Methods and apparatus for rolling film additive manufacturing with modified polymerizable material

Abstract

Provided according to embodiments of the application are methods of making a three-dimensional object that include modifying polymerizable material prior to additively manufacturing the object, for example, by a rolling film additive manufacturing process. Apparatus for making the three-dimensional objects are also provided.

Description

[0001] Attorney Docket No. 1151.261.WO

[0002] METHODS AND APPARATUS FOR ROLLING FILM ADDITIVE MANUFACTURING WITH MODIFIED POLYMERIZABLE MATERIAL RELATED APPLICATIONS

[0003] This application claims priority from U.S. Provisional Application No.

[0004] 63 / 773,934, filed March 18, 2025, the disclosure of which is incorporated by reference in its entirety.

[0005] FIELD OF THE INVENTION

[0006] The present invention relates to apparatus and methods for additive manufacturing, and in particular, apparatus and methods for rolling film additive manufacturing.

[0007] BACKGROUND

[0008] A group of additive manufacturing techniques sometimes referred to as "stereolithography" create a three-dimensional object by the sequential polymerization of a light polymerizable resin. Such techniques may be "bottom-up" techniques, where light is projected into the resin onto the bottom of the growing object through a light transmissive window, or "top down" techniques, where light is projected onto the resin on top of the growing object, which is then immersed downward into a pool of resin.

[0009] The introduction of a rapid stereolithography technique sometimes referred to as

[0010] continuous liquid interface production (CLIP) has expanded the usefulness of stereolithography from prototyping to manufacturing. See e.g., J. Tumbleston, et al., Continuous liquid interface production of 3D objects, Science, 347, 1349-1352; R. Janusziewicz, et al., Layerless fabrication with continuous liquid interface production, PNAS, 113, 11703-11708 (18 October 2016); and U.S. Pat. Nos. 9,211 ,678, 9,205,601 , and 9,216,546.

[0011] Inkjet 3D printers typically operate by depositing resin droplets that are partially cured in flight in a layer-by-layer fashion. This process may allow for voxel-level control of color and voxel-control of material properties. However, this process requires inks that are very low in viscosity, typically less than 10 centipoise (cP). This imposesAttorney Docket No. 1151.261.WO

[0012] practical limitations on the materials that can be printed using this technique as high-performance resins are typically much higher in viscosity (~1,000 - 20,000 cP, or higher).

[0013] Rolling film printing (also referred to as "RFP") additive manufacturing methods are known in the art. For example, apparatus and methods for RFP are described in U.S. Patent Nos. 10,792,868, 11,654,625, and 11,376,787, and in WO Publication No. WO2024 / 197214, the contents of each of which are herein incorporated by reference in their entirety. RFP provides the ability to print with very viscous resins. However, RFP apparatus and methods have their own challenges. For example, excess unreacted resin may be transferred from the film to the printed part due to wicking and adhesion of uncured resin to the cured part. In addition, traditional RFP methods do not allow for voxel-by-voxel control of color. Accordingly, new methods and apparatus for additive manufacturing are needed.

[0014] SUMMARY

[0015] Some embodiments of the present invention are directed to a method of making a modified three-dimensional object, including: (a) coating polymerizable material onto an optically transparent film; (b) optionally modifying the polymerizable material (e.g., by depositing pigment thereon and / or by pre-irradiating) on the film; (c) positioning modified and / or unmodified polymerizable material between a radiation source and a build platform such that the modified and / or unmodified polymerizable material contacts the build platform; (d) irradiating a portion of the modified and / or unmodified polymerizable material through the optically transparent film (e.g., in a predetermined pattern) with the radiation source to solidify the modified and / or unmodified polymerizable material and laminate it to the build platform, thus forming an object attached to the build platform; (e) positioning additional modified and / or unmodified polymerizable material between the radiation source and the build platform such that the additional modified and / or unmodified polymerizable material contacts the object attached to the build platform; (f) irradiating a portion of the additional modified and / or unmodified polymerizable material (e.g., in a predetermined pattern) with the radiation source to solidify and laminate theAttorney Docket No. 1151.261.WO

[0016] additional modified and / or unmodified polymerizable material to the object, thus adding an object layer to the object; and (g) repeating steps (e) and (f) until the object attached to the build platform forms the three-dimensional object or an intermediate having the same shape, or the shape to be imparted to, the three-dimensional object, wherein the object or intermediate includes at least one object layer formed from modified polymerizable material.

[0017] In some embodiments, modifying the polymerizable material includes depositing at least one compound (e.g., one or more pigments) on a surface of the polymerizable material.

[0018] In some embodiments, the at least one compound includes a pigment.

[0019] In some embodiments, the pigment is present in a UV-curable and / or conductive ink.

[0020] In some embodiments, the at least one compound includes a UV-stabilizer, an antioxidant, an antistatic compound, a filler, and / or a compound that is reactive with the polymerizable material.

[0021] In some embodiments, the at least one compound contacts the polymerizable material for a time in a range of one second to one minute before irradiation in step (d) or step (f).

[0022] In some embodiments, the at least one compound is deposited in a pattern that corresponds to (e.g., is the same or overlaps with) a pattern of irradiation in step (d) or step (f).

[0023] In some embodiments, the at least one compound (e.g., a pigment) is only deposited onto portions of the polymerizable material that, once irradiated, will form an outward facing surface of the three-dimensional object.

[0024] In some embodiments, the at least one compound is deposited onto polymerizable material that has been partially cured (e.g., by pre-irradiation).

[0025] In some embodiments, modifying the polymerizable material includes irradiating the polymerizable material to partially cure a portion of the polymerizable material prior to contacting the build platform in step (c) or contacting the object in step (e).Attorney Docket No. 1151.261.WO

[0026] In some embodiments, irradiation in steps (d) and / or (f) is from a primary radiation source and the partially curing of the polymerizable material uses radiation from a secondary radiation source.

[0027] In some embodiments, an interface between the partially cured polymerizable material and unreacted polymerizable material is removed (e.g., ablated with a laser) to decrease contact between the partially cured polymerizable material and the unreacted polymerizable material, optionally wherein a thickness of the unreacted polymerizable material on the optically transparent film is decreased (e.g., by laser ablation).

[0028] In some embodiments, the partially cured polymerizable material is cleaned to remove excess unreacted polymerizable material prior to contacting the partially cured polymerizable material with the build platform in step (c) or contacting the object in step (e).

[0029] In some embodiments, the method further includes partially curing a first type of polymerizable material and irradiating (e.g., in step (d) or step (f)) to form a first portion of an object layer, and then partially curing a second type of polymerizable material and irradiating (e.g., in step (d) or step (f)) to form a second portion of the object layer, thereby forming a composite object layer.

[0030] In some embodiments, the method further includes partially curing a first type of polymerizable material and irradiating (e.g., in step (d) or step (f)) to form a first portion of an object layer, and then applying a second type of unreacted polymerizable material to the first portion of the object layer, and irradiating the second type of unreacted polymerizable material to form a composite object layer.

[0031] Some other embodiments of the present invention are directed to a method of making a three-dimensional object, including: (a) positioning polymerizable material on an optically transparent film between a radiation source and a build platform such that the polymerizable material contacts the build platform; (b) irradiating a portion of the polymerizable material through the optically transparent film with the radiation source to solidify and laminate the polymerizable material to the build platform, thus forming an object attached to the build platform; (c) optionally depositing at least one compound (e.g., a pigment) onto a surface of the object (e.g., in a predetermined pattern); (d) optionally irradiating the surface of the object; (e) positioning additionalAttorney Docket No. 1151.261.WO

[0032] polymerizable material between the radiation source and the build platform such that the additional polymerizable material contacts the object; (f) irradiating a portion of the additional polymerizable material through the optically transparent film (e.g., in a predetermined pattern) with the radiation source to solidify and laminate the portion of the additional polymerizable material to the object, thus forming an additional object layer on the object; (g) optionally depositing at least one compound (e.g., pigment / ink) onto a surface of the additional layer of the object (e.g., in a predetermined pattern); (h) optionally irradiating the additional layer of the object; and (i) repeating steps (e) - (h) until the object forms the three-dimensional object or an intermediate having the same shape, or the shape to be imparted to, the three-dimensional object, wherein the object or intermediate includes at least one object layer having at least one compound (e.g., pigment) deposited thereon.

[0033] In some embodiments, the at least one compound includes a pigment (e.g., in a UV-curable and / or conductive ink).

[0034] In some embodiments, the at least one compound includes a UV-stabilizer, an antioxidant, an antistatic compound, a filler, and / or a compound that is reactive with the polymerizable material.

[0035] In some embodiments, the at least one compound is deposited in a pattern that corresponds to (e.g., is the same or overlaps with) a pattern of irradiation in step (b) and / or step (f).

[0036] In some embodiments, the at least one compound is only deposited onto portions of the polymerizable material that form an outward facing surface of the three-dimensional object.

[0037] In some embodiments, the polymerizable material has at least 50 weight percent, 60 weight percent, or 70 weight percent of the solid filler particles. In some embodiments, the solid filler particles are present in the resin at a concentration in a range of 60, 65, or 70 weight percent to 85, 90 or 95 weight percent, including 60, 56, 70, 75, 80, 85, 90, and 95 weight percent, and any range defined between any two of the foregoing values.

[0038] In some embodiments, the polymerizable material includes an energetic and / or propellant compound.Attorney Docket No. 1151.261.WO

[0039] Some other embodiments of the present invention are directed to an apparatus for forming a three-dimensional object, including: (a) at least one radiation source, and optionally a primary radiation source and at least one secondary radiation source; (b) a build platform on which the three-dimensional object is formed; (c) an applicator for coating polymerizable material onto an optically transparent film; (d) optionally an applicator for depositing at least one compound onto the polymerizable material or an object layer; (e) a film transport assembly for moving the optically transparent film between the at least one radiation source and the build platform; (f) at least one controller and / or drive assembly in communication with the radiation source, the build platform, the film transport assembly, the applicator for coating polymerizable material, and optionally the applicator for depositing pigment; and (g) optionally a housing and / or frame for supporting, and optionally connecting, one or more of the radiation source, the build platform, the film transport assembly, the applicator for coating polymerizable material, the applicator for depositing pigment, and the at least one controller and / or drive assembly, wherein the apparatus includes at least one of a secondary radiation source and an applicator for depositing at least one compound onto the polymerizable material or an object layer.

[0040] In some embodiments, the at least one controller and / or drive assembly is configured to direct the apparatus to perform one or more of the methods described herein.

[0041] Some other embodiments of the present invention are directed to an object formed by a method and / or apparatus of the invention.

[0042] BRIEF DESCRIPTION OF THE FIGURES

[0043] Figure 1 is a schematic of a conventional embodiment of a rolling film apparatus. Figure 2 is a flow chart illustrating the steps of a conventional rolling film printing method.

[0044] Figure 3 is a flow chart illustrating the steps of a rolling film printing method according to certain embodiments of the invention.

[0045] Figure 4 is a flow chart illustrating the steps of a rolling film printing method according to certain embodiments of the invention.Attorney Docket No. 1151.261.WO

[0046] Figure 5A is an illustration of the deposition of a pigment compound onto polymerizable material according to some embodiments of the invention.

[0047] Figure 5B is an illustration of the deposition of the pigment compound shown in Figure 5A after the pigment absorbs into the polymerizable material.

[0048] Figure 5C is an illustration of a pattern formed by the deposition of a pigment compound onto polymerizable material.

[0049] Figure 5D illustrates irradiation of the pigmented polymerizable material in Figure 5C during an irradiation step according to some embodiments.

[0050] Figure 6A is an illustration of depositing a pigment compound onto a patterned object layer according to certain embodiments of the invention.

[0051] Figure 6B is an illustration of the deposition of the pigment compound shown in Figure 6A after the pigment absorbs into the object layer.

[0052] Figure 7 is an illustration of a rolling film process using unmodified polymerizable material.

[0053] Figures 8A-8C are illustrations of rolling film processes according to embodiments of the invention. Figure 8A illustrates a rolling film process that uses a secondary radiation source to modify the polymerizable material. Figure 8B illustrates a rolling film process that uses multiple secondary radiation sources to modify the polymerizable material. Figure 8C illustrates a rolling film process that uses a cleaning device to remove excess unreacted polymerizable material from the partially cured polymerizable material.

[0054] Figure 9A is an illustration depicting how nonuniformity in thickness of polymerizable material on the optically transparent film may result in nonuniformity in a surface profile of partially cured polymerizable material.

[0055] Figure 9B is an illustration depicting that a decrease in the depth of penetration of the radiation produces a more uniform profile of the partially cured polymerizable material.Attorney Docket No. 1151.261.WO

[0056] Figure 9C is an illustration depicting a cleaning device removing excess unreacted polymerizable material from the partially cured polymerizable material.

[0057] Figure 9D is an illustration depicting how a radiation profile used to form partially cured polymerizable material may be varied to account for variations in a profile of a lower surface of the growing three-dimensional object.

[0058] Figure 9E is an illustration depicting a cleaning device removing excess unreacted polymerizable material from non-uninform portions of the partially cured polymerizable material.

[0059] Figure 10 is an illustration of a rolling film process that uses laser radiation to remove excess unreacted polymerizable material, reducing the amount of unreacted polymerizable material contacting partially cured polymerizable material and the three-dimensional object.

[0060] Figures 11A-11C illustrate a rolling film process that uses a single radiation source to perform certain methods of the invention. Figure 11A is an illustration depicting the formation of partially cured polymerizable material using a primary radiation source.

[0061] Figure 11 B illustrates cleaning of the partially cured polymerizable material formed in Figure 11A to remove unreacted polymerizable material. Figure 11C illustrates lamination of the cleaned partially cured polymerizable material from Figure 11 B onto a surface of the three-dimensional object according to embodiments of the invention.

[0062] Figures 12A-12D illustrate a rolling film process of the invention that produces composite three-dimensional objects. Figure 12A illustrates the formation of an object layer using partially cured polymerizable Material A. Figure 12B shows the growing object including a patterned object layer of Material A. Figure 12C illustrates the subsequent formation of a pattern of partially cured polymerizable Material B. Figure 12D shows the patterned partially cured polymerizable Material B being laminated within the patterned object layer of Material A.

[0063] Figures 13A-13D illustrate another rolling film process of the invention that produces composite three-dimensional objects. Figure 13A illustrates the formation of a patterned object layer using partially cured polymerizable Material A. Figure 13B shows the growing object including a patterned object layer of Material A. Figure 13CAttorney Docket No. 1151.261.WO

[0064] illustrates the application of unreacted polymerizable material to the patterned object layer of Material A and subsequent irradiation. Figure 13D shows the resulting object including an object layer including Material A and Material B.

[0065] Figures 14A-14C illustrate another rolling film process of the invention that produces composite three-dimensional objects. Figure 14A illustrates the application of unreacted polymerizable Material B to a pattern of partially cured polymerizable Material A to create a pattern of partially cured polymerizable material including Material A and Material B. Figure 14B illustrates the lamination of the partially cured polymerizable material including Material A and Material B to the three-dimensional object. Figure 14C shows the resulting object including an object layer including Material A and Material B.

[0066] Figure 15 illustrates a process of modifying polymerizable material by both irradiation and deposition of a compound according to some embodiments of the invention. Figure 16 is an illustration of an apparatus according to some embodiments of the invention.

[0067] Figure 17 is an illustration of a controller and a user interface used in apparatus according to some embodiments of the invention.

[0068] Figure 18 provides photographs of a three-dimensional object formed partially using traditional RFP methods and partially using methods of the invention.

[0069] DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS OF THE INVENTION

[0070] In the following discussion that addresses several embodiments and applications of the present invention, reference is made to the accompanying drawings that form a part thereof, where depictions are made, by way of illustration, of specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized, and changes may be made without departing from the scope of the invention.

[0071] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an" and "the" are intended to include plural forms as well,Attorney Docket No. 1151.261.WO

[0072] unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements components and / or groups or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups or combinations thereof.

[0073] As used herein, the term "and / or" includes any and all possible combinations or one or more of the associated listed items, as well as the lack of combinations when interpreted in the alternative ("or").

[0074] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the specification and claims and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Well-known functions or constructions may not be described in detail for brevity and / or clarity.

[0075] It will be understood that when an element is referred to as being "on," "attached" to, "connected" to, "coupled" with, "contacting," etc., another element, it can be directly on, attached to, connected to, coupled with and / or contacting the other element or intervening elements can also be present. In contrast, when an element is referred to as being, for example, "directly on," "directly attached" to, "directly connected" to, "directly coupled" with or "directly contacting" another element, there are no intervening elements present. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed "adjacent" another feature can have portions that overlap or underlie the adjacent feature.

[0076] Spatially relative terms, such as "under," "below," "lower," "over," "upper" and the like, may be used herein for ease of description to describe an element's or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is inverted, elementsAttorney Docket No. 1151.261.WO

[0077] described as "under" or "beneath" other elements or features would then be oriented "over" the other elements or features. Thus the exemplary term "under" can encompass both an orientation of over and under. The device may otherwise be oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. Similarly, the terms "upwardly," "downwardly," "vertical," "horizontal" and the like are used herein for the purpose of explanation only, unless specifically indicated otherwise.

[0078] It will be understood that, although the terms first, second, etc., may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. Rather, these terms are only used to distinguish one element, component, region, layer and / or section, from another element, component, region, layer and / or section. Thus, a first element, component, region, layer or section discussed herein could be termed a second element, component, region, layer or section without departing from the teachings of the present invention. The sequence of operations (or steps) is not limited to the order presented in the claims or figures unless specifically indicated otherwise.

[0079] All patents or published patent applications referenced are herein incorporated by reference in their entirety. In the case of conflicting terminology, the present application controls.

[0080] It is noted that aspects or features of the devices described with respect to one embodiment, may be incorporated in a different embodiment although not specifically described relative thereto. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination. Applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to be able to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. These and other objects and / or aspects of the present invention are explained in detail in the specification set forth below.

[0081] Figure 1 provides an example of a RFP apparatus 100 that includes (a) a radiation source 105; (b) a build platform 110 on which a three-dimensional object 115 is formed; (c) an applicator 120 for coating polymerizable material 125 onto anAttorney Docket No. 1151.261.WO

[0082] optically transparent film 130; and (d) a film transport assembly 135 for moving the optically transparent film 130 between a radiation source 105 and the build platform 110. The apparatus 100 may further include a resin removal device 121 to remove the excess polymerizable material 125 remaining on the film 130. Although not shown in Figure 1, the RFP apparatus also typically includes at least one controller and / or drive assembly to energize and / or control the apparatus or one or more parts thereof, including the radiation source assembly, the build platform, the applicator, and / or the film transport assembly. Also not shown in Figure 1, the RFP apparatus further typically includes a housing and / or frame that connects and / or supports one or more parts of the apparatus. The film transport assembly 135 and radiation source 105, and optionally other components such as the applicator 120 and resin removal device 121, may be referred to herein as the "print head carriage."

[0083] RFP methods typically include the steps outlined in Figure 2. Referring to step 240, a polymerizable material may be coated onto an optically transparent film. Referring to step 245, the polymerizable material may then be positioned between a radiation source and a build platform such that a portion of the polymerizable material contacts the build platform. Referring to step 250, a portion of the polymerizable material may then be irradiated through the optically transparent film with the radiation source to solidify and laminate the polymerizable material to the build platform to form an object (e.g., an object layer) attached to the build platform. Referring to step 255, additional polymerizable material may then be positioned between the radiation source and the build platform such that the additional polymerizable material contacts the object attached to the build platform. Referring to step 260, at least a portion of the additional polymerizable material may then be irradiated through the optically transparent film with the radiation source to solidify and laminate the portion of the additional polymerizable material to the object, thus adding a layer to the object attached to the build platform. The process of irradiating polymerizable material to add an additional object layer formed from polymerizable material to an object may be referred to herein as a "lamination." Referring to step 265, if the object is the desired three-dimensional object or an intermediate having the same shape, or the shape to be imparted to, the three-dimensional object, then the object or intermediate formation process may end (see step 266). However, if theAttorney Docket No. 1151.261.WO

[0084] object or intermediate is not the desired three-dimensional object or intermediate, then process steps 255 and 260 will repeat until the desired three-dimensional object or intermediate, is formed.

[0085] In some embodiments, RFP methods may be performed such that the film transport assembly 135 conveys the optically transparent film 130 to the desired position and the build platform 110 only moves in the vertical (or Z) direction, so that the build platform contacts the polymerizable material 125 in a "stamping" motion (referred to herein as "stamping RFP methods"). However, in other embodiments, the build platform, the print head carriage, and / or the film transport assembly may be translated in a horizontal (X-Y) direction during contact (referred to herein as "scrolling RFP methods"). For example, in addition to moving in the vertical direction, the build platform may also move in the horizontal direction, optionally wherein the build platform or object contacts the polymerizable material (e.g., in step 245 or 255) and / or the polymerizable material is irradiated (e.g., in step 250 or 260) while the build platform, and optionally the optically transparent film, are moving (e.g., in a horizontal motion). For example, referring again to Figure 1, as the polymerizable material 125 on the film 130 moves over the radiation source 105, build platform 110 may also move in the same direction (e.g., at roughly the same rate) while lowering to contact the polymerizable material 125. Then, after lamination, the build platform 110 may raise up and reposition to repeat the process. As another example, the print head carriage may move in addition or alternatively to the movement of the film itself, and the print head carriage may move in the same direction or the opposite direction as the film. In some embodiments, the build platform may remain stationary in the X direction and the print head carriage may translate to scroll across the build platform or part thereon. Both stamping and scrolling platform RFP processes are envisioned to be used with the methods and apparatus of the present invention.

[0086] Provided according to embodiments of the invention are RFP apparatus and methods for making three-dimensional objects that include coating polymerizable material onto an optically transparent film, modifying at least a portion of the polymerizable material, and then using the modified polymerizable material in an RFP process.Attorney Docket No. 1151.261.WO

[0087] Specifically, referring to Figure 3, in some embodiments, a method of the present invention may include the following steps. First, referring to step 340, polymerizable material may be coated onto an optically transparent film. Then, referring to step 341, a portion of the polymerizable material on the film may then optionally be modified. Next, referring to step 345, the modified and / or unmodified polymerizable material may be positioned (e.g., moved, rolled, conveyed with a film transport assembly) to contact the build platform. In some embodiments, polymerizable material that contacts the build platform in a particular layer or "slice" may have regions of modified polymerizable material and regions of unmodified polymerizable material. For example, in a particular object layer, there may be pigmented and non-pigmented regions therein. Furthermore, not every object layer may be formed of modified polymerizable material so some layers or slices may be formed only with unmodified polymerizable material while other layers or slices may be formed from only modified polymerizable material. However, at least one layer in the object is formed using modified polymerizable material.

[0088] Next, referring to step 350, some or all of the modified and / or unmodified polymerizable material contacting the build platform is irradiated through the optically transparent film with a radiation source (e.g., to partially or fully cure the modified or unmodified polymerizable material) to solidify and laminate the polymerizable material to the build platform, thus forming a modified or unmodified object (e.g., an object layer) attached to the build platform (lamination). The object may be partially or fully cured. As used herein, an object or object layer having any portion formed from modified polymerizable material is considered a modified object or object layer, respectively.

[0089] Next, referring to step 355, additional modified and / or unmodified polymerizable material on the optically transparent film is positioned to contact the (modified or unmodified) object attached to the build platform. The additional modified and / or unmodified polymerizable material is coated and optionally modified as described in step 341. Such additional polymerizable material may be coated and / or modified at any time before or after either of steps 345 and 350 and is typically present on the same length of optically transparent film as the polymerizable materialAttorney Docket No. 1151.261.WO

[0090] described in steps 341, 345, and 350. Referring to step 360, the additional modified and / or unmodified polymerizable material contacting the object is then irradiated through the optically transparent film with the radiation source to solidify and laminate the polymerizable material to the object, thus adding an additional modified or unmodified layer to the object. The object layer may be fully or partially cured. Referring to step 365, if the object thus formed is the desired three-dimensional object or an intermediate having the same shape as, or the shape to be imparted to, the three-dimensional object, then the process (e.g., printing or additive manufacturing process) may end, as described in step 366. However, if the object is not yet the desired three-dimensional object or intermediate, then steps 355 and 360 are repeated until the desired three-dimensional object is formed. In this process, one or more of the layers or slices of the object is / are formed, at least in part, from modified polymerizable material. In some embodiments, only a portion of the object and / or intermediate is formed from modified polymerizable material, and in some embodiments, all of the object and / or intermediate is formed from modified polymerizable material.

[0091] In some embodiments of the invention, the modification of the polymerizable material occurs after it has been formed into an object layer attached to the build platform or object. Referring to Figure 4, in some embodiments, a method of the present invention may include the following steps. Referring to step 440, polymerizable material may be coated onto an optically transparent film. Referring to step 445, the polymerizable material may then be positioned (e.g., moved, rolled, conveyed with a film transport assembly) to contact the build platform, and referring to step 450, at least some of the polymerizable material may be irradiated through the optically transparent film to solidify and laminate the polymerizable material to the build platform, thus forming an object (e.g., an object layer) attached to the build platform. The object may be fully or partially cured. Referring to step 451, the object may then optionally be modified while attached to the build platform. Referring to step 452, the modified object may also be irradiated. If step 451, and optionally step 452, are performed on the object, the object is considered a modified object. As an example, in step 451, the object may be modified by depositing / coating a compound (e.g., a pigment) on the object. In some cases, irradiation in step 452 may be performed to fix the compound to, or react the compound with, the object. However,Attorney Docket No. 1151.261.WO

[0092] in some embodiments, depending on the compound deposited, irradiation step 452 may not be necessary.

[0093] Referring to step 455, additional polymerizable material on the optically transparent film may then be positioned to contact the (modified or unmodified) object attached to the build platform. The additional polymerizable material may be coated as described with respect to step 440. Such polymerizable material may be coated and / or optionally modified before or after any of steps 445, 450, 451, and 452, and is typically present on the same length of optically transparent film as the polymerizable material described in steps 440, 445, and 450. Referring to step 460, the additional polymerizable material contacting the object may then be irradiated through the optically transparent film with the radiation source to solidify and laminate it to the object, thus adding an additional layer to the object. The additional layer may be partially or fully cured. Referring to steps 461 and 462, the additional layer of the object is optionally modified and optionally further irradiated in the manner described with respect to steps 451 and 452.

[0094] Referring to step 465, if the object thus formed is the desired three-dimensional object or an intermediate having the same shape as, or the shape to be imparted to, the three-dimensional object, then the process (e.g., printing or additive manufacturing process) may end (see step 466). However, if the object is not yet the desired three-dimensional object or intermediate, then steps 455 and 460 (and optionally steps 461 and 462) are repeated until the desired three-dimensional object is formed. In this process, one or more of the layers or slices of the object or intermediate are modified. In some embodiments, only a portion of the object or intermediate is formed from modified object layers, and in some embodiments, all of the object or intermediate is formed from modified object layers.

[0095] Polymerizable Material

[0096] Polymerizable materials (also referred to herein as resins) that may be used in the present methods and apparatus are known and described in, for example, DeSimone et al., U.S. Pat. Nos. 9,211,678; 9,205,601; and 9,216,546. Dual cure resinsAttorney Docket No. 1151.261.WO

[0097] for additive manufacturing are known and described in, for example, Rolland et al., U.S. Pat. Nos. 9,676,963; 9,598,606; and 9,453,142, and WO Publication No. 2025 / 080931. Non-limiting examples of dual cure resins include, but are not limited to, resins that include precursors to polymers such as polyurethane, polyurea, and copolymers thereof; epoxies; cyanate esters; silicone, etc. Any suitable resin may be used in the methods described herein, including single cure, dual cure, elastomer-forming resins, thermoplastic, and thermoset-forming resins. In particular embodiments, the polymerizable material includes a polybutadiene polymer or precursor.

[0098] The polymer resins typically include at least one UV reactive monomer or prepolymer and at least one photoinitiator. Further, additional optional additives, including but not limited to, reactive diluents, heat and / or moisture-curable monomers or prepolymers, crosslinkers, non-reactive diluents, UV absorbers, pigments, dyes, antioxidants, plasticizers, fillers, radical inhibitors, heat expandable microspheres, and thermal inhibitors, may also be present in the polymerizable liquid. Such additives may also be deposited onto the polymerizable material, as discussed below, and the additives described below with respect to deposition may also be included in the polymerizable material as well.

[0099] In some embodiments, the polymerizable material may be a viscous or highly viscous liquid (e.g., having a viscosity in a range of 5,000 cP to 100,000 cP, 500,000 cP, 1 McP, or greater). In some embodiments, the polymerizable material may be a paste or plastic fluid, or other materials that do not flow until a critical stress is achieved. In particular embodiments, the viscous material comprises a silicone. In particular embodiments, the polymerizable material is a highly filled resin, such that it includes a high concentration of solid particles (either as powders or suspended or dispersed in a liquid) including, for example, metallic, organic / polymeric, inorganic, composites, or mixtures thereof. In some embodiments, the polymerizable material has at least 50 weight percent, 60 weight percent, or 70 weight percent of the solid filler particles. In some embodiments, the solid filler particles are present in the resin at a concentration in a range of 60, 65, or 70 weight percent to 85, 90 or 95 weight percent, including 60, 56, 70, 75, 80, 85, 90, and 95 weight percent, and any range defined between any two of the foregoing values. The particles can be nonconductive, semi-conductive, or conductive (including metallicAttorney Docket No. 1151.261.WO

[0100] and non-metallic or polymer conductors); and the particles can be magnetic, ferromagnetic, paramagnetic, or nonmagnetic. The particles can be of any suitable shape, including spherical, elliptical, cylindrical, etc. The particles can be of any suitable size (for example, ranging from 1 nm to 20 pm average diameter). In some embodiments, the resin includes particles having multiple (two or more) different particle sizes, in order to increase loading of the particles in the resin.

[0101] In particular embodiments, energetic material such as an explosive and / or propellant compound, as described in further detail below, is included in the polymerizable material, such as, for example, in a highly filled resin.

[0102] Optically Transparent Film

[0103] The polymerizable material is coated on (dispensed or otherwise applied to) an optically transparent film. The optically transparent film is a polymer film that is transparent to actinic radiation or light at wavelengths used to cure the polymerizable material (e.g., emitted by one or more radiation source used herein). In some embodiments, the optically transparent film is permeable to a polymerization inhibitor (e.g., an oxygen inhibitor). Examples include but are not limited to fluorinated ethylene propylene film, cyclic olefin polymers, polyethylene, including ultra-high molecular weight polyethylene, thin flexible ceramics like willow glass or sapphire films; Silicone base films can coated films (e.g. PDMS).

[0104] The polymerizable material may be applied to the optically transparent film by a number of possible methods, including, e.g., rollers (e.g., and application and / or metering rollers), dispensers, sprayers, blades, baths, and any combination thereof.

[0105] Modification of the Polymerizable Material or Object Layers

[0106] As used herein, the term "modifying" refers to changing the composition of the polymerizable material or object layer, either by adding a compound / component thereto and / or by irradiating (e.g., UV irradiation) or otherwise applying energy sufficient to produce a chemical reaction (e.g., partial curing) therein.Attorney Docket No. 1151.261.WO

[0107] In some embodiments of the invention, a polymerizable material or object layer is modified by depositing one or more compounds onto a portion, the majority (e.g., greater than 50%), substantially all (e.g., 80%, 90%, 95%, or 99%), or all (100%) of the polymerizable material in an object layer. The compound may be deposited by a number of possible methods, including, e.g., by spraying, ink-jetting, coating, dropping, rolling, via gravity, or any other suitable method. The deposition may occur from above, the side, or below the polymerizable material or object layer, depending on the orientation of the film and / or object layer.

[0108] In particular embodiments of the invention, modifying the polymerizable material or an object layer includes depositing one or more pigments (which includes any particles or compounds, including dyes, which add or change the color of the polymerizable material or object layer, intermediate, and / or three-dimensional object) on a surface of the polymerizable material or object layer. Many different types of pigments may be deposited. As used herein, the term "pigment" refers to both the pigment compound itself and any formulation (solution, dispersion, or suspension) in which the pigment is present. For example, in some embodiments, the pigment is present in a UV curable ink. In some embodiments, the pigment is present in a conductive ink. Examples include, but are not limited to, nanoparticle inks and / or metal organic decomposition inks. Multiple pigments may be deposited on the polymerizable material or object layer concurrently and / or sequentially, and on the same or different portions of the polymerizable material or object layer. In some embodiments, the polymerizable material is devoid of pigment or only includes white pigment. In some embodiments, the deposited pigment includes one or more of white, black, cyan, magenta, and yellow pigment. In some embodiments, the pigment is present in water soluble ink. In some embodiments, the pigment is present in another additional compound. For example, the pigment may be present in a second polymerizable material or attached to a filler material. In some embodiments, the pigment is present on the outer-facing surface of the object layer and / or object.

[0109] In some embodiments of the invention, alternative to or in addition to depositing pigment(s), the polymerizable material may be modified by depositing one or more other compounds onto the polymerizable material or object layer. ForAttorney Docket No. 1151.261.WO

[0110] example, a UV-stabilizer, a light absorber, an antioxidant, an antistatic compound, a filler, a woven fiber (e.g., carbon fiber or fiberglass composite), a compound that is reactive with the polymerizable material, or any combination of the foregoing, may be deposited onto a surface of the polymerizable material or object layer.

[0111] Any suitable filler may be included in the polymerizable material or deposited onto the polymerizable material during a modification step, depending on the properties desired in the part or object to be made. Thus, fillers may be solid or liquid, organic or inorganic, and include but are not limited to reactive and non-reactive rubbers (siloxanes and / or acrylonitrile-butadiene rubbers); reactive and non-reactive thermoplastics (including but not limited to: poly(ether imides), maleimide-styrene terpolymers, polyarylates, polysulfones and polyethersulfones, etc.); inorganic fillers such as silicates (such as talc, clays, silica, and / or mica); glass; carbon nanotubes; graphene; cellulose nanocrystals; including combinations of all of the foregoing. Suitable fillers include tougheners, including but not limited to core-shell rubbers.

[0112] In some embodiments, solid particles (either as powders or suspended or dispersed in a liquid) may be included in the polymerizable material or deposited onto the polymerizable material during a modification step. Any suitable solid particles can be used, depending upon the end product being fabricated. The particles can be metallic, organic / polymeric, inorganic, or composites or mixtures thereof. The particles can be nonconductive, semi-conductive, or conductive (including metallic and non-metallic or polymer conductors); and the particles can be magnetic, ferromagnetic, paramagnetic, or nonmagnetic. The particles can be of any suitable shape, including spherical, elliptical, cylindrical, etc. The particles can be of any suitable size (for example, ranging from 1 nm to 20 pm average diameter). The particles can comprise an active agent or detectable compound. For example, magnetic or paramagnetic particles or nanoparticles can be employed.

[0113] In some embodiments, the at least one additional compound is an energetic material such as an explosive and / or propellant. Example materials include but are not limited to those described in Tan et al., 3D Printing for Explosives and Propellant Applications, Additive Manufacturing Frontiers 2 (2024) 200151. Other energetic materials include but are not limited to those described in Fleck et al., AdditiveAttorney Docket No. 1151.261.WO

[0114] Manufacturing of Multifunctional Reactive Materials, Additive Manufacturing 17 (2017) 176-182.

[0115] Light absorbers may be included in the polymerizable material or deposited onto the polymerizable material during a modification step. Suitable examples of light absorbers include, but are not limited to titanium dioxide, carbon black, and / or an organic ultraviolet light absorber such as a hydroxybenzophenone, hydroxyphenylbenzotriazole, oxanilide, benzophenone, thioxanthone, hydroxyphenyltriazine, and / or benzotriazole ultraviolet light absorber (e.g., Mayzo BLS® 1326). Examples of suitable organic ultraviolet light absorbers include, but are not limited to, those described in U.S. Pat. Nos. 3,213,058; 6,916,867; 7,157,586; and 7,695,643, the disclosures of which are incorporated herein by reference.

[0116] Microspheres, including heat expandable microspheres and pre-expanded microspheres, may be included in the polymerizable material or deposited onto the polymerizable material during a modification step. Microspheres may be used, for example, as a powder or suspended, dispersed, or dissolved in a liquid. Heat expandable microspheres (sometimes also referred to as "microballoons") are known and described in, for example, U.S. Pat. Nos. 10,030,115 and 10,023,712 (both to Matsumoto), U.S. Pat. Nos. 9,902,829, 9,062,170, and 8,388,809 (all to Akzo Nobel) and U.S. Pat. No. 10,029,550 (to 3M), U.S. Pat. No. 3,615,972 (to Dow), and others.

[0117] Stabilizers may be included in the polymerizable material or deposited onto the polymerizable material during a modification step. Stabilizers include, but are not limited to, hydroquinones (e.g., hydroquinone and hydroquinone monomethyl ether) and catechols (e.g., 4-tert-butylcatechol) for stabilizing reactive monomers or oligomers such as acrylates or methacrylates. Stabilizers can also include antioxidants and additives used for increasing the long-term stability of printed polymer-based materials. Examples include, for example, hindered amine light stabilizers, primary and secondary antioxidants, including hindered or semi-hindered phenols, thiosynergists, phosphites, hydroxylamines, and hindered amines.

[0118] In some embodiments, a compound that is reactive with the polymerizable material or object layer may react without further processing, but in some embodiments, the compound that is reactive with the polymerizable material mayAttorney Docket No. 1151.261.WO

[0119] react upon irradiation with the UV (or other) light or actinic radiation. The compound may also react with the polymerizable material with the application of heat and / or contacting with water. Accordingly, although not specifically described in Figures 3 and 4, modification may occur by contacting the polymerizable material or object layer with water, either by itself or after depositing a compound that is reactive with the polymerizable material or object layer. In some embodiments, the reactive compound may include a chain extender such as a thiol, polyamine, or polyol, which may be useful in particular with polyurethane (e.g., reactive blocked polyurethanes).

[0120] In some embodiments, additionally or alternatively to other depositions, a layer (including a continuous or patterned layer) of the same or different resin composition may be deposited onto the polymerizable material or object layer. This may allow for composite three-dimensional objects and / or intermediates having a unique properties or non-uniform properties, which may be advantageous in certain applications.

[0121] Deposition of one or more compounds (which, as used herein, includes elements, compounds, and compositions) may occur by several possible methods. An example deposition method is illustrated in Figures 5A-5D. Figures 5A, 5B, 5C, and 5D illustrate a portion of polymerizable material 525 on an optically transparent film 530 and a pigment compound 526 deposited thereon. While in this example, a pigment compound 526 is deposited, this example applies to any compound deposited onto the polymerizable material 525. In this example, pigment compound 526 is deposited using a compound applicator 527 that applies pigment compound 526 droplets on the polymerizable material 525. As shown in Figure 4A, in some embodiments, the pigment compound 526 only penetrates a portion of the polymerizable material 525 (e.g., 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or any range defined between any two of the foregoing values, of the thickness of the polymerizable material 525).

[0122] As shown in Figure 5B, in some embodiments, the pigment compound 526 penetrates or absorbs into the polymerizable material, for example, through the entire thickness of the polymerizable material 525. In particular embodiments, once the pigment compound 526 is deposited onto the polymerizable material 525, it is allowed to contact the polymerizable material 525 for a time (e.g., in a range of 1 second to 3 minutes, e.g., 5 sec, 10 sec, 15 sec, 25 sec, 40 sec, 50 sec, 60 sec, or any range betweenAttorney Docket No. 1151.261.WO

[0123] any two of the foregoing values) to allow the polymerizable material 525 to absorb pigment compound 526 (and / or one or more other compounds or compositions) before contacting a build platform or object in a rolling film print process. Referring again to Figure 3, in some embodiments, such absorption may be part of the modification step 341 and absorption / penetration may be allowed to occur before proceeding to step 345.

[0124] In some embodiments of the invention, a compound such as pigment compound 526 is deposited in a pattern, and in particular embodiments, the deposited pigment 526 is applied in a pattern that corresponds to (is the same or overlaps with) a subsequent pattern of irradiation (e.g., in steps 350 or 360 in Figure 3). For example, referring to Figures 5C and 5D, pigment compound 526 may be applied in selected areas (e.g., in a pattern), and when radiation source 505 irradiates actinic radiation or light through the optically transparent film 530 (e.g., while the polymerizable material 525 contacts the build platform 510), the actinic radiation or light is applied to the same selected areas as the deposited pigment compound 526 and thus, an object layer 528 formed by the irradiation, will also include the deposited pigment compound 526.

[0125] In some embodiments of the invention, such as those methods described with reference to Figure 4, a compound is deposited on an object layer. For example, in some embodiments, referring to Figures 6A and 6B, a pigment 626 is deposited on an object layer 628 when it is attached to a build platform 610 (directly or via another object layer 628). Figure 6A illustrates deposition of pigment 626 on a patterned object layer 628 (in this case the compound applicator 627 is a roller applicator). In some embodiments, the pigment compound 626 only penetrates a portion of the object layer 628 (e.g., 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or any range defined between any two of the foregoing values, of the thickness of the object layer 628).

[0126] As shown in Figure 6B, in some embodiments, pigment compound 626 penetrates into the object layer, for example, through the entire thickness of the object layer 628. In particular embodiments, once the pigment compound 626 is deposited onto the object layer 628, it is allowed to contact the object layer 628 for a time (e.g.,Attorney Docket No. 1151.261.WO

[0127] in a range of 1 second to 3 minutes, e.g., 5 sec, 10 sec, 15 sec, 25 sec, 40 sec, 50 sec, 60 sec, or any range between any two of the foregoing values) to absorb pigment compound 626 (and / or one or more other compounds) before proceeding with the RFP process. The object layer 628 may also be irradiated to facilitate the attachment of a compound or generate a chemical reaction in the object layer 628. In some embodiments, only a portion of an object layer may have a compound (e.g., a pigment) deposited thereon, while in other embodiments, all of the object layer may have the compound deposited thereon. Additionally, in some embodiments, only some of the object layers in the object are modified with a compound, while in other embodiments, all of the object layers in the object are modified with a compound.

[0128] In some embodiments, a compound (such as a pigment) is only deposited onto portions of the polymerizable material or object layer that form, or will form, an outward facing surface of the three-dimensional object.

[0129] Alternative to or in combination with (e.g., concurrently and / or sequentially) the deposition of a compound onto the polymerizable material, methods of the invention further include modifying the polymerizable material by pre-irradiating the polymerizable material prior to contacting with the build platform or object during an RFP process.

[0130] Referring to Figure 7, RFP methods may use polymerizable material having a thickness 731 on the optically transparent film 730 that is in excess 732 of the slice thickness 733 (e.g., a thickness that produces the desired object layer thickness after lamination) to prevent or minimize bubbles and defects (not shown) that can arise due to intermittent contact between the polymerizable material 725 and the object 715 when the polymerizable material thickness 731 approaches the desired slice thickness 733. For example, in some cases, excess polymerizable material may be up to 1% to 50% (e.g., 1%, 5%, 10%, 20%, 25%, 30%, 40%, 50%, or any range defined between any two or more of the foregoing values). While using an excess of polymerizable material 732 may improve reliability with reduced tolerances on the coating and alignment precision, the excess polymerizable material 732 between the film 730 and the object 715 is required to be squeezed out, or it may be deposited on the object 715, such as by creating beads 734 of coating on the surface of the objectAttorney Docket No. 1151.261.WO

[0131] 715, which creates the need to remove the excess polymerizable material 732 after the object is formed.

[0132] Of note, Figure 7 illustrates a RFP method wherein the build platform 710 contacts the polymerizable material 725 while moving in the same direction as film 730. Such a method may be advantageous because it facilitates contact with the polymerizable material 725 and removes air bubbles therefrom. However, such a method may also increase the size of beads 734 formed on the surface of the object 715. Such beads 734 may also form using other RFP methods, including stamping methods.

[0133] Accordingly, in some embodiments of the invention, modifying the polymerizable material includes exposing the polymerizable material on the optically transparent film with radiation (e.g., patterned radiation) prior to the polymerizable material contacting the build platform or object (e.g., a previous object layer). This may partially cure the polymerizable material so that it is in a less flowable state such as a solid, semi-solid, rubber, or gel. In some embodiments, the partially cured polymerizable material may have a width or thickness that is approximately the desired slice (object layer) thickness or may only have a thin layer of excess polymerizable material thereon.

[0134] Referring to Figure 8A, in some embodiments, an apparatus of the invention may include a primary radiation source 805 and a secondary radiation source 806. The primary radiation source 805 is the radiation source that produces object layers 828 attached to build platform 810 to form the object 815. The secondary radiation source 806 irradiates (or "pre-irradiates") the polymerizable material 825 while on the optically transparent film 830 prior to contact with the build platform 810 or previous object layers 828. In some embodiments, the irradiation from the secondary radiation source 806 is patterned, such as, for example, a pattern that corresponds to (is the same or overlaps with) a pattern subsequently used by the primary radiation source 805. The irradiation from the secondary radiation source 806 may partially cure, solidify, and / or increase the viscosity of the polymerizable material 825. In Figure 8A, polymerizable material 825 that has not been pre-irradiated is referred to herein as unreacted polymerizable material 825a and polymerizable material that is partiallyAttorney Docket No. 1151.261.WO

[0135] cured by the secondary radiation source 806 is referred to herein as partially cured polymerizable material 825b.

[0136] As shown in Figure 8A, when partially cured polymerizable material 825b contacts the object 815 and / or is compressed by the roller apparatus 835, a smaller and / or temporary bead 834 is formed. The compression while the partially cured polymerizable material 825b contacts the build platform 810 or an object 815 may, in some embodiments, be such that the partially cured polymerizable material 825b temporarily has a slice thickness that is less than the desired slice thickness of the object layer 828. This creates a localized compression zone in the partially cured polymerizable material 825b and part 815 under the roller apparatus 835 that squeezes out any bubbles or voids while creating a transient mild deformation in the partially cured polymerizable material 825b. However, once compression is decreased, the transient deformation may relax and the partially cured polymerizable material 825b may return or substantially return to the prior relaxed state. The relaxation after transient compression may lead to no net flow of the resin and hence a reduced accumulation of a coating bead 834. Typically, irradiation by the primary radiation source 805 occurs after this expansion to the desired slice thickness. In some embodiments, there may be a dead zone (or liquid film layer) of polymerization under the partially cured polymerizable material 825b due to the oxygen (or other polymerization inhibitor) permeating through the optically transparent film 830. Such a dead zone may also be present during lamination using the primary radiation source 805, which may facilitate the separation of the object layer from the film 830. There may also be a dead zone on an upper surface of the partially cured polymerizable material 825b due to contact with air. This dead zone (or liquid release layer) may facilitate lamination of the partially cured polymerizable material 825b onto object 815.

[0137] In some embodiments, there may be more than one secondary radiation source 806, for example, an additional secondary radiation source may be present opposite of the first secondary radiation source 806, as shown in Figure 8B. For example, the first and second secondary radiation sources 806 may be on opposite sides of the film 830 or may face opposite surfaces of the film 830. The dead zone (liquid filmAttorney Docket No. 1151.261.WO

[0138] layer) on the upper surface of the partially cured polymerizable material 825b may facilitate lamination of the partially cured polymerizable material 825b to the object 815. A single secondary radiation source 806 may also be used to irradiate different portions of the unreacted polymerizable material 825a and / or may provide more than one kind of irradiation.

[0139] Referring to Figure 8C, in some embodiments, the apparatus also includes a cleaning device 836 that acts to remove at least a portion of the unreacted polymerizable material 825a prior to contacting the build platform 810 or object 815. For example, in some embodiments, the cleaning device 836 includes, but not limited to, a doctor's blade, squeegee, roller, vacuum, air blade, blower, heater, electrostatic applicator, laser ablation, or a combination of any two or more of the foregoing. Removal of unreacted polymerizable material 825a may reduce undesired contact between unreacted polymerizable material 825a and object 815. For example, cleaning may reduce undesired transfer of unreacted polymerizable material 825a on upward facing transition surfaces of the object layer 828, may reduce a meniscus of unreacted polymerizable material 825 at transition edges of object layers 828, may reduce unreacted polymerizable material 825 transfer into fine features of the object 815, and may reduce print stress warpage.

[0140] Referring to Figures 9A-9E, in some embodiments, the amount or intensity of the radiation used to form the partially cured polymerizable material 925b may be varied to address non-uniformity in the coating thickness of the unreacted polymerizable material 925a. Referring to Figure 9A, if a coating thickness of the unreacted polymerizable material 925a on an optically transparent film 930 is not completely uniform, and it is irradiated sufficiently so that the partially cured polymerizable material 925b extends to the surface of the coating, the partially cured polymerizable material 925b may also be non-uniform and thus may not have the desired tolerance profile for precision manufacturing. Accordingly, referring to Figure 9B, in some embodiments of the invention, the radiation may be reduced or the intensity decreased so that partial curing does not extend throughout the coating thickness. Thus, the partially cured polymerizable material 925b may have a more uniform thickness and be within desired tolerances. Referring to Figure 9C, excessAttorney Docket No. 1151.261.WO

[0141] unreacted polymerizable material 925a on the upper surface of the partially cured polymerizable material 925b may, in some embodiments, be removed by a cleaning device 936, shown as a roller. The cleaning device 936 may also optionally remove at least some of the unreacted polymerizable material 925a adjacent to the portions of partially cured polymerizable material 925b.

[0142] In some embodiments of the invention, the radiation used to form the partially cured polymerizable material 925b may be applied in a non-uniform profile. For example, referring to Figure 9D, in some cases, using an optical device and / or force sensor (not shown), a profile of a lower surface of the growing three-dimensional object 915 may be determined, and a controller (not shown) may direct the secondary radiation source (not shown) to apply radiation such that the partially cured polymerizable material 925b has a complementary upper profile. Thus, when the upper surface of partially cured polymerizable material 925b contacts the lower surface of the object 915, there will be improved surface contact and increased fidelity to the intended part geometry. Referring to Figure 9E, excess polymerizable material 925a may be removed from non-uninform portions of partially cured polymerizable material 925b by a cleaning device 936, such as a roller.

[0143] Referring to Figure 10, in some embodiments of the invention, unreacted polymerizable material 1025a and / or partially cured polymerizable material 1025b may be removed by using laser irradiation from a laser secondary radiation source 1006b. Specifically, a secondary irradiation source 1006a may be used to form partially cured polymerizable material 1025b and then secondary radiation source 1006b, a I aser radiation source, may be used to ablate or otherwise remove portions or all of the unreacted polymerizable material 1025a and optionally portions of partially cured polymerizable material 1025b. In some embodiments, only a portion of the unreacted polymerizable material 1025a adjacent to the partially cured polymerizable material 1025b is removed.

[0144] Alternatively, or additionally, in some embodiments, laser radiation (e.g., ablation) may be used to reduce the height of the polymerizable material 1025a. By reducing the height and / or the contact of the polymerizable material 1025a with adjacent partially cured polymerizable material 1025b, the contact between unreactedAttorney Docket No. 1151.261.WO

[0145] polymerizable material 1025a and the object 1015 or object layers 1028 may be reduced or eliminated, thus resulting in less unreacted polymerizable material 1025a attached to the object 1015, which may reduce or eliminate the need to clean the object after formation. In some embodiments, all of unreacted polymerizable material 1025a is removed by the laser. However, by only removing the unreacted polymerizable material 1025a that contacts the object 1015 or object layers 1028, some unreacted polymerizable material 1025a may be recycled or recovered. Laser radiation may also be used to pattern partially cured polymerizable material 1025b in addition to, or as an alternative to, patterning with a patterned radiation source 1005 or 1006. Laser radiation may also be used to ablate an upper surface of partially cured polymerizable material 1025b to create a particular profile (e.g., stepped or gradient), which may be used, for example, to create composite layers, as discussed herein, and / or to make a surface more planar or uniform, for example to facilitate lamination with an object 1015.

[0146] In some embodiments, as shown in Figures 8A-8C and 10, formation of the partially cured polymerizable material is achieved by using a secondary radiation source. However, referring to Figures 11A-11C, pre-irradiation steps may also be achieved using a single radiation source. In Figure 11 A, polymerizable material 1125a is first irradiated with the primary radiation source 1105 (e.g., using patterned radiation) to form regions of partially cured polymerizable material 1125b while not in contact with the build platform 1110 or the object 1115. Then, as shown in Figure 11 B, the polymerizable material 1125a, 1125b may be transferred away from the primary radiation source 1105 to clean excess unreacted polymerizable material 1125a from the partially cured polymerizable material 1125b by any of the methods described herein (e.g., using a cleaning device 1136 and / or laser ablation). Then, referring to Figure 11C, the cleaned partially cured polymerizable material 1125b may then be positioned so that it contacts the build platform 1110 or the object 1115, followed by a lamination step, as described herein. While in some embodiments, the primary radiation source 1105 uses the same amount and / or intensity of light in the formation of the partially cured polymeric material 1125b as during the lamination step, in other embodiments, the primary radiation source 1105 varies the amount, type, or intensity of radiation depending on the irradiation step performed. For example, forming theAttorney Docket No. 1151.261.WO

[0147] partially cured polymerizable material 1125b may use less radiation (or a lower intensity of radiation) than that used in a lamination step.

[0148] Referring to Figures 12A- 14C, methods of the invention may also be useful to make composite articles (objects made of two or more different types of polymerizable materials). As an example, Figure 12A shows a growing object 1215 that is formed of two materials, Material A and Material B. In Figure 12A, partially cured polymerizable material 1225b of Material A that has been cleaned contacts the object 1215 to engage in the lamination of the partially cured polymerizable material 1225b using irradiation from primary radiation source 1205. As shown in Figure 12B, this results in an object layer 1228 formed from Material A. Then, referring to Figure 12C, partially cured polymerizable material 1225b of Material B (optionally cleaned) is positioned (e.g., using film transport assembly 1235) so that it can contact the growing object 1215. As shown in Figure 12D, object 1215 may then contact the partially cured polymerizable material 1225b of Material B to laminate the Material B portion of object layer 1228 to object 1215. In some embodiments, Material B may be patterned so that it fits within some or all of the empty spaces of the Material A pattern in object layer 1228.

[0149] Figures 13A-13D illustrate another method of the invention for forming a composite object. Similar to Figure 12A, Figure 13A shows a growing object 1315 that is formed of two materials, Material A and Material B. In Figure 13A, partially cured polymerizable material 1325b of Material A, which has been cleaned, contacts object 1315 to engage in the lamination of the partially cured polymerizable material 1325b thereon by irradiation with radiation source 1305. Thus, as shown in Figure 13B, this results in an object layer 1328 formed from Material A. In Figure 13C, unreacted polymerizable material 1325a is applied to the patterned object layer 1328, shown here by rolling the optically transparent film 1330 with the unreacted polymerizable material 1325a thereon such that unreacted polymerizable material 1325a is applied to the empty spaces in the patterned object layer 1328. Then, the unreacted polymerizable material 1325a and optionally object layer 1328 may be irradiated to form an object layer 1328 having both Material A and Material B portions, as shown in Figure 13D. While in the embodiment shown in Figure 13C-13D, all of the unreactedAttorney Docket No. 1151.261.WO

[0150] polymerizable material 1325a of Material B applied to the empty spaces in patterned object layer 1328 is irradiated, but in other embodiments, only a portion of the unreacted polymerizable material 1325a of Material B is irradiated (and optionally subsequently cleaned) so that empty spaces may be present in object layer 1328.

[0151] Referring to Figures 14A-14C, in some embodiments, the formation of a composite object layer may be formed by using a primary radiation source 1405 and a secondary radiation source 1406. For example, Figure 14A illustrates a pattern formed of partially cured polymerizable material 1425b of Material A having unreacted polymerizable material 1425a applied (e.g., coated onto) of Material B being applied thereon (e.g., in empty spaces formed by the pattern of partially cured polymerizable material 1425b). Then, the unreacted polymerizable material 1425a of Material B may be irradiated to form a composite pattern of partially cured polymerizable material 1425b of Material A and Material B, which may be optionally subsequently cleaned by a method described herein. Referring to Figure 14B, the composite pattern of partially cured polymerizable material 1425b may then contact object 1415 (with a space shown for clarity only), followed by irradiation of the composite pattern of partially cured polymerizable material 1425b to laminate it to object 1415 and form a composite object layer 1428. Referring to Figure 14C, a composite three-dimensional object 1415 may thus be formed. As described with respect to Figure 10, the pattern formed of partially cured material 1425b of Material A may also be formed using laser radiation to pattern a larger portion of partially cured material 1425b and may also optionally be used to create a particular profile or more uniformly planar surface. While Figures 12A-12D, Figures 13A-13D, and Figures 14A-14C describe composite objects formed of two different materials (Material A and Material B), it should be understood that more than two different materials may also be used (e.g., three, four, five, or more).

[0152] In some embodiments of the invention, the polymerizable material may be modified by two or more different methods prior to the rolling film printing process. For example, the polymerizable material may be both pre-irradiated / partia I ly cured and have a compound (e.g., a pigment) applied thereto. As an example, Figure 15 illustrates a process wherein unreacted polymerizable material 1525a is applied to anAttorney Docket No. 1151.261.WO

[0153] optically transparent film 1530, the film is irradiated using a secondary radiation source to form a portion (e.g., patterned portion) of partially cured polymerizable material 1525b. Such partially cured polymerizable material 1525b may then optionally be treated with a laser secondary radiation source to remove unreacted polymerizable material 1525a, for example, at the edges of the partially cured polymerizable material 1525b and / or to reduce the height of the unreacted polymerizable material 1525a, as described above. Then, a compound such as a pigment may be applied to the partially cured polymerizable material 1525b before it is contacted with the object (or build platform) and laminated. The compound may be deposited in any suitable method including those described with respect to Figures 3 and 4. This additional compound may be further processed, before lamination, including the application of heat, radiation, exposure to other substances, or other forms of energy.

[0154] The three-dimensional object or intermediate may be further processed. For example, a dual cure resin may be further cured (e.g., by applying heat and / or contacting with moisture). In addition, the three-dimensional object or intermediate may be cleaned to remove excess resin. In certain embodiments of the invention, the three-dimensional object is not cleaned during post-processing (the methods are devoid of a cleaning step) due to the reduced amount of excess resin on the object after a method of the invention. In some embodiments, a three-dimensional object is formed that has only a pigment on the outer surface (e.g., the outer 1-2 mm surface).

[0155] Any type of object may be fabricated according to embodiments of the invention. Accordingly, provided according to embodiments of the invention are objects formed by a method and / or apparatus described herein. In addition, provided is an object that includes at least one layer or slice formed from modified (e.g., pigmented or pre-irradiated) polymerizable material. In some embodiments, the objects of the invention are dental appliances (e.g., prosthetic denture bases, partial dentures, and teeth such as inlays, onlays, veneers, long term provisionals), footwear portions (e.g., insoles or outsoles), or saddles. As an example, a method of the invention may be used to create dentures with different shades of color or other anatomical features printed into the part. Examples of other parts that may beAttorney Docket No. 1151.261.WO

[0156] fabricated by a method and / or apparatus of the invention include but are not limited to 1) parts with internal channels for fluid routing or cooling; 2) parts with internal conductive features for thermal management or electrical performance such as 3D via, interposers, imbedded electrical devices and passive components (inductors, capacitors, etc.); 3) parts with internal optically transparent components for light routing and integrated photonics; and 4) overfolded parts or parts where additional parts are inserted into the parts being printed (e.g., overmolded electronic components).

[0157] Rolling Film Printing

[0158] A. General Process

[0159] Provided according to embodiments of the invention are apparatus for forming a modified three-dimensional object from polymerizable material. For example, referring to Figure 16, such apparatus 1600 may include (a) at least one radiation source 1605, and optionally a primary radiation source 1605 and at least one secondary radiation source 1606; (b) a build platform 1610 on which a modified three-dimensional object 1615 is formed; (c) an applicator 1620 for coating polymerizable material 1625 onto an optically transparent film 1630; (d) optionally, an applicator 1627 for depositing pigment onto the polymerizable material 1625 or a polymerized object portion; (e) a film transport assembly 1635 for moving the optically transparent film 1630 between a radiation source 1605 and the build platform 1610; (f) at least one controller and / or drive assembly 1670; and (g) optionally a housing and / or frame 1675. Optionally, a coating removal / scraper 1621 (which may be associated with a resin recycling system) may also be included. Referring to Figure 16, the elements having dashed lines may be omitted in some embodiments, but typically at least one of a secondary radiation source 1606 and an applicator 1627 for depositing a compound (e.g., a pigment) will be present unless the primary radiation source is configured to perform all of the radiation steps necessary for a method described herein. In addition, while the film transport assembly 1635 is depicted as a roller apparatus, other types of film transport assemblies 1635 may be used. In addition, other variations of the non-optional elements are envisioned. For example, the coatingAttorney Docket No. 1151.261.WO

[0160] applicator 1620 may be integrally associated with the film transport assembly 1635. As another example, there may be multiple controllers and / or drive assemblies 1670, which may each be operatively associated with one or more of the elements of the apparatus 1600. The apparatus 1600 of the invention may be configured to perform one or more of the RFP methods described herein, and the apparatus may be configured to operate in a number of different manners including stamping RFP methods and / or scrolling build platform RFP methods.

[0161] A number of suitable radiation sources may be used. In some embodiments, the radiation source is an actinic radiation source, such as one or more light sources, and in particular one or more ultraviolet light sources. Any suitable light source can be used, such as incandescent lights, fluorescent lights, phosphorescent or luminescent lights, a laser, light-emitting diode, etc., including arrays thereof. The radiation source may include a pattern-forming element operatively associated with the controller.

[0162] In some embodiments, the irradiation is carried out with patterned irradiation. The patterned irradiation may be a fixed pattern or may be a variable pattern created by a pattern generator (e.g., a DLP, LCD, etc.) as discussed below, depending upon the particular item being fabricated. In particular embodiments, the light source or pattern forming element comprises a digital (or deformable) micromirror device (DMD) with digital light processing (DLP), a spatial modulator (SLM), or a microelectromechanical system (MEMS) mirror array, a mask (aka a reticle), a silhouette, or a combination thereof.

[0163] The build platform is the surface, typically planar, on which the three-dimensional object is formed. The build platform is operatively connected to a controller and / or drive assembly that may translate the build platform in the vertical (Z direction), and optionally, horizontal (X and Y) direction.

[0164] Referring to Figure 17, controller 1770 may be of any suitable type, such as a general-purpose computer. Typically, the controller 1770 will include at least one processor 1770a, a volatile (or "working") memory 1770b, such as random-access memory, and at least one non-volatile or persistent memory 1770c, such as a hard drive or a flash drive. The controller 1770 may use hardware, software implementedAttorney Docket No. 1151.261.WO

[0165] with hardware, firmware, tangible computer-readable storage media having instructions stored thereon, and / or a combination thereof, and may be implemented in one or more computer systems or other processing systems. The controller 1770 may also utilize a virtual instance of a computer. As such, the devices and methods described herein may be embodied in any combination of hardware and software that may all generally be referred to herein as a "circuit," "module," "component," and / or "system." Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable media having computer readable program code embodied thereon.

[0166] Any combination of one or more computer readable media may be utilized. The computer readable media may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable readonly memory (EPROM or Flash memory), an appropriate optical fiber with a repeater, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

[0167] A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. Program code embodied on a computerAttorney Docket No. 1151.261.WO

[0168] readable signal medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0169] The at least one processor 1770a of the controller 1770 may be configured to execute computer program code for carrying out operations for aspects of the present invention, which computer program code may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, or the like, conventional procedural programming languages, such as the "C" programming language, Visual Basic, Fortran 2003, COBOL 2002, PHP, ABAP, dynamic programming languages such as Python, PERL, Ruby, and Groovy, or other programming languages.

[0170] The at least one processor 1770a may be, or may include, one or more programmable general purpose or special-purpose microprocessors, digital signal processors (DSPs), programmable controllers, application specific integrated circuits (ASICs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), trusted platform modules (TPMs), or a combination of such or similar devices, which may be collocated or distributed across one or more data networks.

[0171] Connections between internal components of the controller 1770 are shown only in part and connections between internal components of the controller 1770 and external components are not shown for clarity, but are provided by additional components known in the art, such as busses, input / output boards, communication adapters, network adapters, etc. The connections between the internal components of the controller 1770, therefore, may include, for example, a system bus, a Peripheral Component Interconnect (PCI) bus or PCI-Express bus, a HyperTransport or industry standard architecture (ISA) bus, a small computer system interface (SCSI) bus, a universal serial bus (USB), IIC (I2C) bus, an Advanced Technology Attachment (ATA) bus, a Serial ATA (SATA) bus, and / or an Institute of Electrical and Electronics Engineers (IEEE) standard 1394 bus, also called "Firewire."

[0172] The controller 1770 may be associated with a user interface 1771. The user interface 1771 may be of any suitable type. The user interface 1771 may include a display and / or one or more user input devices. The display may be accessible to theAttorney Docket No. 1151.261.WO

[0173] at least one processor 1770a a via the connections between the system components. The display may provide graphical user interfaces for receiving input, displaying intermediate operation / data, and / or exporting output of the methods described herein. The display may include, but is not limited to, a monitor, a touch screen device, etc., including combinations thereof. The input device may include, but is not limited to, a mouse, keyboard, camera, etc., including combinations thereof. The input device may be accessible to the at least one processor 1770a via the connections between the system components. The user interface 1771 may interface with and / or be operated by computer readable software code instructions resident in the volatile memory 1770b that are executed by the processor 1770a.

[0174] In some embodiments, the method further include the steps of (prior to additive manufacturing), (i) providing digital model(s) of at least one object; (ii) determining a desired configuration of the object(s) on the build platform (e.g., a configuration determined by a computer processor as providing an optimal orientation based on factors including maximum parts per build, minimal resin use, and the like); (iii) creating a digital model of the object(s) in the desired configuration; (iv) processing the digital model in step (iii) to form processed data for use by the additive manufacturing apparatus; and transmitting the processed data to the additive manufacturing apparatus, followed by manufacturing the object(s) by a methods and / or apparatus described herein.

[0175] In some embodiments, the first and / or second drive assemblies may be consolidated together as an XYZ drive, or some may be existing drive components of a CNC machine, to which an "applicator assembly" comprised of the supply chamber(s), rollers, blades, optionally additional drive components, light source, or at least rollers, all on a corresponding mounting frame, may be mounted or retrofitted. Examples of suitable CNC machines include, but are not limited to, the HAAS VF-2, VF-4, and VF-12 / 40 vertical CNC machines, and the HAAS EC-400 and EC-400 horizontal CNC machines, available from Haas Automation, Inc., 2800 Sturgis Road, Oxnard, Calif., 93030 U.S.A.

[0176] In some embodiments of the invention, the apparatus may include a device or system that monitors a height and / or profile of an object layer and / or partially curedAttorney Docket No. 1151.261.WO

[0177] polymerizable material. Accordingly, in some embodiments, the apparatus may include an optical device such as a scanner (e.g., laser scanner, optical surface profilometer, or other profilometer) to measure the height or profile of an object layer and / or partially cured polymerizable material. In some embodiments, apparatus include a load cell (or other force detection sensor) that measures the force during lamination of an object layer. The optical and / or force detection devices may monitor slice height, excess coating thickness, and profile irregularities and the controller may thus be configured to modify coating thickness, build plate z-position, and / or slice location in subsequent layers to adjust for object layers and / or partially cured polymerizable material that are outside of the desired tolerances.

[0178] EXAMPLE

[0179] Figure 18 shows the effect of pre-irradiation of polymerizable material on the formed object. In Figure 18, a first set of object layers were formed in the first portion of the print without modifying the polymerizable material before lamination. As can be seen, significant beading of excess unreacted polymerizable material is present on the sidewalls of these object layers. Then, in subsequent layers, unreacted polymerizable material is partially cured prior to lamination. As can be seen in Figure 18, the excess polymerizable material present on the side walls is significantly decreased.

[0180] The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. The invention is defined by the following claims, with equivalents of the claims to be included therein.

Claims

Attorney Docket No. 1151.261.WOWe claim:

1. A method of making a modified three-dimensional object, comprising:(a) coating polymerizable material onto an optically transparent film;(b) optionally modifying the polymerizable material (e.g., by depositing pigment thereon and / or by pre-irradiating) on the film;(c) positioning modified and / or unmodified polymerizable material between a radiation source and a build platform such that the modified and / or unmodified polymerizable material contacts the build platform;(d) irradiating a portion of the modified and / or unmodified polymerizable material through the optically transparent film (e.g., in a predetermined pattern) with the radiation source to solidify the modified and / or unmodified polymerizable material and laminate it to the build platform, thus forming an object attached to the build platform;(e) positioning additional modified and / or unmodified polymerizable material between the radiation source and the build platform such that the additional modified and / or unmodified polymerizable material contacts the object attached to the build platform;(f) irradiating a portion of the additional modified and / or unmodified polymerizable material (e.g., in a predetermined pattern) with the radiation source to solidify and laminate the additional modified and / or unmodified polymerizable material to the object, thus adding an object layer to the object; and(g) repeating steps (e) and (f) until the object attached to the build platform forms the three-dimensional object or an intermediate having the same shape, or the shape to be imparted to, the three-dimensional object, wherein the object or intermediate comprises at least one object layer formed from modified polymerizable material.

2. The method of claim 1, wherein modifying the polymerizable material comprises depositing at least one compound (e.g., one or more pigments) on a surface of the polymerizable material.Attorney Docket No. 1151.261.WO3. The method of claim 2, wherein the at least one compound comprises a pigment.

4. The method of claim 3, wherein the pigment is present in a UV-curable and / or conductive ink.

5. The method of claim 2, wherein the at least one compound comprises a UV-stabilizer, an antioxidant, an antistatic compound, a filler, and / or a compound that is reactive with the polymerizable material.

6. The method of any one of claims 2-5, wherein the at least one compound contacts the polymerizable material for a time in a range of one second to one minute before irradiation in step (d) or step (f).

7. The method of any one of claims 2-6, wherein the at least one compound is deposited in a pattern that corresponds to (e.g., is the same or overlaps with) a pattern of irradiation in step (d) or step (f).

8. The method of any one of claims 2-7, wherein the at least one compound (e.g., a pigment) is only deposited onto portions of the polymerizable material that, once irradiated, will form an outward facing surface of the three-dimensional object.

9. The method of any one of claims 2-8, wherein the at least one compound is deposited onto polymerizable material that has been partially cured (e.g., by preirradiation).

10. The method of claim 1, wherein modifying the polymerizable material comprises irradiating the polymerizable material to partially cure a portion of the polymerizable material prior to contacting the build platform in step (c) or contacting the object in step (e).Attorney Docket No. 1151.261.WO11. The method of claim 10, wherein irradiation in steps (d) and / or (f) is from a primary radiation source and the partially curing of the polymerizable material uses radiation from a secondary radiation source.

12. The method of claims 10 or 11 , wherein an interface between the partially cured polymerizable material and unreacted polymerizable material is removed (e.g., ablated with a laser) to decrease contact between the partially cured polymerizable material and the unreacted polymerizable material, optionally wherein a thickness of the unreacted polymerizable material on the optically transparent film is decreased (e.g., by laser ablation).

13. The method of any one of claims 10-12, wherein the partially cured polymerizable material is cleaned to remove excess unreacted polymerizable material prior to contacting the partially cured polymerizable material with the build platform in step (c) or contacting the object in step (e).

14. The method of any one of claims 10-13, further comprising partially curing a first type of polymerizable material and irradiating (e.g., in step (d) or step (f)) to form a first portion of an object layer, and then partially curing a second type of polymerizable material and irradiating (e.g., in step (d) or step (f)) to form a second portion of the object layer, thereby forming a composite object layer.

15. The method of any one of claims 10-13, further comprising partially curing a first type of polymerizable material and irradiating (e.g., in step (d) or step (f)) to form a first portion of an object layer, and then applying a second type of unreacted polymerizable material to the first portion of the object layer, and irradiating the second type of unreacted polymerizable material to form a composite object layer.

16. A method of making a three-dimensional object, comprising:(a) positioning polymerizable material on an optically transparent film between a radiation source and a build platform such that the polymerizable material contacts the build platform;Attorney Docket No. 1151.261.WO(b) irradiating a portion of the polymerizable material through the optically transparent film with the radiation source to solidify and laminate the polymerizable material to the build platform, thus forming an object attached to the build platform;(c) optionally depositing at least one compound (e.g., a pigment) onto a surface of the object (e.g., in a predetermined pattern);(d) optionally irradiating the surface of the object;(e) positioning additional polymerizable material between the radiation source and the build platform such that the additional polymerizable material contacts the object;(f) irradiating a portion of the additional polymerizable material through the optically transparent film (e.g., in a predetermined pattern) with the radiation source to solidify and laminate the portion of the additional polymerizable material to the object, thus forming an additional object layer on the object;(g) optionally depositing at least one compound (e.g., pigment / ink) onto a surface of the additional layer of the object (e.g., in a predetermined pattern);(h) optionally irradiating the additional layer of the object; and(i) repeating steps (e) - (h) until the object forms the three-dimensional object or an intermediate having the same shape, or the shape to be imparted to, the three-dimensional object, wherein the object or intermediate comprises at least one object layer having at least one compound (e.g., pigment) deposited thereon.

17. The method of claim 16, wherein the at least one compound comprises a pigment (e.g., in a UV-curable and / or conductive ink).

18. The method of claim 16, wherein the at least one compound comprises a UV-stabilizer, an antioxidant, an antistatic compound, a filler, and / or a compound that is reactive with the polymerizable material.

19. The method of any one of claims 16-18, wherein the at least one compound is deposited in a pattern that corresponds to (e.g., is the same or overlaps with) a pattern of irradiation in step (b) and / or step (f).Attorney Docket No. 1151.261.WO20. The method of any one of claims 16-19, wherein the at least one compound is only deposited onto portions of the polymerizable material that form an outward facing surface of the three-dimensional object.

21. An apparatus for forming a three-dimensional object, comprising:(a) at least one radiation source, and optionally a primary radiation source and at least one secondary radiation source;(b) a build platform on which the three-dimensional object is formed;(c) an applicator for coating polymerizable material onto an optically transparent film;(d) optionally an applicator for depositing at least one compound onto the polymerizable material or an object layer;(e) a film transport assembly for moving the optically transparent film between the at least one radiation source and the build platform;(f) at least one controller and / or drive assembly in communication with the radiation source, the build platform, the film transport assembly, the applicator for coating polymerizable material, and optionally the applicator for depositing pigment; and(g) optionally a housing and / or frame for supporting, and optionally connecting, one or more of the radiation source, the build platform, the film transport assembly, the applicator for coating polymerizable material, the applicator for depositing pigment, and the at least one controller and / or drive assembly,wherein the apparatus includes at least one of a secondary radiation source and an applicator for depositing at least one compound onto the polymerizable material or an object layer.

22. The apparatus of claim 21, wherein the at least one controller and / or drive assembly is configured to direct the apparatus to perform one or more of the methods described herein.

23. An object formed by a method and / or apparatus of the invention.

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