A reconfigurable, maintainable, and cost-effective dynamic inline mixer for an additive manufacturing (three‑dimensional printing) end-effector

Abstract

A dynamic inline mixer for an additive manufacturing device receiving a plurality of distinct material streams to form a printable material is provided. For example, the dynamic inline mixer may be used as part of an end effector of a robotic additive manufacturing device for additively manufacturing a cementitious or slurry-based material. The inline mixer comprises a rotary mixer component, a motor in driving engagement with the rotary mixer component, a mixing barrel component comprising a plurality of segments assembled that together define an internal chamber in which the rotary mixer component is at least partially disposed and rotates. The mixing barrel is configured to process the printable material. The inline mixer also comprises a terminal extrusion nozzle connected to an outlet of the mixing barrel through which the printable material passes.

Description

Attorney Docket No. 2115-008424-WO-POAA RECONFIGURABLE, MAINTAINABLE, AND COST-EFFECTIVE DYNAMIC INLINE MIXER FOR AN ADDITIVE MANUFACTURING (THREE-DIMENSIONAL PRINTING) END-EFFECTORCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 688,014, filed on August 28, 2024. The entire disclosure of the above application is incorporated herein by reference.FIELD

[0002] The present disclosure relates to a dynamic, reconfigurable, inline mixer for an additive manufacturing device receiving a plurality of distinct material streams to form a printable material that is deposited via additive manufacturing / three-dimensional printing.BACKGROUND

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] Additive manufacturing (AM) also commonly referred to as three-dimensional (3D) printing, can be used to print cementitious materials, like concrete or other slurry-based materials. Additive manufacturing (AM) / three-dimensional (3D) printing is a process by which flowable and extrudable material is applied in an additive, layer-by-layer formation technique. Additive manufacturing can form structures having complex geometries and freeform shapes and is of particular interest in the construction industry. 3D printing of cementitious materials, like concrete can be referred to as concrete additive manufacturing or concrete three-dimensional printing - 3DP (3DCP).

[0005] Additive manufacturing can comprise depositing a printable (e.g., cementitious or slurry-based) composition on a toolpath by passing the printable composition through a printhead of a robotic additive manufacturing device to deposit the cementitious composition onto a target. The printhead is often part of an end effector of a robotic arm. The printing head / printhead typically comprises at least one aperture, for example, an aperture of a nozzle of a 3D printhead, where the printable cementitious composition passes and is deposited onto a target. Notably, the printhead / aperture may define different extruded shapes, such as round, rectangular, or irregular shapes. In the fresh state, the cementitious composition is flowable and extrudable. Thus, the cementitious or other printable composition may be deposited in a flowing continuous stream thatAttorney Docket No. 2115-008424-WO-POA is formed by a deposited ribbon or filament of the cementitious material. The deposited composition also transforms into a hardened state.

[0006] Existing 3DCP technologies are mainly one component (IK), two component (2K), and more than two component (2K+) systems. In all these systems, a concrete or other slurry mix is pumped to the end effector having a printhead, depositing the material layer by layer. A significant difference lies in the 2K and 2K+ 3DCP systems, where an admixture such as concrete accelerators, aggregates, or fibers are pumped to the end effector and mixed with the slurry just before the deposition to enhance or control specific properties for the primary 3D printed slurry.

[0007] 3D printing complex geometries with slurry materials such as concrete, cementitious, clay, and wood-based slurries requires advanced control over the rheological properties of the slurry. In certain aspects, the use of 2K (two-component) and 2K+ (greater than two component) systems can provide such advanced control. For example, these additive manufacturing systems allow for the introduction of admixtures, such as accelerators, superplasticizers, and thickeners, to the primary slurry material, which provides a higher level of control over the setting time and open time (e.g., working window) of the slurry. By precisely managing these parameters, the printing process can achieve the desired structural integrity and surface finish of the printed components, while also accommodating the complexities of intricate geometric designs. Despite their advantages, 2K and 2K+ additive manufacturing systems are expensive and difficult to maintain and repair. It would be desirable to address the drawbacks of the current 2K and 2K+ systems to provide enhanced multi-component additive manufacturing systems for printing slurry based materials.SUMMARY

[0008] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0009] In certain variations, the present disclosure contemplates an inline mixer for an additive manufacturing device receiving a plurality of distinct material streams to form a printable material. The inline mixer includes a rotary mixer component, a motor, a mixing barrel component, and a terminal extrusion nozzle. The motor is in driving engagement with the rotary mixer component. The mixing barrel component includes a plurality of segments assembled together to define an internal chamber in which the rotary mixer component is at least partially disposed and rotates. The mixing barrel component is configured to process the printable material. The terminal extrusion nozzle is connected to an outlet of the mixing barrel component through which the printable material passes.Attorney Docket No. 2115-008424-WO-POA

[0010] In one aspect, the motor includes a servo motor-gearbox assembly.

[0011] In one further aspect, the plurality of segments are respectively connected to one another via a fluid tight lap joint.

[0012] In one further aspect, the plurality of segments are respectively connected to one another via a plurality of connectors.

[0013] In one further aspect, the inline mixer further includes a sealing gasket at each respective lap joint disposed between respective segments.

[0014] In one further aspect, the sealing gasket is an O-ring.

[0015] In one further aspect, the rotary mixer component includes a shaft having at least one of a screw or mixing pins disposed thereon.

[0016] In one further aspect, the plurality of segments include an uppermost segment that is interchangeable and has at least two distinct inlets.

[0017] In one further aspect, a robotic additive manufacturing device for additively manufacturing a cementitious or slurry-based material includes an end effector including the inline mixer. The printable material comprises the cementitious or slurry-based material.

[0018] In certain further variations, the present disclosure contemplates an inline mixer for an additive manufacturing device receiving a plurality of distinct material streams to form a printable material. The inline mixer includes a rotary mixer component, a motor, a mixing barrel component, and a terminal extrusion nozzle. The motor is in driving engagement with the rotary mixer component. The mixing barrel component includes a plurality of segments assembled together to define an internal chamber in which the rotary mixer component is at least partially disposed and rotates. Each of the plurality of segments includes a first annular member extending from a first end to a second end opposite the first end, and a second annular member extending from a first end to a second end opposite the first end. The first end of the second annular member is disposed on the second end of the first annular member. The first end of the first annular member of a first segment abuts the second end of the first annular member of an adjacent segment. The mixing barrel component is configured to process the printable material. The terminal extrusion nozzle is connected to an outlet of the mixing barrel component through which the printable material passes.

[0019] In one aspect, the motor includes a servo motor-gearbox assembly.

[0020] In one further aspect, the plurality of segments are respectively connected to one another via a fluid tight lap joint.

[0021] In one further aspect, the plurality of segments are respectively connected to one another via a plurality of connectors.Attorney Docket No. 2115-008424-WO-POA

[0022] In one further aspect, the inline mixer further includes a sealing gasket at each respective lap joint disposed between respective segments.

[0023] In one further aspect, the sealing gasket is an O-ring.

[0024] In one further aspect, the rotary mixer component includes a shaft having at least one of a screw or mixing pins disposed thereon.

[0025] In one further aspect, the plurality of segments include an uppermost segment that is interchangeable and has at least two distinct inlets.

[0026] In one further aspect, a robotic additive manufacturing device for additively manufacturing a cementitious or slurry-based material includes an end effector including the inline mixer. The printable material comprises the cementitious or slurry-based material.

[0027] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.DRAWINGS

[0028] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0029] FIG. 1 shows an additive manufacturing system for additively manufacturing a cementitious or slurry-based material according to certain variations of the present disclosure;

[0030] FIG. 2 shows a printhead of a robotic additive manufacturing device for additively manufacturing a cementitious or slurry-based material according to certain variations of the present disclosure;

[0031] FIG. 3 shows an assembly for a dynamic inline mixer that may be used with an end effector for a robotic additive manufacturing device for printing cementitious or slurry-based materials, including a rotating rotor blade and a multicomponent stator according to certain aspects of the present disclosure; and

[0032] FIG. 4 shows an exploded view of a schematic of a dynamic inline mixer for an end effector for a robotic additive manufacturing device for printing slurry based materials, including multiple segments of a stator according to certain aspects of the present disclosure.

[0033] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.Attorney Docket No. 2115-008424-WO-POADETAILED DESCRIPTION

[0034] Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific compositions, components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

[0035] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, elements, compositions, steps, integers, operations, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Although the open-ended term “comprising,” is to be understood as a non-restrictive term used to describe and claim various embodiments set forth herein, in certain aspects, the term may alternatively be understood to instead be a more limiting and restrictive term, such as “consisting of’ or “consisting essentially of.” Thus, for any given embodiment reciting compositions, materials, components, elements, features, integers, operations, and / or process steps, the present disclosure also specifically includes embodiments consisting of, or consisting essentially of, such recited compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of “consisting of,” the alternative embodiment excludes any additional compositions, materials, components, elements, features, integers, operations, and / or process steps, while in the case of “consisting essentially of,” any additional compositions, materials, components, elements, features, integers, operations, and / or process steps that materially affect the basic and novel characteristics are excluded from such an embodiment, but any compositions, materials, components, elements, features, integers, operations, and / or process steps that do not materially affect the basic and novel characteristics can be included in the embodiment.

[0036] Any method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed, unless otherwise indicated.Attorney Docket No. 2115-008424-WO-POA

[0037] When a component, element, or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other component, element, or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0038] Although the terms first, second, third, etc. may be used herein to describe various steps, elements, components, regions, layers and / or sections, these steps, elements, components, regions, layers and / or sections should not be limited by these terms, unless otherwise indicated. These terms may be only used to distinguish one step, element, component, region, layer or section from another step, element, component, region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first step, element, component, region, layer or section discussed below could be termed a second step, element, component, region, layer or section without departing from the teachings of the example embodiments.

[0039] Spatially or temporally relative terms, such as “before,” “after,” “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially or temporally relative terms may be intended to encompass different orientations of the device or system in use or operation in addition to the orientation depicted in the figures.

[0040] Throughout this disclosure, the numerical values represent approximate measures or limits to ranges to encompass minor deviations from the given values and embodiments having about the value mentioned as well as those having exactly the value mentioned. Other than in the working examples provided at the end of the detailed description, all numerical values of parameters (e.g., of quantities or conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term “about” whether or not “about” actually appears before the numerical value. “About” indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; approximately or reasonably close to the value; nearly). If the imprecision provided by “about” is not otherwise understood in the art with this ordinary meaning, then “about” as used herein indicates at leastAttorney Docket No. 2115-008424-WO-POA variations that may arise from ordinary methods of measuring and using such parameters. For example, “about” may comprise a variation of less than or equal to 5%, optionally less than or equal to 4%, optionally less than or equal to 3%, optionally less than or equal to 2%, optionally less than or equal to 1%, optionally less than or equal to 0.5%, and in certain aspects, optionally less than or equal to 0.1%.

[0041] In addition, disclosure of ranges includes disclosure of all values and further divided ranges within the entire range, including endpoints and sub-ranges given for the ranges.

[0042] Example embodiments will now be described more fully with reference to the accompanying drawings.

[0043] In various aspects, the present disclosure provides new designs for a printhead of a robotic additive manufacturing device for additively manufacturing a cementitious or other slurry-based materials (e.g., concrete, clay, and wood-based slurries) where at least two components are added and mixed together (2K and 2K+ 3DCP systems). The nomenclature of IK, 2K, and 2K+ refers to printhead technologies and the number of component inlets, either one component inlet (IK), two component inlets (2K), or more than two component inlets (2K+), with subsequent evolutions of the technology. Generally, dry material, water, and optional additives are introduced together. They may be mixed and pumped as a slurry through an extrusion system, where the 3DCP printer device forms a construct or three-dimensional printed structure from the printed material. One main difference in the 2K system, relative to a IK system, is its rapid stiffening of a concrete mix at the printhead by introducing chemical accelerators via one of the inlets / material streams. An accelerator is pumped separately and mixed with the concrete slurry in the printhead just before deposition, allowing precise control over the material’s open time (working window) and setting times. In certain aspects, 2K+ technology includes introduction of multiple additives (e.g., accelerators, thickeners, and superplasticizers) added at the printhead, thus providing greater control over the slurry’s properties than possible with basic 2K systems.

[0044] The additive manufacturing device may be used in the additive manufacturing (AM) of a cementitious or slurry -based (e.g., concrete, clay, and wood-based slurries) composition for a cementitious composite material. In certain variations, the cementitious composite material may comprise a cementitious binder material and at least one reinforcement particle or fiber. In certain variations, the cementitious composite material is an engineered cementitious composite (ECC) structure. ECC, a strain-hardening fiber-reinforced cementitious material, features high tensile strength and ductility.

[0045] The broad family of cementitious and slurry-based materials is compatible with typical concrete processing methods (e.g., pouring into molds or forms / formwork, spraying, andAttorney Docket No. 2115-008424-WO-POA the like) and can exhibit strain-hardening behavior by way of inclusion of a volume fraction amount of distributed polymer fibers or other reinforcing materials. Printable cementitious and slurry-based compositions have been developed for the purpose of improving durability and resiliency of critical structural and infrastructural components, while being compatible with additive manufacturing processes.

[0046] In certain aspects, the present disclosure contemplates an automated additive manufacturing system. The present disclosure contemplates an automated additive manufacturing device that can utilize robotics and other computer numerical control (CNC) driven machinery, such as a robotic device or a computer numerical control (CNC) gantry. The at least one robotic device or CNC gantry may have a printhead on an end effector, as described herein, that provides an ability to manufacture complex three-dimensional printed structures with high resolution and minimal defects.

[0047] FIG. 1 shows a non-limiting and representative example of one variation of a suitable additive manufacturing system 10 that includes a feeding system 20 and an extruding system 22. The feeding system 20 includes a hopper 26 that receives material 28, which may be a cementitious material in a fresh state that flows and is pumpable. In various aspects, the material 28 comprises a cementitious or slurry-based (e.g., concrete, clay, and wood-based slurries) composition. The material 28 may be mixed upstream (in a mixer not shown) in batches, or by a continuous, controllable process, whereby a machine(s) measures the constituent ingredients, mixes and mixes and pushes this material into the feeding system 20. The material 28 in the hopper 26 is then processed by one or more pumps 32 (e.g., a peristaltic pump, rotary screw, rotary lobe pump, auger-type (Archimedean screw) pumps, etc.). In other embodiments, the pump 32 may instead be a progressive cavity design. The one or more pumps 32 are in fluid communication with a conduit, such as a supply line, like a concrete hose 34, through which pressurized material 28 is pumped. As will be appreciated by those of skill in the art, the feeding system may have other conventional components, including valves, actuators, flow rate, temperature, pressure and / or flow rate monitors, pulsation dampers, and the like.

[0048] The extruding system 22 is connected to the feeding system 20 via the concrete hose 34. A pressure transducer 36 is connected to the concrete hose 34. After the pressure transducer 36, the concrete hose 34 is connected to a main inlet or main feed conduit 38 (e.g., main input) of an additive manufacturing device 40. As described above, the additive manufacturing device 40 may include a CNC or robotic controlled deposition head 50 (e.g., extrusion tool and / or printhead 50), which synchronously deposits a printable composition 42 in subsequent layers to form a three-dimensional component or structure 43 (FIG. 1). As will beAttorney Docket No. 2115-008424-WO-POA discussed in greater detail below accompanying the discussion of FIGS. 2-4, the extruding system 22 is generally designed for rapid disassembly to facilitate easy cleaning and repair.

[0049] With reference to FIGS. 1-2, the material 28 is introduced to the printhead 50 of the additive manufacturing device 40 via the main feed conduit 38. The main feed conduit 38 is connected to one or more feed pumps (not shown) (FIG. 1). The pressure transducer 36 (FIG. 1) at the inlet of the feed pump (e.g., PC pump) provides feedback to the one or more pumps to maintain a constant inlet pressure, even as the one or more feed pumps starts / stops or varies flow. The extruding system 22 may thus be fed by one or more demand-based feed pumps which may be controlled by a central Programmable Logic Control (PLC) system 45.

[0050] The printable composition 42 for additive manufacturing may have a fresh state, where the composition may be in a semi-liquid phase that flows and may be extruded for the additive manufacturing spraying process. The printable composition may be a cementitious composition. After hydraulic setting and reaction proceeds; the cementitious composition is in a hardened state. The cementitious composition may comprises a cementitious material, which may include a cement or pozzolan. In certain variations, such a cementitious composition comprises ordinary Portland cement. The printable composition 42 may include a slurry or paste that includes clay, earth-based materials, starch, and the like.

[0051] The printable cementitious composition may comprise a variety of additives, such as an aggregate, like a fine aggregate, water, and other typical ingredients known to those of skill in the art, such as fly ash, plasticizers, water reducers, accelerators, and the like. In certain aspects, the printable composition comprises an additive selected from the group consisting of: an accelerator, a retardant, a binder, a fiber, a reinforcing particle, a reinforcing aggregate, a mineral, a water reducer, a viscosity modifying admixture, a chemical admixture, and combinations thereof, by way of non-limiting example.

[0052] A Portland cement typically comprises inorganic compounds, such as dicalcium silicate (C2S or 2CaO-SiO2), tricalcium silicate (C3S or 3CaO-SiO2), tricalcium aluminate (C3A or 3CaO-A12O3), and tetracalcium aluminoferrite (C4AF or 4CaO-A12O3-Fe2O3), which may be hydrated. Commercially available Portland cement often includes additives, such as gypsum (calcium sulfate) that serves as a set retardant, and pozzolans, like fly ash and ground granulated blast furnace slags (GGBFS), that can react with calcium hydroxide and water to form calcium silicate hydrates or calcium aluminate hydrates. When pozzolans are added to Portland cement, they are considered blended cements. ASTM, International Test C 150 called the “Standard Specification for Portland Cement” provides eight types of ordinary Portland cement for different applications, namely: Types I, IA, II, IIA, III, IIIA, IV, and V. In certain non-limiting aspects, theAttorney Docket No. 2115-008424-WO-POAPortland cement used in the cementitious composition is Type I. The Portland cement may be present in the cementitious composition at greater than or equal to about 50 mass / weight % to less than or equal to about 98 mass % of the total mass of cementitious binder components, optionally at greater than or equal to about 60 mass / weight % to less than or equal to about 90 mass % of the total mass of cementitious binder components, and in certain variations, optionally at about 72% by mass of the total mass of the cementitious binder components.

[0053] In certain variations, the printable cementitious composition may further comprise a fly ash that can be added to the cementitious composition and serves as a pozzolan / cementitious material. Fly ash is an industrial byproduct, for example, collected from effluent of a coal burning boiler unit. It can be used as a substitute for a portion of the Portland cement to reduce energy consumption required to form the overall product and increase the environmental friendliness of the cementitious composition, while contributing to the cementitious properties of the matrix / binder system of the concrete composite. In one variation, the fly ash may be a Class F fly ash as designated by ASTM C618, which is formed from combustion of anthracite and / or bituminous coals. ASTM C618 requires that Class F fly ash contain at least 70% pozzolanic compounds (silica oxide, alumina oxide, and iron oxide). The fly ash may be present in the cementitious composition at 0 mass / weight % to less than or equal to about 45 mass % of the total mass of cementitious binder components, optionally at 0 mass % to less than or equal to about 35 mass % of the total mass of cementitious binder components, and in certain aspects, optionally at about 23 mass % of the total mass of cementitious binder components. In other aspects, the fly ash may be present in the cementitious composition at 0 mass % to less than or equal to about 25 mass % of the total cementitious composition.

[0054] The printable cementitious composition may also include a fine aggregate, such as an inert sand or inert finely crushed stone. Fine aggregates may have a particle size distribution having approximately 95% passing on a 9.5 mm sieve (3 / 8 inch sieve). In certain variations, the fine aggregate is sand. The solid aggregate is distributed within the cementitious matrix to form a composite. In certain variations, the aggregate may be substantially homogeneously distributed within the cementitious composite (e.g., concrete) that is formed. The fine aggregate may comprise sand that has an average particle size of less than or equal to about 2 mm. In one nonlimiting variation, the aggregate may be an F-75 silica or quartz sand commercially available from U.S. Silica. The fine aggregate may be present in the cementitious composition at greater than or equal to about 20 mass / weight % to less than or equal to about 65 mass % of the total mass of cementitious binder components, optionally at greater than or equal to about 30 mass / weight % to less than or equal to about 60 mass % of the total mass of cementitious binder components, andAttorney Docket No. 2115-008424-WO-POA in certain variations, optionally at about 45 mass % of the total mass of cementitious binder components.

[0055] The cementitious composition may also include a high range water reducing agent (HRWRA), also known as a plasticizer / superplasticizer. Inclusion of the HRWRA can serve to reduce water content needed in the cementitious composition by about 10% to about 30%. The HRWRA can create high fluidity with good flowability properties for the printable cementitious composition, contributing to making the cementitious composition suitable for extrusion via additive manufacturing by helping to eliminate the need for any vibration or compaction after deposition. An example of a suitable HRWRA is a low viscosity polycarboxylate based high- range water-reducing admixture commercially available from W.R. Grace as ADVA® 190. The HRWRA may be present in the cementitious composition at greater than or equal to about 0.3 mass / weight % to less than or equal to about 1.5 mass % of the total mass of cementitious binder components.

[0056] Water is also included in the printable cementitious composition. A mass ratio of water to cementitious binder components (e.g., Portland cement, and any other pozzolanic materials, like fly ash) may be greater than or equal to about 0.2 to less than or equal to about 0.55. Water temperature can be used intentionally to manipulate the fresh state properties of a particular cementitious material composition. Water temperature affects fresh state rheological properties due to the accelerated activation of pozzolanic reactions of the cementitious materials. Water may be present in the cementitious composition at greater than or equal to about 5 mass % to less than or equal to about 35 mass % of the total cementitious composition.

[0057] Further, the cementitious structural component may be a fiber-reinforced cementitious composite structure that comprises at least one type of fiber (e.g., discrete or chopped fibers) distributed or dispersed within the cementitious matrix to form a composite (in combination with the aggregate solid material). In certain variations, the plurality of fibers may be substantially homogeneously distributed within the printed cementitious composite (e.g., concrete) that is formed. In certain aspects, the fibers may have a single composition or may include a mixture of different compositions or other combinations of select properties, such as different lengths or diameters. The fibers may include a variety of distinct materials, such as carbon fibers, glass (e.g., fiberglass, quartz, silica, borosilicates, etc.), polymer fibers (e.g., polyvinyl alcohol (PVA) or polyalkylene fibers, such as polyethylene (PE) or polypropylene (PP), including high tenacity polypropylene (HTPP) fibers), aramid fibers (such as KEVLARTM paraaramid synthetic fibers and TWARONTM para-aramid synthetic fibers)), basalt fibers, boron fibers, ceramic fibers, natural fibers, including plant-based fibers (derived from plants) andAttorney Docket No. 2115-008424-WO-POA animal-based fibers (derived from animals), such as sisal, jute, hemp, bamboo, curaua fibers, cellulose-based fibers, goat hair, and the like, artificial fibers, and any combination thereof.

[0058] By way of non-limiting example, an aspect ratio or ratio between a length of the fiber (L) and a diameter (D) of the fiber (AR=L / D) may be greater than or equal to about 150. In certain variations, the AR may be greater than or equal to about 150 to less than or equal to about 900.

[0059] In certain variations, a suitable fiber may have a length of greater than or equal to about 4 mm to less than or equal to about 20 mm, optionally greater than or equal to about 6 mm to less than or equal to about 15 mm, optionally greater than or equal to about 8 mm to less than or equal to about 12 mm, and in certain variations, optionally greater than or equal to about 8 mm to less than or equal to about 10 mm. In certain variations, a fiber in the fiber-reinforced cementitious composite structure has a diameter of greater than or equal to about 10 micrometers (pm) to less than or equal to about 200 pm. In one variation, the fiber is a glass fiber. In another variation, the fiber is a carbon fiber. The fiber may be present in the fiber-reinforced cementitious composite structure at greater than or equal to about 1 vol. % to less than or equal to about 4.5 vol. % of the total volume of the fiber-reinforced cementitious composite structure, optionally at greater than or equal to about 1.8 vol. % to less than or equal to about 4 vol. %, and in certain variations, optionally at about 2 vol. %.

[0060] Thus, in certain variations, one or more additives (e.g., accelerators, retardants, binders, fibers, reinforcing particles and / or aggregates, mineral additives, water reducers, viscosity modifying admixtures (e.g., thickeners), superplasticizers, other chemical admixtures, and the like) are introduced to the printhead 50 via one or more ancillary or additive inlets or feed conduits 39 (e.g., the ancillary or additive inputs). The main feed conduit 38 and the one or more ancillary or additive feed conduits 39 are in fluid communication with a mixing barrel 46, where the material from the conduits 38, 39 are mixed together (e.g., the material 28 and the one or more additives). In other words, the material 28 and the one or more additives are mixed through the mixing barrel 46 and combined to form the printable composition 42. In certain variations, such as when the extruding system 22 is free of one or more additives, the printable composition 42 comprises only the material 28. In certain variations, the printable composition 42 further comprises the one or more additives mixed with the material 28. As can be appreciated by a person skilled in the art, when the printable composition 42 comprises one or more additives, the feeding system 20 may include an additional hopper or storage unit containing the one or more additive materials that is in fluid communication with the ancillary feed conduit 39.Attorney Docket No. 2115-008424-WO-POA

[0061] In certain variations, like that shown in FIGS. 2-4, the printhead 50 comprises three main portions. A first portion is an uppermost or top portion 60, comprising a motor 62 (FIG. 2). The motor 62 may include a servo motor-gearbox assembly (FIG. 2). A second portion is a mixing assembly 70 (also referred to as “the inline mixer 70” or “the inline mixing assembly 70”) including the mixing barrel 46, as will be described further herein in FIGS. 3-4. A third portion is a terminal end portion 74 in the form of an extrusion nozzle 76. The extrusion nozzle 76 may be a cold extrusion nozzle. In certain variations, the extrusion nozzle 76 has a length or height of greater than or equal to about 6 inches to less than or equal to about 15 inches. After passing through the printhead 50, the printable composition 42 is extruded through the extrusion nozzle 76 as a filament or bead deposited on a target. The shape, size, and configuration of the extrusion nozzle 76 can be tailored or changed to suit varying needs and cross-sections of the deposited bead of printable composition 42. In a non-limiting example, an opening of the extrusion nozzle 76 may have a dimension of greater than or equal to about 10 mm to less than or equal to about 100 mm, optionally greater than or equal to about 25 mm to less than or equal to about 50 mm. The opening of the extrusion nozzle 76 may be circular, rectangular, or any other suitable shape to form a desired filament shape of printed material.

[0062] In various aspects, the mixing assembly 70 comprises a plurality of distinct parts or segments. For example, the mixing assembly 70 may comprise open ring structures 80 that may be nested within one another to define the mixing barrel 46 assembly that further defines an interior region or internal chamber through which the printable material will pass. The mixing barrel 46 may be a stationary stator (also referred to as “the stator 46”). In certain variations, the mixing assembly 70 comprises two parts: a) the mixing barrel 46 assembly and b) a rotary mixer component 122.

[0063] As discussed above, the mixing barrel 46 may be discretized into a series of smaller segments or stator rings 80, which may seat or nest within one another. In certain variations, one or more of the stator rings 80 have a series of stationary mixing pins 81 (FIG. 3) that extend radially inward. These discretized stator rings 80 may be assembled together to form a fluid tight sealed joint, for example, through a lap joint. The stator rings 80 may be further secured by a plurality of connectors (e.g., screws) (not shown). A sealing gasket 82, such as an O-ring, may be placed at the interface of each discretized stator ring 80 to seal the joint (e.g., lap joint) with an adjacent stator ring 80 and prevent fluid leakage in the mixing barrel 46. This design can provide one or more of the following advantages: a) reducing the manufacturing costs for the mixing barrel 46, b) allowing ease of maintenance in case of failure of one of the discrete parts of the mixing barrel 46, c) allowing the reconfiguration of the mixing barrel 46 by introducing new parts orAttorney Docket No. 2115-008424-WO-POA removing existing parts from the mixing barrel 46 (e.g., to utilize stator rings 80 having different configurations of stationary mixing pins 81), and d) allowing for the use of various rotor mixing blades 132.

[0064] As best shown in FIG. 4, each of the stator rings 80 comprises a first annular member 84 extending from a first end 86 to a second end 88 opposite the first end 86. A first average dimension or length 89 of the first annual member 84 is defined between the first end 86 and the second end 88. The first annular member 84 has an outer surface 90 and an inner surface 92 opposite the outer surface 90. The inner surface 92 defines a second average dimension or diameter 93. The outer surface 90 defines a third average dimension or diameter 97 that is larger than the diameter 93. In certain variations, the stationary mixing pins 81 extend radially inward from the inner surface 92. Each of the sealing gaskets 82 may define a diameter 95 that is the same as or slightly greater than the diameter 93 of the first annular member 84.

[0065] In the example embodiment of FIG. 3, four stationary mixing pins 81 extend radially inward from the inner surface 92 of the first annular member 84. However, any number of stationary mixing pins 81 is possible (e.g., the ring 80 may be free of stationary mixing pins 81, optionally include one or more stationary mixing pins 81, optionally include greater than four mixing pins 81, or optionally include greater than 10 mixing pins 81). In the example embodiment of FIG. 3, each of the stationary mixing pins 81 has a generally cylindrical shape, although stationary mixing pins 81 having varying lengths, cross-sections, and diameters are contemplated.

[0066] Each of the stator rings 80 comprises a second annular member 94 extending from a first end 96 to a second end 98 opposite the first end 96. A first average dimension or length 99 of the second annular member 94 is defined between the first end 96 and the second end 98. In certain variations, the length 99 of the second annular member 94 is less than the length 89 of the first annular member 84. The second annular member 94 has an outer surface 100 and an inner surface 102 (FIG. 3). The inner surface 102 defines a second average dimension or diameter (not shown). In certain variations, the diameter of the inner surface 102 of the second annular member 94 is the same as the diameter 93 of the first annular member 84. The outer surface 100 defines a third average dimension or diameter 107. In certain variations, the diameter 107 of the second annular member 94 is less than the diameter 97 of the first annular member 84.

[0067] The first end 96 of the second annular member 94 is disposed adjacent to and / or disposed on the second end 88 of the first annular member 84. In certain variations, the first annular member 84 and the second annular member 94 are integrally formed. Alternately, the first annular member 84 and the second annular member 94 may be joined together (e.g., via welding, adhesives, fasteners, etc.). While in the example embodiment of FIGS. 2-4 the second annularAttorney Docket No. 2115-008424-WO-POA member 94 is positioned on top of the first annular member 84, it is contemplated that the orientation may be reversed in other configurations (e.g., the second annular member 94 extends from the first end 86 of the first annular member 84).

[0068] As best shown in FIG. 4, each of the stator rings 80 and sealing gaskets 82 are configured such that, when assembled, one of the sealing gaskets 82 abuts the first end 86 of the first annular member 84 of a first stator ring 80' and the second end 88 of the first annular member 84 of an adjacent stator ring 80". The second annular member 94 of the adjacent stator ring 80" is disposed proximate to and nested within the first end 86 of the first annular member 84 of the first stator ring 80'. In certain variations, the outer surface 100 of the second annular member 94 of the adjacent ring 80" contacts or is slightly spaced apart from the inner surface 92 of the first annular member 84 of the first ring 80'. The sealing gaskets 82 may be disposed between all or a portion of the rings 80.

[0069] When assembled (e.g., when all of the stator rings 80 are nested in position), the stator rings 80 cooperate to define a mixing chamber or cavity 110. A user may dissemble and remove one or more (a portion) of the stator rings 80 to facilitate easy repair or cleaning of the mixing barrel 46. In this manner, the mixing barrel 46 allows for a reconfigurable, maintainable, and economical 2K+ robotic (or any computer numerical controlled (CNC) apparatus) end effector for mixing cementitious or slurry fluids with liquid admixtures, short fibers for tensile reinforcement, and coarse aggregates, among other streams.

[0070] Thus, the present disclosure contemplates the dynamic inline mixing assembly 70 for the additive manufacturing device 40 receiving a plurality of distinct material streams (e.g., the material 28 and the one or more additive materials) to form the printable composition 42. The inline mixing assembly 70 includes a rotary mixer component 122 that rotates in operation. The rotary mixer component 122 is at least partially disposed in the mixing chamber 110 of the mixing barrel 46. The motor 62 is in driving engagement with the rotary mixer component 122. The mixing barrel 46 is configured to process the printable composition 42, for example, to combine multiple streams of materials together (e.g., the material 28 and the one or more additive materials) via the rotary mixer component 122 to form the printable composition 42. In certain variations, the rotary mixer component 122 cooperates with the stationary mixing pins 81 of the stator rings 80 to mix and process the printable composition 42. The inline mixing assembly 70 also comprises a terminal extrusion nozzle 124 (FIGS. 2 and 4) connected to an outlet 126 of the mixing barrel 46 through which the printable composition 42 passes.

[0071] An uppermost stator part or segment 130 of the mixing assembly 70 can be interchanged based on the desired use for either liquid-liquid mixing or solid-liquid mixing. ForAttorney Docket No. 2115-008424-WO-POA example, in a liquid-liquid mixing embodiment, the uppermost stator segment 130 may feature the following: a) the main feed conduit 38 (e.g., a main inlet for slurry fluids) and b) one or more additional or ancillary feed conduits 39 (e.g., inlets for liquid additives). In a solid-liquid mixing embodiment, an additional third feed conduit or inlet for the introduction of solids may be provided.

[0072] In this manner, an improved design and functionality of a two-component or greater than two-component (2K+) robotic end-effector for 3D printing is provided, particularly for mixing slurry fluids with liquid admixtures, fibers, and coarse aggregates. The present disclosure enables the reconfigurability, maintainability, and cost-effectiveness of the mixer components in the end effector / printhead.

[0073] Thus, in certain aspects, the present disclosure contemplates the dynamic inline mixing assembly 70 that has interchangeable components (e.g., stator rings 80, uppermost stator segment 130 and / or terminal extrusion nozzle 124), which may be used as the end effector / printhead 50 of the robotic additive manufacturing device 40 for additively manufacturing a cementitious or slurry-based material. For example, the mixing assembly 70 for the printhead 50 comprises a plurality of components, including an uppermost or top part 60, which may be the motor 62 including servo motor-gearbox assembly, a mixing assembly 70, which may be a mixing barrel 46, a rotary mixer component 122 and a terminal extrusion nozzle 124, which are designed to be interchangeable, allowing for versatility in different 3D printing applications.

[0074] In other aspects, the present disclosure contemplates that the mixing barrel 46 has a design that includes multiple components (e.g., stator rings 80) that may be assembled together to define the mixing chamber 110. For example, the mixing barrel 46 may be composed of discretized parts. One or more of the segments or discrete parts (e.g., the stator rings 80) may optionally host the stationary mixing pins 81 extending radially inwards. Further, each of the segments or discrete parts (e.g., the stator rings 80) may be assembled using water-tight or sealed joints, such as lap joints sealed with sealing gaskets 82, like O-rings. Such a design allows for easy reconfiguration by introducing or removing parts. Further, discretized parts or segments can be individually replaced in case of failure, facilitating maintenance and reducing downtime. Additionally, this discretization into multiple components reduces the manufacturing costs for the mixing barrel 46.

[0075] Such a mixing barrel component further enables enhanced versatility for the rotor mixing blades 132. The mixing assembly 70 can support various rotor mixing blades 132 seated with the mixing barrel 46, where the mixing blades 132 are selected for different mixing scenarios (e.g., liquid-liquid and solid- liquid). Thus, the rotary mixer component 122 may comprise a shaftAttorney Docket No. 2115-008424-WO-POA131 (also referred to as “the central shaft 131”) and the mixing blade 132. The mixing blade 132 comprises at least one of a screw or mixing pins disposed thereon. For liquid-liquid mixing, the rotary mixer / rotor blade 132 may feature the central shaft 131 with mixing pins disposed thereon that extend outwardly. The solid- liquid mixing rotor blade 132 may have the central shaft 131 with a material-feeding screw on the upper portion / top part and mixing pins extending outwardly on a lower portion / bottom part.

[0076] Further, the uppermost stator segment 130 of the mixing assembly 70 can have interchangeable material inlets 38, 39. In this manner, the uppermost stator segment 130 of the mixing assembly 70 can be interchanged to accommodate either liquid- liquid or solid-liquid mixing.

[0077] The present disclosure further contemplates a sealing mechanism for the mixing barrel 46 comprised of multiple assembled components that ensures a fluid-tight and / or leak-proof assembly that maintains the integrity of the mixing process. This may be achieved through the use of lap joints, O-rings, and connecting screws in one variation. The discretized parts of the stator (e.g., the stator rings 80) are joined together using lap joints, which provide a strong and secure connection. At each interface between the discretized parts, the sealing gasket 82 is placed to seal the lap joint, preventing any fluid from leaking out of the mixing barrel 46. Additionally, the parts may be held together with connecting screws, ensuring that the assembly remains tight and stable under operational conditions. This combination of lap joints, O-rings, and connecting screws creates a robust sealing mechanism that is both reliable and easy to maintain.

[0078] In other aspects, the inline dynamic mixing assembly 70 is specifically designed to function as a robotic end effector for 3D printing, providing precise and efficient mixing of materials to ensure high-quality printed components.

[0079] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

Attorney Docket No. 2115-008424-WO-POACLAIMSWhat is claimed is:

1. An inline mixer for an additive manufacturing device receiving a plurality of distinct material streams to form a printable material, the inline mixer comprising: a rotary mixer component; a motor in driving engagement with the rotary mixer component; a mixing barrel component comprising a plurality of segments assembled together to define an internal chamber in which the rotary mixer component is at least partially disposed and rotates, wherein the mixing barrel component is configured to process the printable material; and a terminal extrusion nozzle connected to an outlet of the mixing barrel component through which the printable material passes.

2. The inline mixer of claim 1, wherein the motor comprises a servo motor- gearbox assembly.

3. The inline mixer of claim 1, wherein the plurality of segments are respectively connected to one another via a fluid tight lap joint.

4. The inline mixer of claim 3, wherein the plurality of segments are respectively connected to one another via a plurality of connectors.

5. The inline mixer of claim 3, further comprising a sealing gasket at each respective lap joint disposed between respective segments.

6. The inline mixer of claim 5, wherein the sealing gasket is an O-ring.

7. The inline mixer of claim 1, wherein at least one of the plurality of segments comprises stationary mixing pins extending into the internal chamber.

8. The inline mixer of claim 1, wherein the rotary mixer component comprises a shaft having at least one of a screw or mixing pins disposed thereon.

9. The inline mixer of claim 1, wherein the plurality of segments comprises an uppermost segment that is interchangeable and has at least two distinct inlets.

10. A robotic additive manufacturing device for additively manufacturing a cementitious or slurry-based material, the robotic additive manufacturing device comprising an end effector comprising the inline mixer of claim 1, wherein the printable material comprises the cementitious or slurry-based material.

11. An inline mixer for an additive manufacturing device receiving a plurality of distinct material streams to form a printable material, the inline mixer comprising: a rotary mixer component;Attorney Docket No. 2115-008424-WO-POA a motor in driving engagement with the rotary mixer component; a mixing barrel component comprising a plurality of segments assembled together to define an internal chamber in which the rotary mixer component is at least partially disposed and rotates, wherein: each of the plurality of segments comprises a first annular member extending from a first end to a second end opposite the first end, and a second annular member extending from a first end to a second end opposite the first end, the first end of the second annular member is disposed on the second end of the first annular member, the first end of the first annular member of a first segment abuts the second end of the first annular member of an adjacent segment, and the mixing barrel component is configured to process the printable material; and a terminal extrusion nozzle connected to an outlet of the mixing barrel component through which the printable material passes.

12. The inline mixer of claim 11, wherein the motor comprises a servo motor-gearbox assembly.

13. The inline mixer of claim 11, wherein the plurality of segments are respectively connected to one another via a fluid tight lap joint.

14. The inline mixer of claim 13, wherein the plurality of segments are respectively connected to one another via a plurality of connectors.

15. The inline mixer of claim 13, further comprising a sealing gasket at each respective lap joint disposed between respective segments.

16. The inline mixer of claim 15, wherein the sealing gasket is an O-ring.

17. The inline mixer of claim 11, wherein at least one of the plurality of segments comprises stationary mixing pins extending into the internal chamber.

18. The inline mixer of claim 11, wherein the rotary mixer component comprises a shaft having at least one of a screw or mixing pins disposed thereon.

19. The inline mixer of claim 11, wherein the plurality of segments comprises an uppermost segment that is interchangeable and has at least two distinct inlets.

20. A robotic additive manufacturing device for additively manufacturing a cementitious or slurry-based material, the robotic additive manufacturing device comprising an end effector comprising the inline mixer of claim 11, wherein the printable material comprises the cementitious or slurry-based material.

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