REMOVABLE BUILD PLATFORM FOR AN ADDITIVE MANUFACTURING
APPARATUS
RELATED APPLICATIONS
[0001] This applications claims priority to U.S. Provisional Application Serial No. 62/738,056, filed September 28, 2018, the disclosure of which is hereby incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention concerns additive manufacturing in general, and particularly concerns high throughput systems employing streolithography-type additive manufacturing.
BACKGROUND
[0003] 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 include "bottom-up" techniques, where light is projected into the resin through a light-transmissive“window” onto the bottom of the growing object, which object is carried up and out of the resin pool on a“build platform.”
[0004] The recent introduction of a more rapid stereolithography technique sometimes referred to as continuous liquid interface production (CLIP) has expanded the usefulness of stereolithography from prototyping to manufacturing. See J. Tumbleston, D. Shirvanyants, N. Ermoshkin et al., Continuous liquid interface production of 3D objects , SCIENCE 347, 1349- 1352 (published online 16 March 2015); US Patent Nos. 9,211,678; 9,205,601; and 9,216,546 to DeSimone et al.; see also R. Janusziewicz, et al., Layerless fabrication with continuous liquid interface production, PNAS 113, 11703-11708 (18 Oct. 2016).
[0005] Dual cure resins for additive manufacturing were introduced shortly after the introduction of CLIP, expanding the usefulness of stereolithography for manufacturing a broad variety of objects still further. See Rolland et al., US Patent Nos. 9,676,963, 9,453,142 and 9,598,606; J. Poelma and J. Rolland, Rethinking digital manufacturing with polymers, SCIENCE 358, 1384-1385 (15 Dec. 2017).
[0006] The foregoing developments have in turn lead to a need for build platforms that can be more rapidly exchanged in bottom-up additive manufacturing apparatus, while maintaining good alignment, so that greater numbers of objects can be produced on the apparatus. SUMMARY
[0007] In some embodiments, a removable build platform for a bottom-up stereolithography apparatus includes (a) a body having a top portion, a bottom portion, a front portion, a back portion, and opposite side portions, said bottom portion having a build surface on which objects can be produced by stereolithography; (b) a plurality of clamp draw-in pins connected to said body top portion and extending upward therefrom; and (c) a lifting slot formed in each of said side portions, with said lifting slots parallel to and aligned with one another.
[0008] In some embodiments, the build surface is rectangular. The build surface may have at least one elongate slot formed therein to facilitate the flow of polymerizable resin beneath the build surface during additive manufacturing of at least one object thereon),
[0009] In some embodiments, the lifting slots extend through said body back portion.
[0010] In some embodiments, the lifting slots are internal and face one another.
[0011] In some embodiments, the plurality of clamp draw-in pins comprise four draw-in pins.
[0012] In some embodiments, the build platform further comprises (d) an outward facing handle connected to each of said side portions.
[0013] In some embodiments, the body has a unique identifier (e.g., an NFC tag) connected thereto.
[0014] In some embodiments, the build surface is substantially planar.
[0015] In some embodiments, the top portion has a plurality of weight-reducing hollows formed therein.
[0016] The foregoing and other objects and aspects of the present invention are explained in greater detail in the drawings herein and the specification set forth below. The disclosures of all United States patent references cited herein are to be incorporated herein by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a bottom perspective view of a platform according to some embodiments;
[0018] FIG. 2 is a back view of the platform of FIG. 1;
[0019] FIG. 3 is a front view of the platform of FIG. 1;
[0020] FIG. 4 is a side view of the platform of FIG. 1;
[0021] FIG. 5 is a bottom view of the platform of FIG. 1; and
[0022] FIG. 6 is an top view of the platform of FIG. 1. DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS
[0023] The present invention is now described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art.
[0024] Like numbers refer to like elements throughout. In the figures, the thickness of certain lines, layers, components, elements or features may be exaggerated for clarity. Where used, broken lines illustrate optional features or operations unless specified otherwise.
[0025] 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, 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.
[0026] 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").
[0027] 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 farther 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.
[0028] 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.
[0029] 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, elements 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.
[0030] 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.
[0031] 1. ADDITIVE MANUFACTURING APPARATUS.
[0032] Conventional (or“single cure”) resins, or dual cure resins, can be used in carrying out aspects of the present invention. Examples include but are not limited to those described in DeSimone et ah, US Patent No. 9,211,678; in Rolland et ah, US Patent No. 9,676,963; 9,598,606; and 9,453,142, and in Wu et al., US Patent Application Pub. No. US2017/0260418, the disclosures of which are incorporated herein by reference. Example dual cure resins include, but are not limited to, Carbon Inc. EPU 40, EPU 41, FPU, RPU 70, SIL 30, and EPX 82 resins, all available from Carbon Inc. 1089 Mills Way, Redwood City, CA 94063 USA.
[0033] Apparatus and methods for carrying out additive manufacturing are known. Suitable techniques include bottom-up or top-down additive manufacturing, generally known as stereolithography. Such methods are known and described in, for example, U.S. Patent No. 5,236,637 to Hull, US Patent Nos. 5,391,072 and 5,529,473 to Lawton, U.S. Patent No. 7,438,846 to John, US Patent No. 7,892,474 to Shkolnik, U.S. Patent No. 8,110,135 to El- Siblani, U.S. Patent Application Publication No. 2013/0292862 to Joyce, and US Patent Application Publication No. 2013/0295212 to Chen et al. The disclosures of these patents and applications are incorporated by reference herein in their entirety.
[0034] In some embodiments, the intermediate object is formed by continuous liquid interface production (CLIP). CLIP is known and described in, for example, US Patent No. 9,211,678, US Patent No. 9,205,601, US Patent No 9,216,546, and in J. Tumbleston, D. Shirvanyants, N. Ermoshkin et al., Continuous liquid interface production of 3D Objects, Science 347, 1349-1352 (published online 16 March 2015). See also R. Janusziewcz et al., Layerless fabrication with continuous liquid interface production, Proc. Natl. Acad. Sci. USA 113, 11703-11708 (October 18, 2016). In some embodiments, CLIP employs features of a bottom-up three-dimensional fabrication as described above, but the irradiating and/or said advancing steps are carried out while also concurrently maintaining a stable or persistent liquid interface between the growing object and the build surface or window, such as by: (i) continuously maintaining a dead zone of polymerizable liquid in contact with said build surface, and (ii) continuously maintaining a gradient of polymerization zone (such as an active surface) between the dead zone and the solid polymer and in contact with each thereof, the gradient of polymerization zone comprising the first component in partially cured form. In some embodiments of CLIP, the optically transparent member comprises a semipermeable member (e.g., a fluoropolymer), and the continuously maintaining a dead zone is carried out by feeding an inhibitor of polymerization through the optically transparent member, thereby creating a gradient of inhibitor in the dead zone and optionally in at least a portion of the gradient of polymerization zone. Other approaches for carrying out CLIP that can be used in the present invention and potentially obviate the need for a semipermeable "window" or window structure include utilizing a liquid interface comprising an immiscible liquid ( see L. Robeson et al., WO 2015/164234, published October 29, 2015), generating oxygen as an inhibitor by electrolysis (see I Craven et al., WO 2016/133759, published August 25, 2016), and incorporating magnetically positionable particles to which the photo activator is coupled into the polymerizable liquid ( ee J. Rolland, WO 2016/145182, published September 15, 2016).
[0035] In preferred embodiments, the additive manufacturing apparatus is a bottom-up stereolithography apparatus (including but not limited to apparatus carrying out CLIP), employing a removable window cassette, such as described in B. Feller et al., Three- dimensional printing with build plates having reduced pressure and/or channels for increased fluid flow, PCT Patent Application Pub. No. WO 2018/006029, or B. Feller et al., Three-dimensional printing method and apparatus for reducing bubbles by de-gassing through build plate, PCT Patent Application Pub. No. WO 2018/006018 (where“build plate” refers to the“window cassette”).
[0036] 2. BUILD PLATFORM
[0037] As shown in FIGS. 1-6, a removable build platform 100 for a bottom-up stereolithography apparatus includes a body 110 having a top portion 120, a bottom portion 130, a front portion 140, a back portion 150, and opposite side portions 160. The bottom portion 130 includes a build surface 132 on which objects can be produced by stereolithography. The build platform 100 includes a plurality of clamp draw-in pins 122 connected to the body top portion 120 and extending upward therefrom. A lifting slot 162 is formed in each of the side portions 160 such that the lifting slots 162 are parallel to and aligned with one another.
[0038] In this configuration, the claim draw-in pins 122 may be used to removably secure the removable build platform 100 in position on a stereolithography apparatus. The stereolithography apparatus may include a mounting plate configured to receive the clamp draw-in pins 122 for mounting the build platform 100 thereto.
[0039] As illustrated, the build platform 100 further includes an outward facing handle 166 connected to each of said side portions 160. The lifting slots 162 extend through the body back portion 150 to define an opening 164, and the lifting slots 162 are internal and face one another. Thus, a lifter, for example, having parallel extending arms that cooperate with the lifting slots 162, may be used to move the platform 100 by inserting lifting arms through the openings 164 and engaging with the lifting slots 162. Build platforms according to some embodiments can be more rapidly exchanged in a bottom-up additive manufacturing apparatus by using the lifting slots 162. In some embodiments, the lifter may be a robotic lifter that provides automated placement/mounting and/or removal of the platform 100 in a stereolithography apparatus. However, a manual lifter may also be used to manually place or mount the platform 100 and/or remove the platform 100 from a stereolithography apparatus.
[0040] In some embodiments, the plurality of clamp draw-in pins 122 comprise four draw-in pins; however, it should be understood that any suitable number of draw-in pins 122 may be used (more or less than four). The clam draw-in pins 122 may be used to secure the platform lOOin a stereolithography apparatus by affixing the build platform to a corresponding mounting plate. For example, mating receptacles may be provided on the stereolithography apparatus, such as on a mounting plate, to receive the clamp draw-in pins 122 of the platform 100 in a particular orientation and to secure the platform 100 at a desired alignment with respect to the stereolithography apparatus. The mounting plate may be configured to move the build platform 100 away from a corresponding build surface of a build window during the formation of a three-dimensional object, e.g., to move the object affixed to the build platform 100 away from the corresponding build surface of the build window. Thus, the clamp draw- in pins 122 may be used to securely affix the build platform 100 to the stereolithography apparatus at a desired orientation. In addition, clam draw-in pins 122 may be used to remove the platform 100 from a stereolithography apparatus after use.
[0041] Clamp draw-in pins (also referred to as clamping pins, draw-in bolts, and pull-in nipples), and their associated clamping mechanisms, are known and described in, for example, US Patents Nos. 8,066,289; 6,283,465; and 5,961,261. In preferred embodiments, the clamp and associated draw-in pins are VERO-S NSE mini quick-change pallet system components, available from Schunk Intec Inc., 211 Kitty Hawk Drive, Morrisville, NC 27560 USA.
[0042] In some embodiments, the build surface 132 is rectangular. The build surface 132 may be substantially planar and have at least one elongate slot 134 formed therein to facilitate the flow of polymerizable resin beneath the build surface 132 during additive manufacturing of at least one object thereon.
[0043] In some embodiments, the body 110 has a unique identifier (e.g., an NFC tag) connected thereto. Accordingly, the platform 100 may be identified by a tag reader, for example, for tracking the usage of the platform 100 or identifying a type of platform or platform history in the stereolithography apparatus.
[0044] In some embodiments, the top portion 120 has a plurality of weight-reducing hollows 124 formed therein. The weight-reducing hollows 124 are separated by brackets 126 for increased strength and stability
[0045] 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.