Laser patterning embedded sheet

Abstract

The apparatus includes a laser, a clamp, and a workpiece positioner. The laser is operable as a pulsed laser for cutting the sheet. The clamp is displaceable relative to a work zone of the apparatus. The workpiece positioner is configured to support the workpiece within the work zone with the workpiece. During a bonding stage, the clamp and workpiece positioner are operable to cooperatively press the sheet and workpiece toward each other, and a selective bond between the sheet and the workpiece is formed during the bonding stage. During a cutting stage, the clamp is displaceable away from the work zone to allow the laser to cut the sheet along a perimeter of the selective bond.

Description

[Technical Field]

[0001] Related Applications This application claims the benefit of priority to Singapore Patent Application No. 10202300437T, filed on February 20, 2023, the contents of which are incorporated herein by reference in their entirety for all purposes.

[0002] Technical Field FIELD OF THE DISCLOSURE The present disclosure relates to laser-based manufacturing methods and apparatus, and products made by the laser-based manufacturing methods and apparatus. [Background technology]

[0003] Lightening the weight of components, or lightweighting, is one important method for sustainable energy use. Lightweighting is a challenge. This is especially true in applications where strength and safety are key requirements. The selection of raw materials, shape, and dimensions are chosen to meet safety requirements. For example, lightweight replacements for many components in aircraft, automobiles, buildings, etc. must be as strong as the original, conventionally manufactured components. The number of materials with the required strength-to-weight ratio is limited. Using lighter materials may not meet the strength and safety requirements. An alternative is to consider using hollow structures (such as honeycomb structures) to replace solid structures. Hollow structures are traditionally more difficult to manufacture. Mass production of such hollow structures presents an additional technical challenge. Summary of the Invention [Means for solving the problem]

[0004] In one aspect, the present application discloses an apparatus comprising a laser, a clamp, and a workpiece positioner. The laser is operable as a pulsed laser for cutting a sheet. The clamp is displaceable relative to a work zone of the apparatus. The workpiece positioner is configured to support the workpiece within the work zone. During a bonding stage, the clamp and the workpiece positioner are operable to cooperatively press the sheet and the workpiece toward each other, forming a selective bond between the sheet and the workpiece during the bonding stage. During a cutting stage, the clamp is displaceable away from the work zone to allow the laser to cut the sheet along a periphery of the selective bond.

[0005] In another aspect, the present application discloses a method including, in a bonding step, simultaneously forming a selectively bonded portion between the sheet and the workpiece, cooperatively forcing the sheet and a first surface of the workpiece between a clamp and a workpiece positioner, displacing the clamp away from the work zone, and, in a cutting step, laser cutting along a periphery of the selectively bonded portion.

[0006] In yet another aspect, the present application discloses an article comprising an array of cells, each of the cells comprising at least one cell wall defining an interior space, the at least one cell wall comprising multiple layers bonded together using any embodiment of the method described above. [Brief explanation of the drawings]

[0007] [Figure 1] 1A through 1G schematically illustrate manufacturing methods according to some embodiments of the present disclosure. [Figure 2] 2A to 2G schematically illustrate a method according to another embodiment of the present disclosure. [Figure 3] 3A to 3E schematically illustrate a method according to yet another embodiment of the present disclosure. [Figure 3F] FIG. 3C is a schematic diagram of a top view of an article made according to the method of FIGS. 3A-3E. [Figure 4A] FIG. 10 is a top view of the clamp plate. [Figure 4B] 1 is a perspective view of an apparatus according to various embodiments of the present disclosure. [Figure 4C] FIG. 4C is an enlarged perspective view of a portion of FIG. 4B. [Figure 5A] 1 is a perspective view of an apparatus according to various embodiments of the present disclosure. [Figure 5B] FIG. 5B is an enlarged perspective view of a portion of FIG. 5A. [Figure 6A] 1A-1D are schematic diagrams of apparatuses at various steps of methods according to some embodiments of the present disclosure. [Figure 6B] 1A-1D are schematic diagrams of apparatuses at various steps of methods according to some embodiments of the present disclosure. [Figure 6C] 1A-1D are schematic diagrams of apparatuses at various steps of methods according to some embodiments of the present disclosure. [Figure 7] 10 is a schematic diagram of a portion of an apparatus according to another embodiment. [Figure 8] 10 is a schematic diagram of a portion of an apparatus according to yet another embodiment. [Figure 9] 10 is a schematic diagram of a portion of an apparatus according to another embodiment. [Figure 10] 10 is a schematic diagram of a portion of an apparatus according to another embodiment. [Figure 11] 10 is a schematic diagram of a portion of an apparatus according to yet another embodiment. [Figure 12] 10A-10C are schematic diagrams illustrating bonding steps according to an alternative embodiment of the present disclosure. [Figure 13] 5A-5C are schematic diagrams illustrating bonding steps according to another embodiment. [Figure 14] FIG. 1 is a schematic diagram showing an example of rotary friction welding. [Figure 15] FIG. 1 is a schematic diagram showing an example of translational friction welding. [Figure 16] 1 is a perspective view of an article that can be made using the apparatus. [Figure 17]1 is a perspective view of an article that can be made using the apparatus. [Figure 18] 18A and 18B show perspective and top views of an article made using the apparatus. [Figure 19] Figures 19A through 19E are images of articles made using the device. [Figure 20] 1 shows an image of the test specimen used in the tensile strength test. DETAILED DESCRIPTION OF THE INVENTION

[0008] The following detailed description is made with reference to the accompanying drawings, which illustrate, by way of example, details and embodiments of the present disclosure. Features described in the context of an embodiment may be applicable to the same or similar features of other embodiments, even if not explicitly described therein. Additional and / or combinations and / or alternatives to features described in the context of an embodiment may be applicable to the same or similar features of other embodiments.

[0009] The term "and / or" includes any and all combinations of one or more of the associated listed items.

[0010] The terms "about" and "approximately" as applied to a stated numerical value encompass the exact value and a reasonable variance, and the terms "generally" and "substantially" should be understood equivalently unless otherwise specified. For example, in the context of various embodiments, the term "about" or "approximately" as applied to a stated numerical value will generally be understood by those skilled in the art to encompass the exact value and a reasonable variance as commonly understood in the relevant art, e.g., within 10% of the specified value.

[0011] The word "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. As used herein, the singular forms "a," "an," and "the" may be construed to include the plural "one or more" unless the context clearly indicates otherwise.

[0012] Terms such as "first" and "second" are used in the description and claims for brevity and clarity only and do not necessarily imply a priority or order unless required by context.

[0013] Some methods may be described as steps merely to aid in understanding and / or for convenience of reference. Distinctions between one step and another may be for convenience of reference in this disclosure only. It will be understood that in actual implementations, there may not be a clear division or transition from one step to another subsequent step. There may be some overlap between steps, and / or two or more steps may occur or be performed concurrently in time.

[0014] A three-dimensional (3D) array of repeating units or cells can collectively form a larger article having one or more hollow interior spaces, such that the article is relatively lighter in weight than a fully solid article of similar size. A natural example of such a 3D array is a beehive. Each unit in a 3D array can be described as a closed or partially closed cell. For simplicity, as used herein, unless otherwise specified, the term "cell" refers to any type of cell in a 3D array, including, but not limited to, closed and partially closed cells. Similarly, the term "cell" can refer to any or a combination of multiple closed and / or partially closed cells.

[0015] As used herein, the term "closed cell" or "isolated pore" may refer to a unit having one or more walls that completely enclose an interior space (isolated space), which is not in fluid communication with the exterior of the unit. The interior spaces of two immediately adjacent closed cells are not in fluid communication with each other.

[0016] As used herein, the term "partially closed cell" refers to a unit having one or more struts and / or walls that partially define an interior space, the interior space being in fluid communication with the exterior of the unit. For example, a partially closed cell may be described as having a cell with an opening in its wall. For example, the interior spaces of two immediately adjacent partially closed cells may be in fluid communication with each other and / or with the interior spaces of other partially closed cells. In some cases, multiple partially closed cells may define one or more complex channels.

[0017] Arrays of cells, such as honeycomb-like structures, are useful in a wide range of applications. Using conventional methods, fabricating arrays of cells to the required strength can be challenging. For example, traditional additive manufacturing methods such as extrusion can build cells by extruding a viscous extrudate and depositing it onto previously deposited layers of material. The deposited layers are then cured (e.g., polymer extrudates) or sintered (e.g., ceramic or metal extrudates) to solidify the extrudate. Sintered cells typically lack the strength required for high-performance engineering applications, such as aerospace components, or the durability required for applications in harsh environments.

[0018] Another conventional method that can be used to build layered structures is sheet lamination. The strength of the finished product depends on the strength of the adhesion and / or bonding between the layers. For example, the tensile yield strength achievable using conventional laser foil printing of 304 stainless steel is reportedly about 632 MPa (megapascals), which may not meet the requirements of some high-performance engineering applications.

[0019] While various techniques theoretically allow for the creation of closed cells, it is even more difficult to ensure that the interior spaces are free of powder or cutouts. 3D arrays of cells and complex channels are particularly difficult to mass-produce in a continuous or fully automated process. Some methods inevitably result in precursor material being trapped in the interior spaces of the cells or complex channels. Even in the case of partially closed cells or complex channels, it would be difficult to completely remove such trapped material from the 3D array of partially closed cells, even if the production was interrupted to manually remove the trapped material within the cells.

[0020] Embodiments of the method and apparatus of the present invention are described to illustrate the ability to form cells of various shapes and sizes that address the technical problems faced by conventional methods.

[0021] 1A through 1G schematically illustrate various steps in a manufacturing method or process 200 according to an embodiment of the present disclosure.

[0022] 1A illustrates a setup step 201 in which a partially formed workpiece 110 is provided to a work zone 440. A sheet 130 in the form of a solid sheet is provided in the work zone 440 in a feed direction 811 (e.g., interchangeably referred to as being displaced along a first axis 401 810). For clarity, the sheet 130 is illustrated as a discrete, planar portion, although the sheet 130 may be part of a continuous roll of material. Illustratively, the workpiece 110 is shown with a wall 112 defining an open cavity 170. The workpiece 110 may be constructed using additive manufacturing techniques, including the method 100 of the present invention.

[0023] 1B illustrates step 202 of aligning sheet 130 with first surface 111 of workpiece 110, e.g., a solid sheet or sheet 130 aligned with open cavity 170 of workpiece 110. Workpiece 110 may be pushed in push direction 821 (along second axis 820) toward sheet 130.

[0024] FIG. 1C illustrates a bonding step (bonding step) 203. In this example, the bonding step includes laser welding, in which the sheet 130 is laser welded while under tension. For example, the sheet 130 may be stretched or pulled by opposing pulling directions 851 / 852 (e.g., along a pulling axis 850) so that the sheet 130 is flat or substantially flat to minimize or reduce creases or warping. The pulling axis 850 and the feed axis 810 may be parallel to and coincident with a reference plane 101 on which the sheet 130 is disposed. Optionally, the pulling axis 850 and the feed axis may both be disposed in the reference plane 101 and non-parallel to each other. During the bonding step, the sheet 130 in the work zone is at least partially clamped between the workpiece positioner 500 and the clamp 600.

[0025] The apparatus is configured to switch from an adhesive configuration to a cutting configuration as the process 200 transitions from an adhesive phase to a cutting phase. The transition may include displacing at least a portion of the clamp 600 away from the work zone 440.

[0026] For ease of reference, the area where sheet 130 is in physical contact with first surface 111 of workpiece 110 is referred to as selected area 140. Pulsed laser 150 is directed to scan within selected area 140 (e.g., where sheet 130 overlaps first surface 111 of workpiece 110) such that sheet 130 is joined or adhered (e.g., by laser welding) to workpiece 110 in one or more contiguous portions within selected area 140. Laser parameters of pulsed laser 150 may be selected to enable laser welding of sheet 130 to first surface 111 of workpiece 110. Commercially available laser sources may be used. Laser 150 may be configured to direct the pulsed laser opposite build direction 840, such that workpiece 110 is built in build direction 840 by the addition of sheet 130.

[0027] FIG. 1D illustrates a laser cutting step 204 in which the same pulsed laser 150 is directed to scan along the perimeters 141, 142 of the selected region 140. Laser parameters may be selected to enable laser cutting. For example, the same pulsed laser 150 used in laser welding (FIG. 1C) is used in laser cutting along each of the outer perimeter 141 and inner perimeter 142 of the selected region 140. A cutout 144 in the sheet 130 is formed by laser cutting along the inner perimeter 142. The cutout 144 of material is observed to emerge from the sheet 130, as illustrated in FIG. 1D. The sheet 130 now defines a through hole that is now part of the cavity 170 in the workpiece 110. The cutout 144 of material does not fall into the cavity 170 in the workpiece 110. Alternatively, depending on the laser parameters and layer / workpiece material, cutout 144 may be burned and / or vaporized so that no part of cutout 144 remains or falls into cavity 170.

[0028] If the sheet 130 is metal, the same pulsed laser may be used to remove oxides from the material layer in a cleaning step 205, as illustrated in FIG. 1E. The cleaning step 250 may include surface remelting using the same pulsed laser 150 to reduce surface defects. Cleaning may be performed over a treated area 160 (illustrated by the dotted / dashed line) that is larger than the selected area.

[0029] Debris and burrs (e.g., resulting from the laser cutting of FIG. 1D) may be removed by mechanical grinding or polishing in polishing step 206. For example, apparatus 400 may include a polishing device including sandpaper rotatable by polishing motor 450.

[0030] 1G shows the resulting workpiece with one or more layers built in build direction 840. That is, sheet 130 has become part of workpiece 110. The material layers form part of the walls around the cavity.

[0031] To form closed cells, a new layer of material can be laser welded to a new top surface of the workpiece, with the new layer of material being free of through-holes. For example, to form closed cells, the laser welding step involves laser welding along the selected region 140 without laser cutting along the inner periphery 142 of the selected region 140. The ability to create and stack through-holes without having to stop the process and remove cutouts and / or powder from the cavity allows for a continuous process of forming multiple cells. The methods and apparatus proposed herein can further be applied to forming 3D arrays of cells with complex configurations.

[0032] 2A-2G schematically illustrate another embodiment of a method 200 of the present invention. Figures 2A and 2B show a workpiece 110 formed by a first layer of a first material 131 bonded to a second layer of a first material 130. As described above, a cavity 170 may be formed in the workpiece 110.

[0033] For example, the second layer 132 of the first material (e.g., sheet 130) may be aligned against the first layer 131 of the first material. The first layer 131 and the second layer 132 are pressed or compressed toward each other. In this example, there are no cavities in the first layer of the first material. The second layer 132 of the first material may be placed under tension along opposing directions parallel to the reference plane 101 defined by the first layer 301 of the first material. A pulsed laser 150 may be used to weld one or more portions of the second layer 132 to the first layer 131. For example, the pulsed laser 150 may weld two parallel, spaced-apart lines that are orthogonal or substantially orthogonal to the direction of tension. The pulsed laser 150 may then be used to cut along the perimeter of the selected area to form a cutout. The cutout is observed to protrude from the second layer 132 of the first material.

[0034] After the cavity 170 is formed in the second layer 132 (also referred to as the first cavity 171 for clarity), a quantity of powder 182 of the second material may be deposited into the first cavity 171, as illustrated in FIGS. 2C and 2D. As illustrated in FIG. 2D, excess powder may be scraped off. FIG. 2E shows the pulsed laser 150 laser sintering the powder 182 of the second material. As shown in FIG. 2F, a further layer 192 of the second material may be built up by adding more powder of the second material and laser sintering the added powder. The first cavity 171 serves as a template that defines the shape and dimensions of the part made of the second material.

[0035] 2F also shows that a second cavity can be formed. In this example, the second cavity is directly adjacent to both the first material and the second material. For example, the second cavity can be partially defined by the first material and partially defined by the second material.

[0036] As shown in Figures 2F and 2G, a quantity of powder of a third material can be added to the second cavity and laser sintered.

[0037] The resulting article can be a monolithic solid body of multiple materials.

[0038] 3A-3E illustrate another embodiment of a method 200 of the present invention. In this example, a first layer 131 of a first material is provided. As shown in FIG. 3A, a second layer 132 of a second material is aligned with the first layer of the first material. The first layer 131 and the second layer 132 are pressed or pressed toward each other to selectively bond them to each other. For example, the selective bonding may include welding selected areas of the second layer 132 to the first layer with a pulsed laser 150 (the same pulsed laser 150 used for laser welding). The pulsed laser 150 is then used to cut along the perimeter of the selected areas to allow separation of the welded areas of the second layer 132 from the unwelded areas 136 of the second layer 132. The unwelded areas 136 of the second layer 136 can then be displaced away from the first layer 131. An "isolated pattern" 135 or "island" of the second layer (in this case, the second material) is formed, and the isolated pattern 135 is welded to the first layer 131 (FIG. 3B). The sides of the isolated pattern can be cleaned and / or deburred using a pulsed laser 150.

[0039] 3C shows a step in which a pulsed laser 150 is used to cut cavities 137 in a third layer 133 of a third material. The third layer 133 may also be described as a layer having at least one cavity 137 that defines a connecting pattern 138. The connecting pattern 138 (in this example, the cavity 137) may be configured to complementarily mate with the contour or shape of the isolated pattern 135. After the required one or more cavities 137 are formed in the third layer 133, the connecting pattern 138 may be transferred and aligned with the remaining portions of the corresponding one or more isolated patterns 135; for example, the cavity 137 in the third layer 133 may be aligned with the isolated pattern 135 in the second layer 132.

[0040] In various embodiments of the method 200, one or more isolated patterns 135 are formed before one or more corresponding connecting patterns 138 are formed.

[0041] As shown in Figure 3D, the connecting pattern 138 (e.g., cavity 137) and the isolated pattern 135 can be interdigitated. A pulsed laser 150 is used to weld the third layer 133 (e.g., one or more selected areas) to the first layer 131. Figure 3D shows the interface 139 between the through hole of the third layer 133 and the isolated pattern 135 of the second layer 132.

[0042] 3E shows an interface 139 between the first and second materials being welded using the same pulsed laser 150. That is, the periphery of the isolated pattern 135 can be welded to the connecting pattern 138 at the interface 139.

[0043] The result is a heterogeneous article or workpiece 110. Method 200 can be repeated to obtain various configurations of a multi-material article. Method 200 may be modified with respect to the depth of the cuts; for example, cutting isolated and / or connecting patterns need not be cuts through the entire thickness of the sheet. For example, cuts may be made through the entire thickness of a sheet of material (e.g., a through cut as described in the example above), or cuts may be made less than the entire thickness of the material (e.g., similar to engraving).

[0044] In some embodiments, various embodiments of method 200 may be implemented to form a 3D array of cells in which different cells are formed from different materials. In some embodiments, various embodiments of method 200 may be implemented to form a 3D array of cells in which at least one cell is formed from multiple materials.

[0045] FIG. 4A is an example of a clamp 600 that may be used to facilitate or enable the biasing of a workpiece and a sheet toward one another. In this example, the clamp 600 may include a clamp plate 610. The clamp plate 610 may include a plurality of bar clamps 612. The bar clamps 612 may be spaced apart to define a plurality of elongated openings 614. The clamp plate 610 may be in the form of a grid as shown in FIG. 4A or other more porous pattern (e.g., when more complex geometries are to be welded in the first pass of the laser). In some other embodiments, the clamp plate 610 may be a plate that is transparent to the laser without physical through-holes in the plate.

[0046] Figure 4B is a perspective view of a prototype of apparatus 400 having clamping plate 610 of Figure 4A. Clamping plate 610 can be alternately displaced in and out of working zone 440. Figure 4C is an enlarged view of working zone 440 of the apparatus of Figure 4B with clamping plate 610 positioned in working zone 440.

[0047] The apparatus 400 includes a sheet holder, such as a sheet feeder 410. Embodiments of the sheet feeder 410 may include, but are not limited to, a roll-to-roll setup, a set of roller drums, and the like. The sheet feeder 410 is oriented to input or provide a sheet-like material, a layer of material, or a sheet 130 of material to a work zone 440. For brevity, the terms "sheet" and "layer" may be used interchangeably in this disclosure. For example, the sheet feeder 410 may include a second roller drum 412 configured to provide individual sheets 130 or a continuous sheet 130. The sheet feeder 410 may include a first roller drum 411 for collecting the sheet 130. The first roller drum 411 may be operable by a first motor 416 to draw the continuous sheet 130 across the work zone 440. The sheet 130 may be displaced across the work zone 440 between the roller drums of the sheet feeder 410 in a feed direction 811 along a first axis 810 of the reference plane 101. Optionally, the sheet 130 may be passed through additional pairs of rollers 418 to help keep the sheet 130 flat. For simplicity, saying that a sheet or layer of material is flat will be understood to include the sheet or layer of material being substantially flat and / or completely flat.

[0048] Further details of apparatus 400, which may not be visible in the view of Figure 4B but will be described below with reference to other figures, may include a workpiece positioner displaceable along a second axis 820, which is orthogonal to first axis 810. Second axis 820 may be defined to be parallel to build direction 840.

[0049] Apparatus 400 includes a clamp 600 having a clamp plate 610 supported on reference surface 101 by a lattice support 430. In this example, lattice support 430 (and therefore clamp plate 610) can be displaced back and forth along a third axis 830 within reference surface 101. For example, clamp plate 610 can be displaced in a third direction 831 toward work zone 440 for a bonding step. For example, clamp plate 610 can be displaced in a fourth direction 832, opposite third direction 831 and away from work zone 440. In some embodiments, as illustrated in FIG. 4B , third axis 830 and first axis 810 can be coplanar and perpendicular to each other. Alternatively, in some other embodiments, third axis 830 and first axis 810 can be coplanar and parallel to each other. In still other embodiments, third axis 830 and first axis 810 can be coplanar and have an angular displacement relative to each other. The clamp plate 610 may be displaced by a second motor 436. The lattice support 430 may be attached to a belt 434 and pulley 432 such that operation of the second motor 436 displaces the lattice support 430 and the clamp plate 610. For example, the second motor 436 may include a stepper motor configured to displace the lattice support 430 into and out of the work zone 440 along the third axis 830.

[0050] The clamping plate 610 may be positioned parallel to the reference surface 101. The clamping plate 610 may be displaceable parallel to the reference surface 101, for example, along a first axis 810 and / or a third axis 830. The second axis 820 may be defined as an axis perpendicular to the reference surface 101 or the build direction. When the clamping plate 610 is in the work zone 440, the pulsed laser 150 may scan along a scan path defined by the elongated opening 614 in the clamping plate 610. For example, the pulsed laser 150 may scan along the length of a scan path parallel to any one of the reference surface 101, the first axis 810, and the third axis 830.

[0051] 1A-3E, the sheet feeding apparatus 410 may be operable to feed the sheet 130 of the first material along the first axis 810 to position the sheet 130 parallel to the reference surface 101 in the work zone 440 of the apparatus 400.

[0052] The workpiece positioner 500 may be configured to support the workpiece such that the workpiece positioner 500 (or workpiece 110) is displaceable along a second axis 820 to abut the first surface 111 of the workpiece 110 against the sheet 130 in the work zone 440. The second axis 820 may be defined to be perpendicular to the reference plane 101 or parallel to the build direction 840. It has been found that the pushing or clamping direction 821 / 822 along the second axis need not be "upward" / "downward" or "perpendicular" to the ground. Prototypes have been built and verified to be operable with pushing directions 821 in various directions, including, but not limited to, a "lateral" direction. Similarly, it will be understood that the reference plane 101 need not be "horizontal" to the ground as shown in FIGS. 4B and 5A.

[0053] The clamp 600 and workpiece positioner 500 (or workpiece 110) can cooperate to flatten the sheet 130 between the clamp 600 and the first surface 111 of the workpiece 110. The clamp 600 can be configured to define at least one elongated opening 614 in the reference surface 101 such that the laser 150 can be configured to irradiate the sheet 130 through the at least one elongated opening 614. The laser 150 is configured to scan or operate along a scan path defined by the at least one elongated opening 614. The laser 150 is a pulsed laser that can alternately operate to bond (adhere) the sheet 130 to the workpiece 110 (e.g., by heating or laser welding) and cut the sheet 130. That is, one pulsed laser 150 is sufficient to perform all laser-related operations of the apparatus 400.

[0054] The bonding step preferably occurs with the first bond or first joint occurring in a continuous bond length rather than in a spot. In examples where the bonding step includes laser welding, the laser 150 is operable to form the first joint between the sheet 130 and the workpiece 110 such that the first joint is a continuous weld length parallel to the reference plane 101. This is in contrast to spot welding. Without being bound by theory, it has been observed that forming a continuous weld length between the sheet 130 and the workpiece 110 in a single pass of the laser (without prior spot welding between the sheet 130 and the workpiece 110) produces an article of surprisingly good quality with respect to layer flatness and article tensile strength. That is, as used herein, the term “first joint” refers to a joint formed between the sheet 130 and the first surface 111 of the workpiece 110 that is not otherwise or previously welded.

[0055] FIG. 5A illustrates another prototype of an apparatus 400 used to fabricate a multi-material article or workpiece, such as that of FIG. 2G or FIG. 3E. In this example, the apparatus 400 includes a gantry system 490 for enabling relative movement of the laser 150, work zone 440, 110, etc. Similar to the example of FIG. 4A, the apparatus 400 enables displacement of a new layer of material along a first axis 810 relative to the work zone 440 in a feed direction 811. For example, a first motor 416 and a sheet feeder 410 may be provided to extend and displace the layer of material along the first axis 810. Similar to the example of FIG. 4A, the gantry system 490 of FIG. 5A enables displacement of a clamp 600. In this example, the clamp 600 includes a clamp plate 620 supported by a grid support 430. The clamp plate 620 may be displaced along a third axis 830 orthogonal to the first axis 810. The apparatus 400 includes a pulsed laser 150 supported by an actuator 152 such that the pulsed laser 150 can be positioned at various positions relative to the work zone 440. The apparatus 400 includes a workpiece positioner 500 that can be positioned at various positions relative to the work zone 440 and / or the pulsed laser 150. For example, the gantry system 490 may be configured with a motorized pulley belt system or a motorized slide rail system such that the workpiece positioner 500 can be displaced along a first axis 810 and / or a third axis 830. The workpiece positioner 500 may be configured to be displaceable along a second axis 820, which is orthogonal to the first axis 810 and the third axis 830. For example, the second axis 820 may coincide with the build direction 840. For example, the second axis 820 may be vertically parallel to one or more horizontally arranged layers 130 of material supported by the workpiece positioner 500.

[0056] Figure 5B is an enlarged view of the clamp plate 620 of Figure 5A, showing variations of the elongated openings 624. For example, the clamp plate 620 may include two or more rows 626 of elongated openings 624, each defined by a spaced apart clamp bar 622.

[0057] In some embodiments, apparatus 400 may be configured with an automated material feeder (also referred to as workpiece positioner 500) to enable more efficient and automated construction of the multiple layers required to form a 3D array of cells. Workpiece positioner 500 may cooperate with clamps 600 to clamp to sheet 130 within work zone 440. For example, workpiece positioner 500 may cooperate with clamps 600 to support workpiece 110 such that a portion of layer 130 is held stationary in a flat or substantially flat configuration to receive pulsed radiation from laser 150.

[0058] FIG. 6A illustrates a portion of the apparatus 400 near the work zone 440. The roller drums of the sheet feeder 410 may be located on either side of the work zone 440 and may be cooperatively rotatable to stretch the sheet 130 through the work zone 440. In the illustrated example, the sheet 130 may be displaced along a first axis 810 (e.g., in a feed direction 811 from left to right in the figure or in a feed direction 811 from right to left in the figure). In some embodiments, the sheet feeder 410 may be configured to displace the sheet in either of two opposing directions 811 / 812 along the first axis 810, for example, to reposition the sheet 130 relative to the workpiece 110. The sheet feeder 410 may be locked or prevented from rotating when pulling or stretching the layer 130 relatively flat. The pulling axis 850 may be parallel to the first axis 810 or angularly displaced relative to the first axis 810. In some instances, the tension axis 850 may be parallel to the third axis 830 (into or out of the paper).

[0059] The workpiece positioner 500 is illustrated as an assembly disassembled along the second axis 820 to better illustrate the various components. The workpiece positioner 500 may include a positioning actuator 510. In some embodiments, the positioning actuator 510 may be displaceable along the second axis 820 (e.g., closer to the layer 130 or farther from the sheet 130). Prior to the bonding stage, the positioning actuator 510 may be displaced in a build direction 840 or a push direction 821. When the clamp 600 is unclamped, for example to allow displacement of the sheet 130, the positioning actuator 510 may be displaced in a direction 822 opposite the build direction 840 or a direction opposite the push direction 821. The positioning actuator 510 may be motor-driven, pneumatically driven, manually operable, etc.

[0060] The workpiece positioner 500 may include a heater / cooler 530 for controllably adjusting the temperature of the workpiece 110. The workpiece positioner 500 may include a base plate 540 to which the workpiece 110 may be releasably secured. The base plate 540 may be heated by the heater / cooler 530 to reduce residual stresses. Alternatively, the base plate 540 may be cooled by the heater / cooler 530 to increase the cooling rate and impart a particular desired microstructure to the material. One or more (compression) force sensors 520 may be coupled below the base plate 540.

[0061] Laser welding is performed using a pulsed laser 150 that scans a portion of layer 130 along an elongated opening in clamping plates 610 / 620. Figure 6B shows the laser welding of Figure 1C performed with sheet 130 clamped between clamping plate 460 and first surface 111 of workpiece 110. Clamping force 512 directed along second axis 820 can be controllably adjusted in response to feedback from one or more force sensors 520 disposed on workpiece positioner 500. Clamping force 512 (in pushing direction 821) on sheet 130 is controllably variable in response to feedback signals from force sensors 520.

[0062] A blower or suction 154 may be provided to cool the layer 130 during laser welding and / or laser cutting. The blower or suction 154 may also aid in material removal during cutting. While cut pieces have been observed to fly off the layer 130, other methods may alternatively be used to remove unwanted material from the workpiece, such as using vacuum, fans, magnets, brushes, tape, or gravity (e.g., by permanently rotating the entire setup upside down). Alternatively, unwanted areas may be cut from the layer 130 and left on the base plate 540 to provide support for the next layer of material. Springs 512, 469 may be provided to provide some tolerance for the part and to provide a resilient bias for the clamping of the layer 130.

[0063] In the grinding step (FIG. 6C), the laser 150 and clamping plates 610 / 620 may be displaced away from the work zone 440 (e.g., in a direction 822 opposite to the pushing direction 821). A grinding device 450 may be applied to deburr and grind the surface of the workpiece 110 in preparation for receiving another sheet 130.

[0064] FIG. 7 is a schematic diagram illustrating a portion of another embodiment of the apparatus 400. The workpiece 110 may initially be supported by a base plate 540, which may be displaced along a second axis 820 (e.g., in a build direction 840 / in a direction 822 opposite to the build direction 840) as the number of layers (or thickness) of the workpiece 110 increases. The positioning actuators 510 in this example take the form of at least a pair of positioning rollers 514 on either side of the workpiece 110. The base plate 540 is optional if the workpiece 110 is sufficiently thick so that the sides of the workpiece 110 can slidably engage the positioning rollers 514. At least one shear force sensor 524 may be provided on the positioning rollers 514 to provide feedback regarding the position of the workpiece 110. Heaters or coolers 534 may be provided on either side of the workpiece 110 to act as guides for the workpiece and to regulate the temperature of the workpiece 110.

[0065] During the bonding stage (e.g., during laser welding), the positioning rollers 514 may support the workpiece 110 in a position where it is pressed against the clamp plates 610 / 620. When the workpiece 110 is ready to have another layer 130 added, the positioning rollers 514 may rotate in opposite directions (one clockwise, the other counterclockwise) to lower the workpiece 110 (to accommodate the new layer of material). This configuration advantageously, and theoretically, allows for an unlimited build height for the workpiece 110; that is, the apparatus 400 places no limit on the number of layers that may be added to the workpiece 110.

[0066] The laser parameters of the pulsed laser 150 are controllably variable depending on the type of material selected for the sheet 130. For example, the laser power, scan speed, and / or pulse frequency of the pulsed laser 150 are selected to enable bonding of the sheet 130 to the first surface of the workpiece 110. The laser welding can be further enhanced by subsequent use of a heater 534 (e.g., a radiant heater, hot air gun, etc.) or a lamp that directs heat and / or radiation at the workpiece 110.

[0067] 8 is a schematic diagram of a portion of apparatus 400 according to another embodiment of the present disclosure. Instead of clamp plates 610 / 620, clamp 600 includes a pair of roller clamps 630. Pulsed laser 150 is positioned between first roller clamp 631 and second roller clamp 632. New sheet 130 (unwelded area 233) is placed between workpiece 110 and roller clamps 630.

[0068] In this example, during the bonding stage or bonding step 203 (e.g., FIGS. 1C, 3D, etc.), the first roller clamp 631 and the second roller clamp 632 are rotated in the same direction (e.g., both rotated clockwise). At the same time, the roller clamps 630 press against the sheet 130, creating tension in the sheet 130. The tension is sufficient to minimize or eliminate any gap between the sheet 130 and the workpiece 110. In this example, the sheet feeder 410 (if used to provide the sheet 130) does not need to provide tension.

[0069] During the bonding step, the pulsed laser 150 and the roller clamps 630 can be moved in tandem in the same direction. For example, the bonding direction 501 and the clamp displacement direction 601 can be parallel. The bonding direction 501 is the direction in which the bond between the sheet 130 and the workpiece 110 develops or increases. If the bonding step includes laser welding, the bonding direction 501 is also essentially the laser scanning direction. For example, the laser scanning speed and the clamp displacement speed can be the same or substantially the same. As the laser 150 advances into the unwelded region 233 of the layer 130, the path traveled by the laser 150 becomes part of the welded region 232. The unwelded region 233 of the layer 130 is joined to the workpiece 110 within the opening between the slidable clamps 640 (becoming part of the welded region 232).

[0070] 9 is a schematic diagram of a portion of apparatus 400 according to yet another embodiment of the present disclosure. Instead of clamp plates 610 / 620, clamp 600 includes a pair of slidable clamps 640. Pulsed laser 150 is positioned between first slidable clamp 641 and second slidable clamp 642. New sheet 130 is placed between workpiece 110 and slidable clamps 640.

[0071] In this example, during laser welding step 203 (e.g., FIGS. 1C, 3D, etc.), first slidable clamp 641 and second slidable clamp 642 are displaced in the same direction 601 (e.g., both slide in the same direction along first axis 810). At the same time, slidable clamp 640 presses against sheet 130, creating tension in sheet 130. The tension is sufficient to minimize or eliminate a gap between sheet 130 and workpiece 110. In this example, sheet feeder 410 (if used to transport sheet 130 in and out of work zone 440) does not need to provide tension.

[0072] The pulsed laser 150 and the slidable clamp 640 are moved simultaneously in the same direction 601 (e.g., along the first axis 810) at the same speed (laser scanning speed 605 and slidable clamp speed 704). As the laser 150 advances into the unwelded region 233 of the layer 130, the path traveled by the laser 150 becomes part of the welded region 232. The unwelded region 233 of the layer 130 is joined to the workpiece 110 within the opening between the slidable clamps 640 (becoming part of the welded region 232).

[0073] 10 is a schematic diagram of a portion of apparatus 400 according to yet another embodiment of the present disclosure. Instead of clamp plate 460, clamp 600 includes a pair of slidable clamps 640. Pulsed laser 150 is positioned between first slidable clamp 641 and second slidable clamp 642. New sheet 130 is placed between workpiece 110 and slidable clamps 710.

[0074] In this example, during laser welding step 203 (e.g., FIGS. 1C, 3D, etc.), first slidable clamp 641 and second slidable clamp 642 are displaced relative to one another in opposite directions 601 / 602 (e.g., both slide in opposite directions parallel to first axis 810). Simultaneously, slidable clamp 640 presses against sheet 130, creating tension in sheet 130. The tension is sufficient to minimize or eliminate any gap between sheet 130 and workpiece 110. In this example, similar to the example of FIG. 9, sheet feeder 410 (if used to dispense layer 130) similarly does not need to provide tension to keep layer 130 flat or substantially flat.

[0075] The pulsed laser 150 may scan the area between the two slidable clamps 640. As the area of ​​the welded region increases, the slidable clamps 640 may be displaced further apart to expose areas where the layer 130 is unwelded or unbonded to the workpiece 110. The unwelded areas 233 of the layer 130 are bonded to the workpiece 110 within the opening between the slidable clamps 640.

[0076] In another example, one of the slidable clamps 640 (e.g., first slidable clamp 641) may be stationary relative to the pulsed laser 150, while the other of the slidable clamps 640 (e.g., second slidable clamp 642) may be displaced increasingly farther away from the stationary slidable clamp 641. The displacement of the second slidable clamp 642 may be parallel to a portion of the scanning direction of the pulsed laser 150, such as parallel to the first axis 810. As the laser 150 advances into the unwelded region 233 of the layer 130, the path traveled by the laser 150 becomes part of the welded region 232. The unwelded region 233 of the layer 130 is bonded to the workpiece 110 within the opening between the slidable clamps 640.

[0077] FIG. 11 is a schematic diagram of another embodiment of a portion of the apparatus 400. The method and apparatus of the present invention are suitable for bidirectional printing, for example, to increase production efficiency. One or more workpieces 110 can be processed simultaneously. The base plate 540 is optional, for example, if one workpiece 110 is built simultaneously in a different build orientation. The sheet 130 is clamped between the workpiece 110 and a displaceable clamp 600. The displaceable clamp 600 can include any one of the following types of clamping components: clamp plates 610 / 620, a rotatable clamp 630, and / or a slidable clamp 640. A pulsed laser 150 and a polishing device 540 can be provided at each end of the setup.

[0078] 12 schematically illustrates a portion of an apparatus 400 suitable for use in forming cell arrays and / or complex channels, where the bonding step can be based on methods other than laser welding. For example, the apparatus 400 can include a heat dissipation zone 910. The heat dissipation zone 910 can be different from the heater / cooler 530. For example, the heat dissipation zone 910 can be located proximate the sheet 130 before the sheet reaches the work zone 440, and the heater / cooler 530 can be located proximate the workpiece.

[0079] In use, the heat sink 910 may be used to preheat the sheet 130 before it is pressed against a workpiece. This embodiment of the apparatus 400 may be used in instances where the sheet 130 is formed from a carbon fiber reinforced composite and / or a polymer. The polymer may include a thermoplastic such as, but not limited to, thermoplastic polyurethane (TPU).

[0080] 13 schematically illustrates another embodiment of apparatus 400. In this example, apparatus 400 includes a friction welding tool 920 that also serves as clamp 600, holding sheet 130 in contact with workpiece 110 at reference surface 101. During the bonding stage, sheet 130 is "clamped" or held to workpiece 110 and bonded to workpiece 110 by friction welding. Thereafter, friction welding tool 920 is removed and laser 150 can be positioned in the work zone to perform laser cutting and cut the newly bonded sheet 130 into the desired pattern.

[0081] FIG. 14 schematically illustrates an example of friction welding, i.e., rotary friction welding or rotary friction welding. FIG. 15 schematically illustrates an example of friction welding, i.e., linear friction welding or translational friction welding. In these examples, the friction welding tool 920 may include a holder or grip for firmly holding individual pieces of sheet 130. Friction between the sheet 130 and the workpiece 110, e.g., friction caused by relative motion 903 between the sheet 130 and the workpiece 110 in physical contact, generates heat that welds the sheet 130 to the workpiece 110. In the example of rotary friction welding (FIG. 14), continuous rotational relative motion 903 may be provided between the sheet 130 and the workpiece 110. In the example of linear friction welding (FIG. 15), oscillating sliding relative motion 903 may be provided between the sheet 130 and the workpiece 110.

[0082] In some examples, the apparatus 400 may be configured to provide the relative motion 903 by holding the workpiece 110 stationary while moving the friction welding tool 920. In some other examples, the apparatus 400 may be configured to provide the relative motion 903 by holding the friction welding tool 920 stationary while moving the workpiece 110. In still other examples, both the workpiece 110 and the sheet 130 are moving, resulting in the relative motion 903 that creates the friction welding effect therebetween. The workpiece 110 may be moved or held stationary by the workpiece positioner 500.

[0083] In some examples, the bonding step may include applying an adhesive between the sheet 130 and the workpiece 110 and pressing the sheet 130 and the workpiece 110 together. The sheet 130 and the workpiece 110 may be pressed together using any one of the clamps described above.

[0084] Various embodiments of the apparatus 400 can be used to perform the methods disclosed herein to manufacture articles formed of multiple materials (e.g., as part of a continuous production line in mass manufacturing). The apparatus 400 can include a sheet feeder 410, a workpiece positioner 500, and a clamp 600. The clamp 600 and the workpiece positioner 500 can cooperate to flatten the sheet 130 between the clamp 600 and the workpiece 110. The clamping provided by the clamp 600 and the workpiece 110 helps apply tension to the sheet 130 and aids in compliance of the sheet 130 with the first surface 111 of the workpiece 110. The clamp 600 can define at least one elongated opening 614 through which the laser 150 can irradiate the sheet 130 along a scan path. The laser 150 is preferably a pulsed laser that can be alternately operated to join the sheet to the workpiece and to cut the sheet. A method 200 of making an article using the apparatus 400 may include welding a selected area 140 of a sheet 130 of a first material to a workpiece 110, cutting along a periphery 141 of the selected area 140 to form an isolated pattern 135, cutting a sheet of a second material to form a connecting pattern 138, mating the connecting pattern 138 with the isolated pattern 135, and welding an interface 139 therebetween.

[0085] In various embodiments, the clamp 600 may be described as including at least one clamp member (e.g., clamp bar 610 / 620, rotatable clamp 630, slidable clamp 640, etc.) displaceable along the first axis 810. In some embodiments, the at least one clamp member is displaceable by rotation or sliding. In some embodiments, the clamp 600 includes two clamp members spaced apart to define an elongated opening 614, and at least one of the two clamp members is displaceable along the scanning direction of the laser 150 (e.g., a direction parallel to the reference surface 101). In some embodiments, one of the two clamp members is displaceable away from the other of the two clamp members. Preferably, the displacement of the at least one clamp member is along a direction (e.g., parallel to the reference surface 101) that helps improve compliance (or flattening) of the sheet 130 relative to the first surface 111 of the workpiece 110.

[0086] The above description of various examples of apparatus 400 is non-exhaustive and merely illustrative. Apparatus 400 includes at least one displaceable clamp 600. At least one displaceable clamp 600 cooperates with workpiece 110 (supported by workpiece positioner 500) so that a flat or substantially flat region of sheet 130 is presented to pulsed laser 150. Such effective and dynamic clamping allows pulsed laser 150 to scan a length or portion of layer 130 to bond to workpiece 110 and is not limited to spot welding. The relatively narrow width (compared to the dimensions of work zone 440) of opening 614 between portions of displaceable clamp 600 limits any warping of layer 130 within work zone 440.

[0087] Figures 16 and 17 are perspective views of 3D articles that can be fabricated using the method and apparatus of the present invention. Figures 18A and 18B are images of the 3D array of cells of Figure 17 fabricated using the method and apparatus of the present invention. Each marking on the ruler in Figure 18B represents 1 mm. These demonstrate that the method and apparatus of the present invention can form 3D arrays of cells. Figures 19A through 19E are images of articles of various materials fabricated using the method and apparatus of the present invention. These demonstrate the broad applicability of the method and apparatus of the present invention for fabricating articles of different materials. For example, closed cells of stainless steel 304L (SS304L) were fabricated (Figure 19A). Carbon fiber reinforced composite specimens were successfully fabricated (Figure 19B). A 3D array of honeycomb structures was fabricated using SS304L (Figure 19C). An article of ethylene propylene diene monomer (EPDM) was fabricated (Figure 19D). It has been demonstrated that paper and other naturally occurring materials can also be used with the methods and devices of the present invention (Figure 19E).

[0088] Without being bound by theory, the ability to provide a flat or substantially flat layer 130 may enable pulsed laser scanning or laser bonding / welding in lengths or sections (as opposed to spot welding), providing conditions conducive to stronger bonds and / or microstructures. FIG. 20 shows images of exemplary specimens fabricated using the method and apparatus of the present invention for tensile strength testing. Test results indicated that the ultimate tensile strength (UTS) of the produced specimens can be in the range of 800 MPa or greater. A UTS of approximately 1700 MPa was experimentally achieved with a yield strength of approximately 980 MPa (0.2% offset yield strength). This is a significant improvement over what can be achieved using conventional methods. For example, laser foil printing has reported yield strengths of less than 600 MPa and UTSs of less than 1000 MPa.

[0089] In one aspect, the present disclosure describes various embodiments of an apparatus including a laser, a clamp, and a workpiece positioner. The laser is operable as a pulsed laser for cutting a sheet. The clamp is displaceable relative to a work zone of the apparatus. The workpiece positioner is configured to support a workpiece within the work zone. During a bonding stage, the clamp and the workpiece positioner are operable to cooperatively press the sheet and the workpiece toward each other, forming a selective bond between the sheet and the workpiece during the bonding stage. During a cutting stage, the clamp is displaceable away from the work zone to allow the laser to cut the sheet along a periphery of the selective bond.

[0090] The apparatus may further include a sheet feeder. The sheet feeder may be operable to feed a sheet along a first axis to position the sheet parallel to a reference plane within the work zone. The workpiece positioner may be displaceable along a second axis to press a first surface of a workpiece against the sheet within the work zone, the second axis being perpendicular to the reference plane. The clamp and the workpiece positioner may be configured to cooperatively flatten the sheet between the clamp and the first surface of the workpiece, and the clamp may define at least one continuous scan path within the reference plane. The laser may be configured to irradiate the sheet along the scan path, and the laser is a pulsed laser alternately operable to join the sheet to the workpiece and cut the sheet.

[0091] The laser may be operable to form a first joint between the sheet and the workpiece, the first joint including at least one continuous weld length parallel to the reference plane.

[0092] The sheet feeding device may include a first drum roller and a second drum roller, the first drum roller and the second drum roller configured to rotate in the same direction, and the sheet is a continuous sheet that is fed by the second drum roller and collected by the first drum roller.

[0093] The workpiece positioner may include a base plate coupled to a compression force sensor, wherein in response to feedback from the compression force sensor, the base plate may be controllably urged toward the reference surface to cooperatively clamp the workpiece and the sheet together.

[0094] The workpiece positioner may include positioning rollers coupled to shear force sensors, the positioning rollers may be positioned to engage opposite sides of the workpiece, and in response to feedback from the shear force sensors, the positioning rollers may be controllably rotated to displace the workpiece away from the reference surface.

[0095] The clamp may include at least one clamp member displaceable along the first axis.

[0096] The at least one clamping member may be displaceable by one of rotation and sliding.

[0097] The clamp may include two clamp members spaced apart to define an elongated opening, and at least one of the clamp members may be displaceable along a scanning direction of the laser.

[0098] One of the two clamping members may be displaceable away from the other of the two clamping members.

[0099] The workpiece positioner may be displaceable along a second axis to press a first surface of the workpiece against the sheet, the second axis being perpendicular to the reference plane. The clamp and the workpiece positioner may be configured to cooperatively flatten the sheet between the clamp and the first surface of the workpiece. The laser may be configured to cut the sheet along at least one scan path, the at least one scan path being defined by the clamp to be at least one continuous path.

[0100] The apparatus may further include a heat sink configured to preheat the sheet prior to the bonding step.

[0101] The selective adhesion may include an adhesive bond.

[0102] The clamp and the workpiece positioner may be configured to provide relative movement between the sheet and the workpiece, and the selective adhesion includes a friction weld joint.

[0103] The apparatus may further include a sheet feeder operable to feed the sheet along a feed direction to position the sheet in the work zone.

[0104] In another aspect, the present disclosure describes various embodiments of a method that includes cooperatively forcing a sheet and a first surface of the workpiece between a clamp and a workpiece positioner during a bonding step while simultaneously forming a selective bond between the sheet and the workpiece, displacing the clamp away from the work zone, and during a cutting step, laser cutting along a perimeter of the selective bond.

[0105] The forming of the selective bond may include any one of laser welding, preheating, friction welding, and adhesive bonding.

[0106] The method may further include placing the sheet on a reference surface within the work zone and displacing the workpiece along a second axis to press the first surface of the workpiece against the sheet in the work zone, the second axis being perpendicular to the reference surface.

[0107] The method may further include feeding the sheet along a first axis to position the sheet in a work zone, the first axis being parallel to the reference plane.

[0108] The method may include cooperatively flattening the sheet between the clamp and the first surface of the workpiece.

[0109] This may include bonding the sheet to the first surface of the workpiece by using a laser to irradiate the sheet along a scanning path defined by the clamp, the laser being a pulsed laser operable alternately to bond the sheet to the workpiece and cut the sheet.

[0110] The method, wherein the laser is operable to form a first joint between the sheet and the workpiece, the first joint including at least one continuous weld length parallel to the reference plane.

[0111] The method wherein the workpiece can be pressed against the reference surface to cooperatively clamp the workpiece and the sheet together.

[0112] The method wherein the workpiece can be controllably displaced along the second axis toward the reference surface in response to feedback from a compressive force sensor.

[0113] The method, wherein the workpiece is displaceable away from the reference surface by positioning rollers, the positioning rollers being positioned to engage opposite sides of the workpiece.

[0114] The method, wherein the workpiece is controllably displaced away from the reference surface by rotating the positioning roller in response to feedback from a shear force sensor.

[0115] The method, wherein the clamp includes at least one clamp member displaceable along the first axis.

[0116] The method, wherein the at least one clamping member is displaceable by one of rotation and sliding.

[0117] The method, wherein the clamp includes two clamp members spaced apart to define the elongated opening, and at least one of the two clamp members is displaceable along a scanning direction of the laser.

[0118] The method may further include welding a selected area of ​​the sheet of the first material to the first surface of the workpiece and cutting along a periphery of the selected area to form an isolated pattern.

[0119] The method may further include cutting along an inner periphery of the selected region to form a cavity surrounded by the selected region.

[0120] The method may further include cutting a sheet of a second material to form a connection pattern, the connection pattern including cavities complementary to the selected region; mating the connection pattern with the isolated pattern; and welding an interface between the first material and the second material, the interface being defined by the perimeter of the selected region.

[0121] In yet another aspect, the present disclosure describes various embodiments of an article comprising an array of cells, each of the cells comprising at least one cell wall defining an interior space, the at least one cell wall comprising multiple layers bonded together using any of the embodiments of the methods described above.

[0122] The article, wherein the at least one cell wall comprises multiple materials.

[0123] All examples described herein, whether of devices, methods, materials, or articles of manufacture, are presented for illustrative purposes and to aid in understanding, and are not intended to be limiting or exhaustive. Modifications may be made by those skilled in the art without departing from the scope of the invention as claimed.

Claims

1. a laser, the laser being operable as a pulsed laser for cutting the sheet; a clamp, the clamp being displaceable relative to a working zone of the device; a workpiece positioner configured to support a workpiece within the work zone comprising the workpiece; and An apparatus comprising: during a bonding step, the clamp and the workpiece positioner are operable to cooperatively press the sheet and the workpiece toward one another, and a selective bond between the sheet and the workpiece is formed during the bonding step; During a cutting step, the clamps are displaceable away from the work zone to allow the laser to cut the sheet along the periphery of the selective adhesive. Device.

2. The device comprises: a sheet feeding apparatus operable to feed a sheet along a first axis to position the sheet parallel to a reference plane within the work zone; Equipped with the workpiece positioner is displaceable along a second axis to press a first surface of a workpiece against the seat within the work zone, the second axis being perpendicular to the reference plane; the clamp and the workpiece positioner are configured to cooperatively flatten the sheet between the clamp and the first surface of the workpiece, the clamp defining at least one continuous scan path within the reference plane; the laser may be configured to illuminate the sheet along the scan path; the laser is a pulsed laser operable alternately to bond the sheet to the workpiece and to cut the sheet; 10. The apparatus of claim 1.

3. 3. The apparatus of claim 2, wherein the laser is operable to form a first joint between the sheet and the workpiece, the first joint including at least one continuous weld length parallel to the reference plane.

4. 4. The apparatus of claim 2, wherein the sheet feeding device comprises a first drum roller and a second drum roller, the first drum roller and the second drum roller configured to rotate in the same direction, and the sheet is a continuous sheet provided by the second drum roller and collected by the first drum roller.

5. 5. The apparatus of claim 2, wherein the workpiece positioner comprises a base plate coupled to a compression force sensor, and in response to feedback from the compression force sensor, the base plate is controllably urged toward the reference surface to cooperatively clamp the workpiece and the sheet together.

6. 6. The apparatus of claim 2, wherein the workpiece positioner comprises positioning rollers coupled to shear force sensors, the positioning rollers positioned to engage opposite sides of the workpiece, and in response to feedback from the shear force sensors, the positioning rollers are controllably rotated to displace the workpiece away from the reference surface.

7. 7. The apparatus of claim 2, wherein the clamp comprises at least one clamping member displaceable along the first axis.

8. The apparatus of claim 7 , wherein the at least one clamping member is displaceable by one of rotation and sliding.

9. 9. The apparatus of claim 7 or claim 8, wherein the clamp comprises two clamp members spaced apart to define the elongated opening, and at least one of the two clamp members is displaceable along a scanning direction of the laser.

10. 10. The apparatus of claim 9, wherein one of the two clamping members is displaceable away from the other of the two clamping members.

11. the workpiece positioner is displaceable along a second axis to press a first surface of the workpiece against the seat, the second axis being perpendicular to the reference plane; the clamp and the workpiece positioner are configured to cooperatively flatten the sheet between the clamp and the first surface of the workpiece; the laser can be configured to cut the sheet along at least one scan path, the at least one scan path being defined by the clamp to be at least one continuous path; 10. The apparatus of claim 1.

12. 12. The apparatus of claim 1 or claim 11, further comprising a heat sink configured to preheat the sheet prior to the bonding step.

13. 12. The device of claim 1 or claim 11, wherein the selective adhesion comprises an adhesive bond.

14. the clamp and the workpiece positioner are configured to provide relative movement between the seat and the workpiece; the selectively bonded joint comprises a friction welded joint; 12. The apparatus of claim 1 or claim 11.

15. 14. The apparatus of claim 11, further comprising a sheet feeding apparatus, the sheet feeding apparatus operable to feed the sheet along a feed direction to position the sheet in the work zone.

16. during a bonding step, simultaneously forming a selective bond between the sheet and the workpiece, cooperatively compressing the sheet and a first surface of the workpiece between a clamp and a workpiece positioner; displacing the clamp away from the working zone; a cutting step of laser cutting along a periphery of the selectively bonded portion; A method comprising:

17. 17. The method of claim 16, wherein the forming of the selective bond comprises any one of laser welding, preheating, friction welding, and adhesive bonding.

18. placing the sheet on a reference surface within the work zone; displacing the workpiece along a second axis to press the first surface of the workpiece against the sheet in the work zone, the second axis being perpendicular to the reference plane; 18. The method of claim 16 or claim 17, further comprising:

19. feeding the sheet along a first axis to position the sheet in a work zone, the first axis being parallel to the reference plane; 20. The method of claim 18, further comprising:

20. 20. The method of any one of claims 16 to 19, wherein the method includes cooperatively flattening the sheet between the clamp and the first surface of the workpiece.

21. 21. The method of any one of claims 16 to 20, wherein the method includes using a laser to bond the sheet to the first surface of the workpiece by irradiating the sheet along a scan path defined by the clamp, the laser being a pulsed laser alternately operable to bond the sheet to the workpiece and cut the sheet.

22. 22. The method of claim 21, wherein the laser is operable to form a first joint between the sheet and the workpiece, the first joint including at least one continuous weld length parallel to the reference plane.

23. 23. A method according to claim 21 or claim 22, wherein the workpiece is urged towards the reference surface to cooperatively clamp the workpiece and the sheet together.

24. 24. The method of claim 23, wherein the workpiece is controllably displaced along the second axis toward the reference surface in response to feedback from a compressive force sensor.

25. 23. A method according to claim 21 or claim 22, wherein the workpiece is displaceable away from the reference surface by positioning rollers, the positioning rollers being arranged to engage opposite sides of the workpiece.

26. 26. The method of claim 25, wherein the workpiece is controllably displaced away from the reference surface by rotating the positioning roller in response to feedback from a shear force sensor.

27. 27. The method of any one of claims 21 to 26, wherein the clamp comprises at least one clamping member displaceable along the first axis.

28. 28. The method of claim 27, wherein the at least one clamping member is displaceable by one of rotation and sliding.

29. 29. The method of claim 27 or claim 28, wherein the clamp comprises two clamp members spaced apart to define the elongated opening, and at least one of the two clamp members is displaceable along a scanning direction of the laser.

30. welding selected areas of the sheet of the first material to the first surface of the workpiece; cutting along the periphery of the selected area to form an isolated pattern; 30. The method of any one of claims 21 to 29, further comprising:

31. 31. The method of claim 30, further comprising cutting along an inner periphery of the selected region to form a cavity surrounded by the selected region.

32. cutting a sheet of a second material to form a connecting pattern, the connecting pattern including cavities complementary to the selected areas; mating the connection pattern with the isolated pattern; welding an interface between the first material and the second material, the interface being defined by the perimeter of the selected region; 31. The method of claim 30, further comprising:

33. 33. An article comprising an array of cells, each of the cells comprising at least one cell wall defining an interior space, the at least one cell wall comprising a plurality of layers bonded together using the method of any one of claims 16 to 32.

34. 34. The article of claim 33, wherein the at least one cell wall comprises multiple materials.

Images