PRIORITY [0001] This application claims the benefit of priority to U.S. Provisional Patent

Application Serial No. 62/445,572, filed on January 12, 2017; this application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62/549,244, filed on August 23, 2017; and this application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62/583,307, filed on November 8, 2017, the benefit of priority of each of which are claimed hereby, and each of which are incorporated by reference herein in their entirety.

FIELD OF THE DISCLOSURE

[0002] The present disclosure relates to systems and methods of additive

manufacturing, and in particular to a print bed in an additive manufacturing system including a build sheet including a foam material having a glass transition temperature of at least about 140 degrees Celsius, or a build sheet comprising 80 wt to 99 wt of a cellulose fiber material and from 0.5 wt to 10 wt of a binder.

BACKGROUND OF THE DISCLOSURE

[0003] In additive manufacturing a print head and nozzle applies an additive manufacturing material onto a print bed in a series of successive layers to build a three- dimensional part. A build sheet or build sheet is sometimes laid onto the print bed to facilitate removal of the printed part from the print bed. Particular build sheets currently in use include acrylonitrile butadiene styrene (ABS) and polyetherimide (PEI) thermoplastic sheets. Such sheets may be used in thicknesses of from about 1/8 inch to about one-inch, and may have a smooth or textured finish.

[0004] The additive manufacturing material is applied onto the build sheet, which should adhere to the build sheet and hold the first layer (or first few layers) of the printed part to the build sheet and print bed. Adhesion of the printed part to the build sheet keeps the printed part in place on the print bed, which improves printing performance. While the build sheet materials in use today provide acceptable adhesion to some traditional additive manufacturing materials, they do not sufficiently adhere to the wide range of new additive manufacturing materials that have been recently developed. Other build sheet materials stick (e.g., are molded/fused) to the printed part, which can result in damage to the printed part during removal and damage/destruction of the build sheet, limiting reusability of the printed part and increasing cost due to frequent replacement of build sheets. In addition, it is time consuming to continually have to replace the build sheet, which reduces process efficiency.

[0005] Polystyrene foam has been used as a substrate material in small format printing, but its low thermal stability (T _g about 90 °C) results in parts printed thereon being buried within the foam, complicating extraction and cleanup of the printed part. This problem is exacerbated in large format additive manufacturing applications, where printed parts are much heavier than in small format printing applications.

[0006] One method that may be used to improve adhesion is to heat the build sheet prior to its use in the additive manufacturing process. Excessive heating of the build sheet could cause it to warp, however, resulting in manufacturing defects in the printed part due to the build sheet (printing surface) no longer being in its original position.

[0007] Other build sheet constructions have been used to address the shortcomings described herein. These build sheets include plywood, metal, glass and polymer pellets adhered to plywood. These solutions have one or more shortcomings, however, including excessive weight, high cost, preheat requirements, insufficient or too much adhesion, inefficiencies due to the time required to replace expended build sheets with new build sheets, and a limit on the number of uses before another build sheet of the same material is needed.

[0008] These and other shortcomings are addressed by aspects of the present disclosure. SUMMARY

[0009] Aspects of the disclosure relate to an apparatus for additive manufacturing of a part, the apparatus including a print bed including a build sheet, a print head/nozzle system, and a physical control system providing for relative motion between the print head/nozzle system and the print bed. The print head/nozzle system includes at least one print head and nozzle and is configured to apply an additive manufacturing material onto the print bed. The build sheet includes a foam material having a glass transition temperature of at least about 140 °C, such as a temperature of from about 140 °C to about 460 °C. [0010] Alternatively, according to some aspects, the disclosure provides a build sheet for use in an additive manufacturing process including a cellulose fiber material. In some aspects the build sheet comprises from 80 wt to 99 wt%, such as at least 90 wt%, of a cellulose fiber material. The build sheet may further include a binder, such as but not limited to paraffin wax, and such as in 0.5 wt to 10 wt .

[0011] Aspects of the disclosure further relate to a method for additive manufacturing a printed part, the method including applying a plurality of layers of an additive

manufacturing material onto a print bed to form the printed part. The print bed includes a build sheet as described herein.

BRIEF DESCRIPTION OF THE FIGURES

[0012] In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. Like numerals having different letter suffixes may represent different instances of similar components. The drawings illustrate generally, by way of example, but not by way of limitation, various embodiments discussed in the present disclosure.

[0013] FIG. 1 is a side view of an additive manufacturing apparatus according to an aspect of the disclosure.

[0014] FIG. 2 is a side perspective view of a build sheet for use in an additive manufacturing process according to an aspect of the disclosure.

[0015] FIG. 3 is a side perspective view of a build sheet for use in an additive manufacturing process according to an aspect of the disclosure.

[0016] FIG. 4 is a side perspective view of an additively manufactured article including the build sheet of FIG. 3.

[0017] FIG. 5 is a photograph of a portion of a printed part adhered to a portion of a build sheet according to an aspect of the disclosure.

[0018] FIG. 6 is a photograph of a portion of a printed part adhered to a portion of a build sheet according to an aspect of the disclosure.

[0019] FIG. 7 is a photograph of a portion of a printed part following printing onto a build sheet according to an aspects of the disclosure.

[0020] FIG. 8 is a photograph of a portion of a printed part following printing onto a foam-based build sheet. [0021] FIG. 9 is a photograph of a portion of a printed part following printing onto a concrete-based build sheet.

DETAILED DESCRIPTION

[0022] The present disclosure can be understood more readily by reference to the following detailed description of the disclosure and the Examples included therein. In various aspects, the present disclosure pertains to an apparatus for additive manufacturing of a part, the apparatus including a print bed including a build sheet, a print head/nozzle system including at least one print head and nozzle, and a physical control system providing for relative motion between the print head/nozzle system and the print bed. The build sheet in some aspects includes at least 90% cellulose fiber material, and may further include a binder, such as but not limited to paraffin wax.

[0023] In some embodiments, the build sheet includes a foam material having a glass transition temperature (T _g ) of at least about 140 degrees Celsius (°C), such as about 140 °C to about 460 °C, and the print head/nozzle system is configured to apply an additive

manufacturing material onto the print bed. In other embodiments, the build sheet comprises from 80 wt% to 99 wt% of a cellulose fiber material and from 0.5 wt% to 10 wt% of a binder.

[0024] Further aspects of the disclosure relate to a method for additive manufacturing a printed part, including applying a plurality of layers of an additive manufacturing material onto a print bed to form the printed part. The print bed includes a build sheet including a foam material having a T _g of at least about 140 °C.

[0025] Before the present compounds, compositions, articles, systems, devices, and/or methods are disclosed and described, it is to be understood that they are not limited to specific synthetic methods unless otherwise specified, or to particular reagents unless otherwise specified, as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.

[0026] Various combinations of elements of this disclosure are encompassed by this disclosure, e.g., combinations of elements from dependent claims that depend upon the same independent claim.

[0027] Moreover, it is to be understood that unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that an order be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps or operational flow; plain meaning derived from grammatical organization or punctuation; and the number or type of embodiments described in the specification.

[0028] All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited.

Definitions

[0029] It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting. As used in the specification and in the claims, the term "comprising" can include the embodiments

"consisting of and "consisting essentially of." Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. In this specification and in the claims which follow, reference will be made to a number of terms which shall be defined herein.

[0030] As used in the specification and the appended claims, the singular forms "a," "an" and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "a foam material" includes mixtures of two or more foam materials.

[0031] As used herein, the term "combination" is inclusive of blends, mixtures, alloys, reaction products, and the like.

[0032] Ranges can be expressed herein as from one particular value (first value), and/or to another particular value (second value). When such a range is expressed, another aspect includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent 'about,' it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint. It is also understood that there are a number of values disclosed herein, and that each value is also herein disclosed as "about" that particular value in addition to the value itself. For example, if the value "10" is disclosed, then "about 10" is also disclosed. It is also understood that each unit between two particular units are also disclosed. For example, if 10 and 15 are disclosed, then 11, 12, 13, and 14 are also disclosed. [0033] As used herein, the terms "about" and "at or about" mean that the amount or value in question can be the value designated some other value approximately or about the same. It is generally understood, as used herein, that it is the nominal value indicated +10% variation unless otherwise indicated or inferred. The term is intended to convey that similar values promote equivalent results or effects recited in the claims. That is, it is understood that amounts, sizes, formulations, parameters, and other quantities and characteristics are not and need not be exact, but can be approximate and/or larger or smaller, as desired, reflecting tolerances, conversion factors, rounding off, measurement error and the like, and other factors known to those of skill in the art. In general, an amount, size, formulation, parameter or other quantity or characteristic is "about" or "approximate" whether or not expressly stated to be such. It is understood that where "about" is used before a quantitative value, the parameter also includes the specific quantitative value itself, unless specifically stated otherwise.

[0034] As used herein, the terms "optional" or "optionally" means that the

subsequently described event or circumstance can or cannot occur, and that the description includes instances where said event or circumstance occurs and instances where it does not. For example, the phrase "additional optional additives" means that the additives can or cannot be included and the description includes aspects that include and both do not include additional additives.

[0035] Disclosed are the components to be used to prepare the compositions of the disclosure as well as the compositions themselves to be used within the methods disclosed herein. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed that while specific reference of each various individual and collective combinations and permutation of these compounds cannot be explicitly disclosed, each is specifically contemplated and described herein. For example, if a particular compound is disclosed and discussed and a number of modifications that can be made to a number of molecules including the

compounds are discussed, specifically contemplated is each and every combination and permutation of the compound and the modifications that are possible unless specifically indicated to the contrary. Thus, if a class of molecules A, B, and C are disclosed as well as a class of molecules D, E, and F and an example of a combination molecule, A-D is disclosed, then even if each is not individually recited each is individually and collectively

contemplated meaning combinations, A-E, A-F, B-D, B-E, B-F, C-D, C-E, and C-F are considered disclosed. Likewise, any subset or combination of these is also disclosed. Thus, for example, the sub-group of A-E, B-F, and C-E would be considered disclosed. This concept applies to all aspects of this application including, but not limited to, steps in methods of making and using the compositions of the disclosure. Thus, if there are a variety of additional steps that can be performed it is understood that each of these additional steps can be performed with any specific aspect or combination of aspects of the methods of the disclosure.

[0036] Unless otherwise stated to the contrary herein, all test standards are the most recent standard in effect at the time of filing this disclosure.

[0037] Each of the materials disclosed herein are either commercially available and/or the methods for the production thereof are known to those of skill in the art.

[0038] It is understood that the compositions disclosed herein have certain functions.

Disclosed herein are certain structural requirements for performing the disclosed functions and it is understood that there are a variety of structures that can perform the same function that are related to the disclosed structures, and that these structures will typically achieve the same result.

Apparatus for Additive Manufacturing

[0039] With reference to FIG. 1, aspects of the disclosure relate to an apparatus 100 for additive manufacturing of a part 10, the apparatus 100 including a print bed 200, a print head/nozzle system 300, and a physical control system 400 providing for relative motion between the print head/nozzle system 300 and the print bed 200.

[0040] The print bed 200 includes a support table 210 and a build sheet 220. The support table 210 underlies the build sheet 220 and provides support thereto. The support table 210 may be stationary or movable, as discussed in further detail below.

[0041] The build sheet 220 includes a foam material having a T _g of at least about 140

°C, such as about 140 °C to about 460 °C or, alternatively, the build sheet comprises from 80 wt to 99 wt of a cellulose fiber material and from 0.5 wt to 10 wt of a binder. In particular aspects, the foam material includes a polymeric material. The polymeric material may be an amorphous or a semi-crystalline polymeric material.

[0042] In certain aspects, the foam material includes one or more polymeric materials selected from the group consisting of polyetherimide (PEI), polycarbonate (PC),

polyamideimide, polyarylene ethers (e.g., polyphenylene oxides (PPO) and their copolymers, often referred to as polyphenylene ethers (PPE)), polyarylene ether ketones (including polyether ether ketones (PEEK), polyether ketone ketones (PEKK), and the like), polyarylene sulfides (e.g., polyphenylene sulfides (PPS)), polyarylene ether sulfones (e.g.,

polyethersulfones (PES), polyphenylene sulfones (PPS), and the like), polyamide, polyaramide, polyimide, polyphenylenesulfone urea, polyphthalamides (PPA), self-reinforced polyphenylene (SRP) and combinations thereof. The foregoing polymers can be linear or branched, and can be homopolymers or copolymers, for example poly(etherimide-siloxane) or copolycarbonates containing two different types of carbonate units, for example bisphenol A units and units derived from a high heat monomer such as 3,3-bis(4-hydroxyphenyl)-2- phenylisoindolin-l-one. The copolymers can be random, alternating, graft, or block copolymers having two or more blocks of different homopolymers. A combination of at least two different polymers can be used.

[0043] Thus, in certain aspects the foam material may include a polyetherimide polymer, a polycarbonate polymer, or a combination thereof. In particular aspects, the foam material includes a PEI resin. In a specific aspect the polyetherimide resin is an amorphous, transparent, amber polyetherimide resin having a density of about 1200 to about 1400 kilograms per cubic meter (kg/m ³ ). In specific aspects the polyetherimide resin has a density of about 1270 kg/m ³ . The foam material (e.g., polyetherimide resin) and one or more additional optional additives may be formed into the foam material. One polyetherimide suitable for use in aspects of the disclosure is ULTEM™ resin, such as but not limited to ULTEM™ 1000 or ULTEM™ 1010, which can be formed into ULTEM™ foam and used in the build sheet 220. The ULTEM™ foam in some aspects is an open-cell foam and may have a density of about 30 to about 250 kg/m ³ , such as about 30 to about 130 kg/m ³ .

[0044] In some aspects the foam material includes a glass material. In a particular aspect the glass material is foamed glass.

[0045] The foam material has a glass transition temperature (T _g ) of at least about 140

°C. In certain aspects the foam material has a T _g of at least about 145 °C, or a T _g of at least about 150 °C, or a T _g of at least about 160 °C, or a T _g of at least about 170 °C, or a T _g of at least about 180 °C, or a T _g of at least about 190 °C, or a T _g of at least about 200 °C, or a T _g of at least about 210 °C, or a T _g of at least about 215 °C, or a T _g of at least about 220 °C, or a T _g of at least about 230 °C. In particular aspects the foam material has a T _g of about 147 °C (which corresponds to the T _g of polycarbonate), or a T _g of about 217 °C (which corresponds to the T _g of polyetherimide). In further aspects the foam material has a T _g of between about 140°C and about 240 °C. As used herein (and well understood by a person skilled in the art), glass transition temperature refers to the temperature range at which an amorphous polymer (or amorphous regions of a semi-crystalline polymer) changes from a hard, rigid or relatively brittle state to a more pliable, viscous or "rubbery" state. T _g is not a discrete temperature or thermodynamic transition but a range over which the mobility of the chains in the polymer increases significantly.

[0046] Polystyrene foam has been used as a substrate material in small format printing, but its low thermal stability (T _g about 90 °C) results in parts printed thereon being buried within the foam, complicating extraction and cleanup of the printed part. This problem is exacerbated in medium and large format additive manufacturing equipment, where printed parts are much heavier than in small format printing applications.

[0047] In some aspects the foam material has a compressive strength of at least about

30 or at least about 40 pounds per square inch (psi) as tested in accordance with ASTM D 1621 (Compression testing of rigid cellular plastics). In certain aspects the foam material has a compressive strength of about 30 psi to about 300 psi. In further aspects the foam material has a compressive strength of at least about 50 psi, or a compressive strength of at least about 60 psi, or a compressive strength of at least about 70 psi, or a compressive strength of at least about 80 psi, or a compressive strength of at least about 90 psi, or a compressive strength of at least about 100 psi, or a compressive strength of at least about 110 psi, or a compressive strength of at least about 120 psi, or a compressive strength of at least about 130 psi, or a compressive strength of at least about 140 psi, or a compressive strength of at least about 150 psi, or a compressive strength of at least about 160 psi, or a compressive strength of at least about 170 psi. In particular aspects the foam material has a compressive strength of about 40 psi to about 180 psi, or about 50 psi to about 170 psi, or about 50 psi to about 120 psi. All compressive strength measurements described herein are indicated as tested in accordance with ASTM D 1621. Foam materials having compressive strengths as described herein provide sufficient structural support to a printed part 10 applied thereon when the build sheet 220 is used in additive manufacturing operations, particularly in medium and large format additive manufacturing operations in which parts having a large volume and/or weight are formed. The compressive strength and/or the density of the foam material may be modified by selecting different polymeric materials for the foam and/or by adjusting the foaming parameters (e.g., temperature, air flow, agitation).

[0048] Additional optional additives may be incorporated into the foam material and/or the build sheet 220 as desired. In one aspect, an additional additive could include an adhesive to further improve adhesion between the foam material and/or the build sheet 220 and the printed part 10 when used in additive manufacturing operations. Additional optional additives could also include, but are not limited to, thermal stabilizers, adhesives, release additives, other desirable materials typically used to improve build sheet properties, and combinations thereof.

[0049] In addition, the build sheet 220 may include one or more additional optional layers of material as desired. In one aspect, an additional layer could include an adhesive to further improve adhesion between the foam material and/or the build sheet 220 and the printed part 10 when used in additive manufacturing operations. Additional optional layers could also include, but are not limited to, thermal stabilizers, adhesives, release additives, other desirable materials typically used to improve build sheet properties, and combinations thereof.

[0050] The foam material provides stiffness to the build sheet 220 which, combined with the relative porous construction of the foam material, contributes to adhesion of the build sheet 220 to the printed part 10 when used in additive manufacturing operations.

Adhesion of the printed part to the build sheet keeps the printed part in place on the print bed, which improves printing performance.

[0051] The foam material may include other materials, e.g. other polymeric foam materials or other foam materials, with similar densities and stiffness properties as the foam materials described herein.

[0052] In some aspects the foam material is incorporated onto a reinforcing substrate.

The reinforcing substrate may be any material that supports the foam material (and additional optional additives if used) in the build sheet 220. In one aspect the reinforcing substrate is a woven scrim.

[0053] The foam material and additional optional additives may provide the build sheet 220 with properties that make it desirable for use as a build sheet in additive

manufacturing applications. The build sheet 220 may be thermally stable at relatively high additive manufacturing temperatures. This is in contrast to current build sheets made from polymeric materials such as ABS, polystyrene, or metallic materials, which have a tendency to melt or warp at higher additive manufacturing temperatures and thus lack thermal stability, which results in manufacturing defects in the printed part due to the build sheet (printing surface) no longer being in its original position.

[0054] Thus, in some aspects the build sheet 220 according to aspects of the disclosure may be used in additive manufacturing applications at additive manufacturing material 330 application temperatures of at least about 300°F. In certain aspects, the build sheet 220 according to aspects of the disclosure may be used in additive manufacturing applications at additive manufacturing material 330 application temperatures of at least about 400°F, or at additive manufacturing material 330 application temperatures of at least about 500°F, or at additive manufacturing material 330 application temperatures of at least about 600°F, or even at additive manufacturing material 330 application temperatures of at least about 700°F. This is in contrast to current build sheet configurations which only support maximum additive manufacturing material 330 temperatures of about 180 to 200°F due to the issues discussed above. It will be recognized that some foam materials according to aspects of the disclosure may be suitable for higher additive manufacturing material 330 application temperatures than others; for example certain polyetherimide foam materials are thermally stable at higher temperatures than polycarbonate, so may be expected to be more suitable for use at the higher application temperatures described herein. It will also be recognized that at higher additive manufacturing material 330 temperatures the printed part 10 may become embedded within the build sheet 220 and foam material included therein, rather than just adhered to the build sheet 220. Should this occur, the build sheet 220/foam material would need to be removed/cleaned from the printed part 10 upon completion of the method.

[0055] In some embodiments, the build sheet 220 includes a cellulose fiber material.

In certain aspects the build sheet includes at least 80% cellulose fiber material. In further aspects the build sheet includes at least 90% cellulose fiber material, or at least 95% cellulose fiber material, or from about 80% to about 99% cellulose fiber material, or from about 90% to about 99% cellulose fiber material. As described herein, a build sheet including a cellulose fiber material offers several advantages over build sheets including previously known materials, including but not limited to good insulative properties, low cost, low weight, use of post-consumer material, reusability and recyclability. The cellulose fiber material can include, but is not limited to, natural fibers derived from cotton, fiber flax, seed flax, kenaf, jute, hemp, ramie, abaca, sisal, henequen, coir, softwood kraft (including one or more fibers from pine, spruce, cedar, fir, hemlock, larch), and combinations thereof. The cellulose fiber material may also include manufactured/semi- synthetic cellulose fibers, such as but not limited to: cellulose ethers such as methyl cellulose, ethyl cellulose, propyl cellulose and benzyl cellulose; cellulose esters such as cellulose acetate, cellulose propionate and cellulose butyrate; regenerated cellulose (e.g., rayon and viscose); and combinations thereof. In certain aspects the cellulose fiber material includes paper cellulose, or cellulose derived from paper, including any of the cellulose fiber materials described above. The cellulose fiber material may include, but is not limited to, any combination of these natural and manufactured/semi- synthetic cellulose fibers. [0056] In some aspects the build sheet 220 may include a binder. A binder may serve to hold the cellulose fibers in the build sheet 220 together, thereby strengthening the build sheet 220 and giving it stiffness. Suitable binders include, but are not limited to, wax (e.g., animal, plant and/or petroleum-based wax), styrene maleic anhydride copolymer, styrene- acrylate copolymer, carboxymethyl cellulose (CMC), cationic and anionic hydroxyethyl cellulose (EHEC), modified starch, dextrin, styrene butadiene latex, styrene acrylic, proteins, lignins, gelatin, pectin and combinations thereof. In a particular aspect the binder is a petroleum-based wax, such as but not limited to paraffin wax. In certain aspects the binder is present in the build sheet in an amount of from 0.5 wt to about 20 wt%, or in an amount of from 0.5 wt% to about 10 wt% .

[0057] The build sheet 220 may have a density of from about 10 to about 60 pounds per cubic foot (lb/ft ³ ) in some aspects. In further aspects the build sheet 220 has a density of from about 20 to about 30 lb/ft ³ . The cellulose fibers may be compressed to form the build sheet 220.

[0058] An exemplary build sheet suitable for use in aspects of the present disclosure is 440 Homasote®, which is a medium density cellulose fiber board available from the Homasote® Company. 440 Homasote® is sold commercially in standard thicknesses (e.g., ½ inch, 5/8 inch and ¾ inch) and sizes (e.g., 4 foot (ft) x 4 ft, 4 ft x 8 ft and 4 ft x 10 ft) for use in walls/floors of residential or commercial structures as a sound barrier. 440 Homasote® includes about 94-96 wt% paper cellulose, about 1-6 wt% paraffin wax, and a minor content (less than 0.1 wt%) copper metaborate as a biocide. While the off-the-shelf cellulose fiber build sheet described herein includes a biocide to protect the building material from insects, mold, etc., a build sheet 220 according to aspects of the disclosure may or may not include a biocide.

[0059] In some aspects the build sheet 220 includes at least about 85% post- consumer, or recycled, material. The build sheet 220 may thus be considered "green" or "eco-friendly." Further, the build sheet 220 may itself be recyclable.

[0060] It may be desirable in some aspects for the build sheet 220 to be stiff enough and/or have sufficient compressive strength to support large additively manufactured parts 10 (e.g., up to 1200 pounds or more) common in large format additive manufacturing (LFAM) applications. Thus, in certain aspects the build sheet 220 has a Janka hardness of at least about 200 pound-force (lbf). In further aspects the build sheet 220 has a Janka hardness of at least about 230 lbf, or from about 200 lbf to about 500 lbf. Janka hardness is a common property measured in various applications, including but not limited to hardwoods for use in flooring applications.

[0061] The build sheet 220 including a cellulose fiber material may have good thermal insulating properties that supports even and/or consistent cooling of a part 10 additively manufactured on the build sheet 220. Some previously known build sheet materials act as conductors, so that heat from the additively manufactured part conducts through the build sheet at an uneven rate. Uneven cooling of an additively manufactured part 10 can result in undesirable warping of the part. The cellulose fiber material used in the build sheet 220 of the present disclosure is thermally insulative. Accordingly, in some aspects the build sheet 220 is thermally insulative such that the build sheet has an R-value of at least about 3.0 in ^"1 . In further aspects the build sheet has an R-value of at least about 5.0 in ^"1 , or an R-value of from about 3.0 in ^"1 to about 10 in ^"1 , or an R-value of from about 5.0 in ^"1 to about 10 in ^"1 . The build sheet 220 may also have sound dampening properties.

[0062] The build sheet 220 may also have a surface roughness to promote friction between the build sheet 220 and the additively manufactured part 10 so that the part 10 does not slip or move while on the build sheet 220. The surface roughness promotes friction between the build sheet 220 and the additively manufactured part 10, but the additively part 10 is also easily removable from the build sheet 220 without excessive build sheet material sticking to the part 10.

[0063] The build sheet 220 may include one or more optional additional additives as desired. Exemplary optional additional additives include, but are not limited to, thermal stabilizers, adhesives, release additives, binders, biocides, other desirable materials typically used to improve build sheet properties, and combinations thereof.

[0064] The build sheet 220 may be used with any thermoplastic polymer-based additive manufacturing materials. In some aspects the build sheet 220 may be used with thermoplastic polymer-based additive manufacturing materials having a glass transition temperature (Tg) of at least about 30 °C. In particular aspects, the build sheet 220 may be used with thermoplastic polymer-based additive manufacturing materials having a relatively high Tg, such as at least about 85 °C for amorphous polymers or a melt point of at least 120 °C for semi-crystalline polymers. In further aspects, the build sheet 220 may be used with amorphous thermoplastic polymer-based additive manufacturing materials having a Tg of at least about 105 °C, or at least about 145 °C, or at least about 200 °C. In certain aspects, the build sheet 220 may be used with amorphous thermoplastic polymer-based additive manufacturing materials having a Tg of from about 85 °C to about 350 °C, or having a Tg of from about 105 °C to about 300 °C, or having a Tg of from about 105 °C to about 275 °C. In particular aspects the build sheet 220 may be used with semi-crystalline thermoplastic polymer-based additive manufacturing materials having a or a melt point of at least about 120 °C. Exemplary suitable additive manufacturing materials include, but are not limited to, thermoplastic polymers such as polyetherimide (PEI) (e.g., ULTEM™, available from SABIC), polycarbonate (PC), polyphenylsulfone (PPSU), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyimide (e.g., EXTEM™, available from SABIC), poly(ether sulfone) (PES), poly(p-phenylene oxide) (PPO), PPO blends (e.g., PPO and polystyrene (PS)), polysulfone (PSU), polyaryletherketone (PAEK), blends thereof, and combinations thereof. Other exemplary suitable additive manufacturing materials include, but are not limited to, acrylonitrile butadiene styrene (ABS), polybutylene terephthalate (PBT), PBT blends including PC/PBT blends, high density polyethylene (HDPE), poly(phenylene oxide) (PPO), acrylic-styrene-acrylonitrile (ASA), polyamides,

polypropylene (PP), polylactic acid (PLA), blends thereof, and combinations thereof.

[0065] The additive manufacturing material could include a thermoplastic build material (i.e., the thermoplastic material that is used to make the printed part 10), a thermoplastic support material (i.e., the thermoplastic material that is used to make a support/scaffold), or a combination thereof. The thermoplastic build material and

thermoplastic support material may include the same or different thermoplastic polymer. In some aspects the thermoplastic build material or thermoplastic support material includes a thermoplastic polymer having a glass transition temperature of at least about 30 °C. In further aspects the thermoplastic build material or thermoplastic support material includes an amorphous thermoplastic polymer having a glass transition temperature of at least about 85 °C, or at least about 105 °C, or at least about 145 °C, or at least about 200 °C, or from about 85 °C to about 350 °C, or from about 105 °C to about 300 °C, or from about 105 °C to about 275 °C. In particular aspects the thermoplastic build material or thermoplastic support material includes a semi-crystalline thermoplastic polymer having a melt point of at least about 120 °C.

[0066] The print head/nozzle system 300 includes at least one print head 310 and nozzle 320. The print head/nozzle system 300 may be stationary or moveable, as discussed in further detail below. An additive manufacturing material 330 may be loaded into the print head 310. Suitable additive manufacturing materials 330 include, but are not limited to, polymeric base materials such as acrylonitrile butadiene styrene (ABS), polyphenylene sulfide (PPS), polyphenylsulfone (PPSU), polyetheretherketone (PEEK), polyetherimide (PEI), polyphenylene ether (PPO), polycarbonate (PC), and combinations thereof. One purely exemplary PEI resin suitable for use in additive manufacturing applications is

ULTEM™ Resin, available from SABIC. Additional materials may be incorporated into the polymeric base material to enhance the properties of the polymeric base material and/or to provide the additive manufacturing material 330 with additional properties. Purely by way of example, fibers such as carbon fibers or glass fibers may be incorporated into the polymeric base material to improve the strength and thermal stability of the additive manufacturing material 330.

[0067] The additive manufacturing material 330 may be heated and applied onto the print bed 200 in a plurality of layers 340 to form the printed part 10.

[0068] In certain aspects the print head/nozzle system 300 includes one print head

310 and one nozzle 320. In certain aspects (not illustrated), however, multiple individual print head/nozzle systems 300 could be used to apply all of the same additive manufacturing material 330 onto the print bed 200 in a plurality of layers 340 to form the printed part 10, or in other aspects (not illustrated) multiple individual print head/nozzle systems 300 could be used to apply different additive manufacturing materials 330 onto the print bed 200 at selective locations in the plurality of layers 340 to form the printed part 10. In yet other aspects (not illustrated) a single print head/nozzle system 300 could include a plurality of print heads 310, each of the plurality of print heads 310 having its own nozzle 320, with each print head 310 and nozzle 320 applying an additive manufacturing material 330, which may be the same or different, onto the print bed 200 in a plurality of layers 340 to form the printed part.

[0069] Aspects of the apparatus 100 include a physical control system 400 providing for relative motion between the print head/nozzle system 300 and the print bed 200. In some aspects the physical control system 400 may be a system, including but not limited to a gear system, a hydraulic system, an electric system, or other suitable system for moving the print head/nozzle system 300 while keeping the support table 210 stationary to achieve relative motion between the support table 210 and the print head/nozzle system 300. In other aspects the physical control system 400 may be a system, including but not limited to a gear system, a hydraulic system, an electric system, or other suitable system for moving the support table 210 while the keeping print head/nozzle system 300 stationary to achieve relative motion between the support table 210 and the print head/nozzle system 300. As discussed herein, motion refers to a three-dimensional coordinate system having an X-axis, Y-axis and Z-axis that are all perpendicular to one another, and relative motion refers to both horizontal motion along both the X-axis and Y-axis (perpendicular to the print head/nozzle system 300) and vertical motion along the Z-axis (parallel to the print head/nozzle system 300). The printed part 10 is typically printed in a horizontal plane defined by the X-axis and Y-axis (parallel to the support table 210), but it need not be printed in this manner - it could, for example, be printed at an angle relative to the support table 210.

[0070] A controller 500 receives computer-readable instructions for printing the part

10. The computer-readable instructions may be generated by a computer system, and may include, e.g., schematics, diagrams, specifications or other data that would allow the additive manufacturing system to form the printed part 10. The computer-readable instructions may include standard information that is known in the art, and in some aspects are provided as a three-dimensional (3D) computer-aided design (CAD) stereolithography (STL) file format or two-dimensional (2D) CAD file which may be converted into an STL file format. The controller 500 operates the physical control system 400 to print the part 10 in accordance with the computer-readable instructions.

[0071] In some aspects of the present disclosure the apparatus 100 is suitable for use in medium and large format additive manufacturing equipment. In particular, the use of a build sheet 220 including a foam material in/on the print bed 200 allows medium and large format additive manufacturing equipment to be operated with a wider selection of additive manufacturing materials and better customization of the final properties of the printed part. In further aspects the apparatus 100 is suitable for use in medium and large format additive manufacturing equipment, in extrusion additive manufacturing applications and/or in fused filament fabrication applications.

[0072] In addition, medium and large format additive manufacturing equipment utilize a relatively heavy build sheet 220 compared to small format printing. A build sheet used in small format printing needs to be prepared for use, which can include steps such as securing the build sheet to the print bed with pins or latches and/or preheating the build sheet. In contrast, the heavy build sheet 220 utilized in the medium and large format additive manufacturing equipment described in the present disclosure do not require any such preparation - they can be laid down and do not need to be secured to the print bed or preheated. As a result, they are easier to use and printing turnaround time is faster.

Turnaround time is further enhanced by the ability to re -use the build sheet in many cases, unlike many prior build sheet solutions (e.g., polystyrene build sheets) which are

substantially destroyed because the printed part may become embedded within the build sheet. [0073] In some embodiments, because the foam material in the build sheet 220 is a natural insulator, the first few layers of the printed part 10 cool at a slower rate than parts printed with previously known build sheet materials, which improves the final properties of the printed part. In addition, adhesion of the printed part to the build sheet can be achieved without preheating the build sheet/print bed, in contrast to present build sheet materials. Finally, in some aspects a build sheet including a foam material allows printing at much higher temperatures (300-700°F) than previously possible, allowing for more flexibility in the selection of printing materials and part design. Build sheet for Use in Additive Manufacturing

[0074] With reference to FIG. 2, aspects of the disclosure further relate to a build sheet 220 for use in an additive manufacturing process. In some embodiments, the build sheet 220 includes a foam material having a Tg of at least about 140 °C, such as about 140 °C to about 460 °C. In particular aspects, the foam material includes a polymeric material. The polymeric material may be an amorphous or a semi-crystalline polymeric material.

[0075] Alternatively, in some embodiments, the build sheet 220 includes a cellulose fiber material. In particular aspects, the build sheet includes at least 90% cellulose fiber material. The build sheet may further include a binder, such as but not limited to paraffin wax. The build sheet may be formed from any of those materials described herein and/or have any of the properties described above for the apparatus (not duplicated here).

[0076] In some aspects the build sheet 220 includes a single layer of foam material or cellulose fiber. In further aspects the build sheet 220 includes a plurality of layers of foam material or cellulose fiber. Using multiple layers of foam material or cellulose fiber may allow for improved heat resistance as compared to the heat resistance provided by a build sheet 220 formed of a single layer of foam material or cellulose fiber of equivalent thickness.

[0077] In some aspects the foam material or cellulose fiber is incorporated onto a reinforcing substrate. The reinforcing substrate may be any material that supports the foam in the build sheet 220. In one aspect the reinforcing substrate is a woven scrim.

[0078] The foam material or cellulose fiber may provide the build sheet 220 with properties that make it desirable for use as a build sheet 220 in additive manufacturing applications. The build sheet 220 may be thermally stable at relatively high additive manufacturing temperatures. This is in contrast to current build sheets made from polymeric materials such as ABS, polystyrene, or metallic materials, which have a tendency to melt or warp at higher additive manufacturing temperatures and thus lack thermal stability, which results in manufacturing defects in the printed part due to the build sheet (printing surface) no longer being in its original position.

[0079] With reference to FIG. 3, in certain aspects the build sheet 220 further includes a rigid support layer 350 proximate to the foam material or cellulose fiber. The rigid support layer 350 may include, but is not limited to, a wood sheet, a plywood sheet, a metallic sheet, a polymeric sheet, a cement sheet, or a combination thereof. The rigid support layer 350 may be adhered to the foam material or cellulose fiber by any suitable means. In certain aspects the rigid support layer 350 is adhered to the foam material or cellulose fiber with an adhesive or with a plurality of fasteners. In particular aspects the plurality of fasteners include screws or nails.

[0080] The build sheet 200 may be used in any additive manufacturing process. In particular aspects the build sheet is used in a LFAM process.

Method for Additive Manufacturing

[0081] Aspects of the disclosure also relate to methods for additive manufacturing a printed part 10, including applying a plurality of layers 340 of an additive manufacturing material 330 onto a print bed 200 to form the printed part 10. The print bed 200 includes a build sheet 220 including a foam material having a T _g of at least about 140 °C or a cellulose fiber material as described herein. In certain aspects the print bed 200 includes a support table 210, which may underlie the build sheet 220 and provide support thereto. The support table 210 may be stationary or movable, as discussed above.

[0082] In certain aspects of the method the additive manufacturing material 330 is applied onto the print bed 200 through a print head/nozzle system 300 such as that described above. The print head/nozzle system 300 includes at least one print head 310 and nozzle 320. The print head/nozzle system 300 may be stationary or moveable, as discussed above. The additive manufacturing material 330 may be loaded into the print head 310; suitable additive manufacturing materials 330 include, but are not limited to, any of those materials described herein. The print head/nozzle system 300 may include multiple print head/nozzle systems 300 and/or a single print head/nozzle system 300 having a plurality of print heads 310 and nozzles 320 as described above.

[0083] The foam material or cellulose fiber material in the method may include any of those materials described above for the apparatus (not duplicated here).

[0084] In some aspects of the method the foam material or cellulose fiber material is incorporated onto a reinforcing substrate. The reinforcing substrate may be any material that supports the foam material (and additional optional additives if provided) in the build sheet 220. The reinforcing substrate may be, but is not limited to, any of the materials described above with respect to the apparatus (not duplicated here).

[0085] In some aspects of the method the plurality of layers of additive manufacturing material 330 are applied onto the print bed at a temperature of at least about 30 °C. In further aspects the plurality of layers of additive manufacturing material 330 are applied onto the print bed at a temperature of at least about 85 °C, or at least about 145 °C, or at least about 200 °C, or at least about 250 °C.

[0086] In some aspects of the method the plurality of layers of additive manufacturing material are applied onto the print bed at a temperature of at least about 300°F. In certain aspects, the plurality of layers of additive manufacturing material are applied onto the print bed at a temperature of at least about 400°F, or at a temperature of at least about 500°F, or at a temperature of at least about 600°F, or even at a temperature of at least about 700°F.

[0087] As explained herein, the printed part 10 may be easily removable from the build sheet 220 without excessive build sheet material sticking to the part 10. Accordingly, in some aspects of the method the build sheet 220 is reusable for multiple print jobs, and the method includes applying a plurality of layers of additional additive manufacturing material 330 onto the build sheet 220 in a same pattern and location on the build sheet. In certain aspects the build sheet is reusable at least 15 times. In further aspects the build sheet is reusable at least 20 times, or at least 25 times, or at least 50 times.

[0088] In certain aspects of the method relative motion between the print head/nozzle system 300 and the print bed 200 is controlled by a physical control system 400 such as that described above. As discussed, the physical control system 400 may move the print head/nozzle system 300 while maintaining the support table 210 stationary or it may move the support table 210 while maintaining the print head/nozzle system 300 stationary.

Movement of the print head/nozzle system 300 or the support table 210 may be in the horizontal and the vertical direction as described herein. The physical control system 400 may be controlled by a controller 500, which receives computer-readable instructions for printing the part 10 in accordance with the above description.

[0089] Aspects of the method further include applying an additive manufacturing material 330 onto the build sheet 220 in successive layers such that a first layer of the additive manufacturing material 330 is in contact with the build sheet 220, and the method further includes removing the additive manufacturing material 330 from the build sheet 220 such that less than 1% of the build sheet 220 that was in contact with the first layer adheres to the first layer. In further aspects less than 0.5%, or less than 0.2%, or less than 0.1%, or less than 0.01% of the build sheet 220 that was in contact with the first layer adheres to the first layer.

[0090] A particular benefit of the build sheet 220 according to aspects of the disclosure is that the build sheet 220 need not be preheated prior to its use in the method. This is in contrast to previously known build sheet materials, including but not limited to concrete, thermoplastic (ABS, polycarbonate and polyetherimide), metallic and glass build sheet materials.

[0091] In some aspects of the method it may be desirable to secure the build sheet 220 to the print bed 200 during additive manufacturing of the part 10 in order to prevent movement of the build sheet 220 on the print bed 200 relative to the part 10. The build sheet 220 may be secured to the print bed 200 by any suitable method, including clamps, fasteners, or even weights applied around the perimeter of the build sheet 220. In some aspects the print sheet 220 is not secured to the print bed 200.

[0092] In some aspects of the present disclosure the method is used in medium and large format additive manufacturing processes.

[0093] The build sheet 220 may be used with any thermoplastic polymer-based additive manufacturing materials. In some aspects the build sheet 220 may be used with thermoplastic polymer-based additive manufacturing materials having a glass transition temperature (Tg) of at least about 30 °C. In particular aspects, the build sheet 220 may be used with thermoplastic polymer-based additive manufacturing materials having a relatively high glass transition temperature (Tg), such as at least about 85 °C for amorphous polymers or a melt point of at least about 120 °C for semi-crystalline polymers. In further aspects, the build sheet 220 may be used with amorphous thermoplastic polymer-based additive manufacturing materials having a Tg of at least about 105 °C, or at least about 145 °C, or at least about 200 °C. In certain aspects, the build sheet 220 may be used with amorphous thermoplastic polymer-based additive manufacturing materials having a Tg of from about 85 °C to about 350 °C, or having a Tg of from about 105 °C to about 300 °C, or having a Tg of from about 105 °C to about 275 °C. In particular aspects, the build sheet 220 may be used with semi-crystalline thermoplastic polymer-based additive manufacturing materials having a melt point of at least about 120 °C. Exemplary suitable additive manufacturing materials include, but are not limited to, thermoplastic polymers such as polyetherimide (PEI) (e.g., ULTEM™, available from SABIC), polycarbonate (PC), polyphenylsulfone (PPSU), polyphenylene sulfide (PPS), polyether ether ketone (PEEK), polyimide (e.g., EXTEM™, available from SABIC), poly(ether sulfone) (PES), poly(p-phenylene oxide) (PPO), PPO blends (e.g., PPO and polystyrene (PS)), polysulfone (PSU), polyaryletherketone (PAEK), blends thereof, and combinations thereof.

[0094] The additive manufacturing material could include a thermoplastic build material (i.e., the thermoplastic material that is used to make the printed part 10), a thermoplastic support material (i.e., the thermoplastic material that is used to make a support/scaffold), or a combination thereof. The thermoplastic build material and

thermoplastic support material may include the same or different thermoplastic polymer. In some aspects the thermoplastic build material or thermoplastic support material includes a thermoplastic polymer having a glass transition temperature of at least about 30 °C. In further aspects the thermoplastic build material or thermoplastic support material includes an amorphous thermoplastic polymer having a glass transition temperature of at least about 85 °C, or at least about 105 °C, or at least about 145 °C, or at least about 200 °C, or from about 85 °C to about 350 °C, or from about 105 °C to about 300 °C, or from about 105 °C to about 275 °C. In certain aspects the thermoplastic build material or thermoplastic support material includes a semi-crystalline thermoplastic polymer having a melt point of at least about 120 °C.

[0095] The method may be used in any additive manufacturing process. In some aspects the additive 44manufacturing process is a large format additive manufacturing (LFAM) process, an extrusion additive manufacturing process, or a fused filament fabrication process.

Method of Using a Foam or Cellulose Fiber Material in an Additive Manufacturing Process

[0096] Some embodiments of the disclosure further relate to methods of using a foam or cellulose fiber material in an additive manufacturing process, including applying a plurality of layers 340 of an additive manufacturing material 330 onto a print bed 200 to form the printed part 10. The print bed 200 includes a build sheet 220 including a foam material having a T _g of at least about 140 °C, such as about 140 °C to about 460 °C, or a cellulose fiber material as described herein. In certain aspects the print bed 200 includes a support table 210, which may underlie the build sheet 220 and provide support thereto. The support table 210 may be stationary or movable, as discussed above.

[0097] In certain aspects of the method the additive manufacturing material 330 is applied onto the print bed 200 through a print head/nozzle system 300 such as that described above. The print head/nozzle system 300 includes at least one print head 310 and nozzle 320. The print head/nozzle system 300 may be stationary or moveable, as discussed above. The additive manufacturing material 330 may be loaded into the print head 310; suitable additive manufacturing materials 330 include, but are not limited to, any of those materials described herein. The print head/nozzle system 300 may include multiple print head/nozzle systems 300 and/or a single print head/nozzle system 300 having a plurality of print heads 310 and nozzles 320 as described above.

[0098] The foam material or a cellulose fiber material in the method may include any of those materials described above (not duplicated here).

[0099] In some aspects of the method the foam material or cellulose fiber material is incorporated onto a reinforcing substrate. The reinforcing substrate may be any material that supports the foam material or cellulose fiber material in the build sheet 220. The reinforcing substrate may be, but is not limited to, any of the materials described above with respect to the apparatus (not duplicated here). Moreover, the build sheet may further include a rigid support layer 350 proximate to the foam material or cellulose fiber material as described herein.

[00100] In some aspects of the present disclosure the methods described herein are used in a LFAM process. Article Including a Foam or Cellulose Fiber Material and a Rigid Support Layer

[00101] It may be desirable in some aspects for the build sheet to be incorporated into an additively manufactured article, particularly where the build sheet includes the rigid support layer as described herein. In such aspects the rigid support layer could form the outermost layer of the article. Thus, with reference to FIG. 4 further aspects of the disclosure related to an article including a plurality of layers of an additive manufacturing material 340, a build sheet 220 including a foam or cellulose fiber material onto which the additive manufacturing material is applied, and a rigid support layer exterior 350 and adhered to the foam material. The foam material has a glass transition temperature of at least about 140 °C. [00102] It should be appreciated that the present disclosure can include any one up to all of the following aspects:

[00103] Aspect 1: An apparatus for additive manufacturing of a part, the apparatus comprising:

a print bed comprising a build sheet, a print head/nozzle system comprising at least one print head and nozzle, the print head/nozzle system configured to apply an additive manufacturing material onto the print bed; and

a physical control system providing for relative motion between the print head/nozzle system and the print bed,

wherein the build sheet comprises a foam material having a glass transition temperature of at least about 140 degrees Celsius.

[00104] Aspect 2: The apparatus according to Aspect 1, wherein the foam material comprises a polyetherimide resin, a polycarbonate resin, or a combination thereof.

[00105] Aspect 3: The apparatus according to Aspect 1 or 2, wherein the foam material comprises a polyetherimide resin, and the polyetherimide resin is an amorphous, transparent, amber polyetherimide resin having a density of about 1200 kilograms per cubic meter to about 1400 kilograms per cubic meter (kg/m ³ ).

[00106] Aspect 4: The apparatus according to any of Aspects 1 to 3, wherein the foam material has a compressive strength of at least about 50 pounds per square inch as tested in accordance with ASTM D 1621.

[00107] Aspect 5: The apparatus according to any of Aspects 1 to 4, wherein the build sheet further comprises a reinforcing substrate.

[00108] Aspect 6: The apparatus according to any of Aspects 1 to 5, wherein the build sheet further comprises an additional additive.

[00109] Aspect 7: The apparatus according to Aspect 6, wherein the additional additive is a thermal stabilizer, a release additive, an adhesive, or a combination thereof.

[00110] Aspect 8: The apparatus according to any of Aspects 1 to 7, wherein the additive manufacturing is big area additive manufacturing.

[00111] Aspect 9: The apparatus according to any of Aspects 1 to 8, wherein the part adheres to the foam material in the build sheet.

[00112] Aspect 10: A method for additive manufacturing a printed part, comprising applying a plurality of layers of an additive manufacturing material onto a print bed to form the printed part,

wherein the print bed comprises a build sheet comprising a foam material having a glass transition temperature of at least about 140 degrees Celsius.

[00113] Aspect 11: The method according to Aspect 10, wherein the additive manufacturing material is applied onto the print bed through a print head/nozzle system. [00114] Aspect 12: The method according to Aspect 10 or 11, wherein the foam material comprises a polyetherimide resin, a polycarbonate resin, or a combination thereof.

[00115] Aspect 13: The method according to Aspect 10 or 11, wherein the foam material comprises a polyetherimide resin, and the polyetherimide resin is an amorphous, transparent, amber polyetherimide resin having a density of about 1200 kilograms per cubic meter to about 1400 kilograms per cubic meter (kg/m ³ ).

[00116] Aspect 14: The method according to any of Aspects 10 to 13, wherein the foam material has a compressive strength of at least about 50 pounds per square inch as tested in accordance with ASTM D 1621.

[00117] Aspect 15: The method according to any of Aspects 10 to 14, wherein the build sheet further comprises a reinforcing substrate.

[00118] Aspect 16: The method according to any of Aspects 10 to 15, wherein the build sheet further comprises an additional additive.

[00119] Aspect 17: The method according to Aspect 16, wherein the additional additive is a thermal stabilizer, a release additive, an adhesive, or a combination thereof.

[00120] Aspect 18: The method according to any of Aspects 10 to 17, wherein the additive manufacturing is big area additive manufacturing.

[00121] Aspect 19: The method according to any of Aspects 10 to 18, wherein the printed part adheres to the foam material in the build sheet.

[00122] Aspect 20: The method according to any of Aspects 10 to 19, wherein the step of applying the plurality of layers of the additive manufacturing material onto the print bed is performed at a temperature of at least about 300°F.

[00123] Aspect 21. A build sheet for use in an additive manufacturing process comprising either:

(a) a foam material, wherein the foam material in the build sheet has a glass transition temperature in the range of about 140 °C to about 460 °C, or

(b) from 80 wt to 99 wt of a cellulose fiber material and from 0.5 wt to 10 wt of a binder.

[00124] Aspect 22. The build sheet according to aspect 21, wherein the build sheet comprises (a) the foam material, wherein the foam material comprises a polyetherimide resin, a polycarbonate resin, or a combination thereof.

[00125] Aspect 23. The build sheet according to aspect 22, wherein the foam material comprises a polyetherimide resin, and the polyetherimide resin is an amorphous, transparent, amber polyetherimide resin having a density of about 1200 kg/m ³ to about 1400 kg/m ³ .

[00126] Aspect 24. The build sheet according to any one of aspects 22 to 23, wherein the foam material has a compressive strength of from about 30 pounds per square inch (psi) to about 300 psi as tested in accordance with ASTM D 1621.

[00127] Aspect 25. The build sheet according to any one of aspects 22 to 24, wherein the foam material has a glass transition temperature within the range of about 140 °C to about 460 °C.

[00128] Aspect 26. The build sheet according to any one of aspects 22 to 25, wherein the build sheet further comprises an additive selected from the group consisting of a thermal stabilizer, a release additive, an adhesive, and a combination thereof.

[00129] Aspect 27. The build sheet according to aspect 21, wherein the build sheet comprises (b) the cellulose fiber material and binder, wherein the cellulose fiber material comprises natural cellulose fibers, manufactured cellulose fibers, or a combination thereof.

[00130] Aspect 28. The build sheet according to aspect 27, wherein the natural cellulose fibers are selected from the group consisting of fibers derived from cotton, fiber flax, seed flax, kenaf, jute, hemp, ramie, abaca, sisal, henequen, coir, softwood, and combinations thereof.

[00131] Aspect 29. The build sheet according to aspect 27 or 28, wherein the manufactured cellulose fibers are selected from the group consisting of cellulose ether, cellulose ester, regenerated cellulose, and combinations thereof.

[00132] Aspect 30. The build sheet according to any one of aspects 27 to 29, wherein the binder is selected from the group consisting of wax, styrene maleic anhydride copolymer, styrene-acrylate copolymer, carboxymethyl cellulose (CMC), cationic and anionic hydroxyethyl cellulose (EHEC), modified starch, dextrin, styrene butadiene latex, styrene acrylic, proteins, lignins, gelatin, pectin, and combinations thereof.

[00133] Aspect 31. The build sheet according to any one of aspects 27 to 30, wherein the binder is wax, and the wax comprises paraffin wax.

[00134] Aspect 32. The build sheet according to any one of aspects 27 to 31, wherein the build sheet comprises 94 wt to 98 wt cellulose fiber materials comprising paper cellulose and 1 wt to 6 wt of a binder comprising paraffin wax.

[00135] Aspect 33. The build sheet according to any one of aspects 27 to 32, wherein the build sheet further comprises a biocide. [00136] Aspect 34. The build sheet according to any of aspects 27 to 33, wherein the build sheet has a density in the range of about 10 to about 60 lb/ft ³ .

[00137] Aspect 35. The build sheet according to any one of aspects 27 to 34, wherein the build sheet comprises at least about 85% post-consumer material.

[00138] Aspect 36. The build sheet according to any one of aspects 27 to 35, wherein the build sheet comprises a Janka hardness of at least about 200 pound-force (lbf).

[00139] Aspect 37. The build sheet according to aspect 21, wherein the build sheet further comprises a rigid support layer proximate to the foam material or cellulose fiber material.

[00140] Aspect 38. The build sheet according to aspect 37, wherein the rigid support layer comprises a wood sheet, a plywood sheet, a metallic sheet, a polymeric sheet, a cement sheet, or a combination thereof.

[00141] Aspect 39. The build sheet according to aspect 37 or 38, wherein the rigid support layer is adhered to the foam material with an adhesive or with a plurality of fasteners.

[00142] Aspect 40. An article comprising:

a build sheet according to any one of claims 21 to 39; and

a plurality of layers of an additive manufacturing material applied onto the build sheet, wherein the manufacturing material comprises a thermoplastic polymer.

[00143] Aspect 41. An apparatus for additive manufacturing of a part, the apparatus comprising:

a print bed comprising a build sheet according to any one of aspects 21 to 39,

a print head/nozzle system comprising at least one print head and nozzle, the print

head/nozzle system configured to apply an additive manufacturing material onto the print bed; and

a physical control system providing for relative motion between the print head/nozzle system and the print bed.

[00144] Aspect 42. A method of using a build sheet in an additive manufacturing process, comprising applying a plurality of layers of an additive manufacturing material onto a print bed to form a printed part, wherein the print bed comprises a build sheet according to any one of aspects 21 to 39.

[00145] Aspect 43. The method according to aspect 42, wherein the additive manufacturing material is applied onto the build sheet in successive layers such that a first layer of the additive manufacturing material is in contact with the build sheet, and the method further comprises removing the additive manufacturing material from the build sheet, wherein less than 0.01% of the build sheet that was in contact with the first layer adheres to the first layer.

[00146] Aspect 44. The method according to aspect 42 or 43, wherein the additive manufacturing material comprises at least one member selected from the group consisting of polyetherimide, polycarbonate, polyphenylsulfone, polyphenylene sulfide, polyether ether ketone, polyimide, poly(ether sulfone), polyphenylene ether, polysulfone (PSU),

polyaryletherketone, and combinations thereof.

[00147] Each of these non-limiting aspects can stand on its own, or can be combined in various permutations or combinations with one or more of the other aspects.

EXAMPLES

[00148] The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices and/or methods claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.), but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in °C or is at ambient temperature, and pressure is at or near atmospheric. Unless indicated otherwise, percentages referring to composition are in terms of wt%.

[00149] There are numerous variations and combinations of reaction conditions, e.g., component concentrations, desired solvents, solvent mixtures, temperatures, pressures and other reaction ranges and conditions that can be used to optimize the product purity and yield obtained from the described process. Only reasonable and routine experimentation will be required to optimize such process conditions.

[00150] ULTEM™ 1000 resin, the properties of which are described herein, was foamed and formed into a build sheet in a Large Format Additive Manufacturing (LFAM) additive manufacturing process according to aspects described herein. An additive manufacturing material was applied onto the ULTEM™ foam build sheet. As shown in

FIGS. 5 and 6, the initial layers of the printed part adhered better to the foam build sheet than has been observed with other build sheet materials, which resulted in a more consistent relationship of the in-progress part to the print head. In other words, the printed part did not move, rotate, or warp as much as it typically might, helping to produce a more accurate finished part. The foam material in the build sheet also enables the production of models from materials that would not otherwise easily adhere to any other known build sheet material. Moreover, the foam build sheet insulated the first several layers of the printed part, slowing the cooling rate of these layers. As a result, the layers of the printed part cooled more uniformly, further improving the properties of the printed part.

[00151] A medium density cellulose fiber board (440 Homasote®) was used as a build sheet in a Large Format Additive Manufacturing (LFAM) additive manufacturing process according to aspects described herein. An additive manufacturing material was applied onto the cellulose fiber build sheet to form a printed part. The cellulose fiber build sheet sufficiently held the layers of additive manufacturing material in place, and neither the printed part nor the build sheet warped, indicating that the build sheet properly insulated the printed part so that the various portions of the printed part cooled at a relatively even rate. When the printed part had cooled the part was removed from the cellulose fiber build sheet. As shown in FIG. 7, very little of the cellulose fiber material in the build sheet adhered to the printed part. This is in contrast to what has been observed with foam-based build sheets (FIG. 8) and concrete-based build sheets (FIG. 9), where substantially more of the build sheet material adhered to the printed part.

[00152] In addition, because the build sheet was left relatively intact during use and removal of the printed part, the build sheet could be used to print numerous parts in the same pattern and on the same portion of the build sheet before replacement of the build sheet was required. The build sheet used in the example herein was used 22 times to print the same part in the same location on the build sheet.

[00153] Tables 1A and IB provide a summary of comparative properties of prior art build sheet materials as compared to the cellulose fiber build sheet of the present disclosure (the last row in each table). As shown in the tables, only the cellulose fiber build sheet includes the properties: easy to use (just put in place and use); available from local vendors; compatible with a wide range of materials; reusable for 20+ uses; no preparation time required prior to use; low cost; no warpage issues; relatively light weight; good insulative properties (i.e., not a heat sink) without the need for preheating; and environmental friendliness/recyclability.

Table 1A Concrete Place and use Local Few <20 1-4 hrs sheet

Plywood Sticking issues Local Limited <10 1-4 hrs

ABS sheet Needs to be Supplier Limited <10 1-4 hrs fastened down

PC sheet Place and use Supplier Wide range <10 1 hr

ULTEM™ Needs to be Supplier Few <10 None sheet fastened down

Pellets on Place and use Local Wide range <10 1-4 hrs plywood

Metal sheet Sticks not enough Supplier Few 20+ 1 hr

or too much

Glass Sticking issues Supplier Limited 20+ 1 hr

Cellulose Place and use Local Wide range 20+ None fiber

Table IB

* - Bui d sheet must be heated prior to use

[00154] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the invention can be practiced. These embodiments are also referred to herein as "examples." Such examples can include elements in addition to those shown or described. However, the present inventors also contemplate examples in which only those elements shown or described are provided. Moreover, the present inventors also contemplate examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[00155] In the event of inconsistent usages between this document and any documents so incorporated by reference, the usage in this document controls.

[00156] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In this document, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms "including" and "comprising" are open-ended, that is, a system, device, article, composition, formulation, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects.

[00157] Method examples described herein can be machine or computer- implemented at least in part. Some examples can include a computer-readable medium or machine- readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples. An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non- volatile tangible computer-readable media, such as during execution or at other times.

Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.

[00158] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. Other embodiments can be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is provided to comply with 37 C.F.R. § 1.72(b), to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. This should not be interpreted as intending that an unclaimed disclosed feature is essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that such embodiments can be combined with each other in various

combinations or permutations. The scope of the invention should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.