A method for controlling the honeycomb printing path in a concrete 3D printer

Abstract

This invention provides a method for controlling the honeycomb printing path in a concrete 3D printer, belonging to the technical field of concrete 3D printing equipment. It enables the creation of a honeycomb path, using the nozzle diameter *a* and the radius *R* of the inscribed circle of the outer layer path of each unit cell as path parameters to control the width and overall size of the printing path. The filling units of the honeycomb path are unit cells, double cells, triple cells, and multi-cell cells. Planar structures are created by combining and connecting these filling units. Path parameters are added to the planar structures according to the specific shape of the slice to form a continuous, one-stroke printing path. This content is then modularized and embedded into the 3D printer. This invention enables the creation of a novel honeycomb printing path, allowing the printing of large structural components using small to medium-sized concrete 3D printers. Furthermore, by adjusting the parameters, this path is not only suitable for printing large building structures but also for printing small non-concrete materials.

Description

Technical Field

[0001] This invention belongs to the technical field of concrete 3D printing equipment. Specifically, it relates to a control method for a honeycomb-shaped path in the concrete 3D printing process, which is a control method for a continuous honeycomb-shaped printing path suitable for rotary concrete 3D printers. Background Technology

[0002] Regarding printing paths, path planning methods for concrete 3D printing utilize improved versions of conventional methods such as parallel scan paths or contour offset methods. While these methods generally meet the requirements of concrete 3D printing, they struggle to achieve complete global continuity of the printing path. Furthermore, printed components using these methods exhibit significant anisotropy, severely impacting mechanical properties. Research indicates that structures printed using loop paths demonstrate superior mechanical properties. Honeycomb structures, a type of loop structure, are currently considered the best known topology for covering a two-dimensional plane, possessing excellent mechanical and structural properties and widely used in lightweight structural design. However, concrete 3D printing methods using extrusion molding processes cannot continuously print honeycomb array structures, presenting a technical challenge. Summary of the Invention

[0003] To address the global discontinuity problem in existing concrete 3D printing paths and to mitigate the anisotropy of the mechanical properties of printed products, this invention provides a method for controlling the honeycomb printing path of a concrete 3D printer, which can achieve a continuous honeycomb printing path.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A method for controlling the honeycomb printing path in concrete 3D printing, the method comprising: determining the filling unit, determining the planar structure, determining the path parameters, and determining the path trajectory, specifically including the following steps:

[0006] Step S1: Construct filling units for the honeycomb printing path, wherein the filling units include single cells, double cells, triple cells, and multi-cell cells.

[0007] Furthermore, the specific implementation steps of S1 are as follows:

[0008] Step S1.1: Constructing a single cell (e.g.) Figure 1 As shown in the diagram, the unit cell path is a continuous path formed by connecting inner and outer paths through an inner semicircular arc. The inner and outer paths are concentric "quasi-"regular hexagons, and the beginning and end points of the unit cell path are located at the two vertices of any side L of the outer regular hexagon.

[0009] The path L is continuous with the opening side of the inner hexagon, but discontinuous with the outer hexagon. Specifically, in the outer hexagonal structure, there is an opening between edge L and one of its adjacent edges L1 (the opening is located on edge L1), defined as interface 1. Similarly, there is an opening between edge L and another adjacent edge L2 (the opening is located on edge L), defined as interface 2 at the vertex of this intersection. The opening size at interface 2 is 'a'. Interfaces 1 and 2, serving as the starting and ending points of the unit cell path trajectory, are essentially two vertices on one side of the outer hexagon. These interfaces also connect to other unit cell paths.

[0010] Furthermore, the diameter of the semicircular arc is a; the distance between the inner and outer paths is a; and the distance between the tangent point of the semicircular arc and its opposite inner path edge m after parallel movement and the inner edge m is also a.

[0011] Furthermore, 'a' refers to the diameter of the printhead, meaning the spacing between the inner and outer paths is driven by the printhead diameter 'a', thus the print path spacing is controllable.

[0012] Step S1.2: Construct a twin-cell path, which is formed by connecting and combining two single-cell paths through an interface according to connection rules.

[0013] Furthermore, the connection rules state that there are four ways to connect the interfaces of two units: one unit connects to the other unit via interface 1 or interface 2. The two units are also arranged closely in a structure similar to a natural honeycomb.

[0014] Step S1.3: Construct a triploid, similar to the process of constructing a twin. The combination scheme can use three single cells, or it can choose to use a twin plus a single cell. The connection rules are the same as in step S1.2.

[0015] Step S1.4: Construct a multicellular structure by combining and generating the various filling units constructed in the above steps.

[0016] Step S2: Construct a planar structure with a honeycomb printing path. This planar structure has two factors: geometric shape and geometric size. Essentially, it is a further combination and extension of the infill units from Step S1, incorporating commonly used shapes in concrete 3D printing components based on practical experience. Specifically: the geometric shape of the planar structure is determined by the combination of infill units, and the geometric size is driven by the path parameters: the radius R of the inscribed circle of the outer layer path of the unit cell and the printing nozzle diameter a.

[0017] Furthermore, the specific implementation steps of S2 are as follows:

[0018] Step S2.1: Based on the graphic characteristics of the structure to be printed during the actual printing process, select one or more filling units generated in step S1 as the basis for building the planar structure.

[0019] Step S2.2: Based on the selected filling units, connect and combine them according to the connection rules described in step S1.2 to generate a planar structure suitable for filling the structure to be printed.

[0020] Step S3: Calculate the path parameters of a layer based on the slice data of the structure to be printed.

[0021] Step S4: Add the calculated path parameters to the planar structure built in step S2, so that the planar structure completely fills the slice of this layer. Repeat the process of steps S3 and S4 until all slices are filled to form a complete path trajectory.

[0022] The present invention has the following beneficial effects:

[0023] This invention achieves global continuity of the printing path through a double-layered honeycomb structure. Simultaneously, due to the presence of printing paths in different directions within the printed component, a multi-directional disordered arrangement is generated macroscopically, thereby reducing the anisotropy of the printed component. Furthermore, the hollow portions of the smallest unit cell constituting the honeycomb printing path can be subsequently filled with various fillers, such as reinforcing bars, coarse aggregates, grout, and other thermal insulation materials, to increase the versatility of the wall. Moreover, the path method of this invention allows for controllable printing path spacing, adapting to printing equipment with different nozzle outlet diameters, and is also suitable for extrusion-based 3D printing of materials such as polymers and metals. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the trajectory of a single cell in a honeycomb-shaped printing path.

[0025] Figure 2 Example diagram of the fill cell trajectory for a honeycomb-shaped printing path; Figure 2 In the diagram, A represents a single-cell example, B represents a twin-cell example, C represents a triplet example, and D represents a multi-cell example. 1 represents interface 1, and 2 represents interface 2.

[0026] Figure 3 Example diagram of a planar structure with a honeycomb-shaped printing path; Figure 3 In the diagram, E represents a single-layer hollow structure and a single-layer solid structure; F represents a double-layer structure; G represents a polygonal structure; and H represents a three-layer straight structure.

[0027] Figure 4 This section describes the specific connection process for the double-layered hexagonal structure.

[0028] Figure 5This section compares the printing paths under different path parameters, using a double-layer hexagonal structure module as an example. Figure 5 In the diagram, IR = 70mm, a = 25mm; JR = 70mm, a = 15mm; KR = 60mm, a = 25mm; LR = 60mm, a = 15mm. (Where R represents the radius of the inscribed circle of the outer layer path of the unit cell, and a represents the diameter of the printing nozzle.) Detailed Implementation

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0030] A method for controlling the honeycomb printing path in concrete 3D printing, the method comprising: determining the filling unit, determining the planar structure, determining the path parameters, and determining the path trajectory, specifically including the following steps:

[0031] Part 1: Constructing the filling cells of the honeycomb printing path, including building the connecting paths and the filling shape, the steps are as follows:

[0032] Step S1: Construct filling units for the honeycomb printing path, wherein the filling units include single cells, double cells, triple cells, and multi-cell cells. The specific implementation steps of S1 are as follows:

[0033] Step S1.1: Construct a single cell, such as... Figure 1 As shown, the unit cell path is a continuous path formed by connecting inner and outer paths through an inner semicircular arc. The inner and outer paths are concentric "quasi-"regular hexagons, and the beginning and end points of the unit cell path are located at the two vertices of any side L of the outer regular hexagon.

[0034] The path L is continuous with the opening side of the inner hexagon, but discontinuous with the outer hexagon. Specifically, in the outer hexagonal structure, there is an opening between edge L and one of its adjacent edges L1 (the opening is located on edge L1), defined as interface 1. Similarly, there is an opening between edge L and another adjacent edge L2 (the opening is located on edge L), defined as interface 2 at the vertex of this intersection. The opening size at interface 2 is 'a'. Interfaces 1 and 2, serving as the starting and ending points of the unit cell path trajectory, are essentially two vertices on one side of the outer hexagon. These interfaces also connect to other unit cell paths.

[0035] The diameter of the semicircular arc is 'a'; the distance between the inner and outer paths is 'a'; the distance between the point of tangency of the semicircular arc and its corresponding inner path edge 'm' after parallel movement and the inner path edge 'm' is also 'a'. 'a' represents the diameter of the printhead, meaning the distance between the inner and outer paths is driven by the printhead diameter 'a'.

[0036] Step S1.2: Construct a twin-cell path, whereby the twin-cell path is formed by connecting and combining two single-cell paths through an interface according to connection rules. For example... Figure 2 -B shows a twin cell with the left cell as the initial cell and the right cell as the connecting cell. The interface 2 of the initial cell is connected to the interface 1 of the connecting cell, and the two cells are arranged in a tight honeycomb pattern.

[0037] Step S1.3: Constructing a triploid, similar to the process of constructing a twin. The combination scheme can use three single cells, or it can choose to use one twin plus one single cell. The connection rules are the same as in step S1.2. For example... Figure 2 -C The three-cell structure shown is composed of three unit cells connected together. The interface 2 of the upper unit cell is connected to the interface 2 of the middle unit cell, and the interface 1 of the middle unit cell is connected to the interface 2 of the lower unit cell. The three unit cells are arranged in a tight honeycomb pattern.

[0038] Step S1.4: Construct a multicellular structure by combining and generating the various filling units constructed in the above steps. Figure 2 -D represents an example of a heptacellular organism. Figure 2 -B is based on the combination of twins.

[0039] Part Two: Constructing the planar structure of the honeycomb printing path. The planar structure of the honeycomb printing path is further combined from the fill cells, as follows:

[0040] Step S2: Construct a planar structure with a honeycomb printing path. This planar structure has two factors: geometric shape and geometric size. Essentially, it is a further combination and extension of the infill units from Step S1, incorporating commonly used shapes in concrete 3D printing components based on practical experience. The geometric shape of the planar structure is determined by the combination of infill units, and its geometric size is driven by the path parameters: the radius R of the inscribed circle of the outer layer path of the unit cell and the printing nozzle diameter a. The specific implementation steps of S2 are as follows:

[0041] Step S2.1: Based on the graphic characteristics of the structure to be printed during the actual printing process, select one or more filling units generated in step S1 as the basis for building the planar structure.

[0042] Step S2.2: Based on the selected filling units, connect and combine them according to the connection rules described in step S1.2 to generate a planar structure suitable for filling the structure to be printed. Figure 3 The document demonstrates four commonly used planar structural examples, and their formation process is as follows:

[0043] (1) Single-layer hexagonal structure: divided into single-layer hollow structure and single-layer solid structure, among which Figure 3-E The single-layer hollow structure on the left is based on the twin cells in the filling unit. Starting from any twin cell, it is combined in the direction of the arrow to finally form the structure. Figure 3 The single-layer solid structure on the right side of -E can be seen as a combination of twin cells, starting from the central single cell.

[0044] (2) Multi-layer hexagonal structure: A large structure formed by rotating and connecting 2N+1 cells as the basic unit. By analogy, a hexagonal honeycomb structure with a larger space in the middle can be designed. Figure 3 -F represents a double-layered hexagonal structure formed using triplets as basic units, where the arrow indicates the direction of structure formation. See [link to details] for the specific formation process. Figure 4 Starting with the triplet within the rectangular dashed frame, the triplets are combined in the direction of the arrows to form a structure, which is then connected to the triplet within the elliptical dashed frame. This process is repeated until a double-layered hexagonal structure is finally formed.

[0045] (3) Broken-line composite structure: It uses 2N+1 cells as the basic unit, but the direction of rotation is different from that of the multi-layer hexagonal structure. In addition, there are repeated single cells at the change of direction for smooth connection. Figure 3 -G represents a broken-line structure formed using heptacells as the basic unit.

[0046] (4) Multi-layer linear structure: It is formed by connecting twin or multi-cell filling units. The difference between it and the other structures mentioned above is that the generation route of the multi-layer linear structure is a straight line. Figure 3 -H is an example of a three-layer linear structure with hexacells as the basic unit. The connection order of this structure is shown by the arrows in the figure.

[0047] Part Three: Fill Path Planning. Taking a hemispherical structure to be printed as an example, the specific steps are as follows:

[0048] Step S3: Based on the slice data of one layer of the structure to be printed, calculate the path parameters for that layer. The path parameters include two parameters: the printing nozzle diameter *a* and the radius *R* of the inscribed circle of the outer layer path of the unit cell, which affect the specific length of the honeycomb path. Figure 5 This section describes the changes in unit cell size and the size of the double-layer hexagonal structure under two different path parameters. By adjusting the path parameters, the unit cell size can be adjusted while keeping the spacing between the honeycomb printing paths constant, thus adapting to printed components of various sizes.

[0049] Since the structure to be printed is hemispherical, and each layer after slicing is circular, in step S2, a multi-layer hexagonal structure in the planar structure is selected as the slicing filling path, and the specific values ​​of the path parameters are calculated.

[0050] Step S4: Substitute the calculated path parameters into the planar structure to complete the filling of one layer of slices. Select the next layer of slices and repeat step S3 until all slices are filled, forming a complete path trajectory.

[0051] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for controlling the honeycomb printing path in a concrete 3D printer, characterized in that, The control method includes: determining the filling unit, determining the planar structure, determining the path parameters, and determining the path trajectory, specifically including the following steps: Step S1: Construct filling units for the honeycomb printing path, wherein the filling units include single cells, double cells, triple cells, or multiple cells; specifically: Step S1.1: Construct a unit cell. The unit cell path is a continuous path formed by connecting inner and outer paths through an inner semicircular arc. The inner and outer paths are concentric "quasi" regular hexagons, and the beginning and end points of the unit cell path are located at the two vertices of any side L of the outer regular hexagon. The edge L is a continuous path connected to the opening side of the inner regular hexagon, but a discontinuous path connected to the outer regular hexagon. That is, in the outer hexagonal structure, there is an opening between edge L and one of its adjacent edges L1, which is defined as interface 1. There is also an opening between edge L and another adjacent edge L2, and the vertex of edge L and edge L2 is defined as interface 2. The opening size at the location of interface 2 is a. Interface 1 and interface 2 serve as the starting and ending points of the unit cell path trajectory. Essentially, they are two vertices on one side of the outer hexagon. At the same time, the two interfaces also have the function of connecting other cell paths. The diameter of the semicircular arc is a; the distance between the inner and outer paths is a; the distance between the point of tangency of the semicircular arc and its opposite inner path after parallel movement and the inner edge m is also a. The 'a' refers to the diameter of the printhead, meaning the spacing between the inner and outer paths is driven by the printhead diameter 'a', thus the print path spacing is controllable. Step S1.2: Construct a twin cell. The twin cell path is formed by connecting two single cell paths through an interface according to connection rules. The connection rules are that there are four ways to connect the interfaces of the two single cells, namely, connecting the interface 1 or interface 2 of one single cell to the interface 1 or interface 2 of the other single cell; and the two single cells are arranged closely in a structure similar to a natural honeycomb. Step S1.3: Construct a triploid, similar to the process of constructing a twin. The combination scheme can use three single cells, or it can choose to use a twin plus a single cell. The connection rules are the same as in step S1.

2. Step S1.4: Construct a multicellular structure by combining and generating the various filling units constructed in the above steps; Step S2: Construct a planar structure for the honeycomb printing path. The planar structure includes two factors: geometric shape and geometric size. The geometric shape of the planar structure is determined by the combination of filling units, and the geometric size of the planar structure is driven by the path parameters: the radius R of the inscribed circle of the outer layer path of the unit cell and the diameter a of the printing nozzle. Step S3: Based on the slice data of one layer of the structure to be printed, calculate the path parameters of that layer; Step S4: Add the calculated path parameters to the planar structure built in step S2, so that the planar structure completely fills the slice of this layer. Repeat the process of steps S3 and S4 until all slices are filled to form a complete path trajectory.

2. The method for controlling the honeycomb printing path of a concrete 3D printer according to claim 1, characterized in that, The specific steps of S2 are as follows: Step S2.1: Based on the graphic characteristics of the structure to be printed during the actual printing process, select one or more filling units generated in step S1 as the basis for building the planar structure. Step S2.2: Based on the selected filling units, connect and combine them according to the connection rules described in step S1.2 to generate a planar structure suitable for filling the structure to be printed.

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