Single-layer lattice structure 3D printing method based on six-axis mechanical arm printing

Abstract

The invention discloses a 3D printing method for a single-layer lattice structure based on six-axis mechanical arm printing, and belongs to the crossing field of additive manufacturing and intelligent building. A first point sequence arranged according to the first arrangement sequence and a second point sequence arranged according to the second arrangement sequence are calculated, the first point sequence is a C-shaped sequence, and the second point sequence is a Z-shaped sequence; 2, a 3D printing path is generated based on the first point sequence and the second point sequence; and thirdly, the 3D printing path is input into a six-axis mechanical arm for printing, and therefore path planning and printing of the complex special-shaped curved surface lattice structure can be achieved. Experiments show that compared with a traditional cube lattice path planning method, the method has the advantages that the manual path planning time can be shortened by 50%, and the compressive strength of a printing structure is improved by 25%.

Description

Technical Field

[0001] This invention belongs to the technical field of additive manufacturing and intelligent construction, specifically relating to a 3D printing method for a single-layer lattice structure based on a six-axis robotic arm. Background Technology

[0002] Lattice space structures possess numerous advantages, including lightweight, rapid construction, and controllable shape. Six-axis robotic arms offer high-degree-of-freedom construction capabilities, making their use in printing lattice space structures highly valuable in industrial, architectural, and artistic fields. For example, when fabricating building facade panels, closed-cell polyurethane foam insulation can be used to fill the hollow sections of a carbon fiber lattice space structure, which is then covered with glass fiber reinforced concrete. However, because the shape of the lattice space structure varies according to specific needs, and the printing paths for different shapes require manual planning, this undoubtedly increases labor costs. With the increasing demand for lattice space structures, research into the fabrication methods and processes for 3D-printed lattice structure components is of great significance.

[0003] In existing processes for fabricating 3D-printed lattice structures using six-axis robotic arms, most of the fabricated lattice structures are composed of cubic lattices. The printing path planning for these lattice structures is simple, but it does not involve the fabrication of complex, irregularly shaped lattice structures. Therefore, there is an urgent need for a 3D printing method based on a six-axis robotic arm for single-layer lattice structures, capable of path planning and printing complex, irregularly shaped lattice structures. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a 3D printing method for single-layer lattice structures based on a six-axis robotic arm. The technical problem to be solved by this invention is achieved through the following technical solution: In a first aspect, the present invention provides a 3D printing method for a single-layer lattice structure based on a six-axis robotic arm. The single-layer lattice structure includes a plurality of lattice units with topological orientations in the X-axis and Y-axis directions, wherein the number of lattice units in both the X-axis and Y-axis directions is greater than or equal to 1. The method includes: Step 1: Establish a hexahedral model. Based on the hexahedral model, calculate the first point sequence arranged in the first permutation order and the second point sequence arranged in the second permutation order. The first point sequence is a C-shaped sequence and the second point sequence is a Z-shaped sequence. Step 2: Generate the 3D printing path based on the first and second point sequences; Step 3: Input the 3D printing path into the six-axis robotic arm for printing; Step two specifically includes: A preset printing model for a hexahedral model is established. The preset printing model includes planar rods and spatial connecting rods. The planar rods include an upper structure and a lower structure. Based on the C-shaped sequence, generate the printing path for the lower-level structure; Based on the Z-shaped sequence, generate the printing path for the upper-level structure; Based on the Z-shaped sequence, the printing path of the spatial connecting rod frame is generated.

[0005] In one embodiment of the present invention, the hexahedral model includes a front elevation and a rear elevation; Step one specifically includes: Two quadrilateral mesh models with approximately rectangular shapes were created using Rhino software. These two quadrilateral mesh models are model M1 and model M2, and model M1 and model M2 are the front and rear elevations of the hexahedral model, respectively. Extract the boundary lines of model M1 and model M2, and correct the pre-printing positions of model M1 and model M2; Extract equally spaced points on model M1; Extract the division points on model M2; The equally divided points extracted from model M1 and model M2 are arranged according to the first arrangement order to obtain the first point sequence; The second point sequence is formed by arranging the equally divided points extracted from model M1 and model M2 according to the second arrangement order; Output computational logic cluster.

[0006] In one embodiment of the present invention, extracting the boundary lines of model M1 and model M2 and correcting the pre-printing positions of model M1 and model M2 specifically includes: Extract the boundary lines of models M1 and M2. The boundary line is one of the four edge lines generated after the outer contour line of the quadrilateral mesh model is broken by its four corner points. When a boundary line of model M1 and a boundary line of model M2 are close to each other, these two boundary lines are regarded as a group of boundary lines. Models M1 and M2 together form four groups of boundary lines. The four groups of boundary lines are numbered as 0, 1, 2 and 3 respectively. Select one of the four boundary line groups for detection. If the chain boundary lines in the selected boundary line group are coplanar, output True; otherwise, output False. When a set of coplanar boundary lines is identified, the coplanar surfaces within this set are output as Planes. 边线共面 And output the midpoint of the boundary line belonging to model M1 among these two boundary lines as P. 边线中点 And P 边线中点 As Plane 边线共面 The origin; Establish a point P平台中心 As the central point of the printing platform; Move models M1 and M2 so that P 边线中点 and P 平台中心 The lattice structures are overlapped so that one horizontal side of the lattice structure is placed on the printing platform as the bottom surface.

[0007] In one embodiment of the present invention, extracting equally spaced points on model M1 specifically includes: Two opposing boundary lines are selected on model M1, and the two boundary lines are divided into equal-division interpolation curves with the number of equal divisions being Number1. The equally divided tween curve is projected onto the mesh of model M1. The equally divided tween projection curve projected onto the mesh of model M1 is divided equally to obtain the first dividing point. The number of equal segments is Number2. The first division points on model M1 are connected by polylines in a first specific order; Divide the polyline obtained by connecting all the first division points into equal parts to obtain the second division points. The number of divisions is Number1. Then, use polylines to connect the second division points on model M1 in a second specific order. Divide the polyline obtained by connecting all the second division points into equal parts to obtain the third division point. The number of segments is Number2, and the set of the third division points is denoted as DataM1.

[0008] In one embodiment of the present invention, extracting equally spaced points on model M2 specifically includes: Two opposing boundary lines are selected on model M2, and the two boundary lines are divided into equal parts by interpolation curves, with the number of segments being Number1. The equally divided tween curve is projected onto the mesh of model M2. The equally divided tween projection curve projected onto the mesh of model M2 is then divided equally to obtain the fourth dividing point. The number of equal segments is Number2. The fourth division point on model M2 is connected by polylines in a first specific order; Divide the polyline obtained by connecting all the fourth division points into equal parts to obtain the fifth division point. The number of segments is Number1. Then, use polylines to connect the fifth division point on model M2 in a second specific order. Divide the polyline obtained by connecting all the fifth division points into equal parts to obtain the sixth division point. The number of segments is Number2, and the set of the sixth division points is denoted as DataM2.

[0009] In one embodiment of the present invention, the equally divided points extracted from model M1 and model M2 are arranged according to a first arrangement order to obtain a first point sequence, specifically including: Assuming DataM1 = {1, 2, 3} and DataM2 = {A, B, C}, arranging them according to the first permutation order yields the first point sequence, which is a C-shaped sequence, namely {1, 2, 3, A, B, C}. The second point sequence, which is the second arrangement of the equally divided points extracted from model M1 and model M2 according to the second permutation order, specifically includes: Assume DataM1 = {1, 2, 3} and DataM2 = {A, B, C}. Arrange them according to the second permutation order to obtain the second point sequence. The second point sequence is a Z-shaped sequence, which is {1, A, 2, B, 3, C}.

[0010] In one embodiment of the present invention, the computational logic cluster includes {M1, M2, Number1, Number2, the boundary line group number, P}. 平台中心}

[0011] In one embodiment of the present invention, the spatial connecting rod frame includes multiple vertical rods and diagonal rods, the planar rod frame includes an upper planar rod frame and a lower planar rod frame, the two ends of the spatial connecting rod frame are respectively connected to the upper planar rod frame and the lower planar rod frame, and adjacent two vertical rods are connected by diagonal rods; Based on the Z-shaped sequence, the printing path of the spatial connecting rod frame is generated, specifically including: Starting from the nth point of the lower plane frame and ending at the nth point of the upper plane frame, generate the printing path for the vertical pole; Starting from the nth point of the upper plane frame and ending at the (n+1)th point of the lower plane frame, generate the printing path for the diagonal brace; Based on the Z-shaped sequence, the printing paths of the vertical rods and the diagonal rods are arranged in order to obtain the printing path of the spatial connecting rod frame.

[0012] In one embodiment of the present invention, step three specifically includes: Set the nozzle to the position of the point, the extrusion speed of the extruder to 90, pause for 1 second, the moving speed of the nozzle to 10mm / s, and the extrusion speed of the extruder to 20. Based on the 3D printing path generated in step two, the printing is performed in the order of first bottom layer, first top layer, spatial connecting rod frame, second bottom layer and second top layer.

[0013] In one embodiment of the present invention, the point where the end point of the vertical rod and the starting point of the inclined rod in the spatial connecting rod frame coincide is the intersection point; Printing of spatial connecting rod frames, including: Move the nozzle to the starting position of the vertical bar, set the extruder's extrusion speed to 50, and pause for 1 second; Turn on the cooling unit and set the position 1cm away from the end point of each vertical rod as the extrusion stop point. During the process of the nozzle moving from the starting point of the vertical rod to the extrusion stop point, the moving speed of the nozzle is 4mm / s and the extrusion speed of the extruder is 8. When the nozzle reaches the extrusion stop point, the extrusion speed is 0 and the moving speed remains unchanged. When the nozzle is at the junction point, pause for 10 seconds, adjust the extrusion speed to 8, pause for 3.8 seconds, adjust the moving speed to 6 mm / s, adjust the extrusion speed to 30, and move towards the end point of the inclined rod.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: In the above-described scheme of this application, the 3D printing method includes the following steps: Step 1: Establishing a hexahedral model; based on the hexahedral model, calculating a first point sequence arranged in a first order and a second point sequence arranged in a second order, wherein the first point sequence is a C-shaped sequence and the second point sequence is a Z-shaped sequence; Step 2: Generating a 3D printing path based on the first and second point sequences; Step 3: Inputting the 3D printing path into a six-axis robotic arm for printing; Step 2 specifically includes: establishing a preset printing model of the hexahedral model, the preset printing model including planar rods and spatial connecting rods, the planar rods including an upper structure and a lower structure; generating a printing path for the lower structure based on the C-shaped sequence; and generating a printing path for the spatial connecting rods based on the Z-shaped sequence. Using this method, based on two point sequences, the C-shaped and Z-shaped sequences, the printing paths for the planar rods and spatial connecting rods are planned, enabling path planning and printing of complex irregular curved surface lattice structures. The above-described method of this invention reduces the degree of manual intervention in the path planning process, improves the degree of automation, and shortens the production cycle. Meanwhile, the lattice structure components produced using the novel path planning method of this invention exhibit stronger structural performance in certain situations compared to traditional methods.

[0015] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a hexahedral model in an embodiment of the present invention; Figure 2 These are schematic diagrams of model M1 and model M2 in embodiments of the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the outline of model M1 in an embodiment of the present invention; Figure 4 This is a schematic diagram of model M1 and model M2 placed on a horizontal plane in an embodiment of the present invention; Figure 5 This is a schematic diagram of setting equally divided interlacing curves and the first equally divided point on model M1 in an embodiment of the present invention; Figure 6 This is a schematic diagram of the first equally divided point on model M1 using a multi-segment line in an embodiment of the present invention; Figure 7 This is a schematic diagram of the second division point on model M1 connected by a polyline in an embodiment of the present invention; Figure 8 This is a schematic diagram of Data1 and Data2 in an embodiment of the present invention; Figure 9 This is a schematic diagram of the C-shaped sequence in an embodiment of the present invention. Figure 1 ; Figure 10 This is a schematic diagram of the Z-shaped sequence in an embodiment of the present invention. Figure 1 ; Figure 11 This is a schematic diagram of the grid model of the crystal structure in an embodiment of the present invention; Figure 12 This is an exploded view of the planar rod in an embodiment of the present invention; Figure 13 This is a schematic diagram of the decomposed mesh model of the crystal structure in an embodiment of the present invention; Figure 14 This is a schematic diagram of the C-shaped sequence in an embodiment of the present invention. Figure 2 ; Figure 15 This is a schematic diagram of the Z-shaped sequence in an embodiment of the present invention. Figure 2 ; Figure 16 This is a schematic diagram of the lower planar frame and the spatial connecting frame in an embodiment of the present invention. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0018] Please see Figures 1 to 16 This invention provides a 3D printing method for a single-layer lattice structure based on a six-axis robotic arm. The single-layer lattice structure includes several six-lattice units with topological orientations in the X and Y axes. The number of lattice units in both the X and Y axes is greater than or equal to 1. The method includes: Step 1: Establish a hexahedral model. Based on the hexahedral model, calculate the first point sequence arranged in the first permutation order and the second point sequence arranged in the second permutation order. The first point sequence is a C-shaped sequence and the second point sequence is a Z-shaped sequence. Step 2: Generate the 3D printing path based on the first and second point sequences; Step 3: Input the 3D printing path into the six-axis robotic arm for printing; Step two specifically includes: A preset printing model for a hexahedral model is established. The preset printing model includes planar rods and spatial connecting rods. The planar rods include an upper structure and a lower structure. Based on the C-shaped sequence, generate the printing path for the lower-level structure; Based on the Z-shaped sequence, generate the printing path for the upper-level structure; Based on the Z-shaped sequence, the printing path of the spatial connecting rod frame is generated.

[0019] In some embodiments of this application, the 3D printing method for single-layer lattice structures based on six-axis robotic arms mainly completes the generation and fabrication of single-layer lattice structures, which can be used for the construction of prefabricated building wall supports and installation art.

[0020] In some embodiments of this application, Figure 1 A structural diagram of a hexahedral model is shown. In this model, the two opposite faces to be processed using the method described in this application are denoted as the front faces, and the other four faces are denoted as the side faces. Furthermore, the lattice structure units can be rotated in three-dimensional space and twisted or deformed without increasing the difficulty of printing.

[0021] In some embodiments of this application, in step one, two sets of point sequences with a specific spatial order can be calculated from the NURBS surface. NURBS (Non-Uniform Rational B-Spline) surface is a mathematical representation method widely used in computer graphics and CAD (Computer-Aided Design) for accurately modeling free curves and surfaces.

[0022] In the above-described scheme of this application, the 3D printing method includes the following steps: Step 1: Establishing a hexahedral model; based on the hexahedral model, calculating a first point sequence arranged in a first order and a second point sequence arranged in a second order, wherein the first point sequence is a C-shaped sequence and the second point sequence is a Z-shaped sequence; Step 2: Generating a 3D printing path based on the first and second point sequences; Step 3: Inputting the 3D printing path into a six-axis robotic arm for printing; Step 2 specifically includes: establishing a preset printing model of the hexahedral model, the preset printing model including planar rods and spatial connecting rods, the planar rods including an upper structure and a lower structure; generating a printing path for the lower structure based on the C-shaped sequence; and generating a printing path for the spatial connecting rods based on the Z-shaped sequence. Using this method, based on two point sequences, the C-shaped and Z-shaped sequences, the printing paths for the planar rods and spatial connecting rods are planned, enabling path planning and printing of complex irregular curved surface lattice structures. The above-described method of this invention reduces the degree of manual intervention in the path planning process, improves the degree of automation, and shortens the production cycle. Meanwhile, the lattice structure components produced using the novel path planning method of this invention exhibit stronger structural performance in certain situations compared to traditional methods.

[0023] In some embodiments of this application, the hexahedral model includes a front elevation and a rear elevation; Step one specifically includes: Two quadrilateral mesh models with approximately rectangular shapes were created using Rhino software. These two quadrilateral mesh models are model M1 and model M2, and model M1 and model M2 are the front and rear elevations of the hexahedral model, respectively. Figure 2 A schematic diagram of model M1 and model M2 is shown.

[0024] Extract the boundary lines of models M1 and M2, and correct the pre-printing positions of models M1 and M2. Figure 3 A schematic diagram of the extracted boundary lines of model M1 is shown; Extract equally spaced points on model M1; Extract the division points on model M2; The equally divided points extracted from model M1 and model M2 are arranged according to the first arrangement order to obtain the first point sequence; The second point sequence is formed by arranging the equally divided points extracted from model M1 and model M2 according to the second arrangement order; Output computational logic cluster.

[0025] In some embodiments of this application, the hexahedral model itself needs a horizontal surface to be attached to the printing platform during printing. This embodiment designs a horizontal surface determination component to automatically rotate the hexahedral model to a position where the horizontal surface contacts the printing platform.

[0026] In some embodiments of this application, the boundary lines of model M1 and model M2 are extracted, and the pre-printing positions of model M1 and model M2 are corrected, specifically including: Extract the boundary lines of models M1 and M2. The boundary line is one of the four edge lines generated after the outer contour line of the quadrilateral mesh model is broken by its four corner points. When a boundary line of model M1 and a boundary line of model M2 are close to each other, these two boundary lines are regarded as a group of boundary lines. Models M1 and M2 together form four groups of boundary lines. The four groups of boundary lines are numbered as 0, 1, 2 and 3 respectively. Select one of the four boundary line groups for detection. If the chain boundary lines in the selected boundary line group are coplanar, output True; otherwise, output False. When a set of coplanar boundary lines is identified, the coplanar surfaces within this set are output as Planes. 边线共面 And output the midpoint of the boundary line belonging to model M1 among these two boundary lines as P. 边线中点 And P 边线中点 As Plane边线共面 The origin; Establish a point P 平台中心 As the central point of the printing platform; Use the spatial transformation component to move models M1 and M2, so that P 边线中点 and P 平台中心 The lattice structures are overlapped so that one horizontal side of the lattice structure serves as the bottom surface on the printing platform. Figure 4 This diagram shows a set of boundary lines of the coplanar plane of models M1 and M2 placed on a horizontal plane, with the horizontal plane located on a printing platform.

[0027] In some embodiments of this application, if the chain boundary lines in the selected boundary line group are coplanar, the horizontal plane determination component will output True, otherwise False.

[0028] In some embodiments of this application, extracting equally spaced points on model M1 specifically includes: Two opposing boundary lines are selected on model M1, and the two boundary lines are divided into equal parts by interpolation curves, with the number of segments being Number1. The equally divided tweened curve is projected onto the mesh of model M1. The equally divided tweened projection curve projected onto the mesh of model M1 is then divided equally to obtain the first division point. The number of equal segments is Number2. Figure 5 This diagram illustrates the setting of equally spaced tween curves and the first dividing points on model M1. Polylines are used to connect the first dividing points on model M1 in a first specific order, where the first specific order is to connect the first dividing point of the first curve, the first dividing point of the second curve, the first dividing point of the third curve, and so on, until the first dividing point of the last curve. Then, the second dividing point of the first curve, the second dividing point of the second curve, the second dividing point of the third curve, and so on, is connected, connecting all the dividing points. Figure 6 A schematic diagram is shown showing the first division point on model M1 connected by a polyline.

[0029] Divide the polyline obtained by connecting all the first division points into equal parts to obtain the second division points, with the number of segments being Number1. Connect the second division points on model M1 using polylines in a second specific order. The second specific order is to connect the first division point of the first curve, the first division point of the second curve, the first division point of the third curve, and so on, until the first division point of the last curve. Then, connect the second division point of the first curve, the second division point of the second curve, the second division point of the third curve, and so on, until the second division point of the last curve. Continue this process, connecting all the division points. Figure 7A schematic diagram is shown showing the second division point on model M1 connected by a polyline.

[0030] Divide the polyline obtained by connecting all the second division points into equal parts to obtain the third division point. The number of segments is Number2, and the set of the third division points is denoted as DataM1. Figure 8 A schematic diagram of the first, second, and third division points in models M1 and M2 is shown.

[0031] In some embodiments of this application, extracting equally spaced points on model M2 specifically includes: Two opposing boundary lines are selected on model M2, and the two boundary lines are divided into equal parts by interpolation curves, with the number of segments being Number1. The equally divided tween curve is projected onto the mesh of model M2. The equally divided tween projection curve projected onto the mesh of model M2 is then divided equally to obtain the fourth dividing point. The number of equal segments is Number2. The fourth division point on model M2 is connected using polylines in a first specific order. This first specific order is: connecting the first division point of the first curve, the first division point of the second curve, the first division point of the third curve, and so on, until the first division point of the last curve. Then, the second division point of the first curve, the second division point of the second curve, the second division point of the third curve, and so on, is connected, until all the division points are connected.

[0032] Divide the polyline obtained by connecting all the fourth division points into equal parts to obtain the fifth division point, with the number of segments being Number1. Then, connect the fifth division point on model M2 using polylines in a second specific order. The second specific order is to connect the first division point of the first curve, the first division point of the second curve, the first division point of the third curve, and so on, until the first division point of the last curve. Then, connect the second division point of the first curve, the second division point of the second curve, the second division point of the third curve, and so on, until the second division point of the last curve. Continue this process, connecting all the division points.

[0033] Divide the polyline obtained by connecting all the fifth division points into equal parts to obtain the sixth division point. The number of segments is Number2, and the set of the sixth division points is denoted as DataM2.

[0034] In some embodiments of this application, the equally divided points extracted from model M1 and model M2 are arranged according to a first arrangement order to obtain a first point sequence, specifically including: Assuming DataM1 = {1, 2, 3} and DataM2 = {A, B, C}, arranging them according to the first permutation order yields the first point sequence, which is a C-shaped sequence, namely {1, 2, 3, A, B, C}. Figure 9 A schematic diagram of a C-shaped sequence is shown.

[0035] The second point sequence, which is the second arrangement of the equally divided points extracted from model M1 and model M2 according to the second permutation order, specifically includes: Assume DataM1 = {1, 2, 3} and DataM2 = {A, B, C}. Arrange them according to the second permutation order to obtain the second point sequence. The second point sequence is a Z-shaped sequence, which is {1, A, 2, B, 3, C}. Figure 10 A schematic diagram of the Z-shaped sequence is shown.

[0036] In some embodiments of this application, the C-shaped sequence is also called the C-shaped point, and the Z-shaped sequence is also called the Z-shaped point. The C-shaped point and the Z-shaped point are the basic points for printing path planning in this invention.

[0037] In some embodiments of this application, the computational logic cluster includes {M1, M2, Number1, Number2, the boundary line group number, P} 平台中心 When using it, "M1" and "M2" are the mesh-format lattice structure components to be printed, "Number 1" and "Number 2" are integers to control the number of units used to form the lattice structure components, "Boundary line group number" is an integer [0, 3] to select the outer edge, "P 平台中心 "The given input point serves as the center point of the printing platform. The outputs of this cluster are "Is the bottom surface flat", "C-shaped point", and "Z-shaped point". The value of "Is the bottom surface flat" tells the user whether the selected bottom surface is flat. "C-shaped point" and "Z-shaped point" respectively output a set of point sequences with a specific spatial order.

[0038] This cluster can process two arbitrarily approximate rectangular meshes to obtain two sets of point sequences with a specific spatial order, which can then be used to print lattice structure components. When multiple components with different shapes need to be produced, simply changing the input values ​​can immediately yield the two required sets of point sequences, greatly reducing the workload for humans in the process.

[0039] In some embodiments of this application, a complete printing path is derived from two sets of point sequences with a specific spatial order: “C-shaped points” and “Z-shaped points”.

[0040] The complete print path generation method required for printing lattice structure components is as follows: The lattice structure components are disassembled into spatial rods and planar rods. The printing order is determined by the spatial position of each part, and they are printed sequentially from bottom to top.

[0041] Each group of planar members is further divided into two layers, denoted as the upper layer and the lower layer, with the thickness of both layers assumed to be 3mm. Taking the lower planar member as an example, its printing path originates from the first layer's "C"-shaped point and the first layer's "Z"-shaped point. The lower layer uses the first layer's "C"-shaped point as its printing path, while the upper layer, to avoid collisions with the lower layer, uses the first layer's "Z"-shaped point, which is moved vertically upwards by 3mm, as its printing path.

[0042] The spatial members are also divided into two parts: vertical members and diagonal members. Planar members are connected by vertical members, and vertical members are connected by diagonal members. The printing path of the first layer of spatial members comes from the first layer's "Z"-shaped points and the second layer's "Z"-shaped points. Simply put, a vertical member is a line segment that starts from the nth "Z"-shaped point in the first layer and ends at the nth "Z"-shaped point in the second layer; a diagonal member is a line segment that starts from the nth "Z"-shaped point in the second layer and ends at the (n+1)th "Z"-shaped point in the first layer. Figure 11 A schematic diagram of a lattice model of a crystal structure is shown. Figure 12 An exploded view of a planar bar is shown. Figure 13 A schematic diagram of the decomposed grid model of the crystal structure is shown.

[0043] This section presents a novel path planning method proposed in this invention. Unlike traditional printing paths, which do not incorporate the concept of "Z"-shaped points, traditional printing paths for spatial members directly derive from "C"-shaped points. Vertical members are line segments that start at the nth "C"-shaped point in the first layer and end at the nth "C"-shaped point in the second layer; diagonal members are line segments that start at the nth "C"-shaped point in the second layer and end at the (n+1)th "C"-shaped point in the first layer. This novel printing path planning method produces components with a more transparent appearance and greater strength compared to traditional methods. Figure 14 A schematic diagram of the printing path for the C-shaped sequence is shown. Figure 15 A schematic diagram of the printing path for the Z-shaped sequence is shown. Figure 16 A schematic diagram of the printing paths for the lower planar struts and the spatial connecting struts is shown.

[0044] In some embodiments of this application, the spatial connecting rod frame includes multiple vertical rods and diagonal rods, the planar rod frame includes an upper planar rod frame and a lower planar rod frame, the two ends of the spatial connecting rod frame are respectively connected to the upper planar rod frame and the lower planar rod frame, and adjacent two vertical rods are connected by diagonal rods; Based on the Z-shaped sequence, the printing path of the spatial connecting rod frame is generated, specifically including: Starting from the nth point of the lower plane frame and ending at the nth point of the upper plane frame, generate the printing path for the vertical pole; Starting from the nth point of the upper plane frame and ending at the (n+1)th point of the lower plane frame, generate the printing path for the diagonal brace; Based on the Z-shaped sequence, the printing paths of the vertical rods and the diagonal rods are arranged in order to obtain the printing path of the spatial connecting rod frame.

[0045] It is important to note that since the spatial members are situated above the planar members, the Z-coordinate values ​​of the vertical members should be adjusted by adding the thickness of the planar members to their actual starting points. That is, the actual starting point of the vertical member is 6mm vertically upwards from the first layer of the "C"-shaped point. To prevent the ending point of the vertical member from colliding with the lower layer of the planar member, the actual ending point of the vertical member is 3mm vertically downwards from the second layer of the "C"-shaped point. Similarly, the starting and ending points of the diagonal members will also have their Z-coordinate values ​​adjusted to avoid collisions.

[0046] The printing path planning method for the remaining planar and spatial rods can be obtained by following the planning method for planar and spatial rods, thus obtaining the complete printing path for the lattice structure component.

[0047] In some embodiments of this application, robotic arm commands are assigned to points along the complete printing path.

[0048] The complete printing path is a sequence of points with a specific spatial order. The "Robim" plugin is used to assign commands to the robotic arm at each point in the complete printing path. Based on the printing order obtained in step 2, the robotic arm will print sequentially. Step 3 specifically includes: Set the nozzle to the position of the point, the extrusion speed of the extruder to 90, pause for 1 second, the moving speed of the nozzle to 10mm / s, and the extrusion speed of the extruder to 20. Based on the 3D printing path generated in step two, the printing is performed in the order of first bottom layer, first top layer, spatial connecting rod frame, second bottom layer and second top layer.

[0049] The pause is used to locally enlarge the volume of the printed result at the point, which helps to improve the connection between different printed parts.

[0050] In some embodiments of this application, vertical and diagonal members are alternately arranged in the path of the spatial members. The endpoint of the vertical member coincides with the starting point of the diagonal member, and vice versa. The point where the endpoint of the vertical member and the starting point of the diagonal member coincide in the spatial connecting frame is the intersection point. Printing of spatial connecting rod frames, including: Move the nozzle to the starting position of the vertical bar, set the extruder's extrusion speed to 50, and pause for 1 second; Turn on the cooling unit and set the position 1cm away from the end point of each vertical rod as the extrusion stop point. During the process of the nozzle moving from the starting point of the vertical rod to the extrusion stop point, the moving speed of the nozzle is 4mm / s and the extrusion speed of the extruder is 8. When the nozzle reaches the extrusion stop point, the extrusion speed is 0 and the moving speed remains unchanged. When the nozzle is at the junction point, pause for 10 seconds, adjust the extrusion speed to 8, pause for 3.8 seconds, adjust the moving speed to 6 mm / s, adjust the extrusion speed to 30, and move towards the end point of the inclined rod.

[0051] The steps outlined above can complete the printing process for one vertical rod and one diagonal rod. Repeating the three commands above will complete the printing of spatial rods. The command includes a stop point because the material has high fluidity at high temperatures. If extrusion stops at the end of the vertical rod, even with the cooling unit activated to accelerate cooling and shaping, the material inside the nozzle will still flow downwards due to its own weight, causing the upper part of the vertical rod to deform due to excessive weight. However, if extrusion stops at the stop point while the nozzle continues to move towards the end of the vertical rod, the slightly solidified stop point and nozzle will straighten the remaining material inside the nozzle, thus preventing deformation. The 10-second pause at the junction point allows the vertical rod to cool to a more ideal state. Although a longer cooling time will result in better solidification, the printing time must be considered. The same commands can be applied to print all other planar and spatial rods.

[0052] Example 1: like Figure 2 As shown, two approximately rectangular meshes were created in Rhino software, designated as model M1 and model M2. Using model M1 and model M2 as elevations, a structure like... Figure 1 The object shown requires a crystal lattice structure as its constituent units. First, the object must be transformed into a component made of a crystal lattice structure. Then, its printing path is planned. Next, a language file that the robotic arm can recognize is written based on the planned printing path, imported into the robotic arm, and then printed using the robotic arm. The specific method includes the following steps: S1. Extract the four outer edges of model M1; repeat the same steps for model M2. Select a set of outer edges, requiring these edges to be coplanar. The spatial transformation component will move both models M1 and M2 as a whole, so that... Figure 1 The object shown is placed on a horizontal side surface as its bottom surface, as if... Figure 4 On the printing platform shown, the center point of the printing platform is the center of platform P.

[0053] S2. Select the outer edge of M1 and its opposite edge, and create a tween curve that divides these two lines equally, with the number of segments set to "Number 1". Here, "Number 1" is set to 3. The result is as follows: Figure 5 As shown. Project the equally divided tweened curve onto the M1 grid. Divide the tweened curve projected onto the M1 grid into equal parts, with the number of segments being "Number 2". Here, "Number 2" is set to 5. The result is as follows. Figure 5 As shown. Connect the division points with polylines, sequentially connecting the first division point of the first curve, the first division point of the second curve, the first division point of the third curve, and so on, until the first division point of the last curve. Then, sequentially connect the second division point of the first curve, the second division point of the second curve, the second division point of the third curve, and so on, until the second division point of the last curve. Continue this process, connecting all the division points, resulting in the following... Figure 6 As shown. Divide the polyline obtained by connecting all the division points into equal parts, with the number of segments being "Number 1". Connect the division points with polylines, sequentially connecting the first division point of the first curve, the first division point of the second curve, the first division point of the third curve, and so on, until the first division point of the last curve. Then, sequentially connect the second division point of the first curve, the second division point of the second curve, the second division point of the third curve, and so on, connecting all the division points. The result is as shown. Figure 7 As shown. Divide the polyline obtained by connecting all the dividing points into equal segments, with the number of segments being "Number 2". The dividing points are now a sequence of points with a specific spatial order, denoted as "DataM1". Similarly, select an outer edge of M2 corresponding to the selected outer edge of M1 and perform the previous step to obtain "Data M2", as shown. Figure 8 As shown.

[0054] S3. Assume "Data M1" = {1, 2, 3}; "Data M2" = {A, B, C}. Merge the two groups and rearrange the data. The result of the first group is a "C-shaped point" with data {1, 2, 3, A, B, C}; the result of the second group is a "Z-shaped point" with data {1, A, 2, B, 3, C}. Apply these two data arrangement methods to the actual "Data M1" and "Data M2" data to obtain the actual "C-shaped points" and "Z-shaped points". The "C-shaped point" is as follows: Figure 9 As shown, the "Z-shaped point" is as follows Figure 10 As shown.

[0055] S4. Integrate the operational logic of S1, S2, and S3 into a cluster. The inputs of this cluster are "Mesh 1", "Mesh 2", "Number 1", "Number 2", "Select Outer Boundary Group Number", and "P Platform Center", respectively. The outputs are "Whether the Bottom Surface is Plane", "C-shaped Point", and "Z-shaped Point", respectively. "C-shaped Point" and "Z-shaped Point" each output a set of point sequences with a specific spatial position order.

[0056] When multiple components with different shapes need to be made, the two sets of point sequences required can be obtained immediately by simply changing the value of the input terminal.

[0057] S5. Based on the "C-shaped point" and "Z-shaped point", the following can be generated: Figure 11 The crystal structure components shown are disassembled into, for example, the following: Figure 13 The three-layer structure formed by the three sets of spatial rods and the four sets of planar rods shown is printed in the order determined by the spatial position of each part, from bottom to top.

[0058] S6. Each group of planar members is further divided into two layers, denoted as the upper layer and the lower layer, both with a thickness of 3mm. Taking the lower layer planar member as an example, its printing path originates from the "C" shaped point and the "Z" shaped point of the first layer. For example... Figure 16 As shown, the lower layer uses the "C"-shaped points of the first layer as the printing path; as Figure 16 As shown, to avoid collisions with the lower layer, the upper layer uses the first layer's "Z"-shaped point, which moves vertically upwards by 3mm, as the printing path.

[0059] S7. Spatial members are also divided into two parts: vertical members and diagonal members. The printing path of the bottom spatial members comes from the first and second layer "Z" shaped points. Taking the bottom spatial members as an example, the vertical member is a line segment that starts from the nth "Z" shaped point of the first layer and ends at the nth "Z" shaped point of the second layer; the diagonal member is a line segment that starts from the nth "Z" shaped point of the second layer and ends at the (n+1)th "Z" shaped point of the first layer.

[0060] S8. It is important to note that spatial members are located above planar members. Therefore, the Z-coordinate values ​​of the actual starting points of the vertical members should be increased by the thickness of the planar members. That is, the actual starting point of the vertical member is 6mm vertically upward from the first layer "C"-shaped point. To prevent the ending point of the vertical member from colliding with the lower layer of the second layer planar member, the actual ending point of the vertical member is 3mm vertically downward from the second layer "C"-shaped point. Similarly, the starting and ending points of the diagonal members will also have their Z-coordinate values ​​adjusted to avoid collisions. The printing path planning method for the remaining planar and spatial members follows the above method to obtain the complete printing path for the lattice structure components.

[0061] S9. Using the "Robim" plugin, assign robotic arm commands to each point in the complete printing path. The printing order is: lower layer of planar rods, upper layer of planar rods, spatial rods (vertical rods, diagonal rods, vertical rods and diagonal rods), and lower layer of planar rods, etc.

[0062] First, print the lower layer of the planar rods. For this part, we make the following command: First, when the nozzle is at the point, the extruder's extrusion speed is 90, with a pause of 1 second.

[0063] Secondly, when the nozzle moves between 12 points, the nozzle's moving speed is 10 mm / s, and the extrusion speed of the extruder is 20.

[0064] Second, apply the commands of the lower layer to the upper layer of a planar member.

[0065] Third, in the path of the spatial members, vertical and diagonal members are arranged alternately. We call the point where the end point of the vertical member coincides with the starting point of the diagonal member the "intersection point." For this part, we issue the following command: First, when the nozzle is at the starting point of the vertical rod, the extrusion speed of the extruder is 50, and it pauses for 1 second.

[0066] Next, activate the cooling unit. Let the point 1 cm from the end point of each vertical rod be the extrusion stop point. During the movement of the nozzle from the starting point of the vertical rod to the extrusion stop point, the nozzle's moving speed is 4 mm / s, and the extrusion speed of the extruder is 8. When the nozzle reaches the extrusion stop point, the extrusion speed is 0, but the moving speed remains unchanged.

[0067] Finally, when the nozzle is at the junction point, pause for 10 seconds. Adjust the extrusion speed to 8, pause for 3.8 seconds, adjust the moving speed to 6 mm / s, adjust the extrusion speed to 30, and move towards the end of the inclined rod.

[0068] The three commands above can complete the printing process of one vertical rod and one diagonal rod. By repeating these three commands, the printing of spatial rods can be completed. All other planar and spatial rods can be printed using the same commands.

[0069] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0070] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0071] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0072] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A 3D printing method for single-layer lattice structures based on a six-axis robotic arm, characterized in that, The single-layer lattice structure includes a plurality of lattice units with topological orientations along the X and Y axes, wherein the number of lattice units along both the X and Y axes is greater than or equal to 1, and the method includes: Step 1: Establish a hexahedral model. Based on the hexahedral model, calculate the first point sequence arranged in a first arrangement order and the second point sequence arranged in a second arrangement order. The first point sequence is a C-shaped sequence and the second point sequence is a Z-shaped sequence. Step 2: Generate a 3D printing path based on the first point sequence and the second point sequence; Step 3: Input the 3D printing path into the six-axis robotic arm for printing; Step two specifically includes: A preset printing model of the hexahedral model is established. The preset printing model includes a planar frame and a spatial connecting frame. The planar frame includes an upper structure and a lower structure. Based on the C-shaped sequence, the printing path of the lower-level structure is generated; Based on the Z-shaped sequence, the printing path of the upper structure is generated; Based on the Z-shaped sequence, the printing path of the spatial connecting rod frame is generated.

2. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 1, characterized in that, The hexahedral model includes a front elevation and a rear elevation; Step one specifically includes: Two quadrilateral mesh models with approximately rectangular shapes were created using Rhino software. These two quadrilateral mesh models are model M1 and model M2, respectively. Model M1 and model M2 are the front and rear facades of the hexahedral model, respectively. Extract the boundary lines of model M1 and model M2, and correct the pre-printing positions of model M1 and model M2; Extract equally divided points on the model M1; Extract equally divided points on the model M2; The equally divided points extracted from model M1 and model M2 are arranged according to a first arrangement order to obtain the first point sequence; The second point sequence is formed by arranging the equally divided points extracted from model M1 and model M2 according to the second arrangement order. Output computational logic cluster.

3. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 2, characterized in that, Extracting the boundary lines of model M1 and model M2, and correcting the pre-printing positions of model M1 and model M2, specifically includes: Extract the boundary lines of model M1 and model M2. The boundary line is one of the four edge lines generated after the outer contour line of the quadrilateral mesh model is broken by its four corner points. When one boundary line of model M1 and one boundary line of model M2 are close to each other, these two boundary lines are regarded as a group of boundary lines. Model M1 and model M2 together form four groups of boundary lines. The four groups of boundary lines are numbered as 0, 1, 2 and 3 in sequence. Select one of the four boundary line groups for detection. If the chain boundary lines in the selected boundary line group are coplanar, output True; otherwise, output False. When a set of coplanar boundary lines is identified, the coplanarity of this set of boundary lines is output as a Plane. 边线共面 And output the midpoint of the boundary line belonging to model M1 among these two boundary lines as P. 边线中点 And P 边线中点 As Plane 边线共面 The origin; Establish a point P 平台中心 As the central point of the printing platform; Move the models M1 and M2 such that P 边线中点 and P 平台中心 The lattice structures are overlapped so that one horizontal side of the lattice structure is placed on the printing platform as the bottom surface.

4. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 3, characterized in that, Extracting equally spaced points on the model M1 specifically includes: Two opposing boundary lines are selected on the model M1, and the two boundary lines are divided into equal-division interpolation curves with the number of equal segments being Number1. The equally divided tween curve is projected onto the grid of the model M1. The equally divided tween projection curve projected onto the grid of the model M1 is divided equally to obtain the first dividing point. The number of equal segments is Number2. The first equidistant points on model M1 are connected by polylines in a first specific order; Divide the polyline obtained by connecting all the first division points into equal parts to obtain the second division points. The number of divisions is Number1. Then, use polylines to connect the second division points on the model M1 in a second specific order. Divide the polyline obtained by connecting all the second division points into equal parts to obtain the third division point. The number of equal parts is Number2. The set of the third division points is denoted as DataM1.

5. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 4, characterized in that, Extracting equal division points on the model M2 specifically includes: Two opposing boundary lines are selected on the model M2, and the two boundary lines are divided into equal-division interpolation curves with the number of equal segments being Number1. The equally divided tween curve is projected onto the grid of the model M2. The equally divided tween projection curve projected onto the grid of the model M2 is then divided equally to obtain the fourth dividing point. The number of equal segments is Number2. The fourth division point on the model M2 is connected by polylines in a first specific order; Divide the polyline obtained by connecting all the fourth division points into equal parts to obtain the fifth division point, with the number of segments being Number1. Then, connect the fifth division point on the model M2 using polylines in a second specific order. Divide the polyline obtained by connecting all the fifth division points into equal parts to obtain the sixth division point. The number of equal parts is Number2. The set of the sixth division points is denoted as DataM2.

6. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 5, characterized in that, The equally divided points extracted from model M1 and model M2 are arranged according to a first arrangement order to obtain a first point sequence, specifically including: Assuming DataM1 = {1, 2, 3} and DataM2 = {A, B, C}, they are arranged in the first permutation order to obtain the first point sequence. The first point sequence is a C-shaped sequence, and the C-shaped sequence is {1, 2, 3, A, B, C}. The second point sequence, which arranges the equally divided points extracted from model M1 and model M2 according to the second arrangement order, specifically includes: Assuming DataM1 = {1, 2, 3} and DataM2 = {A, B, C}, arranging them according to the second permutation order yields the second point sequence, which is a Z-shaped sequence, namely {1, A, 2, B, 3, C}.

7. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 6, characterized in that, The computational logic cluster includes {M1, M2, Number1, Number2, the boundary line group number, P}. 平台中心 } 8. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 7, characterized in that, The spatial connecting rod frame includes multiple vertical rods and diagonal rods. The planar rod frame includes an upper planar rod frame and a lower planar rod frame. The two ends of the spatial connecting rod frame are respectively connected to the upper planar rod frame and the lower planar rod frame. Adjacent vertical rods are connected by the diagonal rods. Based on the Z-shaped sequence, the printing path of the spatial connecting rod frame is generated, specifically including: The printing path of the vertical rod is generated by taking the nth point of the lower plane frame as the starting point and the nth point of the upper plane frame as the ending point. Starting from the nth point of the upper planar frame and ending at the (n+1)th point of the lower planar frame, the printing path of the inclined rod is generated. Based on the Z-shaped sequence, the printing paths of the vertical rods and the diagonal rods are arranged in order to obtain the printing path of the spatial connecting rod frame.

9. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 8, characterized in that, Step three specifically includes: Set the nozzle to the position of the point, the extrusion speed of the extruder to 90, pause for 1 second, the moving speed of the nozzle to 10mm / s, and the extrusion speed of the extruder to 20. Based on the 3D printing path generated in step two, the printing is performed in the order of first bottom layer, first top layer, spatial connecting rod frame, second bottom layer and second top layer.

10. The 3D printing method for single-layer lattice structures based on a six-axis robotic arm according to claim 9, characterized in that, The point where the end point of the vertical rod and the starting point of the diagonal rod in the spatial connecting rod frame coincide is the intersection point; Printing the spatial connecting rod frame includes: Move the nozzle to the starting position of the vertical bar, set the extruder's extrusion speed to 50, and pause for 1 second; Turn on the cooling unit and set the position 1cm away from the end point of each vertical rod as the extrusion stop point. During the process of the nozzle moving from the starting point of the vertical rod to the extrusion stop point, the moving speed of the nozzle is 4mm / s and the extrusion speed of the extruder is 8. When the nozzle reaches the extrusion stop point, the extrusion speed is 0 and the moving speed remains unchanged. When the nozzle is at the junction point, pause for 10 seconds, adjust the extrusion speed to 8, pause for 3.8 seconds, adjust the moving speed to 6 mm / s, adjust the extrusion speed to 30, and move towards the end point of the inclined rod.

Images