Additive manufacturing process for composite products

Abstract

An additive manufacturing process (100), comprising: Positioning (110) a mat (40) made of composite material; Curing (120) of a predetermined part (41) of the mat (40); Cutting (130) the mat (40) over the perimeter (42) of the predetermined part (41) to produce a previously machined mat (40'); Adding (140) a subsequent mat (50) of composite material onto and into contact with the previously processed mat (40'); Curing (150) of a predetermined part of the subsequent mat (50) so that the predetermined parts of the subsequent mat (50) and the previously processed mat (40') are joined together; and Cutting (160) the subsequent mat (50) around the circumference of its predetermined part (41) to produce a subsequent machined mat, further comprising: Repeating (170) the steps of adding, curing and cutting a subsequent mat for a multitude of cycles, further comprising, prior to the step of adding: Applying (234) an adhesive to the predetermined part of the previously processed mat, further comprising, prior to the step of applying (234): Covering (232) at least part of the previously processed mat (40') that does not correspond to the predetermined part (41), wherein each step of the curing process (150) includes directing heat, light, pressure and an activating agent onto the respective predetermined part (41), where each step of the cutting process is performed by a jet of air, wherein at least one of the cutting steps (160) further comprises: Cutting within the circumference of the predetermined part (41).

Description

INTRODUCTION

[0001] This disclosure relates generally to additive manufacturing, and more particularly to machines and methods for producing composite products.

[0002] Three-dimensional printing (3DP) is an additive manufacturing (AM) process in which a part is built layer by layer. 3DP works by depositing a relatively small amount of material at a time, much like a printer deposits a very small amount of ink at a time to create a single layer of print on a sheet of paper. To borrow this printing analogy, 3DP can be thought of as a process in which successive layers of "ink" (or whatever material is used) are laid down on top of one another. The material used in 3DP is usually a thermoplastic that is molten (or already in liquid form) and injected or deposited in very small quantities onto a substrate or sheet as the first layer.The deposited material solidifies, dries, or hardens immediately after deposition, and the small deposits become very closely packed together, so that they merge or bond together to form a continuous layer. This means that because a layer is built up by the deposition of thousands of small deposits side by side, adjacent deposits merge or bond together to form a continuous layer with no spaces or voids between adjacent deposits. This inter-deposit continuity occurs not only within each layer but also between adjacent layers. Thus, when a successive layer is deposited on top of a preceding / underlying layer, the deposits of the subsequent / topmost layer merge or bond together with the adjacent deposits of the preceding / underlying layer.

[0003] Due to the very small achievable deposit size and the possibility that adjacent deposits can tightly fuse or bond together, the 3DP AM process can be used to build very complex three-dimensional (3D) structures. However, the typical 3DP process is not well suited for the construction of large, structural components that require high load-bearing capacity or wear resistance. For such purposes, 3DP has been adapted to allow small deposits of thermosetting resins containing high-strength particles or short strands of glass fiber, carbon fiber, or similar to be deposited within each deposit. Although this type of 3DP process, which uses thermosetting resins and structural materials, is more suitable for structural, load-bearing, and wear-resistant applications than conventional 3DP with thermoplastic deposits, it still has limitations.

[0004] For example, due to the small size of the individual deposits, the structural material (e.g. cut glass fiber or carbon fiber particles) is provided in very small quantities at the same time, so that the structural material is present in the entire component, but does not run continuously and uninterruptedly in every layer, thus limiting the load-bearing capacity of the entire component.

[0005] It would therefore be desirable to offer an improved method for manufacturing components using 3DP / AM methods that avoids or minimizes these and other limitations.

[0006] DE 10 2009 039 578 A1 describes methods for producing a three-dimensional object by means of a generative manufacturing process according to the LOM method, in which the object is obtained by repeatedly joining a large number of individual surface material sections in layers in the form of a three-dimensional layer composite stack that is formed in the process.

[0007] CN 109 130 243 A relates to a method and an apparatus for producing a carbon fiber reinforced resin matrix composite material with current heating LOM, wherein a prepreg strip made of the carbon fiber reinforced resin-based composite material is conveyed to the upper part of a working platform, the working platform.

[0008] US 6 450 393 B1 describes a method and apparatus for producing a three-dimensional part from several planar layers using an ultrasonic welding device.

[0009] EP 8 465 49 A2 describes an apparatus for forming a three-dimensional object comprising a profile cutter for cutting shapes into sheet material, a sheet material feeder, a computer for supplying instructions to the profile cutter and a laminator. DESCRIPTION

[0010] The object of the invention is to provide an improved method for manufacturing components using 3DP / AM methods, which increases the modification possibilities. This object is achieved by the subject matter according to claim 1.

[0011] As an example of a 3DP AM process, the Fig. 1 and Fig. 2 shown component 10 can be built up layer by layer, as shown in Fig. 3. A first layer L1 is applied to a substrate or plate 12, then a second layer L2 is applied to the first layer L1, and this process of adding successive layers continues until the last layer L12 is completed. Although in Fig. 3 only twelve layers are shown for illustrative purposes, a typical component 10 constructed using a 3DP process may have dozens, hundreds or thousands of layers.

[0012] According to one embodiment, an additive manufacturing method comprises: positioning a mat of composite material; curing a predetermined portion of the mat; cutting the mat around the perimeter of the predetermined portion to create a previous processed mat; adding a subsequent mat of composite material onto and in contact with the previously processed mat; curing a predetermined portion of the subsequent mat such that the predetermined portions of the subsequent mat and the previously processed mat are bonded together; and cutting the subsequent mat around the perimeter of its predetermined portion to create a subsequent processed mat. The method may also comprise repeating the steps of adding, curing, and cutting a subsequent mat for a plurality of cycles.

[0013] Before the adding step, the method may include applying an adhesive to the predetermined portion of the previously processed mats. Before the application, the method may further include masking at least a portion of the previously processed mats that does not correspond to the predetermined portion.

[0014] Before the step of curing a predetermined portion of the subsequent mat, the method may comprise covering at least a portion of the subsequent mat except for the predetermined portion and / or applying pressure to at least the predetermined portion of the subsequent mat.

[0015] The composite material may comprise an X+Y structural member / resin construction, wherein the structural member X is made of carbon fiber, aramid, bamboo, and / or fiberglass, and the resin Y is a thermo-reactive, photo-reactive, pressure-reactive, and / or chemically reactive material.

[0016] Each of the curing steps may involve directing heat, light, pressure, and / or an activating agent onto the respective predetermined portion of a composite mat. Each of the cutting steps may be performed using a laser, a cutting wheel, a drill, a milling tool, a saw, a heat knife, an air jet, and / or a water jet. At least one of the cutting steps may involve cutting within the perimeter of the predetermined portion.

[0017] In another embodiment, an additive manufacturing method for producing a composite product may include: (i) positioning a mat of composite material; (ii) curing a predetermined portion of the mat; (iii) cutting the mat around the perimeter of the predetermined portion to create a previous machined mat; (iv) adding a subsequent mat of composite material onto and in contact with the previously machined mat; (v) curing a predetermined portion of the subsequent mat such that the predetermined portions of the subsequent mat and the previously machined mat are bonded together; (vi) cutting the subsequent mat around the perimeter of its predetermined portion to create a subsequent machined mat; and (vii) repeating the steps of adding, curing, and cutting a subsequent mat for a plurality of cycles.

[0018] Before the addition step, the additive manufacturing method may also include applying an adhesive to the predetermined portion of the previously processed mat. Before the application, the method may further include masking at least a portion of the previously processed mats that does not correspond to the predetermined portion.

[0019] Before the step of curing a predetermined portion of the subsequent mat, the additive manufacturing method may comprise covering at least a portion of the subsequent mat that does not correspond to the predetermined portion and / or applying pressure to at least the predetermined portion of the subsequent mat.

[0020] Each of the curing steps of the additive manufacturing process may involve directing heat, light, pressure, and / or an activating agent to the respective predetermined portion of a composite mat.

[0021] Each of the cutting steps can be performed using a laser, a cutting wheel, a drill, a milling tool, a saw, a heat knife, an air jet, and / or a water jet. At least one of the cutting steps can involve cutting within the perimeter of the predetermined part.

[0022] In another embodiment, an additive manufacturing machine comprises a subsystem for positioning a mat of composite material, a subsystem for curing a predetermined portion of the mat, a subsystem for cutting the mat around the perimeter of the predetermined portion to produce a machined mat, and a controller operatively connected to the positioning, curing, and cutting subsystems.The controller includes logic for performing the steps of: (i) positioning a mat of composite material, (ii) curing a predetermined portion of the mat, (iii) cutting the mat around the perimeter of the predetermined portion to produce a previously machined mat, (iv) adding a subsequent mat of composite material onto and in contact with the previously machined mat, (v) curing a predetermined portion of the subsequent mat such that the predetermined portions of the subsequent mat and the previously machined mat are bonded together, (vi) cutting the subsequent mat around the perimeter of its predetermined portion to produce a subsequent machined mat, and (vii) repeating the steps of adding, curing, and cutting a subsequent mat for a plurality of cycles.

[0023] The curing subsystem may include a heat source, a light source, a pressure source, and / or a source of an activating agent. The cutting subsystem may include a laser, a cutting wheel, a drill, a milling tool, a saw, a heat knife, an air jet, and / or a water jet. The machine may further include a subsystem for masking at least a portion of a selected composite mat that is not the predetermined portion of the mats, wherein the controller is operatively connected to the masking subsystem and has logic for performing the steps of (viii) masking at least a portion of a selected composite mat that is not the predetermined portion of such mat, and (ix) repeating the masking step for a plurality of cycles. BRIEF DESCRIPTION OF THE CHARACTERS Fig. 1 is a plan view of an assembled product according to an embodiment of the disclosure. Fig. 2 is a side view of an assembled product according to an embodiment of the disclosure. Fig. 3 is a side view of the layers for constructing a composite product according to an embodiment of the disclosure. Fig. 4 is a cross-sectional view of a composite mat according to an embodiment of the disclosure. Fig. 5 is a cross-sectional view of another composite mat according to an embodiment of the disclosure. Fig. 6 shows top views of three different layers of processed composite mats according to an embodiment of the disclosure. Fig. 7 is a flowchart for an additive manufacturing process according to an embodiment of the disclosure. Fig. 8 is a flowchart for an additive manufacturing process according to an embodiment of the disclosure. Fig. 9 is a schematic diagram of an additive manufacturing machine according to an embodiment of the disclosure. DETAILED PRESENTATION

[0024] Referring now to the figures, wherein like parts are designated by reference numerals throughout the several views, there is shown and described a method 100 / 200, a machine 300, and composite products made by such methods and machines.

[0025] The inventors of the present disclosure have developed an additive manufacturing process and a machine utilizing the method that overcomes the limitations of previous approaches and is suitable for the production of both large and small structural components. One aspect of the inventors' approach disclosed herein is the use of 20 / 30 mats of composite material, as described in the Fig. The mat 20 made of composite material in Fig. 4 includes an inner layer 22 sandwiched between an upper outer layer 24 and a lower outer layer 26. The inner layer 22 may be a mat, a fabric, or an arrangement of structural material such as carbon fiber, aramid, bamboo, fiberglass, or the like, serving as a structural component. The structural material may be in the form of fabric, batting, fibers, strands, or another suitable arrangement.

[0026] The outer layers 24 / 26 may be made of a resin or other material with adhesive or bonding properties. Suitable materials for these layers include epoxies, adhesives, polyesters, resins, or similar materials. These materials may coat the top and bottom surfaces, or the faces, of the inner layer 22 and may also be molded or dispersed within the inner layer 22. A common arrangement of this structure is in the form of "pre-preg" mats, i.e., mats made of carbon fiber, aramid, bamboo, fiberglass, etc., coated and saturated ("impregnated") with a resin. These prepreg mats are typically "sticky" due to the resin exposed on both surfaces, so they are provided with "tearable" or "peelable" release mats (not shown) covering both surfaces 24 / 26.

[0027] Fig. Figure 5 shows an alternative embodiment of a composite mat or prepreg 30. Here, there is no substantial coating or resin layer on the top and bottom surfaces 34 / 36. Instead, the mat 30 may consist only of structural material (e.g., a carbon fiber mat) and no resin at all, or the mat 30 may consist of structural material with the resin penetrating the interior 32 of the mat 30. As with the Fig. 4, the mat 30 may be provided with separating mats (not shown) covering the top and bottom surfaces 34 / 36 to facilitate handling and positioning of the mats. When using the mat 20 according to Fig. 4 or mat 30 after Fig. 5, which contain resin, the resin in / on the 20 / 30 mats may form the first or "A" part of a two-part "A+B" resin / hardener system. In such a case, the second or "B" part (i.e., a hardener, accelerator, or other curing agent for the "A" resin) may be applied separately as part of a curing step (described below).

[0028] Thus, the 20 / 30 composite mats may contain an "X+Y" structural component / resin combination or composition, where structural component X may be carbon fiber, aramid, bamboo, fiberglass, or similar, and resin Y may be a thermo-reactive material, a photo-reactive material, a pressure-reactive material, a chemically reactive material, or similar. This X+Y combination or composition may take the form of the 20 / 30 mats, as shown in the Fig. shown.

[0029] It should be noted that the terms "top," "bottom," "upper," and "lower" as used herein are relative (not fixed) and refer to the orientation of the composite mat surfaces, as the mats are positioned 20 / 30 for use in the disclosed process. Thus, each surface of a sheet can be a top / bottom layer or a bottom / bottom layer, depending on how the sheet is oriented. Likewise, the words "previous," "previous," "subsequent," and "subsequent" are used herein to denote the relative order or sequence in which a mat may be presented or used, relative to other mats used earlier or later in the 100 / 200 additive manufacturing method according to this disclosure.

[0030] Fig. 6 shows top views of three different layers of composite mats 40 / 50 / 60 according to an embodiment of the disclosure, and Fig. Figure 7 shows a flowchart for an additive manufacturing method 100 according to an embodiment of the disclosure. In step 110, a mat 40 of composite material is positioned (e.g., on a roller 12 of a workstation) as the first layer L1 for further processing. Step 110 can be performed manually by human operators or with the aid of automated material handling equipment.

[0031] In step 120, a predetermined portion, area, or region 41 of the mat 40 is cured. This predetermined portion 41 has a perimeter 42 that fits within the outer perimeter or edge 43 of the composite mat 40. As shown in Fig. As shown, the predetermined portion of each mat or layer corresponds to a laminar "slice" of the desired composite product. The curing step 120 may be accomplished by selectively directing heat, light, pressure, and / or an activating agent to the predetermined region 41 of the composite mat 40. Depending on the type of resin used within or on the surfaces of the mat, a specific type of curing agent (or combination of curing agents) may be used. For example, a photoreactive resin may require that a specific frequency range of light (e.g., ultraviolet (UV), infrared, coherent laser light) be used as the curing agent for curing the portion 41 of the mat 40 exposed to the light. Another example is the curing of a pressure-reactive resin by the application of pressure concentrated on the predetermined portion of the mat.Additionally, a thermoreactive resin may be cured using heat and / or infrared energy directed at the area(s) 41 of the mat 40 to be cured, and a chemically reactive resin may be cured with a suitable chemical agent (e.g., activator, accelerator, catalyst, etc.) as the curing agent. The resin in / on a composite mat 40 may, for example, form the first or "A" part of a two-part "A+B" resin / curing agent system. In such a case, the second or "B" part (i.e., a curing agent, accelerator, or other curing agent for curing the "A" resin) may be applied to the predetermined part 41 as part of the curing step 120, e.g., by a print head scanning over the mat 40. When component "B" comes into contact with component "A" within the predetermined area 41, this area 41 hardens because components "A" and "B" chemically react. Alternatively, the composite mat 40 may contain only structural material (e.g.a woven carbon fiber mat) without resin, and the curing step 120 may comprise applying resin only to the predetermined part 41 and then curing the resin by applying the appropriate curing agent.

[0032] It should be noted that "curing" is a process by which the predetermined portion of the mat, to which the curing agent or curing medium is directed, is transformed from a first, substantially "uncured" state to a second, substantially "cured" state. In this cured state, the resin within the predetermined portion is stiffened, hardened, densified, or the like to a greater extent than before the application of the hardener or curing agent. "Hardener" or "curing agent" herein refers to a substance (e.g., a chemical), a form of energy (e.g., heat or light), or a set of conditions (e.g., the application of pressure) that causes, promotes, facilitates, or accelerates the curing or transformation of the resin.

[0033] In step 130, after the predetermined portion 41 of the mat 40 has cured, the mat 40 is then cut around the perimeter 42 of the predetermined portion 41 to create a previous or initially processed mat 40'. In addition to cutting around (i.e., at or just outside) the perimeter 42 of the predetermined portion 41, the mat may also be cut inside (i.e., within) the perimeter 42 of the predetermined portion 41, as illustrated by the holes 44 / 46 formed by cutting the composite mat at the respective perimeters 45 / 47 of the holes 44 / 46. These internal cuts may be made to "hollow out" certain portions of the composite product or to create holes, pockets, internal cavities, internal surfaces, flow channels, etc. These internal cut portions may be removed and optionally filled with material (e.g., resin, a material with a lower melting point than the resin, etc.).), or the cut sections may be left in place (not removed) to serve as "supports" for cured sections in subsequent layers on those supports (e.g., to prevent sagging). The cutting step 130 may be performed using a laser (e.g., a high-power cutting laser), a cutting wheel, a drill, a milling tool, a saw, a heat knife, an air jet, a water jet, or a similar cutting device.

[0034] In step 140, a successive mat 50 of composite material is added onto and in contact with the previously machined mat 40'. Then, in step 150, a predetermined portion 51 of the subsequent mat 50 is cured so that the predetermined portions 51 / 41 of the subsequent mat 50 and the previously machined mat 40' are bonded together. This predetermined portion 51 has a perimeter 52 that fits within the perimeter or edge 53 of the composite mat 50. Note that the areas 58, 54, and 56 are not cured and correspond to the holes 14, 16, and 18 in Fig. And in step 160, the subsequent mat 50 is cut around the perimeter 52 of its predetermined portion 51 (and optionally also within the perimeter 52 to create uncured regions 54 / 56 / 58 defined by their respective perimeters 55 / 57 / 59) to create a subsequent machined mat 50'.

[0035] Regarding the Fig. 1-3 and 6, it should be noted that layers L1, L2, and L3 can be manufactured with the predetermined portion pattern 41 of mat 40. Likewise, layers L4, L5, and L6 can be manufactured with the predetermined portion pattern 51 of mat 50, and layers L7 to L12 can be manufactured with the predetermined portion pattern 61 of mat 60. After a layer is created by selectively curing and cutting a composite mat to produce a preceding machined mat, a next / subsequent layer is created by placing an uncured / unmachined composite mat on top of the preceding / previously machined mat and then curing and cutting this next / subsequent mat.

[0036] This process is repeated layer by layer until the desired composite product is achieved.

[0037] Note that the reference numbers 40, 50, and 60 without an accent mark represent unprocessed composite mats that have not been cured or cut, while those with an accent mark (i.e., 40', 50', and 60') represent cured and cut / processed mats. The layer-by-layer construction of the composite product can proceed as follows. A first unprocessed mat 40 is positioned, cured, and cut to create a first processed mat 40', which serves as part of layer L1 of the composite product and also as the "previous" processed mat for layer L2. Then, a second (successive) unprocessed mat 40 is placed on top of the first (previous) processed mat 40', cured, and cut to create a second processed mat 40', which serves as layer L2. At this point, only two layers are complete: L1 and L2.Then, a third (consecutive) unprocessed mat 40 is placed on top of the second (previous) processed mat 40', cured, and cut to form a third processed mat 40', which serves as layer L3. Note that the first three layers L1-L3 use the same predetermined portion pattern and perimeter dimensions 41 / 42 / 45 / 47; however, layers L4-L6 use a slightly different predetermined portion pattern and perimeter dimensions 51 / 52 / 55 / 57 / 59 (i.e., these layers have a hole 58 defined by its perimeter 59, which layers L1-L3 did not have).

[0038] After producing layer L3, a fourth (successive) unprocessed mat 50 is placed on the third (previous) processed mat 40', cured, and cut to form a fourth processed mat 50', which serves as layer L4. Then, a fifth (successive) unprocessed mat 50 is placed on the fourth (previous) processed mat 50', cured, and cut to form a fifth processed mat 50', which serves as layer L5. Then, a sixth (successive) unprocessed mat 50 is placed on the fifth (previous) processed mat 50', cured, and cut to form a sixth processed mat 50', which serves as layer L6.It should be noted that for these fourth, fifth and sixth layers L4-L6, the same predetermined portion pattern and the same circumferential dimensions 51 / 52 / 55 / 57 / 59 are used; however, layers L7-L17 use a different predetermined portion pattern and the circumferential dimensions 61 / 62 / 69 (i.e., essentially only an annular region with a hole 68).

[0039] After the production of layer L6, a seventh (successive) unprocessed mat 60 with a perimeter or edge 63 is placed on the sixth (previous) processed mat 50' and cured and cut to form a seventh processed mat 60', which serves as layer L7. Then, an eighth (successive) unprocessed mat 60 is placed on the seventh (previous) processed mat 60' and cured and cut to form an eighth processed mat 50', which serves as layer L8. This process is repeated until the final layer L12 is completed.

[0040] When a successive layer or mat of composite material is positioned over the previously cured and cut layer or mat, the two mats are in contact with each other, with the predetermined portion or area of ​​the subsequent mat positioned directly on the predetermined portion or area of ​​the preceding / previously processed mat. Then, when the predetermined portion of the subsequent mat is cured, the curing resin bonds the two mats together at their predetermined portions (but does not substantially bond the mats together at other areas that are not part of the predetermined portions).

[0041] If the composite product is not yet complete in step 170, the process continues by repeating the steps of adding, curing, and cutting successive mats (steps 140 / 150 / 160) for a plurality of cycles until method 100 is completed (step 180) and a three-dimensional composite product is produced. The composite product may optionally be subjected to further processing, such as sanding, polishing, applying primers, painting, electroplating, autoclaving, drilling or cutting out parts, adding further reinforcements, and the like. For example, holes and cavities created during the layer-by-layer build according to method 100 or drilled / cut into the composite product at the end of method 100 can be filled with additional structural reinforcements (such as metal stakes pressed into holes, clamps attached to cavities, or the like).), or the holes / voids can be filled with additional resin and oriented fibers to increase the out-of-plane strength of the composite product. After a successive composite sheet is placed on top of the preceding processed sheet, the subsequent sheet can be punched or pressed with a tool at selected locations within the predetermined area of ​​the subsequent sheet to achieve "pinning" or "interpass riveting," in which the punched or pressed areas of the subsequent sheet are pressed / driven into the underlying previous sheet.

[0042] Such stamped or pressed areas may be filled with additional resin and / or structural material, as a small crack may develop there. Furthermore, after the initial cure of each layer or mat as per the aforementioned Method 100 and the completion of the layer buildup, the composite product may undergo a further curing or "post-curing" step. This can be done to increase bond strength, mechanical properties, and temperature resistance by subjecting the finished product to an elevated temperature for a specified period of time, either on the same machine used to manufacture the component or in a separate oven, autoclave, or similar.Furthermore, one or more of the mats or layers may also include one or more perforations or seams P40 / P50 / P60 formed as part of the cutting steps, wherein the perforations or seams P40 / P50 / P60 extend from the perimeter 42 / 52 / 62 of each predetermined portion 41 / 51 / 61 to the edge or boundary 43 / 53 / 63 of the respective mats 40 / 50 / 60. These perforations or seams P40 / P50 / P60 may be cut entirely or only partially through the mat 40 / 50 / 60, they may be cut in a straight or non-straight line, and they may be cut in a continuous line or in a perforated, segmented, or "dashed" line. Such P40 / P50 / P60 perforations can facilitate the separation and removal of the finished composite product 10 from the surrounding, uncured sheet layers.Although not shown in the drawings, perforations may also be introduced within the perimeter 42 / 52 / 62 of the predetermined parts 41 / 51 / 61 to facilitate the removal of the uncured inner parts of the mats 40 / 50 / 60.

[0043] Fig. 8 shows a flowchart for an additive manufacturing method 200 for producing a composite product according to another embodiment of the disclosure. In step 210, a mat of composite material is positioned, in step 220 a predetermined portion of the mat is cured, and in step 230 the mat is cut around the perimeter of the predetermined portion of the mat to create a previously machined mat. In step 240, a successive mat of composite material is added onto and in contact with the previously machined mat, and in step 250 a predetermined portion of the subsequent mats is cured such that the predetermined portions of the subsequent mats and the previously machined mats are bonded together. In step 260, the subsequent mat is cut around the perimeter of its predetermined portion to create a subsequent machined mat.If the composite product is not yet completed in step 270, the process continues by repeating the steps of adding, curing, and cutting successive mats (steps 240 / 250 / 260) for a plurality of cycles until the composite product is completed (step 280).

[0044] Before the adding step 240, an additional step 234 may be performed in which an adhesive is applied to the predetermined portion of the previously processed mat. This adhesive may be the same as the resin used in the composite mats, or it may be a different material with compatible adhesive, accelerating, or other advantageous properties. Before this adhesive application step 234, a further additional step 232 may be performed in which at least a portion of the previously processed mat that does not correspond to the predetermined portion of the mat is masked.The mask may contain openings which correspond in shape and size directly to the predetermined portion of the previously processed mats, so that when the mask is placed congruently over the previously processed mat, the predetermined portion of the previously processed mats is exposed through the openings, while the other portions of the previously processed mats are concealed (i.e., covered or masked), so that the adhesive can be applied to (and only to) the predetermined portion of the previously processed mats.

[0045] After step 240 of adding a subsequent composite mat to the previously processed mat, but before step 250 of curing a predetermined portion of the subsequent mat, an additional step 242 may be performed in which at least a portion of the subsequent mat that differs from the predetermined portion is concealed. Similar to the mask described above for step 234, the mask in step 242 may include openings that directly correspond in shape and size to the predetermined portion of the subsequent mat, such that when the mask is placed in registration over the subsequent mat, the predetermined portion of the subsequent mat is exposed through the openings while the other portions of the subsequent mat are concealed (i.e., hidden or covered).If only the predetermined portions of the subsequent mat are exposed through the openings, the curing or hardening process of step 250 may be applied to (and only to) the predetermined portion of the subsequent mat.

[0046] Between step 240 of adding a subsequent mat and step 250 of curing its predetermined portion, a further additional step 244 may be performed in which pressure is applied to at least the predetermined portion of the subsequent mat. This pressure may serve to cure the resin if it is pressure-reactive; however, even if the resin is not pressure-reactive, the applied pressure may be helpful in other ways, e.g., in the curing process if the resin is thermoreactive.

[0047] As with the previously described method 100, the cutting steps 230 / 260 of the method 200 may, in addition to cutting around the perimeter of the predetermined portion of a preceding or succeeding mat, also include cutting a mat within the perimeter of the predetermined portion of the mats (e.g., around the Fig. holes and voids shown). In addition, after the initial cure of each layer or mat as per the aforementioned Method 200 and after the layer build-up is complete, the composite product may undergo a further cure or "post-cure", either on the same machine on which the component was manufactured or in a separate oven, autoclave, or similar device.

[0048] Fig. Figure 9 shows a schematic diagram of an additive manufacturing machine 300 according to one embodiment of the disclosure. The machine 300 includes a subsystem 310 for positioning a mat of composite material, a subsystem 320 for curing a predetermined portion of the mat, and a subsystem 330 for cutting the mat around the perimeter of the predetermined portion to produce a machined mat. The machine 300 also includes a controller 350 operatively connected to the positioning subsystem 310, the curing subsystem 320, and the cutting subsystem 330.The controller 350 has logic to perform the steps of: (i) positioning a mat of composite material, (ii) curing a predetermined portion of the mat, (iii) cutting the mat around the perimeter of the predetermined portion to create a previously machined mat, (iv) adding a subsequent mat of composite material onto and in contact with the previously machined mat, (v) curing a predetermined portion of the subsequent mat such that the predetermined portions of the subsequent mat and the previously machined mat are bonded together, (vi) cutting the subsequent mat around the perimeter of its predetermined portion to create a subsequent machined mat, and (vii) repeating the steps of adding, curing, and cutting a subsequent mat for a plurality of cycles.

[0049] The positioning subsystem 310 may include automated material handling equipment. The curing subsystem 320 may include a heat source, a light source, a pressure source, and / or an activating agent source. The selection of the appropriate curing subsystem 310 depends on the curing agent or curing method required for the resin used. The cutting subsystem 330 may include a laser, a cutting wheel, a drill, a milling tool, a saw, a heat knife, an air jet, and / or a water jet.

[0050] The machine 300 may further include one or more additional subsystems 340 (depicted by the dashed lines in Fig.9). This may include a subsystem 340 for concealing at least a portion of a selected composite mat that is not the predetermined portion of such mat, wherein the controller 350 is operatively connected to the concealing subsystem and has logic for performing the steps of (viii) concealing at least a portion of a selected composite mat that is not the predetermined portion of such mat, and (ix) repeating the concealing step for a plurality of cycles. The machine 300 may also include a means for positioning the composite mats in multiple orientations. This may be particularly useful when using composite mats in which the fibers or structural components are arranged substantially unidirectionally, thereby allowing a variety of fiber directions to increase the strength of the resulting product.This can be accomplished by the positioning subsystem 310 or as a separate subsystem 340, and can include a build platform or mat that rotates about the (vertical) Z-axis, or the subsystem that positions the composite mats could rotate about the build platform or mat. The machine can also include a subsystem 340 for post-curing the composite product after layer buildup is complete, which can include an array of heating elements along with insulated walls to contain the heat generated by the heating elements. If additional subsystems 340 are provided, the controller 350 is operatively connected to each subsystem 340 and includes logic for controlling and / or executing the activity associated with each subsystem 340.

[0051] Each of the subsystems 310 / 320 / 330 / 340 is adapted to interface and communicate with the controller 350 to perform the process described above (which may be similar to the methods 100 / 200 described previously in this communication). The control logic for performing the aforementioned steps may be any suitable combination of hardware, software, and / or firmware.

[0052] The methods 100 / 200 and machine 300 described above, as well as the composite products produced thereby, offer numerous advantages over previously known 3DP / AM processes, machines, and products. For example, the methods 100 / 200 and machine 300 can use commercially available prepreg sheets (containing resin) or "dry" sheets (consisting only of structural material and containing no resin) to create each layer, whereas other 3DP / AM approaches do not use sheets of composite material but rely on a very large number of small, individual depositions to create each layer. Therefore, the cost of the raw material and the time required to produce each layer are greatly reduced for the methods 100 / 200 and machine 300 of this disclosure compared to other known approaches. Furthermore, the range of materials that can be used for the methods 100 / 200 and machine 300 (e.g.,Carbon fiber, aramid, bamboo, polyester, etc., as well as various resin systems / curing methods), as well as the arrangement and format of the structural material of the composite mats (e.g., unidirectional fibers, multidirectional fibers, woven fabrics, tapes, braids, weaves, mats, etc.) are much larger than in other known approaches.

[0053] The above description is intended to be illustrative and not restrictive. While various specific embodiments have been presented, those skilled in the art will recognize that the disclosure may be practiced with various modifications within the spirit and scope of the claims. For example, the above-described embodiments (and / or aspects thereof) may be used in combination with one another. Furthermore, many changes may be made to adapt a particular situation or material to the teachings of the disclosure without departing from the scope of the disclosure. The dimensions and types of materials described herein, while intended to be illustrative, are by no means restrictive or exemplary. Many other embodiments will be apparent to one skilled in the art upon review of the above description.Furthermore, in the following claims, any use of the terms "first," "second," "upper," "lower," etc., is used merely as a label and is not intended to impose any numerical or positional requirements on its objects. Further, the limitations of the following claims are not written in a "means plus function" or "step plus function" format, nor are they intended to be interpreted as such, unless and until such claim limitations expressly use the phrase "means for" or "step for" followed by an explanation of the function without further structure. As used herein, an element or stage recited in the singular and preceded by the word "a" or "an" is to be understood as not excluding the plural of such elements or stages unless such exclusion is expressly stated.Furthermore, references to a particular embodiment or example should not be construed to preclude the existence of additional embodiments or examples that also include the recited features. Furthermore, unless expressly stated otherwise, embodiments that "include" or "have" an element or a plurality of elements with a particular property may include additional elements that do not have that property.

[0054] The flowcharts and block diagrams included in the figures illustrate the architecture, functionality, and / or operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this context, each block in the flowchart or block diagrams may represent a module, segment, or portion of code containing one or more executable instructions for implementing the specified logical function(s).

[0055] It should also be understood that each block of the block diagrams and / or flowchart illustrations, as well as combinations of blocks in the block diagrams and / or flowchart illustrations, may be implemented by special-purpose hardware-based systems that perform the specified functions or acts, or combinations of special-purpose hardware and computer instructions. These computer program instructions may also be stored on a computer-readable medium capable of instructing a controller or other programmable data processing device so that the instructions stored on the computer-readable medium produce an article of manufacture containing instructions for performing any of the functions and / or acts specified in the flowcharts and block diagrams.

[0056] This written description uses examples, including preferred embodiments, to enable those skilled in the art to make and use devices, systems, compositions of matter, and methods according to this disclosure. It is the following claims, including all equivalents, that define the scope of the present disclosure.

Claims

[1] An additive manufacturing process (100) comprising: Positioning (110) a mat (40) made of composite material; Curing (120) a predetermined portion (41) of the mat (40); Cutting (130) the mat (40) over the circumference (42) of the predetermined part (41) to produce a previously machined mat (40'); adding (140) a subsequent mat (50) of composite material on and in contact with the previously processed mat (40'); Curing (150) a predetermined portion of the subsequent mat (50) so that the predetermined portions of the subsequent mat (50) and the previously processed mat (40') are bonded together; and Cutting (160) the subsequent mat (50) around the periphery of its predetermined portion (41) to produce a subsequent machined mat, further comprising: Repeating (170) the steps of adding, curing and cutting a subsequent mat for a plurality of cycles, further comprising, prior to the step of adding: Applying (234) an adhesive to the predetermined portion of the previously processed mat, further comprising, prior to the step of applying (234): Covering (232) at least a part of the previously processed mat (40') which does not correspond to the predetermined part (41), wherein each curing step (150) comprises directing heat, light, pressure and an activating agent onto the respective predetermined part (41), in which each cutting step is carried out by an air jet, wherein at least one of the cutting steps (160) further comprises: Cutting within the circumference of the predetermined part (41). [2] A method (100) according to claim 1, further comprising, prior to the step of curing a predetermined portion of the subsequent mat (40'): Covering at least a part of the subsequent mat (40') that does not correspond to the predetermined part (41). [3] A method (100) according to claim 1, further comprising, prior to the step of curing (150) a predetermined portion (41) of the subsequent mat (40'): Applying pressure to at least the predetermined part (41) of the subsequent mat (40'). [4] A method (100) according to claim 1, wherein the composite material comprises an X+Y structural component / resin combination, wherein the structural component X is at least one of carbon fiber, aramid, bamboo, and glass fiber, and the resin Y is at least one of a thermo-reactive material, a photo-reactive material, a pressure-reactive material, and a chemically reactive material.

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