Patent Description:
Additive manufacturing techniques and processes generally involve the buildup of one or more materials to make a net or near net shape (NNS) object, in contrast to subtractive manufacturing methods. Though "additive manufacturing" is an industry standard term (ASTM F2792), additive manufacturing encompasses various manufacturing and prototyping techniques known under a variety of names, including e.g., freeform fabrication, 3D printing, rapid prototyping/tooling, etc. Additive manufacturing techniques may be used to fabricate simple or complex components from a wide variety of materials. For example, freestanding objects can be fabricated from a computer-aided design (CAD) model.

A particular type of additive manufacturing is commonly known as 3D printing. One such process, commonly referred to as Fused Deposition Modeling (FDM), comprises a process of melting a thin layer of thermoplastic material, and applying this material in layers to produce a final part. This is commonly accomplished by passing a continuous thin filament of thermoplastic material through a heated nozzle, which melts and applies the material to the structure being printed. The heated material may be applied to the existing structure in thin layers, melting and fusing with the existing material to produce a solid finished product.

The filament used in the aforementioned process is generally produced using a plastic extruder, which is comprised of a specially designed steel screw rotating inside a heated steel barrel. Thermoplastic material, in the form of small pellets, can be introduced into one end of the rotating screw. Friction from the rotating screw, combined with heat from the barrel, softens the plastic, which is then forced under pressure through a small round opening in a die attached to the front of the extruder barrel. This extrudes a string of material which is cooled and coiled up for use in the 3D printer.

Melting a thin filament of material in order to 3D print an item may be a slow process, which may be suitable for producing relatively small items or a limited number of items. The melted filament approach to 3D printing may be too slow to manufacture large items. However, the fundamental process of 3D printing using molten thermoplastic materials may offer advantages for the manufacture of large parts or a larger number of items.

In some instances, 3D printing a part may involve a two-step process. In some aspects, 3D printing may utilize a large print bead to achieve an accurate final size and shape. This two-step process, commonly referred to as near-net-shape, may begin by printing a part to a size slightly larger than needed, then machining, milling or routing the part to the final size and shape. The additional time required to trim the part to a final size may be compensated for by the faster printing process.

Print heads of additive manufacturing machines used to print thermoplastic material in relatively large beads generally include a vertically mounted extruder and a print nozzle to direct a round print bead downward onto a surface and/or onto a part being printed. In some cases, the flowable material, such as, e.g., molten thermoplastic material, may be infused with a reinforcing material (e.g., strands of fiber) to enhance the material's strength. The flowable material, while hot and pliable, may be deposited upon a substrate (e.g., a mold), and then pressed down, or otherwise flattened and/or leveled to a consistent thickness. These traditional print heads may include an oscillating plate surrounding the nozzle, the plate being configured to oscillate vertically to flatten the bead of material against the previous layer of material. The deposition process may be repeated so that each successive layer of flowable material is deposited upon an existing layer to build up and manufacture a desired structure for a component or part. In order to achieve proper bonding between printed layers, it may be necessary to ensure that the temperature of the previously-deposited layer is within a certain range. For example, the previously-deposited layer may need to have cooled to an appropriate degree and thereby solidified sufficiently to support the new layer. However, this previously-deposited layer may also be sufficiently warm to soften and fuse with the new layer, thus producing a solid part at the conclusion of the manufacturing process.

One industry that may benefit from additive manufacturing is boat-making. In recent years, boats have been constructed with components produced with the use of molds. These molds may be injected with reinforced plastic materials, such as fiberglass. The separate components formed with these molds may be joined together to form the finished boat. These boats are generally made of two major components, a hull and a deck. The hull may include or form the outside of the boat which floats in the water, while the deck may include or form the inside of the boat. In typical pleasure craft, the shape of the deck generally matches and follows the shape of the inside surface of the hull, to create an area where passengers can stand. Seats or other features may be molded into the deck. The boat is therefore constructed by firmly connecting the separate hull and the deck components together. The video "LSAM 3D Printed Boat Hull" (https://www. com/ watch?v=G1F4P9O_CO8) shows a printed and machined hull of a boat.

Fiberglass boats are traditionally manufactured by applying catalyzed fiberglass material to the inside of a mold. The mold may have a surface that matches the desired shape of the outside of the part. This material then hardens, and the resulting part, for example a boat hull, is removed from the mold.

Before a boat, such as a fiberglass boat, can be produced in this fashion, molds for the hull and deck are typically built. This is generally accomplished by making a pattern, which may be referred to as a "plug", which has the size and shape desired in the final component. Then, fiberglass can be applied to the plug. Once this fiberglass has hardened and is removed from the plug, the resulting fiberglass part forms a mold for that component.

Typically, these plugs are built up using wood, foam, and other materials in a relatively time consuming and expensive process which requires the performance of skilled craftsmen. This conventional process may require months, or even years, to complete. Also, for boats produced in this manner, two separate plugs are needed, one for the hull and one for the deck. Additionally, conventional construction processes can result in boat plugs that lack durability. In such plugs, wear and tear caused by the process of making molds can limit the number of molds that can be pulled from each plug before the plug deteriorates to the point the plug can no longer be used. This process can be improved by a large scale 3D printing process to produce a single plug for both the hull and deck.

Aspects of the present disclosure relate to, among other things, methods and apparatus for fabricating components via additive manufacturing or 3D printing techniques. Each of the aspects disclosed herein may include one or more of the features described in connection with any of the other disclosed aspects. An object of the present disclosure is an approach that uses a large-scale 3D printing process to manufacture boat plugs in a manner that is faster, less expensive, and may be performed by machinery, rather than by skilled craftsman. Additionally, this approach may produce a plug that is more durable than plugs formed by conventional processes.

This approach may use an additive manufacturing process, such as a 3D printing process, to print a hull and deck. The hull and deck may be manufactured as a single part having a shape that generally corresponds to the final boat. This printed structure may then be machined to a desired final size and shape using CNC machinery and subsequently mounted to a rotary support which suspends the part above the floor and allows the part to be rotated so that either the hull or the deck faces upward, as desired.

When the hull is facing upward, fiberglass may be applied and a mold for the hull produced from the printed plug. When the plug is rotated so that the deck is facing upward, fiberglass can be applied and a mold for the deck may be produced. In this way, a single plug can be used to produce both the hull and the deck.

Since the material used for printing the two-sided plug may be significantly more durable than the conventional material typically used to make boats plugs, the material for the two-sided plug can be used to produce considerably more molds without deteriorating. The 3D printing process and subsequent machining may be significantly faster than the traditional approach, reducing the amount of time required to make the plug.

It may also be possible to design features in the deck which cannot be easily printed as part of the initial print process. Alternatively, if desired, these features may instead be printed as separate items and then attached or bonded to the printed deck to produce a deck plug with any desired features.

According to the invention as disclosed in claim <NUM>, an additive manufacturing method may include providing material to an extruder of an additive manufacturing apparatus, heating the material to form a flowable material, and depositing a first layer of the flowable material from a nozzle of the additive manufacturing apparatus to form part of a hull portion of a plug for a marine article. The method may also include depositing a second layer of the flowable material from the nozzle of the additive manufacturing apparatus to form part of a deck portion of the plug for the marine article.

According to the invention as disclosed in claim <NUM>, a system for manufacturing a mold for a marine article may include a plug formed of a thermoplastic material, the plug including: a hull portion having a hull surface facing in a first direction and a deck portion formed integrally with the hull portion, the deck portion having a deck surface facing in a first direction opposite to the second direction, wherein the hull portion and the deck portion are each formed of a thermoplastic material. The system may also include a support configured to rotatably suspend the plug.

In yet another aspect, a method for manufacturing a mold may include providing material to an extruder of an additive manufacturing apparatus and heating the material to form a flowable material. The method may also include depositing the flowable material from a nozzle to form a plug including a hull portion and a deck portion, applying a plastic material to at least one of the hull portion and the deck portion of the plug, and forming a mold by allowing the plastic material to harden and removing the hardened plastic material from the plug.

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary aspects of the present disclosure and together with the description, serve to explain the principles of the disclosure.

The present disclosure is drawn to, among other things, methods and apparatus for fabricating multiple components via additive manufacturing or 3D printing techniques. Specifically, the methods and apparatus described herein may comprise an approach that uses a large scale 3D printing process for making boat plugs in a manner that is faster, less expensive, and that employs machinery to produce a more durable plug.

Referring to <FIG>, an additive manufacturing apparatus such as CNC machine <NUM> may include a bed framework having a pair of transversely spaced side walls <NUM> and <NUM>, a printing gantry <NUM> and a trimming gantry <NUM>, a carriage <NUM> mounted on printing gantry <NUM>, a carrier <NUM> mounted on carriage <NUM>, an extruder <NUM>, and an applicator assembly <NUM> mounted on carrier <NUM>. Printing gantry <NUM> and trimming gantry <NUM> may be supported on side walls <NUM> and <NUM>. A horizontal worktable <NUM> having a support surfaced disposed in an x-y plane may be supported on the bed framework between side walls <NUM> and <NUM>. Printing gantry <NUM> and trimming gantry <NUM> may be disposed so as to extend along a y-axis, supported at respective ends thereof on end walls <NUM> and <NUM>. Printing gantry <NUM> and trimming gantry <NUM> may be movable with respect to an x-axis on a set of shared approximately parallel guide rails <NUM> and <NUM> provided on the upper ends of side walls <NUM> and <NUM>. The printing gantry <NUM> and trimming gantry <NUM> may be displaceable by a one or more (e.g., a set of) servomotors mounted on the printing gantry <NUM> and trimming gantry <NUM>, respectively. For example, printing gantry <NUM> and trimming gantry <NUM> may be operatively connected to tracks provided on the side walls <NUM> and <NUM>. Carriage <NUM> may be supported on printing gantry <NUM> and provided with a support member <NUM> mounted on and displaceable along one or more guide rails <NUM>, <NUM>, and <NUM> provided on the printing gantry <NUM>. Carriage <NUM> may be displaceable along a y-axis along one or more guide rails <NUM>, <NUM>, and <NUM> via a servomotor mounted on the printing gantry <NUM> and operatively connected to support member <NUM>. Carrier <NUM> may be mounted on a set of spaced, vertically-disposed guide rails <NUM> supported on the carriage <NUM> for displacement of the carrier <NUM> relative to the carriage <NUM> along a z-axis. Carrier <NUM> may be displaceable along the z-axis via a servomotor mounted on the carriage <NUM> and operatively connected to the carrier <NUM>. A vertical worktable <NUM> may be attached to one or more conveyor belts <NUM> and <NUM>. Vertical worktable <NUM> may be supported on top of horizontal worktable <NUM>, and may be displaceable along rails <NUM> and <NUM> along the x-axis by one or more servomotors connected to vertical worktable <NUM> and operatively connected to tracks provided on the top of the bed framework.

As best shown in <FIG>, extruder <NUM> may be mounted, in a linearly-movable manner, to carrier <NUM>. In an exemplary configuration, extruder <NUM> may be movably mounted on a set of rails <NUM> and <NUM> and bearings (<FIG>). A servomotor <NUM> may drive extruder <NUM> through a gearbox <NUM> attached to transition housing <NUM>. Extruder <NUM> may receive thermoplastic pellets at the feed housing <NUM> so that the extruder screw transfers the thermoplastic material down through the barrel <NUM> where it is melted by the friction of the screw and heaters <NUM>. This melted thermoplastic material may flow, via extruder <NUM>, to positive displacement gear pump or melt pump <NUM> (<FIG>).

As best shown in <FIG>, gear pump <NUM> may be securely mounted to the bottom of carrier <NUM>. Gear pump <NUM> may be driven by a servomotor <NUM> through a gearbox <NUM>, and may receive molten plastic (e.g., thermoplastic material) from extruder <NUM> (<FIG>), and meter out precise amounts of thermoplastic material at determined flow rates to nozzle <NUM> to print the part. An applicator head <NUM> may be attached at a location below gear pump <NUM>. Applicator head <NUM> may include a bead shaping roller <NUM>, rotationally mounted in carrier bracket <NUM>. Roller <NUM> may provide a means for flattening and leveling an oversized bead of fluid material (e.g., molten thermoplastic) extruded out of nozzle <NUM>. Carrier bracket <NUM> may be adapted to be rotationally displaced by means of a servomotor <NUM>, through a pulley or sprocket <NUM> and belt or chain <NUM> arrangement.

With reference to <FIG>, application head <NUM> may include a housing <NUM> with rotary union mounted therein. Pulley or sprocket <NUM> may be machined into an inner hub <NUM> of the rotary union. Inner hub <NUM> may have an opening with a sufficiently large diameter to allow the heated print nozzle <NUM> to pass through. Inner hub <NUM> may rotate on a set of bearings <NUM> contained within the outer housing <NUM> of the rotary union. The compression roller assembly may be attached to the inner hub <NUM> of the rotary union so that the compression roller <NUM> rotates about the print nozzle <NUM>. The rotary union may also contain barb fittings <NUM> and <NUM> ported into coolant passages <NUM> that encompass or surround inner hub <NUM> and the inside of outer housing <NUM> of the rotary union. The coolant passages <NUM> may extend to quick disconnect fittings <NUM> into an axle <NUM> of the compression roller <NUM>.

With reference to <FIG>, an oversized molten bead of flowable material (e.g., molten thermoplastic) may be provided under pressure from a source disposed on carrier <NUM> (e.g., gear pump <NUM>) or another source. The bead of flowable material may be provided to applicator head <NUM>. Thus, gear pump <NUM>, (or another source of flowable material), may be securely connected to, and in communication with, nozzle <NUM>. In use, the flowable material <NUM> (e.g., thermoplastic material) may be heated sufficiently to form a large molten bead thereof, which may be extruded through applicator nozzle <NUM> to form large, uniform, and smooth rows of deposited material on surface <NUM>. In some aspects, surface <NUM> may be a horizontally-extending surface (e.g., a surface that extends in an X-Y plane as shown in <FIG>). In other aspects, a vertically-extending surface <NUM> (e.g., a surface that extends in an Y-Z plane as shown in <FIG>) may used instead of, or in addition to, surface <NUM>. As shown in <FIG>, surfaces <NUM> and <NUM> are each suitable for receiving a bead of flowable material <NUM>. Such beads of molten material may be flattened, leveled, and/or fused to adjoining layers by bead-shaping compression roller <NUM> with the layers forming 3D printed products, such as a plug for a boat. The use of roller <NUM> to flatten, level, and/or fuse layers may substantially eliminate the occurrence of trapped air between the adjoining layers.

In one aspect, the additive manufacturing apparatus described with respect to <FIG> may be configured to perform a 3D printing process to print a plug <NUM> shown in <FIG>. In one aspect, plug <NUM> may be formed as a single integral part including both a hull <NUM> and deck <NUM>. Plug <NUM> may be formed by printing a plurality of portions that are subsequently joined together to form a single part that includes both hull <NUM> and deck <NUM>. These individual portions may be bonded, fused, or attached in any suitable manner. Whether plug <NUM> is formed during a single continuous printing process, or by bonding or otherwise joining a plurality of separately printed portions, plug <NUM> may have a shape that corresponds to the shape of the final boat as shown in <FIG>. Plug <NUM> may be constructed by an additive manufacturing or 3D printing process such as a horizontal printing process in which nozzle <NUM> extends vertically or a vertical printing process in which nozzle <NUM> extends horizontally. When plug <NUM> is formed by joining two or more separate portions, each of these portions may be formed by either a horizontal or a vertical printing process. The machine shown in <FIG> may be capable of forming plug <NUM> in a single continuous print operation, or in a plurality of separate print operations. Plug <NUM> may have a length or height that is larger than the length of horizontal worktable <NUM> by forming plug <NUM> with two or more portions produced by separate print operations with CNC machine <NUM>. In some aspects, plug <NUM> may be constructed via 3D printing such that at least one first layer forms a part of hull portion <NUM> and at least one second layer forms a part of the deck portion <NUM>. As understood, each of the hull <NUM> and deck <NUM> portions of plug <NUM> may include a plurality of layers of material <NUM> (see <FIG>) that may be fused to form an integral body of plug <NUM>. Once formed, plug <NUM> may be machined to a final size and shape using CNC machinery. With the use of the CNC machinery, the 3D printing process may be performed in a repeatable manner that is less reliant on the performance of skilled craftsmen. Once manufactured (printed, machined, and/or assembled, if necessary), plug <NUM> may be mounted to a plug support frame <NUM> which is connected to one or more floor support <NUM>. When plug <NUM> is so connected to one or more floor supports <NUM>, plug <NUM> may be suspended above the floor. Additionally, floor supports <NUM> may allow plug <NUM> to be rotated (e.g., about an axis <NUM>) so that either the hull <NUM> or deck <NUM> faces upward. Fiberglass may be applied to plug <NUM> (e.g., on at least a portion of hull <NUM> and/or at least a portion of deck <NUM>), to form a mold. As the plug is able to selectively rotate about axis <NUM>, fiberglass may be applied with the plug <NUM> positioned at any desired angle, allowing the selection of the rotational position of hull <NUM> that is best adapted for a particular situation or portion of the process for creating the mold.

As shown in the top view of <FIG> and the side view of <FIG>, the hull <NUM> may be positioned (rotated to and secured in a first position) so as to face upward. With hull <NUM> positioned facing upwards, plastic, such as a plastic that includes include reinforcing fibers (e.g., fiberglass) may be applied to produce a mold for hull <NUM> from printed plug <NUM>. Similarly, plug <NUM> may be rotated so that deck <NUM> faces upward (rotated to a second position), as shown in top view of <FIG> and side view of <FIG>. With the deck <NUM> facing upwards, plastic material such as fiberglass may be applied to produce a mold for the deck <NUM>. The hull <NUM> and deck <NUM> of plug <NUM> may be formed with smooth or finished surfaces (e.g., polished and/or coated surfaces) for receiving the fiberglass material, thereby reducing or eliminating the need to machine a mold formed from the hull <NUM> or deck <NUM>. In this way, a single plug <NUM> may be used to produce molds for both the hull and deck of a boat. Additionally, a single boat plug <NUM> may require less floor space than two or more separate boat plugs for the hull and for the deck, which may reduce costs associated with plug <NUM>. Also, constructing a single boat plug <NUM> (e.g., by 3D printing) for both the hull and deck may be less expensive than preparing two or more separate plugs, further reducing costs associated with plug <NUM>. Further, the material (e.g., thermoplastic material) used for the printing the two-sided plug <NUM> may be significantly more durable than materials such as wood, foam, etc. Therefore, plug <NUM> may be used to produce considerably more molds without deterioration as compared to plugs made of conventional materials. The 3D printing process and subsequent machining may be faster than traditional approaches, reducing the amount of time required to make the plug <NUM>.

Claim 1:
An additive manufacturing method, comprising:
providing material to a horizontally-extending nozzle (<NUM>) from an extruder (<NUM>) of an additive manufacturing apparatus (<NUM>);
heating the material to form a flowable material;
depositing a first layer of the flowable material from a nozzle (<NUM>) of the additive manufacturing apparatus (<NUM>) to form part of a hull portion (<NUM>) of a plug (<NUM>) for a mold of a marine article; and
depositing a second layer of the flowable material from the nozzle (<NUM>) of the additive manufacturing apparatus (<NUM>) to form part of a deck portion (<NUM>) of the plug (<NUM>) for the marine article, wherein the deck portion (<NUM>) has a shape corresponding to an inside of a boat; and
machining the hull portion (<NUM>) and the deck portion (<NUM>) with the additive manufacturing apparatus (<NUM>).