DETAILED CORRESPONDENCE
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 .
Response to Arguments
Applicant's arguments have been fully considered.
Applicant argues that “Rao does not teach the claimed overcuring operation. Rao, paragraph 0051, states that "the dosage of the exposure can be regulated to maximize the buildup of polymerization stress at the interface," which is cited by the Office Action as allegedly teaching an overcuring operation. Office Action, page 6. However, Rao explicitly teaches the opposite approach, where it states that "[t]he total exposure at the support-part interface 121 can be lowered in intensity to lower the crosslink density relative to the part 11 O." Rao, paragraph 0051 ( emphasis added). That is, Rao' s technique involves reducing exposure intensity at the interface to weaken it, not increasing exposure as required by the claimed overcuring operation.”
Examiner does not find this persuasive. Rao teaches multiple ways to make the interface weaker. One way is to undercure the area in order to reduce crosslink density and thus make the part weaker at the area. Another way is to overcure the area in order to make the area more brittle and have stress. The latter is relied upon in the combination and meets the claim.
Specifically, in paragraph 51 Rao states: The total exposure at the support-part interface 121 can be lowered in intensity to lower the crosslink density relative to the part 110. This can result in a lower modulus and fracture strength.” A person of skill in the art would understand that this means the crosslink density is reduced.
However, in paragraph 51 Rao also states: “Additionally, the dosage of the exposure can be regulated to maximize the build-up of polymerization stress at the interface 121, enabling fracture at a lower force than the yield strength of the part 110.” A person of skill in the art would understand that “maximize the build-up of polymerization stress” means the crosslink density is increased.
Rao specifically points to Fig 5B and describes localized embrittlement as a useful method for forming weaker interface area. A person of skill in the art would know that overcuring causes embrittlement. This is evidenced at least by US 20250297044 A1 which teaches (in the field of 3D printing) “If the photoinitiator content is too high, this can lead to so-called “overcuring” of the irradiated composition, i.e. embrittlement”1 or see in US 4100311 A (“With higher and lower doses, overcure (embrittlement) and undercure (poor bonding) have resulted”).
A person of skill in the art would not read “maximize the build-up of polymerization stress at the interface” and interpret this to mean there is undercuring. They would know this refers to overcuring to embrittle the interface area and thereby achieve an interface with an “embrittled region having a lower ultimate tensile stress than the nominally printed region, which therefore does not exhibit the ductility of the nominally printed region, thus resulting in a lower failure strain (e.g., lower breakaway force).” (Rao at P0054). Use of the term “breakaway” further supports the conclusion that Rao envisions embrittlement as a mode of weakening the interface area.
Applicant argues “Rao's entire methodology is premised on reducing exposure intensity at the interface.”.
Examiner does not find this persuasive because this is not accurate. Rao teaches one methodology that is premised on reducing exposure intensity at the interface. Rao also teaches, as explained above, overcuring. See, for example, Fig 5B and description thereof, e.g., quoted above.
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.
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.
Claim 1-8 and 10-12 is/are rejected under 35 U.S.C. 103 as being unpatentable over Barth (US 20180304541 A1) and in view of Rao (US 20220040915 A1) evidenced by US 20250297044 A or US 4100311 A
In reference to claim 1, Barth discloses a method of manufacturing a three-dimensional (3D) object, comprising: (“additive manufacturing typically includes: (a) optionally, but preferably, a base; (b) at least one three-dimensional lattice support connected to the base (when present); (c) at least one three-dimensional object” [Abstract]. And see figures 2 and 6)
fabricating the 3D object on a support base or a build tray, wherein the support base or build tray is connected to the 3D object by a plurality of support structures; and (See abstract, quoted above, and figures 2 and 6)
curing the 3D object, the support base, and the plurality of support structures, wherein portions of the plurality of support structures are subjected to an … operation to facilitate removal of the 3D object from the support structures (“curing step is carried out under conditions in which the least one object is made less frangible than the interconnecting supports” [P0025]. In other words, curing conditions result in supports that are more frangible – easier to break off, remove.).
Barth differs from the claimed invention because Barth does not specify the curing comprises an overcuring operation wherein the overcuring operation exposes the portions of the plurality of support structures to an increased amount of curing radiation compared to other portions of the 3D object, the support base, and the plurality of support structures that are not subjected to the overcuring operation.
In the same field of endeavor or reasonably pertinent to the particular problem faced by the inventor, support removal in additive manufacturing (title), Rao discloses “methods for making it easier to remove support structures… adjusting an intensity of exposure to light at interfaces between the object and support structures” (Abstract) and “modifying an exposure to a light source at one or more locations proximate to or at the interface(s) to reduce at least one of a fracture strength or a ductility of material of at least one of the one or more locations proximate to or at the interface(s);” (P0006);
“Adjusting an intensity of exposure of the deposited material to the light source can result in a strength of the deposited material at or adjacent to the one or more interfaces being weaker than a strength of the deposited material that forms the desired three-dimensional object” (P0008);
“the dosage of the exposure can be regulated to maximize the build-up of polymerization stress at the interface 121, enabling fracture at a lower force than the yield strength of the part 110” (P0051). This means overcuring2.; and,
“the power of the laser and the scan patterns can be adjusted at the support-part interface 121 to alter the degree and rate of cure to selectively lower the tensile strength of the interface 121” (P0053)
In the above, “maximize the build-up of polymerization stress at the interface” means that curing is occurring so much that internal forces make the material easier to break at the interface. This reads on overcuring.
Barth suggests curing to make the parts frangible and Rao teaches localized overcuring to make the interfaces specifically easy to fracture.
Rao improves support removal of Barth by making the support material easier to remove specifically at the interfaces where the supports need to be removed.
Therefore, it would have been obvious to one of ordinary skill in the art with a reasonable expectation of success before the effective filing date of the claimed invention to configure the method of Barth to integrate the step of curing such that curing comprises overcuring the interface, such that the dosage of the exposure can be regulated to maximize the build-up of polymerization stress at the interface and thereby arrive at the invention as claimed.
In reference to claim 2 the cited prior art discloses the invention as in claim 1.
Barth further discloses removing the 3D object from the support base or build tray (“separating each said object from said interconnecting supports, and from said stand-off supports if present, to produce said at least one object” [Claim 15])
In reference to claim 3 the cited prior art discloses the invention as in claim 1.
Barth further discloses wherein each of the plurality of support structures is tapered such that a contact area between the support structure and the 3D object is smaller than a contact area between the support structure and the support base or build tray (See Fig 1-6)
In reference to claim 4 the cited prior art discloses the invention as in claim 1.
Barth further discloses wherein the curing comprises curing using a light source or a heat source (“further curing step is carried out by heating” [Claim 16]); or Rao at P0053.
In reference to claim 5, the cited prior art discloses the invention as in claim 4
Rao further discloses wherein the curing comprises tracing a laser through a photopolymer in a layer-by-layer manner to selectively cure portions of the photopolymer to produce the 3D object, the support base, and the plurality of support structures (“the power of the laser and the scan patterns can be adjusted at the support-part interface 121 to alter the degree and rate of cure to selectively lower the tensile strength of the interface 121” [P0053])
In reference to claim 6, the cited prior art discloses the invention as in claim 1.
Rao further discloses wherein the overcuring operation exposes the portions of the plurality of support structures to an intensity … greater than an intensity used for curing portions of the 3D object, the support base, and the plurality of support structures that are not subjected to the overcuring operation (“Adjusting an intensity of exposure of the deposited material to the light source can result in a strength of the deposited material at or adjacent to the one or more interfaces being weaker than a strength of the deposited material that forms the desired three-dimensional object” [P0008] and “the dosage of the exposure can be regulated to maximize the build-up of polymerization stress at the interface 121, enabling fracture at a lower force than the yield strength of the part 110” [P0051]. Maximizing polymerization stress at the interface implies that the intensity is relatively higher at the interface.);
Rao does not disclose that the curing at the interface is at least 1.5 times the object, however, where the general conditions of the invention are taught it is not inventive to claim an optimized value. Here, 1.5 times curing intensity, or curing 150% is an optimization of the teaching of Rao to provide additional curing to embrittle the support material (see Fig 5B of Rao).
In reference to claim 7 the cited prior art discloses the invention as in claim 1.
Barth further discloses wherein the support structure and the 3D object on the support structure are fabricated using an additive manufacturing process (“construction of a three-dimensional object is performed in a step-wise or layer-by-layer manner.)” [P0003])
In reference to claim 8 the cited prior art discloses the invention as in claim 1.
Rao further discloses wherein the overcuring operation is performed in a single pass during the additive manufacturing process (“scan pattern can be used, for example, to build the support structure on a layer-by-layer basis” [P0012]).
In reference to claim 10 the cited prior art discloses the invention as in claim 1.
Barth further discloses wherein the additive manufacturing process is performed in a stepwise manner, wherein a different layer of the 3D object is fabricated at each step, and wherein the overcuring is performed at one or more predetermined layers of an overcure region (“construction of a three-dimensional object is performed in a step-wise or layer-by-layer manner.)” [P0003] and “the further curing step is carried out under conditions in which the least one object is made less frangible than the interconnecting supports” [P0025]. Further curing the entire object reads on multiple layers.)
In reference to claim 11 the cited prior art discloses the invention as in claim 1.
Rao further discloses wherein the one or more predetermined layers of the overcure region correspond to less than the top 15% of layers of the support structures that are adjacent to the 3D object (“modifying print instructions for forming the interface(s) to change one or more mechanical properties of the material within the one or more layers” [P0006]).
In reference to claim 12 the cited prior art discloses the invention as in claim 1.
Rao further discloses wherein the 3D object is a multi-layer object (“build the support structure on a layer-by-layer basis” [P0012]), and wherein:
fabricating the support structure and fabricating the 3D object each comprise selectively curing a photocurable polymer at specified locations using a first exposure time and a first energy level that are selected to cure a first thickness of the photocurable polymer corresponding to a layer; and (“resin 141 is cured layer-by-layer” [P0039])
the overcuring operation comprises curing the photocurable polymer at an overcure region using a second exposure time and a second energy level that are selected to cure a second thickness of the photocurable polymer, wherein at least one of a) the second exposure time is greater than the first exposure time or b) the second energy level is greater than the first energy level (“the dosage of the exposure can be regulated to maximize the build-up of polymerization stress at the interface 121, enabling fracture at a lower force than the yield strength of the part 110” [P0051]; and,
“the power of the laser and the scan patterns can be adjusted at the support-part interface 121 to alter the degree and rate of cure to selectively lower the tensile strength of the interface 121” [P0053])
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 nonprovisional extension fee (37 CFR 1.17(a)) 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 mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to NICHOLAS KRASNOW whose telephone number is (571)270-1154. The examiner can normally be reached M-R: 8am-5pm.
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/NICHOLAS KRASNOW/Examiner, Art Unit 1744
1 Additionally, while not cited, this
2 Rao teaches multiple ways to make the interface weaker. One way is to undercure the area in order to reduce crosslink density and thus make the part weaker at the area. Another way is to overcure the area in order to make the area more brittle and have stress.
Specifically, in paragraph 51 Rao states: The total exposure at the support-part interface 121 can be lowered in intensity to lower the crosslink density relative to the part 110. This can result in a lower modulus and fracture strength.” A person of skill in the art would understand that this means the crosslink density is reduced.
However, in paragraph 51 Rao also states: “Additionally, the dosage of the exposure can be regulated to maximize the build-up of polymerization stress at the interface 121, enabling fracture at a lower force than the yield strength of the part 110.” A person of skill in the art would understand that “maximize the build-up of polymerization stress” means the crosslink density is increased.
Rao specifically points to Fig 5B and describes localized embrittlement as a useful method for forming weaker interface area. A person of skill in the art would know that overcuring causes embrittlement. This is evidenced at least by US 20250297044 A1 which teaches (in the field of 3D printing) “If the photoinitiator content is too high, this can lead to so-called “overcuring” of the irradiated composition, i.e. embrittlement” or see in US 4100311 A (“With higher and lower doses, overcure (embrittlement) and undercure (poor bonding) have resulted”).
A person of skill in the art would not read “maximize the build-up of polymerization stress at the interface” and interpret this to mean there is undercuring. They would know this refers to overcuring to embrittle the interface area and thereby achieve an interface with an “embrittled region having a lower ultimate tensile stress than the nominally printed region, which therefore does not exhibit the ductility of the nominally printed region, thus resulting in a lower failure strain (e.g., lower breakaway force).” (Rao at P0054). Use of the term “breakaway” further supports the conclusion that Rao envisions embrittlement as a mode of weakening the interface area.
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