System, method and part for additive manufacturing

Abstract

The invention relates to a system for additive manufacturing by means of continuous lamination, which comprises at least one unrolling device (1) that provides material continuously to at least one conveyor unit (3); at least one laser cutting unit (2) designed to make cut-outs as the material is conveyed, in accordance with the geometry of a three-dimensional part (10) to be obtained, producing at least one inner cut-out (2.2) and / or one outer cut-out (2.1) from the material of the reel (1.1). The laser cutting unit (2) comprises at least one head (2.4) with a system of galvanometers that direct a beam of light in accordance with a predefined shape of the cut-out (2.1, 2.2) to be made, and at least one manipulation module (4) towards which the inner cut-outs (2.2) and / or outer cut-outs (2.1) move, wherein the manipulation module (4) is configured to stack the inner cut-outs (2.2) and / or the outer cut-outs (2.1) to form the three-dimensional part (10).

Description

[0001]

[0002] ADDITIVE MANUFACTURING INSTALLATION, METHOD AND PART

[0003] TECHNICAL SECTOR

[0004] The present invention is related to the additive manufacturing industry, and more specifically to the additive manufacturing industry by stacking sheets of material.

[0005] BACKGROUND OF THE INVENTION

[0006] Currently, additive manufacturing processes for parts by stacking sheets of material, whether of natural fibers, metals, or plastic, are widely known.

[0007] This manufacturing method is one of the 7 types defined by ISO / ASTM 52900-2015 as an additive manufacturing process.

[0008] Its objective is the construction of a 3D part by stacking and laminating thin sheets of material.

[0009] Within the additive manufacturing process of stacking and laminating paper sheets, there is a process known as LOM (Laminated Object Manufacturing). This technique is generally used for prototyping, where sheets of material, typically cellulose coated with adhesive, plastic, or metal laminates, are cut with a blade or laser and glued together successively.

[0010] Documents such as European patent EP3341183B1 disclose a method for manufacturing a three-dimensional object from a stack of pre-cut substrate layers. The layers of the stack are then joined together to construct the three-dimensional object.

[0011] Another document, US2015251351 A1, describes an apparatus and method of manufacture for an integral three-dimensional object of unlimited complexity formed from individually contoured laminations (layers) produced from thin sheet materials.

[0012] This technology requires a support material onto which the sheet is attached, and the cutting of said geometry is performed with the sheet fixed in the cutting position.

[0013] Despite the aforementioned state of the art, the reality is that this type of manufacturing remains very manual, and there is currently no industrialized manufacturing process in which continuous automated production takes place.

[0014] Given the described disadvantage or limitation of existing solutions, a solution is needed that allows the additive manufacturing technique to be implemented by stacking and laminating sheets of material, while providing an industrialized system for the application of this technology in different industries and sectors.

[0015] EXPLANATION OF THE INVENTION

[0016] In order to achieve this objective and solve the technical problems discussed so far, as well as provide additional advantages that may arise later, the present invention provides a continuous lamination additive manufacturing installation, which comprises:

[0017] - at least one unwinder configured to continuously supply material arranged on a reel to at least one transport unit;

[0018] - at least one laser cutting unit configured to perform cuts during material transport according to the geometry of a three-dimensional part to be obtained, obtaining at least one internal and / or one external cut of the coil material. The laser cutting unit consists of a plurality of light beams distributed transversely to the material transport direction and in a fixed position with respect to that direction; therefore, each light beam is independently orientable during material transport according to a predefined shape of the cut to be made; and

[0019] at least one manipulation module to which the inner and / or outer cutouts are moved, where the manipulation module is configured to stack the inner and / or outer cutouts to form the three-dimensional part.

[0020] Depending on the installation requirements, there is a transport unit and a handling module for processing the external trim and another transport unit with its handling module for the internal trim, on different production lines. This three-dimensional part, according to the alternatives described below, can be a finished piece, a mold, or a preform ("prepreg").

[0021] Thanks to this configuration, manufacturing is automated, resulting in high-speed processing, increased productivity, and the elimination of errors caused by the current manual process. Additionally, it provides flexible, continuous manufacturing that accommodates new batches and different part numbers on the fly, without the need for downtime as required by the current state of the art. This allows for the large-scale production of complex, three-dimensional objects with high dimensional accuracy. An example of its application would be the manufacture of prefabricated partition walls.

[0022] Preferably, the installation comprises at least one application unit configured for applying adhesive to the inner and / or outer cutouts for subsequent consolidation of the formed three-dimensional part, or for impregnating the material with resin for subsequent curing.

[0023] This process is carried out depending on the material on the roll, which is preferably a natural fiber. For example, if the material is cellulose, adhesive is applied, and the scraps are then stacked and consolidated to form the piece. This application is preferably done using rollers that apply adhesive to the underside before stacking.

[0024] On the other hand, if the material used is a natural, non-cellulosic fiber, the offcuts are impregnated with resin, after which a pre-curing process is carried out, resulting in a "prepreg" that will subsequently be fully consolidated. For this purpose, it is preferable to keep the prepreg in a refrigerated cabinet to maintain the pre-curing reaction until pressing. The adhesive is applied automatically in the required amount, and a strong piece is obtained after consolidation, as correct application is ensured. If non-cellulosic materials are used in the process, instead of adhesive, the necessary resin is applied according to the type of material and the intended use of the final piece, resulting in stronger pieces.

[0025] According to one feature of the invention, the installation comprises at least one consolidation module configured to apply pressure and / or temperature to the stack of scraps to form the three-dimensional part. In this way, the pressure and / or temperature can be controlled according to the intended use of the part, the amount of adhesive or resin applied, and the material used.

[0026] According to an alternative of the invention, the consolidation module comprises at least one support base for the stack of offcuts. This base can be either the lower support base or the upper pressing base, and it has a predefined geometry so that the resulting three-dimensional piece adopts this geometry after pressure is applied. This allows for easier creation of complex configurations by combining complex geometries obtained from the offcuts with external shapes.

[0027] According to another feature of the invention, the inner and outer cutouts are joined by predetermined micro-joints created by the laser cutting unit during the cutting process, for subsequent separation once stacked. Therefore, they pass through the other modules of the installation together, that is, the bonding and handling modules, so that once stacked, before the inner, outer, or both cutouts are consolidated, they are separated. This ensures alignment, preventing irregularities or the need for subsequent machining of the resulting three-dimensional part.

[0028] Additionally, the laser cutting unit is configured to make the cuts that will form the three-dimensional part according to different orientations with respect to the transport direction. The handling module is configured to rotate the inner and / or outer cuts to stack them in a way that aligns their geometry. Preferably, this handling will be performed by a vision-equipped robot. This method, especially when using natural fiber as the material, allows the fibers of the sheets to interlock, providing greater strength to the final part and compensating for any thickness variations that may exist between different points along the width of the material coming from the roll.

[0029] According to another feature of the invention, the installation comprises a circuit printing unit configured to print circuits on the upper or lower surface of the inner cutouts and / or on the outer cutouts before stacking. In this way, the final part comprises circuits located in intermediate zones of the stack or in final layers, depending on their function within the part.

[0030] This results in a three-dimensional part, as described, which incorporates one or more circuits that provide different functionalities depending on the circuit printed on its cutouts. Examples of circuits used include resistors for heating the part or electrical circuits for providing specific functionalities, resulting in factory-integrated sensorized products.

[0031] According to another aspect of the invention, a method for manufacturing a three-dimensional part is contemplated, comprising having a material that is continuously supplied to the installation from a coil, cutting the material by means of a laser cutting unit during simultaneous displacement of said material, obtaining at least one inner and / or one outer cutout, which are transferred by at least one transport unit to a handling module configured to stack the inner and / or outer cutouts in alignment, passing previously through an adhesive or resin application unit to form at least one stack that is finally consolidated in a consolidation module in a consolidation stage by applying pressure and / or heat for the formation of the three-dimensional part.

[0032] According to another aspect, the invention also contemplates a method of consolidating external cutouts for the manufacture of a three-dimensional part by means of an additive manufacturing installation by lamination where, the external cutouts are stacked in alignment, having previously in the cutting stage made holes to house fixing means, fixing the stack between two bases and by adjusting the fixing means they exert pressure for the generation of the three-dimensional part.

[0033] The invention also contemplates a three-dimensional piece obtained by the method described above, where said final three-dimensional piece has mold functions.

[0034] Thanks to this configuration, the consolidation method is reversible, that is, by simply removing the fixing means, it gives the final piece versatility in terms of being able to add cutouts and modify the height of the piece or even allows the change of a part of the piece if it has been damaged with use, such as due to the degradation derived from its use as a mold, or if it is desired to change its geometry.

[0035] BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 shows a schematic view of an installation with a manufacturing line for generating external cutouts to obtain a three-dimensional part.

[0037] Figure 2 shows a schematic view of an installation with a manufacturing line for generating internal cutouts to obtain a three-dimensional part.

[0038] Figure 3 shows a schematic view of the steps for generating interior and exterior cutouts in the same installation.

[0039] Figure 4 shows a schematic view of an installation comprising two independent lines, one for the outer cutouts, and one for the inner cutouts.

[0040] Figure 5 shows the practical implementation of Figure 4 in a plan view.

[0041] Figure 6 shows an alternative implementation of a method for consolidating the cuts.

[0042] Figure 7 shows a cross-sectional view of the embodiment of Figure 6.

[0043] PREFERRED EMBODIMENT OF THE INVENTION

[0044] The figures correspond to a non-limiting example of practical implementation and variations may occur in the configuration of the complement as long as the essence of it is not altered, which is to have an installation for additive manufacturing by continuous lamination of three-dimensional parts.

[0045] Thus, according to a first embodiment of the invention, as shown in Figure 1, the installation comprises an unwinder (1) from which material is continuously supplied from a reel (1.1) to a laser cutting unit (2). According to an alternative design, the unwinder (1) could incorporate a splicer (manual or automatic) for joining the end of material from one reel (1.1) to the beginning of another, allowing for a constant supply of material and preventing interruptions during reel reloading.

[0046] The material supplied in coil form (1.1) is preferably a natural fiber material, more preferably a cellulosic material but materials such as linen or jute are also applicable.

[0047] The material is fed to the laser cutting unit (2). This laser cutting unit (2) comprises at least one cutting head (2.4) and preferably a plurality of heads arranged transversely to the material feed direction. Preferably, it consists of a dynamic laser cutting unit with a wavelength of 10.6 micrometers and an effective power of approximately 1000-1200 W, configured to perform real-time cuts as the material advances via a transport unit (3). These cuts precisely reproduce the geometry defined by the system's software, which, through control means, determines the perimeter and surface area of ​​each layer of the final three-dimensional part (10), in this case defining an external cutout (2.1). These control means regulate the unwinding speed and adjust the cutting speeds of the cutting unit (2) accordingly.

[0048] To increase the effective working width and better synchronize with the material feed speed, this laser cutting unit (2) can be equipped with more than one laser head (2.4). Each head (2.4) preferably incorporates a galvanometer system (galvanometric mirrors) that directs the laser and allows for precise cuts in an effective area of ​​up to 500 x 500 mm, so that the installation is expected to be able to automatically cut a 3000 x 6000 mm sheet to the shape corresponding to its respective pre-designed specifications. Additionally, longitudinal cuts in the material feed direction can be made with rotating mechanical blades. Preferably, as shown in Figure 1, the cutting unit (2) that performs the outer cutouts (2.1) is configured to leave micro-joints between these cutouts (2.1) to displace the inner cutouts to be discarded along with the outer cutouts (2.1).These micro-joints are maintained until reaching a consolidation unit (6) in which, before carrying out said consolidation operation, the stack of outer cuttings (2.1) is separated from the stack of inner cuttings to be discarded.

[0049] For transporting the material after cutting, the transport unit (3) is configured to move the outer offcuts (2.1) through the installation by means of the material margins (2.3) generated by the longitudinal cut. Preferably, these material margins (2.3) pass through guides (3.3) of the transport unit (3) in the form of at least two wheels, upper and lower, through which the material margins (2.3) pass, causing the offcut material to advance continuously to a collection reel.

[0050] In an alternative embodiment, the transport unit (3) consists of a material conveyor belt.

[0051] Subsequently, the outer cutouts (2.1), in sheet form, reach the handling module (4) for stacking. Before this stage, the outer cutouts (2.1) pass through an application unit (5) where adhesive, preferably water-based, is applied. Preferably, the application unit (5) comprises adjustable rollers and a glue reservoir. For its operation, the glue is poured into the reservoir, and one of the rollers is positioned flush with the glue level to become coated with it. To control the amount and uniformity of glue applied to the sheet, the distance between the applicator roller and the coated roller in the reservoir is adjusted. In this way, the sheets of outer cutouts (2.1) collected by the handling module (4) pass through, touching the applicator roller on their underside, before being stacked.

[0052] According to an alternative embodiment, the material supplied by the unwinder (1) is intended to already include the adhesive.

[0053] Thus, once the adhesive is applied, the outer cutouts (2.1) reach the handling module (4). This module is configured to stack the outer cutouts (2.1) in an aligned manner. As can be seen in Figure 1, this handling module (4) will preferably be a vacuum stacking system composed of longitudinal beams, each with an orthogonal geared motor, and vacuum suction cups positioned at a preferred distance of 300 mm. In this way, the movements of each motor are synchronized so that certain rows suction the outer cutouts (2.1), while the other rows deposit the previously suctioned sheet onto the stacking table, and so on simultaneously after each passage of the outer cutout sheet (2.1). In Figure 1, the beams can be seen in the initial suction position and the final stacking position.

[0054] Once the complete stack is obtained, the final stage of shaping the three-dimensional part (10) is carried out in a consolidation module (6). Preferably, this consolidation module (6) is a pressing system capable of ensuring that the glued and stacked outer cutouts (2.1) acquire sufficient consistency to subsequently meet mechanical requirements. The consolidation module (6) is comprised of a press with a specific compressive force that compacts the stacked and glued outer cutouts together to form the final three-dimensional part (10).

[0055] According to a second alternative embodiment, as can be seen in figure 2, in this case the cutting unit (2) performs the cut in such a way that some internal cuts are generated (2.2), with the external cuts being discarded.

[0056] In this case, the transport unit (3) is in the form of a conveyor belt that carries the inner cutouts (2.2) to the application unit (5) for adhesive application, subsequent stacking, and final consolidation in the consolidation module (6). This is a practical example of an inner cutout (2.2), but the features of the first embodiment are also applicable.

[0057] According to another alternative embodiment, the cutting is carried out according to different orientations with respect to the transport direction so that the three-dimensional piece (10) formed by a plurality of cutouts (2.1, 2.2) is as strong and homogeneous as possible. This configuration ensures that the fibers of a cutout (2.1, 2.2) interlock during the consolidation process, as they have different directions relative to each other, and compensates for any thickness differences that may exist between different points of the width of the material coming from the reel (1.1). According to another alternative embodiment, the inner cutouts (2.2) of Figure 2 are made of a natural non-cellulosic fiber material. These inner cutouts (2.2) pass through the application unit (5), where resin is applied to obtain a pre-impregnated material, optionally with the application of heat using heated rollers to achieve pre-curing.Thus, a stack of interior cutouts (2.2) of pre-cured composite is obtained, which form the three-dimensional piece (10) that will be stored in an isothermal storage system for its final curing.

[0058] According to another alternative embodiment, the interior cuts (2.2) in their consolidation stage can form different geometries when applying pressure with bases of predefined geometry.

[0059] Figure 3 shows an example of micro-joints, where starting from a sheet of the coil (1.1) the cuts are made with micro-joints, obtaining some outer cuts (2.1), and some inner cuts (2.2), which will later be stacked and consolidated separately.

[0060] In another preferred embodiment, as shown in Figures 4-5, the cutting unit (2) makes the complete cut between the inner cutouts (2.2) and the outer cutouts (2.1). In this way, once separated, they continue along independent lines within the installation.

[0061] According to another preferred embodiment, as shown in Figure 6, the external cutouts (2.1) do not pass through the application unit (5). In this case, either in the cutting unit (2) or subsequently, a plurality of holes (13) are made to accommodate fastening means (11). These fastening means (11) preferably secure the stack between two bases (12) that are fitted above and below the stack as lids. By adjusting the fastening means (11), the necessary pressure is applied for the consolidation and generation of the three-dimensional part (10), as shown in Figures 3 and 4.

[0062] These three-dimensional pieces are preferably used as molds, as can be seen in Figure 7, which shows a cross-section of the generated three-dimensional piece (10). This provides great versatility because, since permanent consolidation is not required, the fixing means (11) can be removed, allowing modifications to the three-dimensional piece (10), for example, in its height or geometry, and also permitting the replacement of one or more cutouts (2.1) or sheets if these have been damaged by use.

[0063] Finally, and to give the three-dimensional piece greater functionality, the installation includes a circuit printing unit (not shown in the figures) configured to print on the cutouts (2.1, 2.2) before stacking.

[0064] The printed circuits in the cutouts (2.1, 2.2) are of the resistor circuit type to heat the three-dimensional piece (10) or electronic circuit that allows the piece to have different functionalities depending on its intended use.

Claims

CLAIMS 1.- Installation for additive manufacturing by continuous lamination, comprising: - at least one unwinder (1) configured to supply material arranged on a reel (1.1), continuously, to at least one transport unit (3); - at least one laser cutting unit (2) configured to perform cuts during the transport of the material in the transport unit (3), according to the geometry of a three-dimensional part (10) to be obtained, obtaining at least an inner cut (2.2) and / or an outer cut (2.1) from the material of the coil (1.1), said laser cutting unit (2) comprising at least one head (2.4) with a galvo system that directs the light beam and allows precise cuts to be made, the light beam being orientable during the transport of the material according to a predefined shape of the cut (2.1, 2.2) to be made; and at least one manipulation module (4) towards which the inner cutouts (2.2) and / or outer cutouts (2.1) are moved, wherein the manipulation module (4) is configured to stack the inner cutouts (2.2) and / or outer cutouts (2.1) to form the three-dimensional part (10).

2. Installation according to claim 1, comprising at least one application unit (5) configured for applying adhesive to the inner cutouts (2.2) and / or outer cutouts (2.1) for subsequent consolidation of the formed three-dimensional piece (10), or for applying resin for impregnation of the material for subsequent curing.

3. Installation according to claim 2, comprising at least one consolidation module (6) configured to apply pressure and / or temperature to the stack of cutouts (2.1, 2.2) to form the three-dimensional piece (10).

4. Installation according to claim 3, wherein the consolidation module (6) comprises at least one base (6.1) for supporting the stack of cutouts (2.1, 2.2) with a predefined geometry so that the three-dimensional piece (10) obtained after applying pressure adopts said geometry.

5. Installation according to any one of the preceding claims, wherein the inner cutout (2.2) and the outer cutout (2.1) are joined by means of predetermined micro-joints generated by the laser cutting unit (2) during the making of the cutouts (2.1, 2.2), for their subsequent separation once stacked.

6. Installation according to any of the preceding claims, wherein the material disposed on the reel (1.1) is a natural fiber material.

7. Installation according to any of the preceding claims, wherein the laser cutting unit (2) is configured to make the cuts (2.1, 2.2) that will form the three-dimensional piece (10) according to different orientations with respect to the transport direction, the handling module (4) being configured to rotate the inner cut (2.2) and / or outer cut (2.1) to stack the cuts coincidentally according to their geometry.

8. Installation according to any of the preceding claims, comprising a circuit printing unit configured to print circuits on the inner cutouts (2.2) and / or on the outer cutouts (2.1) before stacking.

9. Installation according to any of the preceding claims, comprising an independent line for each cut (2.1, 2.2) where after the cut is made the outer cut (2.1) is moved by a first transport unit (3.1) and the inner cut (2.2) falls into a second transport unit (3.2). 10.- Method for manufacturing a three-dimensional part (10) by means of an additive manufacturing installation by lamination according to any one of the preceding claims, comprising having a material that is continuously supplied to the installation from a coil (1.1), cutting the material by means of a laser cutting unit (2) during the simultaneous displacement of said material, obtaining at least one inner cutout (2.2) and / or one outer cutout (2.1), which are transferred by at least one transport unit (3) to a handling module (4) configured to stack the inner cutouts (2.2) and / or outer cutouts (2.1) in alignment, having previously passed through an adhesive or resin application unit (5) to form at least one stack which is finally consolidated in a consolidation module (6) in a consolidation stage by applying pressure and / or heat for the formation of the three-dimensional part (10). 11.- Method of consolidating external cutouts (2.1) for the manufacture of a three-dimensional part by means of an additive manufacturing installation by lamination according to any one of claims 1, 6, 7 and 8, comprising stacking the external cutouts (2.1) in alignment and making holes in the external cutouts (2.1), housing in said holes some fixing means (11), fixing the stack between two bases (12) which by means of the adjustment of the fixing means (11) exert pressure for the generation of the three-dimensional part (10). 12.- Three-dimensional part (10) obtainable by the manufacturing method according to the previous claim wherein the final three-dimensional part (10) has mold functions with replaceable sheets. 13.- Three-dimensional piece (10) obtainable by installation according to claim 9.

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