Prosecution Insights
Last updated: April 19, 2026
Application No. 18/000,288

IRON-BASED POWDER FOR DUST CORE, DUST CORE, AND METHOD OF MANUFACTURING DUST CORE

Non-Final OA §103§112
Filed
May 24, 2023
Examiner
NGUYEN, TUYEN T
Art Unit
2837
Tech Center
2800 — Semiconductors & Electrical Systems
Assignee
JFE Steel Corporation
OA Round
1 (Non-Final)
82%
Grant Probability
Favorable
1-2
OA Rounds
2y 9m
To Grant
82%
With Interview

Examiner Intelligence

Grants 82% — above average
82%
Career Allow Rate
1001 granted / 1226 resolved
+13.6% vs TC avg
Minimal +1% lift
Without
With
+0.8%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
50 currently pending
Career history
1276
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
54.5%
+14.5% vs TC avg
§102
22.9%
-17.1% vs TC avg
§112
17.7%
-22.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1226 resolved cases

Office Action

§103 §112
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. 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 appl icant regards as his invention. Claims 1-20 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 claim 1, applicant should clarify the structure and/or arrangement of the dust core intended by “a median particle size calculated based on cumulative volume frequency of particle of the iron-based powder for dust core is 150 micrometer or less ”. Applicant also should clarify what is intended by “ cumulative volume particle size of the particles with an aspect ration of 0.70 or less is 70% or less, and a median aspect ratio calculated based on cumulative volume frequency is 0.60 or more ”. It is unclear what is/are applicant intended to claim. Claims 2-20 inherit the defects of the parent claim. Claim Rejections - 35 USC § 103 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. Claim (s) 1 -2, 4-6, 8, 11, 16 , as best understood in view of the rejection under 35 USC 112 second paragraph, is/are rejected under 35 U.S.C. 103 as being unpatentable over Hisato et al. [JP 2004-156134A] . Regarding claims 1-2, as best understood in view of the rejection under 35 USC 112 second paragraph , Hisato et al. discloses an Fe-based compact core [dust core] comprising magnetic powder/particle mainly consist of Fe, Si P, C, and B [abstract], wherein the median or average D50 powder size is in range between 45 micrometer and 500 micrometer [para 0015 and 0028]. Hisato et al. further discloses aspect ratio of the powder is about 1.5 or less with the volume of 30% or more and 80% or less [para 0105]. Hisato et al. disclose the instant claimed invention except for the specific calculation based on “ cumulative volume frequency of the particles” . The specific calculation based on “ cumulative volume frequency of the particles ” would have been an obvious matter of design consideration for the purpose of selecting correct particle sizes for the magnetic core. Hisato et al. disclose the instant claimed invention except for the specific aspect ratio. It would have been obvious to one having ordinary skill in the art at the time the invention was made to select or calculate the aspect ratio of the particles of 0.70 or less in 70% or less since it has been held that where the general conditions of a claim are disclosed in the prior art, discovering the optimum or workable ranges involves only routine skill in the art. In re Aller, 105 USPQ 233 [note, Hisato et al. discloses the volume range 30% to 80%]. Regarding claims 4 and 8, Hisato et al. further discloses insulator being added/mixed with magnetic powder to form the compact/dust core. The insulator mixed/added to the magnetic powder/particle would exhibit the insulating coating a thin layer on the surface of the soft magnetic powder/particle. Regarding claims 5 and 11, both Hisato et al. and Miho et al. discloses a compact/dust core formed by the Fe-based composition particles. Regarding claims 6 and 16, the method steps would necessitate by the claimed apparatus. Claim (s) 3 , 7 , 9-10, 12-15 and 17-20 is/are rejected under 35 U.S.C. 103 as being unpatentable over Hisato et al. in view of Miho et al. [JP 2016-003366 A ] . Regarding claims 3 and 7, Hisato et al. further discloses the compact/dust core formed of Fe, Si, B, P and C [para 0025] . Hisato et al. disclose the instant claimed invention except for the specific of the composition. Miho et al. discloses a dust magnetic core comprising Fe-based soft magnetic alloy powder having a composition of Fe a Si b B c P d Cu e Sn f , wherein 79 ≤ a ≤ 86 at%, 0 ≤ b ≤ 10 at%, 1 ≤ c ≤ 14 at%, 1 ≤ d ≤ 15at%, 0.4 ≤ e ≤ 2 at%, and 0.5 ≤ f ≤ 6 at% [see abstract]. It would have been an obvious to one having ordinary skill in the art, before the effective filing date of the claimed invention, to use the composition of Miho et al. [include Cu and/or Sn] for the composition of Hisato et al. for the purpose of improving magnetic performance and thermal/sintering aiding process. Regarding claims 9 -10, Hisato et al. further discloses insulator being added /mixed with magnetic powder to form the compact/dust core. The insulator mixed/added to the magnetic powder/particle would exhibit the insulating coating a thin layer on the surface of the soft magnetic powder/particle. Regarding claims 12 -15, both Hisato et al. and Miho et al. discloses a compact/dust core formed by the Fe-based composition particles. Regarding claims 17 -20, the method steps would necessitate by the claimed apparatus. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to FILLIN "Examiner name" \* MERGEFORMAT TUYEN T NGUYEN whose telephone number is FILLIN "Phone number" \* MERGEFORMAT (571)272-1996 . The examiner can normally be reached FILLIN "Work Schedule?" \* MERGEFORMAT Mon - Fri 8:30-5:30 . Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, FILLIN "SPE Name?" \* MERGEFORMAT Shawki Ismail can be reached at FILLIN "SPE Phone?" \* MERGEFORMAT 571-272-3985 . The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /TUYEN T NGUYEN/ Primary Examiner, Art Unit 2837
Read full office action

Prosecution Timeline

May 24, 2023
Application Filed
Feb 25, 2026
Non-Final Rejection — §103, §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

1-2
Expected OA Rounds
82%
Grant Probability
82%
With Interview (+0.8%)
2y 9m
Median Time to Grant
Low
PTA Risk
Based on 1226 resolved cases by this examiner. Grant probability derived from career allow rate.

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