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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant’s submission filed on 06/15/2026 has been entered.
Response to Amendment
This action is responsive to the amendments filed 06/15/2026. Claims 1-27, 29-31 are pending in this application. As directed, claims 1, 4, 10 and 31 have been amended; claim 28 cancelled; claims 11-27, 29-30 have been withdrawn.
With respect to Claim Objections: Applicant’s amendments to the Claims have overcome the Claim Objections set forth in the Final Office Action dated 04/16/2026. However, Applicant’s amendments to the Claims filed on 06/15/2026 have created another Claim Objections, see details below in the Claim Objections section below.
With respect to 35 U.S.C. 112 Claim Rejections: Applicant’s amendments to the Claims have overcome the 35 U.S.C. 112(a) & 35 U.S.C. 112(b) Claim Rejections set forth in the Final Office Action dated 04/16/2026.
Response to Arguments
With respect to 35 U.S.C. 103 Claim Rejections: Applicant(s)’ arguments filed 06/15/2026 have been fully considered but are moot based on new ground(s) of rejection necessitated by amendments. Specifically, the previously cited NPL Hemmert (NPL, “The GTAW top 10: How to identify and remedy common GTAW mistakes”) is no longer relied upon in any rejections in this office action. Therefore, Applicant(s)’ arguments regarding the reference Hemmert and the combination of Sweeney and Hemmert are moot. Furthermore, the newly cited prior art Gibson et al. (U.S. Pub. No. 2021/0323054 A1, newly cited) is now relied upon to teach the newly added limitation “the ejector is configured to be selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops” as recited in the amended claim 1, and the newly cited prior art Martin (U.S. Patent No. 5,264,679 A, newly cited) is now relied upon to teach the limitation “wherein the alternating electrical current comprises an electron positive (EP) mode in which ions contact a previously-deposited layer of the 3D object and remove an oxide layer from the 3D object, and an electron negative (EN) mode in which the previously-deposited layer of the 3D object is heated” as recited in the amended claim 1. Accordingly, Applicant(s)’ arguments filed 06/15/2026 have been fully considered but are moot based on new ground(s) of rejection necessitated by amendments.
However, in response to Applicant(s)’ arguments regarding the previously cited prior art Sweeney et al. (U.S. Pub. No. 2020/0298479 A1, previously cited), Applicant(s)’ arguments filed 06/15/2026 have been fully considered but they are not persuasive for the following reasons:
Applicant alleges that Sweeney fails to teach or suggest the amended limitation of claim 1 requiring “the ejector is configured to be selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops”. Applicant contends that Sweeney is directed to material extrusion of a thermoplastic material or thermoplastic composite and that Sweeney’s extrusion nozzle controls the feed of thermoplastic filament and extrudes the material in beads, lines, or layers rather than using a selectively activated liquid drop-on-demand ejector. See details on pages 9-11 of the Remarks dated 06/15/2026.
Examiner respectfully disagrees because Sweeney is not limited to deposition of the build material in continuous beads or lines. In particular, Sweeney explicitly discloses that the thermoplastic material may be printed “in droplets or continuous beads” in multiple layers to form the 3D printed part, as indicated by Sweeney Pars.0004 & 0034. Thus, Sweeney explicitly contemplates a droplet-deposition mode in addition to continuous-bead deposition. Accordingly, Applicant’s assertion that Sweeney merely extrudes thermoplastic material in beads, lines, or layers does not account for Sweeney’s disclosure of depositing the build material in droplets.
Examiner acknowledges that Sweeney does not explicitly disclose that its ejector is “selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops” as recited in the amended claim 1. However, the rejection does not rely upon Sweeney alone for this feature. Rather, the newly added reference Gibson is relied upon for teaching the limitation “the ejector is configured to be selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops” as recited in the amended claim 1. The proposed combination does not require modifying Sweeney from a system limited exclusively to continuous-bead deposition into an unrelated droplet-deposition system. As explained above, Sweeney itself explicitly discloses depositing its build material in “droplet or continuous beads”. Gibson is relied upon for selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops. Thus, the proposed modification applies Gibson’s selective drop-ejection control to a droplet-deposition mode already explicitly disclosed by Sweeney. Therefore, Sweeney in view of Gibson properly teaches the limitation “the ejector is configured to be selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops” recited in the amended claim 1. See detailed rejection of the independent claim 1 in the 35 U.S.C. 103 Claim Rejection section below.
Applicant’s arguments regarding dependence claims are the same as those provided for the independent claim 1, see details on pages 11-12 of the Remarks dated 06/15/2026. Therefore, the Examiner’s response to the independent claim 1 generally applies to the dependent claims.
Claim Objections
Claims 1-10 and 31 are objected to because of the following informalities:
Claim 1 recites the limitation “the form” in line 4. This should be changed to “a form” since there is no form recited previously.
Claim 1 (lines 5, 6, 10), claim 8 (line 2), claim 9 (line 2), claim 10 (lines 2, 3) recite the limitation “the plurality of drops”. This should be changed to “the plurality of liquid drops” to properly refer to the corresponding limitation recited in claim 1 (line 4).
Claims 2-10 and 31 are objected by virtue of their dependence on claim 1.
Claim 8 recites the limitation “the drops” in line 2. This should be changed to “the plurality of liquid drops” to properly refer to the corresponding limitation recited in claim 1 (line 4).
Claim 31 recites the limitation “removing the oxide layer from the 3D object or heating the 3D object are performed” in lines 1-2. This appears to be a grammatical error, “are” should be changed to “is”.
Appropriate correction is required.
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, 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.
Claims 1, 2-3, 6-9 are rejected under 35 U.S.C. 103 as being unpatentable over Sweeney et al. (U.S. Pub. No. 2020/0298479 A1, previously cited) in view of Gibson et al. (U.S. Pub. No. 2021/0323054 A1, newly cited), and further in view of Martin (U.S. Patent No. 5,264,679 A, newly cited).
Regarding claim 1, Sweeney discloses a 3D printing system (3D printing system 200a, Sweeney Fig.4 & Pars.0042-0043), comprising:
an ejector (ejector includes the nozzle housing 132 and the nozzle body 120, Sweeney Fig.2) (it is noted that the 3D printing system 200a as shown in Sweeney Fig.4 comprises the nozzle housing 132 and the nozzle body 120 of the extrusion nozzle 104a as shown in Sweeney Fig.2 because Sweeney Fig.4 & Par.0042 discloses the 3D printing system 200a includes a 3D printer 206, and Sweeney Par.0043 discloses: “The 3D printer 206 includes a 3D printer nozzle head, such as the extrusion nozzles 104 a, 104 b shown in FIGS. 2 and 3”) configured to receive a build material (material 102, Sweeney Fig.2), wherein the ejector (ejector includes the nozzle housing 132 and the nozzle body 120, Sweeney Fig.2) comprises a nozzle (nozzle body 120, Sweeney Fig.2), and wherein the ejector (ejector includes the nozzle housing 132 and the nozzle body 120, Sweeney Fig.2) is configured to eject a plurality of liquid drops (“droplets”, Sweeney Par.0004) of the build material (material 102, Sweeney Fig.2) through the nozzle (nozzle body 120, Sweeney Fig.2) (Sweeney Par.0004 discloses: “Layers of composite material are successively deposited in droplets or continuous beads until the final 3D model has been printed”, and Sweeney Par.0038 discloses: “Referring to both FIG. 1 and FIG. 2, the extrusion nozzle 104 a is configured to heat the thermoplastic filament 102 to a molten state and extrude the molten thermoplastic material 102 in successive layers onto the platform bed 110 until the 3D part has been printed.”; therefore, Sweeney discloses the ejector configured to eject a plurality of drops of the material 102 through the nozzle body 120);
a substrate (platform bed 110, Sweeney Fig.1) positioned below the nozzle (nozzle body 120, Sweeney Fig.2) (Sweeney Par.0038 discloses: “Referring to both FIG. 1 and FIG. 2, the extrusion nozzle 104 a is configured to heat the thermoplastic filament 102 to a molten state and extrude the molten thermoplastic material 102 in successive layers onto the platform bed 110 until the 3D part has been printed.”), wherein the plurality of drops (drops formed from heating the thermoplastic filament 102 to molten state, Sweeney Pars.0004 & 0038) fall toward the substrate (platform bed 110, Sweeney Fig.1) after being ejected from the nozzle (nozzle body 120, Sweeney Fig.2) (Sweeney Par.0038 discloses: “Referring to both FIG. 1 and FIG. 2, the extrusion nozzle 104 a is configured to heat the thermoplastic filament 102 to a molten state and extrude the molten thermoplastic material 102 in successive layers onto the platform bed 110 until the 3D part has been printed.”), and wherein the plurality of drops (drops formed from heating the thermoplastic filament 102 to molten state, Sweeney Pars.0004 & 0038) form a 3D object (“3D part”, Sweeney Par.0038) on the substrate (platform bed 110, Sweeney Fig.1) (Sweeney Par.0038 discloses: “Referring to both FIG. 1 and FIG. 2, the extrusion nozzle 104 a is configured to heat the thermoplastic filament 102 to a molten state and extrude the molten thermoplastic material 102 in successive layers onto the platform bed 110 until the 3D part has been printed.”);
a power source (high voltage supply 212, Sweeney Fig.4) configured to generate an alternating electrical current (Sweeney Par.0042 discloses: “a high voltage supply 212, which could may include a direct current (DC) source, pulsed DC source, or alternating current (AC) source”; therefore, the high voltage supply 212 configured to generate an alternating electrical current); and
an electrode (electrodes 140 & 142, Sweeney Fig.2) configured to generate a plasma in response to receiving the alternating electrical current (alternating electrical current generated from the high voltage supply 212, Sweeney Fig.4 & Par.0042) (Sweeney Par.0043 discloses: “The 3D printer 206 includes a 3D printer nozzle head, such as the extrusion nozzles 104 a, 104 b shown in FIGS. 2 and 3, configured to allow a high voltage potential to be applied directly to the nozzle body, to an electrode near the print head, or to a collar surrounding the nozzles. This high voltage potential will excite either a distributed plasma cloud or a focused plasma stream directed at the 3D printed parts.”; therefore, Sweeney discloses electrodes 140 & 142 configured to generate plasma in response to receiving the alternating electrical current generated from the high voltage supply 212), wherein the plurality of drops (drops formed from heating the thermoplastic filament 102 to molten state, Sweeney Pars.0004 & 0038), the 3D object (“3D part”, Sweeney Par.0038), the substrate (platform bed 110, Sweeney Fig.1), or a combination thereof are positioned at least partially within the plasma (plasma is generated in response to receiving the alternating electrical current generated from the high voltage supply 212, as cited and explained previously) (It is noted that the limitation “the drops, the 3D object, the substrate, or a combination thereof” is in alternative form; therefore, only one of these was required during examination. In this case, Sweeney discloses the 3D object is positioned at least partially within the plasma because Sweeney Par.0043 discloses the focused plasma stream directed at the 3D printed parts; specifically, Sweeney Par.0043 discloses: “The 3D printer 206 includes a 3D printer nozzle head, such as the extrusion nozzles 104 a, 104 b shown in FIGS. 2 and 3, configured to allow a high voltage potential to be applied directly to the nozzle body, to an electrode near the print head, or to a collar surrounding the nozzles. This high voltage potential will excite either a distributed plasma cloud or a focused plasma stream directed at the 3D printed parts.”).
Sweeney does not explicitly disclose:
the ejector is configured to be selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops;
wherein the alternating electrical current comprises an electron positive (EP) mode in which ions contact a previously-deposited layer of the 3D object and remove an oxide layer from the 3D object, and an electron negative (EN) mode in which the previously-deposited layer of the 3D object is heated.
Gibson teaches a 3D printing system (Gibson Abstract), comprising:
an ejector (“jetting apparatus” or “nozzle assembly”, Gibson Par.0003) configured to be selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops (Gibson Par.0003 teaches: “Controlled magnetohydrodynamic pulsing may be used to selectively jet individual drops of molten metals and additively build up three-dimensional geometries, in a process known as magnetohydrodynamic printing (here referred to as MHD printing, or MHD). In one embodiment of this process, a jetting apparatus (here referred to as the nozzle assembly) is employed to heat solid metal feedstock above its liquidus temperature to create molten metal, contain the molten metal, keep the molten metal above its liquidus temperature, position the body of molten metal relative to a magnetic field, enable an electric current to be passed through the molten metal to create a magnetohydrodynamic pulse, and direct the flow of molten metal towards the desired target.”)
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 system of Sweeney, by adding the teachings of the ejector is configured to be selectively activated to cause the build material to be ejected in the form of a plurality of liquid drops, as taught by Gibson, in order to provide drop-on-demand control over the timing and frequency of droplet ejection, thereby providing more precise control over the placement and amount of build material deposited during formation of the three-dimensional object and improving print quality.
Sweeney in view of Gibson does not explicitly teach:
wherein the alternating electrical current comprises an electron positive (EP) mode in which ions contact a previously-deposited layer of the 3D object and remove an oxide layer from the 3D object, and an electron negative (EN) mode in which the previously-deposited layer of the 3D object is heated
Martin teaches an alternating electrical current used in additive manufacturing (Martin Abstract):
wherein the alternating electrical current comprises an electron positive (EP) mode in which ions contact a previously-deposited layer of the 3D object and remove an oxide layer from the 3D object, and an electron negative (EN) mode in which the previously-deposited layer of the 3D object is heated (Martin Col.1 lines 38-59 teaches: “Direct current TIG welding is normally accomplished with the electrode negative with respect to the workpiece. This results in the electron flow from the electrode (usually treated to enhance electron emission) to the workpiece. The electron stream heats the workpiece and results in a highly concentrated, deep penetration weld. The electrode is bombarded by positive ions in the shielding gas which clean the electrode surface of contamination. When welding some materials, particularly aluminum, there is a serious problem with rapid oxide formation on the workpiece surface. This oxide contaminates the weld, reducing the weld quality. The use of direct current with the electrode positive eliminates the surface contamination through the cleaning effect of the positive ions. This, however, results in excessive electrode heating and produces a wandering arc with shallow penetration. To overcome these problems, alternating current is commonly used to weld materials (particularly aluminum) encountering this problem. This provides the penetration of electrode negative welding with electrode positive cleaning.”).
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 system of Sweeney in view of Gibson, by adding the teachings of the alternating electrical current comprises an electron positive (EP) mode in which ions contact a previously-deposited layer of the object and remove an oxide layer from the object, and an electron negative (EN) mode in which the previously-deposited layer of the object is heated, as taught by Martin, in order to remove oxide contamination that can adversely affect material bonding while providing localized heating of the deposited material, thereby promoting improved fusion and bonding between successively deposited layers of the 3D object. Thus, increase interlayer bond strength, and improve both surface condition and thermal fusion. This leads to higher adhesion strength and reduce delamination. Therefore, improve the overall print quality.
Regarding claim 2, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, Sweeney does not disclose:
wherein the build material comprises a metal having a melting point greater than or equal to about 700 °C.
Gibson teaches a 3D printing system (Gibson Abstract):
wherein the build material comprises a metal having a melting point greater than or equal to about 700 °C (Gibson teaches the build material comprises a metal having a melting point greater than or equal to about 700 °C because the metal is copper, specifically, Gibson Par.0026 teaches: “the term “liquid metal” shall be understood to include metals and metal alloys in liquid form and, additionally or alternatively, includes any fluid containing metals and metal alloys in liquid form, unless otherwise specified or made clear by the context. Metals suitable for use with the disclosure include aluminum and aluminum alloys, copper and copper alloys, silver and silver alloys, gold and gold alloys, platinum and platinum alloys, iron and iron alloys, and nickel and nickel alloys.”; it is noted that the melting point of copper is 1084.62°C, according to Wikipedia [https://en.wikipedia.org/wiki/Copper, accessed on 08/21/2026], thus, Gibson teaches the build material comprises metal having melting point greater than 700 °C).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Sweeney in view of Gibson and Martin, by adding the teaching of build material comprising copper, as taught by Gibson, in order to offer diverse applications for 3D parts to be printed from the 3D printing system since thermoplastic materials excelling in lightweight, rapid prototyping, consumer goods, and flexible parts due to lower cost and versatility, while metal materials provide superior strength, heat resistance, and durability for critical end-use components in aerospace, automotive, and medical fields. Furthermore, copper provides exceptional thermal and electrical conductivity that enables the creation of high-performance electronics, rocket parts, and complex heat exchangers with optimized internal cooling channels that are impossible to machine or cast conventionally.
Regarding claim 3, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, but Sweeney does not disclose:
wherein the build material comprises copper, brass, titanium, nickel, or a combination thereof.
Gibson teaches a 3D printing system (Gibson Abstract):
wherein the build material comprises copper, brass, titanium, nickel, or a combination thereof (it is noted that the limitation “copper, brass, titanium, nickel, or a combination thereof” is in alternative form; therefore, only one of these was required during examination. In this case, Gibson Par.0026 teaches copper, specifically, Gibson Par.0026 teaches: “the term “liquid metal” shall be understood to include metals and metal alloys in liquid form and, additionally or alternatively, includes any fluid containing metals and metal alloys in liquid form, unless otherwise specified or made clear by the context. Metals suitable for use with the disclosure include aluminum and aluminum alloys, copper and copper alloys, silver and silver alloys, gold and gold alloys, platinum and platinum alloys, iron and iron alloys, and nickel and nickel alloys.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Sweeney in view of Gibson and Martin, by adding the teaching of build material comprising copper, as taught by Gibson, in order to offer diverse applications for 3D parts to be printed from the 3D printing system since thermoplastic materials excelling in lightweight, rapid prototyping, consumer goods, and flexible parts due to lower cost and versatility, while metal materials provide superior strength, heat resistance, and durability for critical end-use components in aerospace, automotive, and medical fields. Furthermore, copper provides exceptional thermal and electrical conductivity that enables the creation of high-performance electronics, rocket parts, and complex heat exchangers with optimized internal cooling channels that are impossible to machine or cast conventionally.
Regarding claim 6, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, and also teaches:
wherein the plasma removes an oxide from the 3D object (Sweeney in view of Gibson and Martin teaches the plasma removes an oxide from the 3D object because Sweeney discloses electrode configured to generate plasma in response to receiving the alternating electrical current, and Sweeney in view of Gibson and Martin teaches the alternating electrical current comprises an electron positive (EP) mode in which ions contact a previously-deposited layer of the 3D object and remove an oxide layer from the 3D object; as cited, explained, and incorporated in the rejection of claim 1 above).
Regarding claim 7, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, Sweeney also discloses:
wherein the 3D printing system (3D printing system 200a [Sweeney Fig.4 & Pars.0042-0043] having the nozzle housing 132 and the nozzle body 120 [Sweeney Fig.2], as cited and explained in the rejection of claim 1 above) does not comprise an enclosure around the ejector (ejector includes the nozzle housing 132 and the nozzle body 120, Sweeney Fig.2) and the substrate (platform bed 110, Sweeney Fig.1) (there is no enclosure around the nozzle housing 132, the nozzle body 120, and the platform bed 110, see Sweeney Figs.1-2, 4).
Regarding claim 8, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, Sweeney also discloses:
wherein the ejector (ejector includes the nozzle housing 132 and the nozzle body 120, Sweeney Fig.2), the substrate (platform bed 110, Sweeney Fig.1), the drops (drops formed from heating the thermoplastic filament 102 to molten state, Sweeney Pars.0004 & 0038), and the 3D object (“3D part”, Sweeney Par.0038) are not in a vacuum environment when the plurality of drops (drops formed from heating the thermoplastic filament 102 to molten state, Sweeney Pars.0004 & 0038) are ejected from the nozzle (nozzle body 120, Sweeney Fig.2) (there is no vacuum environment; therefore, the nozzle housing 132 and the nozzle body 120, the platform bed 110, the drops formed from heating the thermoplastic filament 102 to molten state, and the 3D part are not in a vacuum environment when the drops are ejected from the nozzle body 120).
Regarding claim 9, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, Sweeney also discloses:
wherein the substrate (platform bed 110, Sweeney Fig.1) does not introduce heat into the 3D object (“3D part”, Sweeney Par.0038) when the plurality of drops (drops formed from heating the thermoplastic filament 102 to molten state, Sweeney Pars.0004 & 0038) are ejected from the nozzle (nozzle body 120, Sweeney Fig.2) (the Sweeney platform bed 110 does not introduce heat into the 3D part when the drops are ejected from the nozzle body 120).
Claims 4 and 31 are rejected under 35 U.S.C. 103 as being unpatentable over Sweeney et al. (U.S. Pub. No. 2020/0298479 A1, previously cited) in view of Gibson et al. (U.S. Pub. No. 2021/0323054 A1, newly cited), Martin (U.S. Patent No. 5,264,679 A, newly cited), and further in view of Galle (WO 2019166523 A1, previously cited).
Regarding claim 4, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, but does not explicitly teach:
wherein the plasma heats the 3D object locally to increase a temperature of the previously-deposited layer of the 3D object to be from about 800 °C to about 1800 °C.
Galle teaches a 3D printing system (Galle Fig.1):
wherein the plasma (plasma jet 106 from plasma source 105, Galle Fig.1) heats the 3D object (body 103, Galle Fig.1) locally to increase a temperature of the previously-deposited layer (pre-heated region 104, Galle Fig.1) of the 3D object (body 103, Galle Fig.1) to be from about 800 °C to about 1800 °C (Galle on page 15 lines 18-21 teaches: “The one or more plasma jet sources 105 provide a plasma jet 106 focused on the underlying body 103, with an energy such that the underlying material is heated close to or at the melting temperature, or even slightly above the melting temperature of the underlying material, on a target region of the underlying body, which becomes a pre-heated region 104.”, and Galle on page 24 lines 26-31 teaches: “However, the use or application of the device in accordance with embodiments of the present invention is not limited to aluminum, and it can be used to provide additive manufacturing of bodies including any other highly heat-conductive material, in particular other metals, either pure or mixed with other elements; for example it can be used with steel and steel alloys, stainless steel and alloys thereof, brass, copper, titanium, etc. Moreover, the present invention is not limited to metals. Ceramics, polymers and such can also be used”; therefore, when copper is used, the plasma jet 106 focused on the underlying body 103 with an energy such that the underlying material is heated close to or at the melting temperature of copper, which is approximately 1084.62 °C because the melting temperature of copper is 1084.62 °C, according to Wikipedia [https://en.wikipedia.org/wiki/Copper, accessed on 04/11/2026], which is within the claimed range).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Sweeney in view of Gibson and Martin, by adding the teaching of build material comprising copper and the plasma heats the 3D object locally to increase a temperature of a top portion of the 3D object to be from about 800 °C to about 1800 °C, as taught by Galle, in order to offer diverse applications for 3D parts to be printed from the 3D printing system since thermoplastic materials excelling in lightweight, rapid prototyping, consumer goods, and flexible parts due to lower cost and versatility, while metal materials provide superior strength, heat resistance, and durability for critical end-use components in aerospace, automotive, and medical fields. In this case, copper offers exceptional thermal and electrical conductivity, good corrosion resistance, making them suitable for use in harsh or specific environments. Furthermore, locally increasing a temperature of a top portion of the 3D object to be from about 800 °C to about 1800 °C by plasma jet in order to improve layer adhesion since localized plasma heating effectively raises the temperature of the underlying layer as a new one is deposited, allowing the layers to fuse more completely, thus, this creates a stronger, more cohesive part with more uniform properties throughout. Additionally, the extremely high temperatures allow for the processing of materials that have very high melting points or require specific thermal treatment to achieve desired properties; and the plasma treatment can also be used to clean surfaces, activate materials by altering their chemical structure, and enable direct sintering processes, leading to denser, higher-quality parts.
Regarding claim 31, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, Sweeney in view of Gibson and Martin does not explicitly teach:
wherein removing the oxide layer from the 3D object or heating the 3D object are performed based on a measured property of the 3D object.
Galle teaches a 3D printing system (Galle Abstract):
wherein removing the oxide layer from the 3D object or heating the 3D object are performed based on a measured property of the 3D object (It is noted that the limitation “removing the oxide layer from the 3D object or heating the 3D object” is in alternative form; therefore, only one of these was required during examination. In this case, Galle teaches heating the 3D object is performed based on a measured property of the 3D object because Galle on page 22 lines 4-6 teaches: “one or more temperature sensors can be used for sensing the temperature of the underlying body 103 in at least the area where the extruded product 102 is deposited (at the fusion zone)”, and Galle on page 22 lines 15-29 teaches: “the plasma jet source 105 can be set so its plasma jet 106 can provide energy to a predetermined region 104 of the underlying body 103 to increase its temperature, below the melting temperature of the material of the underlying body 103, but close to it. The sensing means 502 may read the temperature of the pre-heated zone 104 and send the measurement to the control means 501 which, upon detecting that the upper limit of the melting temperature is going to be reached, can control the plasma jet source 106 so the heat provided by the plasma jet is so as to not surpass the melting temperature, preferably not even reach it. Additionally, if the temperature measurements result in a temperature lower than a predetermined lower threshold, the control means 501 can control the plasma source 105 to increase the heat that the plasma jet 106 provides. This predetermined lower threshold may be the melting temperature, or it may be lower, e.g. estimated by look-up tables, and/or based on a thermal model and geometry of the underlying body obtained from the model of the product being manufactured, and/or the necessary energy to provide strong enough joints, depending on the materials and applications.”).
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Sweeney in view of Gibson and Martin, by adding the teaching of heating the 3D object is performed based on a measured property of the 3D object, as taught by Galle, in order to maintain the heated region at desired temperature, avoid excessive heating or melting, and provide sufficient heat to promote strong fusion between deposited layers. Therefore, improve the quality of the 3D printed object.
Claim 5 is rejected under 35 U.S.C. 103 as being unpatentable over Sweeney et al. (U.S. Pub. No. 2020/0298479 A1, previously cited) in view of Gibson et al. (U.S. Pub. No. 2021/0323054 A1, newly cited), Martin (U.S. Patent No. 5,264,679 A, newly cited), Galle (WO 2019166523 A1, previously cited) and further in view of Kritchman et al. (U.S. Pub. No. 2020/0398477 A1, previously cited).
Regarding claim 5, Sweeney in view of Gibson, Martin and Galle teaches the 3D printing system set forth in claim 4, but does not explicitly teach:
wherein a remainder of the 3D object is maintained at a temperature from about 20 °C to about 250 °C.
Kritchman teaches a 3D printing system (100, Kritchman Fig.1):
wherein a remainder (remainder is previously printed layers, see some of previously printed layers in Kritchman annotated Fig.1 below) of the 3D object (3D object, Kritchman annotated Fig.1 below) is maintained at a temperature from about 20 °C to about 250 °C (Kritchman Par.0085 teaches: “the previously printed layers may be maintained at a relatively lower temperature (e.g., about 230° C.) using cooling fan 114”; therefore, Kritchman teaches the temperature of about 230° C, which is within the claimed range).
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It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Sweeney in view of Gibson, Martin and Galle, by adding the teaching of a remainder of the 3D object is maintained at a temperature of about 230 °C, as taught by Kritchman, in order to control cooling to ensure a more uniform temperature distribution throughout the part as it builds, which prevents distortion and improves the final component's dimensional accuracy. Extremely hot where the material needs to bond instantly and warm throughout the rest of the build to ensure the part cools slowly and evenly, resulting in a structurally sound and defect-free final product.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Sweeney et al. (U.S. Pub. No. 2020/0298479 A1, previously cited) in view of Gibson et al. (U.S. Pub. No. 2021/0323054 A1, newly cited), Martin (U.S. Patent No. 5,264,679 A, newly cited), and further in view of Holverson et al. (U.S. Pub. No. 2019/0099769 A1, previously cited).
Regarding claim 10, Sweeney in view of Gibson and Martin teaches the apparatus set forth in claim 1, Sweeney also discloses:
wherein a pressurized stream of gas including, but not limited to, argon, helium, carbon dioxide, and air is induced are introduced around the nozzle (nozzle body 120, Sweeney Fig.2), the plurality of drops (drops formed from heating the thermoplastic filament 102 to molten state, Sweeney Pars.0004 & 0038), the 3D object (“3D part”, Sweeney Par.0038), or a combination thereof when the plurality of drops (drops formed from heating the thermoplastic filament 102 to molten state, Sweeney Pars.0004 & 0038) are ejected from the nozzle (nozzle body 120, Sweeney Fig.2) (Sweeney Par.0039 discloses: “A pressurized stream of gas including, but not limited to, argon, helium, carbon dioxide, and air is induced through the plasma generation channel 134 from the inlet 136 to the outlet 138.”).
It is noted that Sweeney Par.0039 discloses: “A pressurized stream of gas including, but not limited to, argon, helium, carbon dioxide, and air is induced through the plasma generation channel 134 from the inlet 136 to the outlet 138.”. It is further noted that carbon dioxide is neither an inert gas nor a nitrogen gas. However, Sweeney is not specific enough about the carbon dioxide can be used alone as a pressurized stream of gas.
Thus, Sweeney in view of Gibson and Martin does not explicitly teach:
wherein neither an inert gas nor a nitrogen gas is introduced around the nozzle, the drops, the 3D object, or a combination thereof when the drops are ejected from the nozzle.
Holverson teaches a 3D printing system (10, Holverson Fig.1):
wherein neither an inert gas nor a nitrogen gas is introduced around the nozzle (manufacturing tool 20, Holverson Fig.1), the drops (droplets 22, Holverson Fig.1), the 3D object (part 12, Holverson Fig.1), or a combination thereof when the drops (droplets 22, Holverson Fig.1) are ejected from the nozzle (manufacturing tool 20, Holverson Fig.1) (Holverson Par.0029 teaches: “The one or more shielding gases may include, but are not limited to, argon, carbon dioxide, helium, nitrogen, hydrogen, and combinations thereof. ”; thus, Holverson teaches the carbon dioxide gas can be used alone; it is noted that the carbon dioxide gas is neither an inert gas nor a nitrogen gas)
It would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Sweeney in view of Gibson and Martin, by adding the teaching of using the carbon dioxide alone, as taught by Holverson, in order to provide high ionization potential, which helps stabilize the plasma; additionally, the modification would also offer cost-effective printing process since carbon dioxide is generally cheaper than helium and argon, making it an attractive option for large-scale printing processes.
Conclusion
The following prior art(s) made of record and not relied upon is/are considered pertinent to Applicant’s disclosure.
Vader et al. (U.S. Patent No. 9,616,494 B2) discloses a printer that produces objects from liquid conductive material. The printhead has a chamber for containing liquid conductive material surrounded by an electromagnetic coil. A DC pulse is applied to the electromagnetic coil, resulting in a radially-inward force on the liquid conductive material. The force on the liquid conductive material in the chamber results in a drop being expelled from an orifice. In response to a series of pulses, a series of drops fall onto a platform in a programmed pattern, resulting in the formation of an object.
Johnson et al. (U.S. Pub. No. 2017/0266728 A1) discloses apparatus and methods for performing additive manufacturing. The apparatus includes a vacuum chamber for fabricating a workpiece composed of deposited metal, a table positioned within the vacuum chamber, and configured to support fabrication of the workpiece on a substrate, and one or more multiple droplet emitters coupled to the vacuum chamber, and arranged to irradiate the workpiece with a stream of molten metal droplets during fabrication.
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/THAO UYEN TRAN-LE/Examiner, Art Unit 3761 08/21/2026
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