperature in an atmosphere comprising hydrogen and dehydrogenating the microstructure-controlled titanium article to form a densified sintered titanium article.
Sun is similarly concerned with a novel powder metallurgy method for producing Ti alloys (page 5546). Sun teaches that “the hydrogen sintering and phase transformation (HSPT) process is a new method of producing titanium materials via the powder metallurgy (PM) route” (page 5546). Sun teaches that “traditional powder metallurgy titanium processes suffer from the trade-off between cost and performance” (page 5546). Sun teaches that “one of the issues that has plagued PM Ti, especially PM Ti-6Al-4V alloy, is that the microstructure of PM Ti is always too coarse after high temperature sintering in vacuum, and that specifically, the Ti-6Al-4V alloy typically has a coarse lamellar structure that is undesirable from the viewpoint of mechanical properties” (page 5546). Sun teaches that “the HSPT approach addresses this coarse microstructure issue directly by achieving ultra-fine microstructure in the as-sintered state” (page 5546). Sun teaches that “HSPT exhibits a unique capability to generate ultra-fine microstructure, and that the ability to obtain this ultra-fine microstructure, and hence superior mechanical properties in the as-sintered state without subsequent thermo-mechanical processing, offers an opportunity to maximize performance-to-cost ratio during the production of Ti components” (pages 5546-47). Sun teaches that “HSPT consists of three steps for Ti-6Al-4V: (1) sintering at 1473 K (1200 °C) in hydrogen, (2) phase transformation at a moderate temperature 923 K (650 °C) in hydrogen, and (3) dehydrogenating at 1023 K (750 °C) in vacuum” (which reads upon “sintering the debinded titanium article at a sintering temperature in an atmosphere comprising hydrogen to produce a sintered titanium article; holding the sintered titanium article at a phase transformation temperature to form a microstructure-controlled titanium article; and dehydrogenating the microstructure-controlled titanium article to form a densified sintered titanium article”, as recited in the instant claim; page 5548).
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Black to add three step HSPT after debinding, as taught by Sun to generate ultra-fine microstructure, and hence superior mechanical properties in the as-sintered state without subsequent thermo-mechanical processing, and to maximize performance-to-cost ratio during the production of Ti components.
Regarding claim 3, modified Black teaches the method of claim 1 as stated above. Black teaches “providing a layer of a powder bed which comprises a compound of a first metal, and optionally also said first metal in elemental form and/or optionally other elemental metal(s) which are suitable for alloying with said first metal” (paragraph [0024]).
Regarding claim 4, modified Black teaches the method of claim 1 as stated above. Black teaches that “produce pure titanium products, the compound of a first metal used in the powder bed is a titanium compound, for example titanium hydride” (paragraph [0039]). Black is silent regarding the size of the titanium hydride Sun teaches “the starting materials for the samples presented in this study were −325 mesh TiH2 powder (O: 0.175 wt pct, N: 0.019 wt pct, C: 0.002 wt pct) and −325 mesh 60Al/40V master alloy powder” (page 5548; -325 mesh is about 44 µm or less).
Regarding claims 12 and 14, modified Black teaches the method of claim 1 as stated above. Black teaches “a solvent, for example toluene” (paragraph [0072]).
Regarding claim 18, modified Black teaches the method of claim 1 as stated above. Black teaches that “the inks infiltrate the porosity (typically about 40% porosity) in the powder bed lay up” (paragraph [0085]; 40% porosity is 60% density).
Regarding claims 23-24, modified Black teaches the method of claim 1 as stated above. Sun teaches that “Hydrogen sintering was conducted in a tube furnace with a mixed gas flow of 50 pct ultra-high purity (UHP) H2 balanced with UHP Ar” (page 5549). Sun teaches that “the gas flow rate in the present study was regulated by mass flow controllers with an accuracy of ±1.5 pct” (page 5549). Sun teaches “sintering at 1473 K (1200 °C)” (page 5549).
Regarding claim 27, modified Black teaches the method of claim 1 as stated above. Sun teaches “sintering at 1473 K (1200 °C) in hydrogen” (page 5549). Sun teaches “phase transformation at a moderate temperature 923 K (650 °C) in hydrogen” (page 5549).
Claims 1-4, 12-15, 18, and 22 are rejected under 35 U.S.C. 103 as being unpatentable over Black et al. (US 20230166328 A1), in view of Opschoor et al. (US 20200070242 A1).
Regarding claims 1-2, Black teaches that “embodiments of the present disclosure relate to additive manufacturing, also known as 3D printing, and in particular to binder jetting, components used in binder jetting, and resultant products which contain metals or alloys” (which reads upon “a method of making [an] article comprising”, as recited in the instant claim; paragraph [0002]). Black teaches “(i) providing a layer of a powder bed which comprises a compound of a first metal, and optionally also said first metal in elemental form and/or optionally other elemental metal(s) which are suitable for alloying with said first metal” (which reads upon “forming a powder bed of a titanium feedstock”, as recited in the instant claim; paragraph [0024]). Black teaches that “to produce pure titanium products, the compound of a first metal used in the powder bed is a titanium compound, for example titanium hydride, and the functional binder in the ink is a titanium-containing binder” (which reads upon “a densified sintered titanium article, forming a powder bed of a titanium feedstock”, as recited in the instant claim; which reads upon claim 2; paragraph [0039]). Black teaches “jetting a functional binder onto selected parts of said layer, wherein said functional binder infiltrates into pores in the powder bed” (which reads upon “applying a binder to a portion of the powder bed to bind the titanium feedstock together”, as recited in the instant claim; paragraph [0024]). Black teaches that “the infiltrated material may optionally comprise up to 20% by volume of reactive binder (e.g. ROM) with the balance being comprised of particles, other components and carrier, and that together these components act as an infiltrating metallic binder to hold the 3D part in a green state until it can be subsequently consolidated by heat treatment” (which reads upon “thereby forming a green body”, as recited in the instant claim; paragraph [0085]). Black teaches that “the titanium precursor and other materials used in the functional binder are typically dissolved or suspended in a solvent, for example toluene” (paragraph [0072]). Black teaches that “the product may be heat-treated to consolidate and further strengthen, e.g. fuse, the structure” (which reads upon “debinding the green body to remove at least a portion of the binder to form a debinded titanium article; sintering the debinded titanium article at a sintering temperature to produce a sintered titanium article”, as recited in the instant claim; paragraph [0061]; fuse reads on sintering; the toluene will evaporate before the titanium fuses). Black teaches that “this produces a fully-dense-high-strength “green” part, which can then be heat treated to create the correct final microstructure for functional use” (which reads upon “holding the sintered titanium article at a phase transformation temperature to form a microstructure-controlled titanium article”, as recited in the instant claim; paragraph [0106]).
Black is silent regarding sintering the debinded titanium article at a sintering temperature in an atmosphere comprising hydrogen and dehydrogenating the microstructure-controlled titanium article to form a densified sintered titanium article.
Opschoor is similarly concerned with additive manufacturing processes [including] material jetting, material extrusion, direct energy deposition, sheet lamination, binder jetting, powder bed fusion and photopolymerization (paragraph [0002]). Opschoor teaches that “the present invention concerns an indirect layer-by-layer AM process which makes use of a sacrificial binder material to shape metal-containing particles into a three-dimensional metal object” (paragraph [0007]). Opschoor teaches that “the metal in the metal particles is chosen from the group consisting of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, molybdenum, hafnium, tantalum, tungsten and metal alloys thereof” (which reads upon “titanium”, as recited in the instant claim; paragraph [0054]). Opschoor teaches that “the debinding step can further be performed in a protective or hydrogen-containing environment” (paragraph [0108]). Opschoor teaches that “many metals are subject to oxidation when exposed to high temperatures, and that the metal oxide layer thus formed results in an impaired sinterability” (paragraph [0130]). Opschoor teaches that “the oxides of some metals are subject to sublimation far below the sintering temperature” (paragraph [0130]). Opschoor teaches that “heating to above these temperatures in oxygen-containing environments leads to loss of metal” (paragraph [0130]). Opschoor teaches that “sintering is therefore preferably carried out in an inert of vacuum environment, such as under argon, helium or CO2 gas, or in a reducing environment such as under hydrogen or CO gas” (which reads upon “sintering the debinded titanium article at a sintering temperature in an atmosphere comprising hydrogen”, as recited in the instant claim; paragraph [0130]). Opschoor teaches that “the debinding step and the conversion step of metal oxide brown bodies using hydrogen gas can be combined by raising the temperature when the debinding step is also performed in a hydrogen-containing atmosphere” (paragraph [0117]). Opschoor teaches that “the conversion of brown bodies comprising metal precursors in the form of metal hydride to the corresponding metal brown bodies can conveniently take place using a thermal step” (paragraph [0118]). Opschoor teaches that “reference is made to the dehydride step in the well-known Hydride-Dehydride (HDH) process as described in for example U.S. Pat. Nos. 1,835,024 and 6,475,428, and that in this dehydride step, hydrogen is removed from for example titanium, zirconium, vanadium and tantalum hydride, by heating the hydride under high vacuum” (which reads upon “dehydrogenating the microstructure-controlled titanium article to form a densified sintered titanium article”, as recited in the instant claim; paragraph [0118]).
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Black to add sintering the debinded titanium article at a sintering temperature in an atmosphere comprising hydrogen and dehydrogenating the microstructure-controlled titanium article, as taught by Opschoor to improve sinterability and avoid loss of metal.
Regarding claim 3, modified Black teaches the method of claim 1 as stated above. Black teaches “providing a layer of a powder bed which comprises a compound of a first metal, and optionally also said first metal in elemental form and/or optionally other elemental metal(s) which are suitable for alloying with said first metal” (paragraph [0024]).
Regarding claim 4, modified Black teaches the method of claim 1 as stated above. Black is silent regarding the size of the feedstock. Opschoor teaches that “the metal particles that can be used in the slurry as defined hereinbefore have a particle size distribution as determined by laser diffraction that can be characterized by D10, D50 and D90 values of 3 μm, 6 μm and 9 μm, respectively” (paragraph [0088]).
Regarding claims 12 and 14, modified Black teaches the method of claim 1 as stated above. Black teaches “a solvent, for example toluene” (paragraph [0072]).
Regarding claim 13, modified Black teaches the method of claim 1 as stated above. Black is silent regarding the weight % of the binder. Opschoor teaches “2-45 wt % of a polymerizable resin” (paragraph [0018]). It has been held that obviousness exists where the claimed ranges overlap or lie inside ranges disclosed by the prior art. In re Wertheim, 541 F.2d 257, 191 USPQ 90 (CCPA 1976); In re Woodruff, 919 F.2d 1575, 16 USPQ2d 1934 (Fed. Cir. 1990). See MPEP 2144.05 (I). Here, the claimed range of 0.1 - 5 overlaps the range disclosed by the prior art of 2-45. Accordingly, the prior art renders the claim obvious.
Regarding claim 15, modified Black teaches the method of claim 14 as stated above. Opschoor teaches that “the binder can be removed by heating the green body, typically to a temperature of between 90 and 600° C., more preferably to a temperature between 100 and 450° C” (paragraph [0108]).
Regarding claim 18, modified Black teaches the method of claim 1 as stated above. Black teaches that “the inks infiltrate the porosity (typically about 40% porosity) in the powder bed lay up” (paragraph [0085]; 40% porosity is 60% density).
Regarding claim 22, modified Black teaches the method of claim 1 as stated above. Opschoor teaches that “the debinding step can further be performed in a protective or hydrogen-containing environment” (paragraph [0108]).
Claims 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Black et al. (US 20230166328 A1) in view of Sun et al. Phase Transformations and Formation of Ultra-Fine Microstructure During Hydrogen Sintering and Phase Transformation (HSPT) Processing of Ti-6Al-4V. Metall Mater Trans A 46, 5546–5560 (2015). https://doi.org/10.1007/s11661-015-3141-8, as applied to claim 1 above, and further in view of Sun et al., A novel method for production of spherical Ti-6Al-4V powder for additive manufacturing, Powder Technology 301 (2016) 331–335 (“Sun GSD”).
Regarding claims 5-6, Black teaches the method of claim 1 as stated above.
Black is silent regarding wherein the titanium feedstock is produced by granulation-sintering-deoxygenation (GSD).
Sun GSD is similarly concerned with Ti-6Al-4V powder for advanced near-net-shape manufacturing processes including additive manufacturing (page 331). Sun GSD teaches that “the new process synergistically integrates a few common low-cost processing techniques including granulation, sintering, and de-oxygenation to produce spherical Ti alloy powders without relying on costly melting and atomizing techniques” (page 331). Sun GSD teaches that “the new granulation-sintering-deoxygenation (GSD) process can use low-cost source powders such as scrap Ti as the raw material, and that the spherical Ti-6Al-4V powder produced using this process has controlled particle size distribution and low oxygen content (< 0.15%), which meet the Aerospace Material Specification (AMS-4998) for spherical Ti-6Al-4V powder” (which reads upon “wherein the titanium feedstock is produced by granulation-sintering-deoxygenation (GSD)”, as recited in the instant claim; page 331). Sun GSD teaches that “the use of Ti in the industry is extremely limited because it is prohibitively expensive for many consumer applications” (page 331). Sun GSD teaches that “unfortunately, high quality spherical Ti alloy powders that meet the requirements of NNS manufacturing as described above, especially powders for AM Ti are all very costly and in short supply, which hinders the development of Ti for broad applications using AM or any other advanced manufacturing techniques, therefore, a strong need exists in the AM as well as conventional PM industries to develop low cost methods for the production of spherical low oxygen Ti alloy powders that meet all requirements for chemical composition and physical properties” (page 331). Sun GSD teaches that “the spray-dried granules are shown in Fig. 2b, having a very good spherical shape, and that the sintered granules are shown in Fig. 2c, demonstrating that they inherit the desired spherical shape of the spray dried granules” (which reads upon “a sphericity of 0.92 to 0.98 and has a surface morphology of hills and valleys not exceeding 1/10 of a particle size”, as recited in the instant claim; page 333). Sun GSD teaches “a novel method that synergistically combines granule spheroidization, sintering, and de-oxygenation into one integrated process for producing low-cost spherical Ti-6Al-4V powder” (page 335). Sun GSD teaches that “this method is also applicable for producing other spherical titanium alloy or other metal alloy powders such as nickel based super alloy powders and stainless steel powders” (page 335).
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Black to use feedstock produced by GSD, as taught by Sun GSD to obtain a low cost feedstock powder suitable for additive manufacturing.
Where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP § 2112.01 I &II. Therefore, it is expected that the powder of the prior art possesses the properties as claimed in the instant claims since the claimed and prior art products are produced by identical or substantially identical processes (GSD). Since the Office does not have a laboratory to test the reference powder, it is applicant’s burden to show that the reference powder does not possess the properties as claimed in the instant claims. See In re Best, 195 USPQ 430, 433 (CCPA 1977); In re Marosi, 218 USPQ 289, 292-293 (Fed. Cir. 1983); In re Fitzgerald et al., 205 USPQ 594 (CCPA 1980).
Claims 5 and 8 are rejected under 35 U.S.C. 103 as being unpatentable over Black et al. (US 20230166328 A1) in view of Sun et al. Phase Transformations and Formation of Ultra-Fine Microstructure During Hydrogen Sintering and Phase Transformation (HSPT) Processing of Ti-6Al-4V. Metall Mater Trans A 46, 5546–5560 (2015). https://doi.org/10.1007/s11661-015-3141-8, as applied to claim 1 above, and further in view of Zhang et al., Hydrogen assisted magnesiothermic reduction of TiO2, Chemical Engineering Journal 308 (2017) 299–310.
Regarding claims 5 and 8, Black teaches the method of claim 1 as stated above.
Black is silent regarding wherein the titanium feedstock is produced by hydrogen assisted magnesiothermic reduction of TiO2 (HAMR).
Zhang teaches that “the strong affinity of titanium to oxygen dictates that it is very difficult to produce low-oxygen Ti metal from TiO2 directly” (page 299). Zhang teaches that “a hydrogen assisted magnesiothermic reduction (HAMR) process for producing Ti metal powder from TiO2 powder at relatively low temperatures (⩽750 °C) is established” (which reads upon “wherein the titanium feedstock is produced by hydrogen assisted magnesiothermic reduction of TiO2 (HAMR)”, as recited in the instant claim; page 299). Zhang teaches that “this approach has great potential to be a viable method for the production of low-oxygen Ti metal powder from TiO2” (page 299). Zhang teaches that “titanium is also known for being prohibitively expensive for civilian applications, which has limited its use in many industries such as automobiles that would have resulted in a huge benefit for reducing weight and associated energy consumption” (page 300). Zhang teaches that “the oxygen content was reduced to less than 0.15 wt%, as shown in Fig. 3” (which reads upon “an oxygen content of less than 0.2 %”, as recited in the instant claim; page 302). Zhang teaches that “the coarsest hydride powder experienced extensive densification within each particle, while the sintering between particles was minimal (Fig. 12(i) and (l)), and that the particles remained discrete after the heat treatment and the particle surfaces appeared smooth and free of open pours” (which reads upon “a sphericity of 0.6 to 0.9”, as recited in the instant claim; page 303; see FIG. 12L). Zhang teaches that “the results show that this is a viable approach for the production of low-oxygen Ti metal powder from TiO2” (page 309).
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Black to use feedstock produced by HAMR, as taught by Zhang to obtain a low cost feedstock powder.
Regarding the sphericity, where the claimed and prior art products are identical or substantially identical in structure or composition, or are produced by identical or substantially identical processes, a prima facie case of either anticipation or obviousness has been established. In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433 (CCPA 1977). See MPEP § 2112.01 I &II. Therefore, it is expected that the powder of the prior art possesses the properties as claimed in the instant claims since the claimed and prior art products are produced by identical or substantially identical processes (HAMR). Since the Office does not have a laboratory to test the reference powder, it is applicant’s burden to show that the reference powder does not possess the properties as claimed in the instant claims. See In re Best, 195 USPQ 430, 433 (CCPA 1977); In re Marosi, 218 USPQ 289, 292-293 (Fed. Cir. 1983); In re Fitzgerald et al., 205 USPQ 594 (CCPA 1980).
Claim 16-17 and 19-20 are rejected under 35 U.S.C. 103 as being unpatentable over Black et al. (US 20230166328 A1), in view of Opschoor et al. (US 20200070242 A1), as applied to claim 1 above, and further in view of Rushkin et al. (US 20210162502 A1).
Regarding claims 16-17 and 19-20, modified Black teaches the method of claim 1 as stated above. Black teaches “sequentially repeating said steps of applying a layer of powder on top and selectively jetting functional binder, multiple times, to provide a powder bed bonded at selected locations by printed functional binder” (paragraph [0043]). Black is silent regarding the size of the feedstock. Opschoor teaches that “the metal particles that can be used in the slurry as defined hereinbefore have a particle size distribution as determined by laser diffraction that can be characterized by D10, D50 and D90 values of 3 μm, 6 μm and 9 μm, respectively” (paragraph [0088]).
Black is silent regarding layer and feedstock dimensions and debinding time and temperature. Regarding the subject limitations, in order to carry out the invention of Black, it would have been necessary and obvious to look to the prior art for exemplary parameters used in binder jet additive manufacturing of metals.
Rushkin is similarly concerned with methods of additive manufacturing metal-based composite structures by binder jet printing (paragraph [0005]). Rushkin teaches that “layers of metal powder may have a variety of suitable thicknesses” (paragraph [0153]). Rushkin teaches that “a layer of metal powder has a thickness of greater than or equal to 10 microns” (paragraph [0153]). Rushkin teaches that “a layer of metal powder has a thickness of less than or equal to 100 microns” (paragraph [0153]; a d50 particle size of 6 μm is less than 40% of a layer thickness of 100 μm). Rushkin teaches that “following step 60 in which the metal-based composite structure is formed, an ensuing step 70 of heating the metal-based composite structure to de-bind the structure may be performed” (paragraph [0047]). Rushkin teaches that “while the heating to de-bind of step 70 is optional, it may, in certain cases, be useful for removing some or all of the binder from the metal-based composite structure” (which reads upon instant claim 19; paragraph [0047]). Rushkin teaches that “there exists a range of temperatures suitable for de-binding metal-based composite structures” (paragraph [0050]). Rushkin teaches that “an environment in which a metal-based composite structure is positioned is heated to a temperature of less than or equal to 450° C.” (which reads upon “below 850° F”, as recited in the instant claim; paragraph [0050]). Rushkin teaches that “the cubes were heated with a temperature ramp of 2° C./minute in air at ambient pressure in a tube furnace at a flow rate of 0.5 slpm and held for 60 minutes at 245° C. to de-bind the part” (which reads upon “about one hour”, as recited in instant claim 20; paragraph [0202]).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to perform the method of the prior art combination, and adjusting and varying the parameters, such as within the claimed ranges, as taught by Rushkin, motivated to perform a conventional method using known and tested parameters predictably suitable for metal binder jet applications.
Claim 26 is rejected under 35 U.S.C. 103 as being unpatentable over Black et al. (US 20230166328 A1) and Sun et al. Phase Transformations and Formation of Ultra-Fine Microstructure During Hydrogen Sintering and Phase Transformation (HSPT) Processing of Ti-6Al-4V. Metall Mater Trans A 46, 5546–5560 (2015). https://doi.org/10.1007/s11661-015-3141-8, as applied to claim 23 above, and further in view of James D. Paramore, Z. Zak Fang, Pei Sun, 10 - Hydrogen sintering of titanium and its alloys, Editor(s): Ma Qian, Francis H. (Sam) Froes, Titanium Powder Metallurgy, Butterworth-Heinemann, 2015, Pages 163-182.
Regarding claim 26, modified Black teaches the method of claim 23 as stated above.
Black is silent regarding equilibrating the sintered titanium article at an equilibration temperature below the sintering temperature and above a phase transformation temperature for an equilibration time sufficient for the hydrogen within the article to reach equilibrium with the dynamically controlled hydrogen atmosphere and homogenize the sintered titanium article.
Paramore is similarly concerned with hydrogen sintering and phase transformation (HSPT) used to produce titanium alloys with engineered microstructures in the as-sintered state (abstract). Paramore teaches that “Step 2. Homogenization and Phase Transformation: The second step in HSPT refines the microstructure by taking advantage of phase transformations present in Ti–H phase diagrams” (page 171). Paramore teaches that “at the sintering temperature, titanium has very low hydrogen solubility” (page 171). Paramore teaches that “depending on the alloy and desired microstructure, a homogenization step may be included to increase the overall hydrogen content by homogenizing at a temperature below the sintering temperature but above the phase transformation temperature” (which reads upon “equilibrating the sintered titanium article at an equilibration temperature below the sintering temperature and above a phase transformation temperature for an equilibration time sufficient for the hydrogen within the article to reach equilibrium with the dynamically controlled hydrogen atmosphere and homogenize the sintered titanium article”, as recited in the instant claim; page 171).
Accordingly, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Black to include a homogenization step, as taught by Paramore to increase the overall hydrogen content.
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Any inquiry concerning this communication or earlier communications from the examiner should be directed to REBECCA JANSSEN whose telephone number is (571)272-5434. The examiner can normally be reached on Mon-Thurs 10-7 and alternating Fri 10-6.
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/REBECCA JANSSEN/Primary Examiner, Art Unit 1733
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