DETAILED ACTION
Response to Amendment
The Amendment filed 1/15/26 has been entered. Claims 1-10 remain pending in the application. Claim(s) 10 has been withdrawn. New claim(s) 11-13 have been added.
Claim Rejections - 35 USC § 102
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Language from the reference(s) is shown in quotations. Limitations from the claims are shown in quotations within parenthesis. Examiner explanations are shown in italics.
Claims 1-5, 7-9, and 11 are rejected under 35 U.S.C. 102(a)(2) as being anticipated by Ljungblad (US 20220105567 A1).
Regarding claim 1, Ljungblad teaches “a method for heating and preparing of a powder layer at a powder bed for subsequent processing by irradiating said powder bed with an electron beam from an electron source, when manufacturing a three dimensional object by fusing layer by layer of a powder material by means of an electron beam” (which reads upon “a method for processing a powdery material for additive manufacturing of a workpiece comprising the following steps”, as recited in the instant claim; paragraph [0001]). Ljungblad teaches “thin layers of powder are repeatedly spread by a powder distributor over a powder bed 103 and fused by a beam 101 from an energy source 102 to a predetermined geometry for each layer” (which reads upon “a) providing - a device for receiving a powder bed of the powdery material to be processed, and- a beam generator adapted to direct an energy beam to laterally different locations of the powder bed, b) layering the powdery material into the powder bed”, as recited in the instant claim; paragraph [0025]). Ljungblad teaches that “the electron source is designed for fast moving or scanning of the electron beam over the powder bed to different heating positions or heating areas at the powder bed” (which reads upon “c) irradiating an area in the powder bed with the energy beam”, as recited in the instant claim; paragraph [0042]). Ljungblad teaches that “the positioning of consecutive heating positions 301 at the powder bed 304 may be selected randomly, and that the electron beam is moved 302 with high speed to the next beam heating position, and that alternatively, the positioning of consecutive heating positions may be selected randomly but where also the probability of the positioning may be determined by a time dependent mathematical function such as for example a two dimensional gaussian distribution or a two dimensional hyperbolic distribution” (which reads upon “the area being composed of a plurality n of points P1...Pn arranged in two dimensions, which are irradiated successively; wherein d) more than 50 times during the irradiation of the area, two successively irradiated points Pi, Pi+1 are spaced apart from one another in such a way that, in each of the two dimensions, at least one other point P1...Pi-1, Pi+2...Pn to be irradiated is located between the two successively irradiated points Pi, Pi+1”, as recited in the instant claim; paragraph [0046] and FIG. 3). Ljungblad teaches that “the scanning of the electron beam to different positions forms a pattern for maintaining a minimum distance between recently visited positions, to achieve an efficient preheating of the powder bed prior to fusion of the powder by the electron beam” (which reads upon “a pre-defined local minimum distance between two successively irradiated points is respected”, as recited in the instant claim; paragraph [0043]). Ljungblad teaches that “a selected region 205 (or regions) of said powder bed is repeatedly heated for distributing heat over said selected powder bed region” (which reads upon “a pre-defined local maximum distance between two successively irradiated is respected”, as recited in the instant claim; paragraph [0043] and FIG. 2). Ljungblad teaches that “in embodiments, a pattern of powder bed heating positions is provided at said powder layer bed for maintaining a minimum time until a powder bed heating position is repeatedly heated” (which reads upon “a pre-defined minimum time distance around an irradiated point is respected”, as recited in the instant claim; paragraph [0010]).
Regarding claims 2-3, Ljungblad teaches the method of claim 1 as stated above. Ljungblad teaches that “the positioning of consecutive heating positions may be selected randomly where the probability of the positioning may be determined by a time dependent mathematical function” (paragraph [0017]).
Regarding claim 4, Ljungblad teaches the method of claim 1 as stated above. Ljungblad teaches that “the purpose of this invention is to provide a method for heating of a powder bed by an electron beam” (paragraph [0028]). Ljungblad teaches that “in additive manufacturing systems it is desired to preheat the powder bed in a controlled manner before a region of the top powder layer of the powder bed is fused or melted, and that by preheating the powder bed a process temperature can be achieved, providing the advantage that less energy need to be irradiated towards the powder bed in the subsequent fusion step to achieve solidified material” (paragraph [0028]).
Regarding claim 5, Ljungblad teaches the method of claim 1 as stated above. Ljungblad teaches that “after a heating pattern of a selected region of the powder bed is finished, it is possible to repeat heating of the same selected region several times to achieve a desired heating result” (paragraph [0036]).
Regarding claim 7, Ljungblad teaches the method of claim 1 as stated above. Ljungblad teaches that “it is desired to consider a number of different parameters when developing the heating pattern, such as; distance to previous heating positions, amount of energy and electrical charge deposited at a heating position, time duration at a heating position, time required for beam movement between heating positions, time required for the heat and electrical charge to dissipate in the powder bed and beam power and spot size of the electron beam irradiating the powder bed” (paragraph [0038]). Ljungblad teaches that “the positioning of consecutive heating positions may be selected randomly where the probability of the positioning may be determined by a time dependent mathematical function” (paragraph [0017]).
Regarding claim 8, Ljungblad teaches the method of claim 1 as stated above. Ljungblad teaches that “the positioning of consecutive heating positions may be selected randomly where the probability of the positioning may be determined by a time dependent mathematical function” (paragraph [0017]).
Regarding claim 9, Ljungblad teaches the method of claim 1 as stated above. Ljungblad teaches that “when the electron beam spot arrives to a new heating position, it rest or holds a fixed position and heats the powder in that position for a predetermined time” (paragraph [0033]). Ljungblad teaches that “then the electron beam spot moves rapidly with jumping speed to the next heating position, where it again rest or holds a fixed position and heats the powder in that position for a predetermined time” (paragraph [0033]; moving while the beam is “on” reads on wherein the path is exposed). Ljungblad teaches that “said electron source 102 is designed for rapid scanning of the electron beam spot over the powder bed 103, 204, 304 while switching between a high speed or “jumping speed” which is high enough to give negligible local heat and electron transfer to the powder bed 103, 204, 304, and a beam spot holding a heating position 201, 301 to give significant heat transfer to the powder bed 103, 204, 304” (paragraph [0034]).
Regarding claim 11, Ljungblad teaches the method of claim 1 as stated above. Ljungblad teaches that “said powder bed may be irradiated with an electron beam from an electron source for maintaining a powder bed process temperature” (paragraph [0013]).
Claim Rejections - 35 USC § 103
Claims 6 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Ljungblad (US 20220105567 A1), as applied to claim 1 above, and further in view of Lee et al., Correlations of cracking with scan strategy and build geometry in electron beam powder bed additive manufacturing, Additive Manufacturing 32 (2020) 101031, previously cited.
Regarding claims 6 and 12, Ljungblad teaches the method of claim 1 as stated above. Ljungblad teaches that “electron beam powder bed fusion takes place in vacuum and the electron beam may operate in several process steps: it may preheat the powder layers to a semi-sintered state, it may fuse the powder by melting or by solidifying the powder in the powder layers and it may add additional heat to the powder bed to maintain a predetermined temperature of the powder bed throughout the build” (paragraph [0026]).
Ljungblad is silent regarding a molten bath. This term is interpreted as a melt pool, as it is commonly known in the art.
Lee is similarly concerned with electron beam powder bed additive manufacturing (title). Lee teaches that “Inconel 738 feedstock powder produced by gas atomization was used as the powder in the EBM process” (pages 2-5). Lee teaches that “an Arcam Q10 machine was used to create turbine blades on a 304 stainless steel start plate with dimensions of 150 × 150 × 10 mm” (page 2). Lee teaches that “to understand the correlations between temperature distribution and cracking susceptibility, it is important to examine the spatial and temporal evolution of stress during the melting process across all locations in a given layer” (page 5). Lee teaches that “the electron beam heat source is considered as a point-concentrated heat source due to the relatively large element size compared with the melt pool” (which reads upon “wherein the step c) generates a molten bath”, as recited in the instant claims; page 6). Lee teaches that “in this study, two new scan patterns, called random spot-melting and random raster scan, are proposed and tested for the minimization of the impact of radical geometrical transformation” (page 7). Lee teaches that “random spot-melting and random raster scan each randomly select their starting position; then, melting occurs at a random point selected from the group of unmelted points” (which reads upon “a molten bath which is not guided”, as recited in the instant claim; page 7; pointwise melting or spot melting as taught by Ljungblad and Lee does not cause lateral movement of the center of the melt which reads on not guided as explained in the instant specification).
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 Ljungblad to use spot melting for the fusing step of electron beam powder bed fusion, as taught by Lee because the end purpose of Lee is to create an object by electron beam powder bed fusion, not just to preheat the powder bed indefinitely and both Ljungblad and Lee teach heating by causing the electron beam to jump from spot to spot, rather than moving at a constant speed.
Claim 13 is rejected under 35 U.S.C. 103 as being unpatentable over Ljungblad (US 20220105567 A1), as applied to claim 1 above, and further in view of Gerking et al., (US 20160318105 A1).
Regarding claim 13, Ljungblad teaches the method of claim 1 as stated above.
Ljungblad is silent regarding wherein the powdery material has an average grain size D50 in the range of from 10 μm to 150 μm. Regarding the subject limitation, in order to carry out the invention of Ljungblad, it would have been necessary and obvious to look to the prior art for exemplary average grain size of powders used in electron beam powder bed fusion. Gerking provides this teaching. Gerking teaches the manufacturing of metal or ceramic powders suitable for generative methods, also called additive methods, such as laser sintering/melting and electron beam melting (paragraphs [0001]-[0002]). Gerking teaches that it is extremely important that the grain size of the metal powder does not exceed a maximal grain size and that a fluctuation width of a statistical grain size distribution of the manufactured powder is as small as possible, thus that the grain size deviates as little as possible from a desired grain size (paragraph [0002]). Gerking teaches a further trial with a 38 mm rod of stainless steel 1.4462 (paragraph [0095]). Gerking teaches that the mean grain size hereby was d50=49 μm (paragraph [0095]). 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 average grain size of the powder, such as within the claimed ranges, as taught by Gerking, motivated to perform a conventional electron beam powder bed fusion process using known and tested average grain size of the powder predictably suitable for electron beam powder bed fusion applications.
Response to Arguments
Applicant’s arguments with respect to amended claim(s) 1-9 and new claims 11-13 have been considered but are moot because the new ground of rejection does not rely on any reference applied in the prior rejection of record for any teaching or matter specifically challenged in the argument.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any extension fee pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the date of this final action.
Contact Information
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.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. The Examiner requests that interviews not be scheduled during the last week of each fiscal quarter or the last half of September, which is the end of the fiscal year. Q3: 6/22-6/26/26; Q4: 9/21-9/30/26.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Keith Hendricks can be reached on (571)272-1401. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/REBECCA JANSSEN/Primary Examiner, Art Unit 1733
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