Interlayer reinforcement method in the layering direction in a layered 3D printer

Abstract

To construct a high quality building by appropriately performing interlayer reinforcement of a laminated structure when constructing the building by laminating construction materials discharged from a material discharge nozzle of a lamination type 3D printer.SOLUTION: A method of constructing a building by laminating construction materials discharged from a material discharge nozzle 20 of a lamination type 3D printer 10 includes: a laminated structure forming step of forming a laminated structure 90 by discharging the construction materials from the material discharge nozzle 20; and a reinforcement material insertion step of inserting a reinforcement material 80 while penetrating through a layer boundary of the construction materials laminated vertically and inserting the reinforcement material 80 into the construction materials such that a top part of the reinforcement material 80 does not protrude from the construction material located in the uppermost layer and is located inside the construction material further than a surface of the construction material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an interlayer reinforcement method in the stacking direction in a laminated 3D printer.

Background Art

[0002] In recent years, laminated 3D printers, which are construction methods for shaping structures while laminating them using 3D printing technology, have been developed both at home and abroad in the construction field. The materials of laminated 3D printers basically use cement-based materials, pump-mortar kneaded with a mixer, and supply it to a three-dimensional shaping device. Construction using a laminated 3D printer can laminate and shape a structure without a formwork, and is expected to have high superiority compared to conventional concrete construction in terms of labor saving, design freedom, safety, etc.

[0003] Concrete structures shaped by a laminated 3D printer form discontinuous layers such as cold joints between layers because they are shaped while laminating cement-based materials. The existence of this discontinuous layer may cause a strength reduction due to interlayer vulnerability compared to general concrete structures. In the conventional technology, to address such problems, metallic fibers are inserted in the stacking direction to reinforce the interlayer mechanical strength (see, for example, Patent Documents 1 to 3).

[0004] [[ID=第十九]] The technology described in Patent Document 1 relates to an interlayer-reinforced 3D printed concrete structure and a method for constructing the same. This construction method includes the following steps: printing a first layer of printing material; arranging horizontal bars section by section along a first direction of the first layer of printed material for multiple sections of horizontal bars; gradually printing a second layer of printing material along the first direction as the arrangement of horizontal bars progresses, and injecting short bars into pre-set injection positions before printing them into injection positions of short bars. In this step, the horizontal bars are injected into the first layer of printing material, and the tops of the short bars are exposed from the top surface of the first layer of printing material. According to this construction method, by arranging horizontal bars between layers of 3D printed material and injecting short bars, the interlayer adhesion properties of the printed material can be effectively strengthened.

[0005] The technology described in Patent Document 2 involves vertically inserting multiple steel fibers into a lamellar concrete material.

[0006] The technology described in Patent Document 3 relates to a method for manufacturing a component from a curable material. This component manufacturing method includes the following steps: printing at least one layer of the material using a 3D printing process; introducing multiple similar reinforcing elements into the layer; and periodically repeating the above two steps until the component is completed. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 109680954 [Patent Document 2] Chinese Utility Model Application Publication No. 206233586 [Patent Document 3] International Publication No. 2019 / 092162 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] Conventional technologies, including the aforementioned patent documents, do not disclose how to insert fibers to reinforce a structure when building a structure by layering using 3D printing technology. For example, depending on how the fibers protrude in the layering direction, it may obstruct the movement of the layering nozzle. That is, if the heads of the fibers protrude from an already formed layered structure, the fibers will get in the way when forming the next layered structure, causing damage to the layered structure, preventing the formation of the layered structure, or causing the fibers to fall out.

[0009] Furthermore, previous technical literature has insufficient proof of the premise that the interlayer portion is a mechanical weak point. In addition, a comparison of strength between cases with and without fibers in the interlayer has not been disclosed.

[0010] This invention was proposed in view of the circumstances described above, and aims to provide a method for interlayer reinforcement in the layering direction in a layered 3D printer, which enables the creation of high-quality structures by appropriately reinforcing the layers of the layered structure when constructing a structure by layering construction materials extruded from the material extrusion nozzle of the layered 3D printer. [Means for solving the problem]

[0011] The interlayer reinforcement method in the stacking direction in a stacking 3D printer according to the present invention has the following features in order to achieve the above-mentioned objective. That is, the interlayer reinforcement method in the stacking direction in a stacking 3D printer according to the present invention constructs a building by stacking construction materials extruded from the material extrusion nozzle of a stacking 3D printer. In doing so, the interlayers of the laminated structure are reinforced. A method for which a laminated structure formation step and a reinforcing material insertion step are It contains.

[0012] The laminated structure formation process involves discharging construction material from a material discharge nozzle. Consists of multiple layers (for example, two layers, top and bottom) This is the process of forming a layered structure.

[0013] The reinforcing material insertion process is, After forming a laminated structure consisting of multiple layers (for example, two layers, top and bottom), the layer boundaries of the construction material in the laminated structure consisting of multiple layers (for example, two layers, top and bottom) are penetrated from the top layer to the bottom layer of the laminated structure.A step of inserting a reinforcing member into a construction material such that the reinforcing member is inserted into the construction material and the head of the reinforcing member is positioned inside the construction material rather than protruding from the construction material surface without being located in the uppermost layer.

[0014] Also, in the reinforcing member insertion step, when inserting the reinforcing member into the construction material, it is preferable to keep the insertion angle of each reinforcing member constant.

[0015] Also, in the reinforcing member insertion step, it is preferable that the positions of the reinforcing members to be inserted are different from each other in the horizontal direction between the laminated structure unit located in the upper layer and the laminated structure unit located immediately below the laminated structure unit located in the upper layer.

[0016] Also, the reinforcing member preferably has a uniform cross-section (a state where the shape and thickness of the cross-section do not change in the length direction) and is straight.

Advantages of the Invention

[0017] According to the interlayer reinforcement method in the lamination direction in the laminated 3D printer according to the present invention, after discharging the construction material from the material discharge nozzle to form a laminated structure, the reinforcing member is inserted through the layer boundary of the construction materials laminated vertically.

[0018] In this way, when constructing a building by laminating the construction material discharged from the material discharge nozzle of the laminated 3D printer, by appropriately performing interlayer reinforcement of the laminated structure, it becomes possible to construct a high-quality building.

Brief Description of the Drawings

[0019] [Figure 1] Schematic diagram of a laminated 3D printer according to an embodiment of the present invention. [Figure 2] Flowchart of the interlayer reinforcement method in the lamination direction in the laminated 3D printer according to an embodiment of the present invention. [Figure 3] Flowchart of the reinforcing member insertion step. [Figure 4] Schematic diagram of a test specimen for mechanical testing. [Figure 5] Explanatory drawing showing bending test results (comparison with or without reinforcement). [Figure 6] Explanatory drawing showing bending test results (comparison between driving and laminating).

Embodiment for Carrying out the Invention

[0020] Hereinafter, referring to the drawings, a method for interlayer reinforcement in the stacking direction in a stacked 3D printer according to an embodiment of the present invention (hereinafter, may be abbreviated as the interlayer reinforcement method) will be described. FIGS. 1 to 6 illustrate the method for interlayer reinforcement in the stacking direction in a stacked 3D printer according to an embodiment of the present invention. FIG. 1 is a schematic diagram of a stacked 3D printer, FIGS. 2 and 3 are flowcharts of the interlayer reinforcement method, FIG. 4 is a schematic diagram of a test specimen for a mechanical test, FIG. 5 is an explanatory drawing showing bending test results (comparison with or without reinforcement), and FIG. 6 is an explanatory drawing showing bending test results (comparison between driving and laminating).

[0021] <Outline of the Interlayer Reinforcement Method> The interlayer reinforcement method according to an embodiment of the present invention is, as shown in FIG. 1, a method for constructing a building by laminating a construction material (for example, a cement-based material) discharged from a material discharge nozzle of a stacked 3D printer. In doing so, the interlayers of the laminated structure are reinforced. This interlayer reinforcement method includes, as shown in FIG. 2, a laminated structure formation step (S10) and a reinforcement insertion step (S20). Then, the laminated structure formation step (S10) and the reinforcement insertion step (S20) are repeatedly carried out to construct a building.

[0022] <Device Used in the Interlayer Reinforcement Method> As shown in Figure 1, the stacked 3D printer 10 used in the interlayer reinforcement method according to an embodiment of the present invention mainly comprises a material discharge nozzle 20 for dispensing construction material, a robot arm 30 for moving the material discharge nozzle 20 to a desired position, a material supply pump 40 for supplying construction material to the material discharge nozzle 20, and a control device 50 for controlling the drive of each device. The control device 50 may be a device that comprehensively controls each device, or it may be a device that individually controls the robot arm 30, material discharge nozzle 20, material supply pump 40, etc. Furthermore, the stacked 3D printer 10 of this embodiment is equipped with a reinforcement material insertion device 70 for inserting reinforcement material 80 between the layers of the stacked structure 90 formed from construction material.

[0023] Although the stacked 3D printer 10 shown in Figure 1 is a device in which the components are mounted on a mobile trolley 60, the stacked 3D printer 10 used in the interlayer reinforcement method according to the embodiment of the present invention can be appropriately modified to suit various factors such as the scale and shape of the building to be constructed.

[0024] <Construction Materials> The construction material is a material used to construct a building using a 3D printer. It can be any material, such as cement-based material or synthetic resin material, as long as it can be extruded from the material extrusion nozzle 20 and layered to construct a building. In this embodiment, a cement-based material is used. In this embodiment, a layered structure 90 is formed from the construction material extruded from the material extrusion nozzle 20, and the layered structure 90 is assembled to construct a building.

[0025] <Reinforcement material> The reinforcing material 80 is a material used to reinforce the interlayers of a laminated structure 90 formed from construction materials, and uses rigid fibers such as metal or carbon-based (CFRP). In this embodiment, the fibers used as the reinforcing material 80 preferably have a uniform and straight cross-section in order to be inserted straight through the layer boundaries of the laminated material. Therefore, fibers with hook-shaped ends or those with anchors formed at the ends are not suitable. A uniform cross-section means that the shape and thickness of the cross-section do not change in the length direction, and refers to cylindrical or prismatic fibers with approximately the same thickness.

[0026] Furthermore, the fibers used as reinforcing material 80 are inserted perpendicularly through the layer boundaries into the laminated structure 90 to minimize the gap between them and the cement-based material when inserted into the laminated structure 90. When inserting the reinforcing material 80 into the laminated structure 90, it is preferable that the reinforcing material 80 is inserted perpendicularly through the interlayer portion, but a slight inclination of the reinforcing material 80 is acceptable as long as there is no gap between the laminated structure 90 and the reinforcing material 80. In addition, the degree of rigidity of the reinforcing material 80 is sufficient as long as it can be inserted straight into the laminated structure 90, and it may also have elasticity and flexibility.

[0027] <Reinforcement material insertion device> The reinforcing material insertion device 70 is, for example, a device like a rice transplanter, and is designed to insert the reinforcing material 80 straight into the laminated structure 90. In other words, the reinforcing material insertion device 70 can be any device that can insert the reinforcing material 80 straight into the laminated structure 90, and can be appropriately modified according to various factors such as the scale and shape of the construction to be built. In Figure 1, the reinforcing material insertion device 70 is attached to the robot arm 30 and moves together with the robot arm 30, but the reinforcing material insertion device 70 and the robot arm 30 may be moved separately. The reinforcing material insertion device 70 shown in Figure 1 is designed to insert the reinforcing material 80 into the laminated structure 90 immediately after the cement-based material (construction material) constituting the laminated structure 90 is discharged. Immediately after the cement-based material (construction material) constituting the laminated structure 90 is discharged means the state before the cement-based material (construction material) hardens and it becomes impossible to insert the reinforcing material 80 into the laminated structure 90.

[0028] <Laminated structure formation process> The layered structure formation process involves discharging construction material from a material discharging nozzle 20 to form a layered structure 90. In this layered structure formation process, a layered 3D printer 10 is used, and a robotic arm 30 is operated under the control of a control device 50. At the same time, cement-based material (construction material) is discharging from the material discharging nozzle 20 to manufacture a layered structure 90 of the desired shape. In this process, multiple layers of construction material are stacked, but the number of layers can be appropriately changed depending on the shape of the layered structure 90 to be manufactured and the type of construction material.

[0029] <Reinforcement material insertion process> The reinforcing material insertion process, as shown in Figure 3, involves inserting the reinforcing material 80 through the layer boundaries of the stacked construction materials, and inserting the reinforcing material 80 into the construction material such that the head of the reinforcing material 80 does not protrude from the uppermost layer of construction material and is located inside the construction material rather than on the surface of the construction material. Note that the flowchart shown in Figure 3 is an example of the reinforcing material insertion process, and in the interlayer reinforcement method according to the present invention, it is not necessarily required to carry out the process in a way that satisfies all requirements. In this reinforcing material insertion process, once a multi-layered structure 90 is created using the reinforcing material insertion device 70 (S11), the reinforcing material 80 is inserted between the layers present in the multi-layered structure 90.

[0030] Furthermore, in the reinforcing material insertion process, it is preferable to keep the insertion angle of each reinforcing material 80 constant when inserting the reinforcing material 80 into the construction material (S12). Keeping the insertion angle of each reinforcing material 80 constant means that the insertion angles of the multiple reinforcing materials 80 inserted between the layers of the laminated structure 90 are the same as those of each other.

[0031] Furthermore, in the reinforcing material insertion process, it is preferable that the positions of the reinforcing material 80 to be inserted differ horizontally between the upper layer unit of the laminated structure 90 and the layer directly below the upper layer unit of the laminated structure 90 (S13). As described above, the angle at which the reinforcing material 80 is inserted into the laminated structure 90 is preferably such that the reinforcing material 80 penetrates the interlayer portion vertically, but the reinforcing material 80 may be slightly inclined with respect to the laminated structure 90 as long as there is no gap between the laminated structure 90 and the reinforcing material 80.

[0032] The insertion of reinforcing material 80 into the layered structure 90 is performed almost simultaneously with the fabrication of the layered structure 90 by extruding cement-based material from the material extrusion nozzle 20 of the layered 3D printer 10. That is, by using a reinforcing material insertion device 70 attached as an attachment to the layered 3D printer 10, the reinforcing material 80 is immediately inserted into predetermined positions in the fabricated layered structure 90, allowing the fibers to be inserted before the cement-based material hardens. This makes it less likely for misalignment to occur in the insertion position of the reinforcing material 80 between layers. Furthermore, since the reinforcing material 80 is inserted after the fabrication of the layered structure 90, it does not interfere with the operation of the material extrusion nozzle 20.

[0033] When inserting the reinforcing material 80 into the laminated structure 90, the reinforcing material 80 is inserted into the construction material so that its head does not protrude from the uppermost construction material and is located inside the construction material rather than on the surface, so as not to obstruct the operation of the material ejection nozzle 20 when fabricating the next layer (upper layer) of the laminated structure 90. Furthermore, the reinforcing material insertion device 70 is shaped to allow immediate insertion of the reinforcing material 80 after the cement-based material is ejected from the material ejection nozzle 20. For example, a method of inserting the reinforcing material 80 in a roller-like shape, similar to planting rice seedlings, can be employed. In addition, the reinforcing material insertion device 70 needs to be positioned to follow the laminated 3D printer 10. The reinforcing material insertion device 70 controls the insertion speed of the reinforcing material 80 in accordance with the movement speed of the material ejection nozzle 20.

[0034] <Evaluation of inter-story reinforcement methods> Next, the strength evaluation of the laminated structure 90 (construction) fabricated using the interlayer reinforcement method of the present invention will be described. In the strength evaluation of the laminated structure 90 (construction), a test specimen with dimensions of 40 mm × 40 mm × 160 mm was fabricated, as shown in Figure 4. Steel fibers with diameters of 0.55 mm, 0.7 mm, and 1.2 mm were used as the reinforcing material 80. Test specimens with steel fibers of each diameter inserted inside (referred to as S55, S70, and S120, respectively) and a test specimen without steel fibers inserted (referred to as N0) were prepared, and a three-point bending test was performed. Each test specimen was fabricated by inserting steel fibers between layers of cement-based material laminated using a gantry-type 3D printer.

[0035] The test results are shown in Figure 5. As shown in Figure 5, all test specimens with inserted steel fibers showed increased strength compared to test specimens without inserted steel fibers, indicating that inserting steel fibers increased the interlayer strength.

[0036] Figure 6 shows a comparison of the strength of a laminated test specimen fabricated with a 3D printer 10 and a cast test specimen. Both specimens have the same dimensions as the specimen shown in Figure 5, and no fibers are mixed in. As shown in Figure 6, the strength of the laminated test specimen was approximately 36% lower than that of the cast test specimen. This indicates that the interlayers are a mechanical weak point.

[0037] The mechanical data mentioned above pertains to the test specimens used in the experiment. However, it is reasonable to assume that these trends in mechanical data will also appear when the machinery (each component of the 3D printer), construction materials, and various other conditions are changed. [Explanation of Symbols]

[0038] 10. Layered 3D Printers 20 Material Dispensing Nozzles 30 Robot Arms 40 Material supply pump 50 Control device 60 Mobile carts 70 Reinforcement material insertion device 80 Reinforcement material 90 Layered structure

Claims

1. A method for reinforcing the interlayers of a layered structure when constructing a building by layering construction materials extruded from the material extrusion nozzle of a layered 3D printer, A laminated structure formation process involves discharging construction materials from a material discharge nozzle to form a laminated structure consisting of multiple layers, After forming the aforementioned multi-layered laminated structure, a reinforcing material insertion step is performed in which a reinforcing material is inserted into the construction material such that, after forming the aforementioned multi-layered laminated structure, a reinforcing material is inserted into the layer boundary of the construction material in the multi-layered laminated structure so as to penetrate from the upper layer to the lower layer of the laminated structure, and the head of the reinforcing material does not protrude from the construction material located at the uppermost layer, and is located inside the construction material rather than on the surface of the construction material. A method for interlayer reinforcement in the stacking direction in a stacked 3D printer, characterized by including the following:

2. The method for interlayer reinforcement in the stacking direction in a stacking type 3D printer according to claim 1, characterized in that, in the reinforcing material insertion step, the insertion angle of each reinforcing material is kept constant when inserting the reinforcing material into the construction material.

3. The interlayer reinforcement method in the stacking direction of a stacking type 3D printer according to claim 1 or 2, characterized in that, in the reinforcing material insertion step, the positions of the reinforcing material to be inserted in the stacking structural unit located in the upper layer and the stacking structural unit located in the layer directly below the stacking structural unit located in the upper layer are different from each other in the horizontal direction.

4. The interlayer reinforcement method in the stacking direction of a stacking type 3D printer according to any one of claims 1 to 3, characterized in that the reinforcing material has a uniform and straight cross-section.

Images