Practical slicing and path planning method for 3D printing large-scale buildings

Abstract

The present application relates to the technical field of 3D printing, and discloses a 3D printing large-scale building practical slicing and path planning method, which comprises the following steps: globally planning a path for avoiding obstacles in the horizontal and vertical directions of a building model, and dividing a printing area; slicing the printing area; determining a local printing path for a specific wall position, and making a printing path for a force-bearing wall, which is to first walk along the outer contour of the wall and then walk along the inclined web member of the internal truss of the wall; for a non-force-bearing wall, first walk along the outer contour and then walk along the Z shape; the end point of the lower layer is the start point of the upper layer; and analyzing whether the interval time between layers exceeds the initial setting time of the concrete. The present application makes the working radius of the 3D printer free of obstacles and covers the force-bearing wall, and the number of printer movements is minimized; the wall is continuously printed, the concrete printing is ensured not to be interrupted, and the empty walking rate is reduced; the printing head can avoid sharp turns, the amount of printing material is small; and the constructability before the initial setting of the concrete, the printing appearance quality, the eccentric compression strength after the final setting, the stiffness and the stability are satisfied.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of 3D printing technology, in particular to a slice and path planning method for 3D printing large-scale buildings. BACKGROUND

[0002] 3D printing technology is a technology that creates three-dimensional entities by layering materials. This technology uses a computer-controlled printer to stack materials such as plastic, metal, concrete, etc. according to the predetermined design, and finally forms a physical model or product. The application of 3D printing technology in the construction industry uses large 3D printers to print walls, structures and other components of buildings using concrete, mortar or other building composite materials according to digital design drawings. This allows architects and designers to quickly model and prototype, achieve personalized customization of building elements, and has the characteristics of automation, reduced material waste and high efficiency, allowing complex building structures to be completed quickly in continuous operation.

[0003] The key technical steps for printing buildings using 3D printing technology include slicing, printing path planning and printing programming. Traditional slicing algorithms include fixed layer thickness slicing and variable layer thickness slicing. The principle is to use slicing software (such as Cura) to grid the outer surface of the STL model to obtain approximate triangular patches, which are then vertically divided. The intersection of the triangular patches and the horizontal slice is the printing path. This slicing algorithm is more suitable for desktop printers and is not suitable for large-scale building printing and has a large error.

[0004] The printing path is the trajectory of the movement of the center three-dimensional coordinate point of the nozzle of the printer, and the distance between the coordinate points is the distance between the segmentation points on the printing path curve. The segmentation point connecting line approximates the printing path curve between the start and end points. The path planning algorithm currently applied to concrete 3D printing technology includes: Zigzag algorithm, which is the most common printing method, but it has many sharp turns, and this shortcoming will be very obvious for complex boundary or hollow shapes; contour parallel algorithm, which is composed of equidistant parallel lines, which can avoid too many sharp turns, but it leads to more contours and the contours are not connected; Fermat spiral algorithm, which is composed of two interwoven sub-spiral lines, one inward and one outward, which solves the problems of avoiding too many sharp turns and the contours not being connected, but when used for building 3D printing, due to the poor anisotropy of the spiral path, after slicing the three-dimensional model, if the same type of spiral path is used for the adjacent two layers, the paths of the adjacent layers will be superimposed, which is not conducive to the mechanical strength of the printed model in the transverse direction; Galapagos curve genetic algorithm, which uses genetic algorithm to optimize the printing path curve, and through different parameters and functions to evaluate and improve the fitting degree of the curve, so as to achieve a specific design or construction goal, but the actual application is very complex.

[0005] In view of the problems of the above-mentioned building 3D printing path planning algorithm and path optimization algorithm being complex and each having advantages and disadvantages and application scope, it is necessary to research and develop a practical slicing and path planning method for 3D printing large-scale buildings. SUMMARY

[0006] The present application discloses a practical slicing and path planning method for 3D printing large-scale buildings, which provides a complete set of practical methods for 3D printing large-scale buildings by giving the steps of building model global path planning, slicing and printing path planning, and can be applied to complex-shaped buildings, while achieving the purposes of printing path coherence, avoiding sharp turns of the printing head, smaller printing material consumption, and the completed printed building meeting the strength stability requirements.

[0007] The practical slicing and path planning method for 3D printing large-scale buildings comprises the following steps:

[0008] S1, building model, 3D printing equipment and digital model adaptation software preparation: completing the detailed design of the building design digital model, reserving and embedding the line slot of water and electricity pipes; selecting the 3D printing equipment and mechanical arm model according to the engineering plane and elevation size; importing the building design digital model into the digital model adaptation software;

[0009] S2, global path planning for the building model: global path planning for the building model to avoid obstacles in the horizontal and vertical directions, dividing the printing area, setting the position of each region to meet the working radius of the mechanical arm, and determining the printing order according to the positional relationship of each printing area;

[0010] S3, slicing for each printing area: the number of slices = the printing height of a certain printing area / the printing layer thickness, and the printing layer thickness is less than 1 / 2 of the nozzle diameter; the printing order of each printing layer is determined from bottom to top according to the slicing;

[0011] S4, printing path planning for each printing layer: for the wall body positions with specific requirements including steel bars and segmented printing joints, local printing paths are first determined; for the force-bearing wall body with a thickness of ≥200mm, the printing path is determined to first walk along the outer contour of the wall body, and then walk along the inclined web member of the internal truss; for the non-force-bearing wall body, the printing path is determined to walk along the outer contour, and the Z-shaped printing path is determined to walk in the internal space; the connection path between the upper and lower layers of each printing layer in each printing area is corresponding to the path along the contour and the path along the inclined web member, and the lower layer can bear the upper layer; the printing end point of the adjacent lower layer of each printing layer in each printing area is the printing start point of the upper layer (i.e. the coordinates x and y are the same), and each printing area forms a continuous printing path;

[0012] S5, analysis and optimization of slicing and path planning: the length of each printing layer line and the printing time are counted, and whether the interlayer spacing time exceeds the initial setting time of the concrete is analyzed; if there are printing layers that do not meet the requirements, return to step S4 for adjustment;

[0013] S6, input planning and output 3D printing program: the results of global path planning, slicing and printing path planning are summarized, the printing code is compiled by using the digital model adaptation software, and the program for building 3D printing is output.

[0014] Preferably, in step S1, the digital model adaptation software includes Autodesk Revit 2018 three-dimensional building design software, Rhino 3D modeling design software, and Grasshopper visual programming plug-in, and the building model uses FBX format.

[0015] Further, step S2 specifically includes the following steps:

[0016] In horizontal direction, different printing areas are divided according to the range that the mechanical arm can reach; in vertical direction, different printing areas are divided by the variable cross-section parts of the building model, including floor beams, ring beams, door and window openings; according to the positional relationship of each printing area, the printing sequence of each printing area is sorted, and the working position of each stage 3D printer and its extension is set to ensure that the position does not conflict with the printed wall.

[0017] Further, the step S4 specifically comprises the following steps:

[0018] For the force-bearing wall with a thickness ≥ 200mm, the printing path is first moved from the two sides of the outer contour to the inside by 0.4-0.6 times the nozzle diameter to offset the coordinate point directed line, and then the truss inclined web between the printing lines on both sides of the outer contour is made at an angle of 30º-60º with the center line of the wall;

[0019] The printing starting point directed line is determined according to the one-stroke theorem, i.e., the printing path of each printing layer is a graph with only even points, or a graph with only two odd points;

[0020] A certain distance is reserved between the truss inclined web and the outer contour wall; a certain distance is reserved between the later-printed wall and the earlier-printed wall.

[0021] Preferably, the step S4 further comprises the following features:

[0022] The printing path of each printing layer is a graph with only two odd points, the printing path starts from one odd point and ends at the other odd point; the printing starting point position of the first layer of each area is selected at the intersection of the internal truss line and the outer wall line in the middle of the length direction of the printed wall.

[0023] Preferably, in the step S4:

[0024] The division point distance on the printing path curve is 0.5 times the nozzle diameter + 5mm;

[0025] For the force-bearing wall with a thickness ≥ 200mm, the printing path is first moved from the two sides of the outer contour to the inside by 0.5 times the nozzle diameter to offset the coordinate point directed line;

[0026] The truss inclined web between the printing lines on both sides of the outer contour is made at an angle of 45º with the center line of the wall;

[0027] A distance of 20mm is reserved between the truss inclined web and the outer contour wall; a distance of 20mm is reserved between the later-printed wall and the earlier-printed wall.

[0028] Further, the step S5 further comprises the following steps:

[0029] The length of each printing layer line and printing time is counted, and whether the interval time between layers exceeds the initial setting time of the concrete is analyzed; if there is a printing layer that does not meet the requirements, return to step S4 for adjustment; if it is difficult to solve the situation of exceeding the initial setting time by returning to step S4 to adjust the path planning of other printing layers, the mix proportion of the concrete in the printing area is changed to change the initial setting time to meet the requirements.

[0030] Preferably, the step S6 specifically comprises the following steps:

[0031] The Revit2018 model completed deepening design is exported as an FBX format file, opened by Rhino software, opened the visual programming Grasshopper plug-in, and the global path planning, slicing and printing path planning information are input by using the software function; for each printing area, the printing layer to be printed is associated, and the software automatically finds the printing starting point to generate a printing program.

[0032] Compared with the prior art, the technical scheme provided by the application can obtain the following beneficial effects:

[0033] 1. Global path planning is performed before slicing and printing path planning, so that the printer working radius is free of obstacles and can cover the structure stress wall, and the number of printer movements is minimized;

[0034] 2. In the printing path planning of the printing layer, the one-stroke theorem is followed, and the printing end point of the adjacent lower layer is the printing starting point of the upper layer, so that the wall body is continuously printed, the concrete printing is not interrupted, and the empty walking rate is reduced;

[0035] 3. The wall body is provided with a truss inclined web member printing line, the path of the printing layer first walks outside the wall body, and then walks the truss inclined web member inside the wall body, so that the printing head can avoid turning sharp corners, and the amount of printing material is small;

[0036] 4. The interval time between adjacent upper and lower layers is less than the initial setting time of the material, so that the constructability and printing appearance quality are met before the initial setting of the concrete, and the eccentric compression strength and rigidity stability are met after the final setting;

[0037] 5. In the preferred scheme, the printing path of each printing layer is a figure with only two singular points, the printing path starts from one singular point and ends at the other singular point; the printing starting point position of the first layer of each region is selected at the intersection of the internal truss line and the external wall line in the middle of the printing wall length direction, so that the starting point and the ending point connecting curve are the shortest on the same printing layer, and the vertical upper side of the lower layer printing ending point is the upper layer printing starting point, so that the single printing area obtains the optimal printing path, and the printing quality is improved while the printing time is shortened and the material waste is reduced as much as possible. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1This is a schematic diagram illustrating the main steps of the present invention;

[0039] Figure 2 This is an example of an architectural elevation drawing;

[0040] Figure 3 This is a top view of the building in the example;

[0041] Figure 4 This is a schematic diagram of the global path planning for a building, as shown in the example.

[0042] Figure 5 This is a schematic diagram of a slice of the A1 printing area of ​​the building in the example;

[0043] Figure 6 This is a schematic diagram of a slice of the A2 printed area of ​​the building, as shown in the example.

[0044] Figure 7 This is a schematic diagram of a slice of the A3 printed area of ​​the building, as shown in the example.

[0045] Figure 8 This is a schematic diagram of a slice of the printed area of ​​building B1 in the example embodiment;

[0046] Figure 9 This is a schematic diagram of a slice of the B2 printing area of ​​the building in the example embodiment;

[0047] Figure 10 This is a schematic diagram of a slice of the B3 printing area of ​​the building in the example;

[0048] Figure 11 This is a schematic diagram of a slice of the B4 printing area of ​​the building in the example;

[0049] Figure 12 This is a schematic diagram of a single-story building and the paths between floors in an example building;

[0050] Figure 13 for Figure 7 Enlarged view of part M in the middle;

[0051] Figure 14 This is a schematic diagram of the printed path planning for building A1-1, as shown in the example.

[0052] Figure 15 This is a schematic diagram of the printed path planning for building A1-3 floors, as shown in the example.

[0053] Figure 16 This is a schematic diagram of the printed path planning for the A3-1 floor of the building, as shown in the example.

[0054] Figure 17 This is a schematic diagram of the printing path planning for floors B2-4 of the building, as shown in the example.

[0055] Figure 18 This is a schematic diagram of the printed path planning for the B4-2 floor of the building, as shown in the example.

[0056] Figure 19 Printed column construction method schematic diagram;

[0057] Figure 20 Printed cavity construction method schematic diagram.

[0058] Figure annotation: 1, steel bar column. DETAILED DESCRIPTION

[0059] The technical solutions of the present application will be specifically described below with reference to the drawings, and specific embodiments will be provided.

[0060] Referring to Figure 1 The present application discloses a slice and path planning method for 3D printing of large-scale buildings, comprising the following steps:

[0061] S1, building model, 3D printing equipment and digital model adaptation software preparation: complete deepening design of building design digital model, water and electricity line pipe reserved pre-embedded slot; select 3D printing equipment and mechanical arm model according to engineering plane and elevation size; import building design digital model into digital model adaptation software;

[0062] S2, global path planning for building model: global path planning for building model to avoid obstacles in horizontal and vertical directions, divide printing area, set up machine position for each area to meet mechanical arm working radius range, determine printing sequence according to position relationship of each printing area;

[0063] S3, slice each printing area: slice number = printing height of certain printing area / printing layer thickness, printing layer thickness value <1 / 2 nozzle diameter; determine printing sequence of each printing layer from bottom to top according to slice;

[0064] S4, printing path planning for each printing layer: for wall body position with specific requirements including steel bar column and segmented printing joint, first determine local printing path; for stress wall body with thickness ≥200mm, make printing path of walking along wall contour first, then walking along inclined web member diagonal web; for non-stress wall body, make Z-shaped printing path of walking along contour and internal space; the connection path between upper and lower layers of each printing layer of each printing area is corresponding to the path along the contour and the path along the diagonal web, the lower layer can bear the upper layer; the printing end point of each printing layer of each printing area is the printing start point of the upper layer (i.e. the same coordinates x, y), and each printing area forms a continuous printing path respectively;

[0065] S5, analyze and optimize the slice and path planning: statistical analysis of printing layer line length and printing time, analyze whether the layer spacing time exceeds the initial setting time of concrete; if there are printing layers that do not meet the requirements, return to step S4 for adjustment;

[0066] S6, input planning and output 3D printing program: summarize the global path planning, slicing and printing path planning results, use digital model adaptation software to compile printing code, and output the program for building 3D printing.

[0067] The specific embodiments of the application are provided below. Referring to the architectural elevation view, top view and perspective view of Figure 2 , Figure 3 , Figure 4 , the building area of a certain project is about 130 square meters, which is a public service city station integrating functions such as public toilets, management housing, sanitation home, etc., and is designed to be built by using 3D printing technology. The printed wall height is 2.2m, 2.8m, 3.2m, the stress wall thickness is 200mm, and the building width is 6.79m.

[0068] The slicing and path planning method for 3D printing large-scale buildings according to the application is carried out in steps S1-6 in turn:

[0069] Step S1: use Autodesk Revit 2018 three-dimensional building design software to complete the detailed design of the building design digital model, and reserve and embed the water and electricity line groove; export the FBX format building model file, import Rhino 3D modeling design software, open the Grasshopper visual programming plug-in, and select the 3D printing equipment and mechanical arm model according to the engineering plane and elevation size. The mechanical arm model of this project is KR210 R2700-2.

[0070] Step S2: according to the 3D printing equipment and mechanical arm model, determine the working radius of the mechanical arm and the diameter of the printing nozzle, and get the printable space size range. In the horizontal direction, different printing areas are divided according to the range that the mechanical arm can reach; in the vertical direction, the variable cross-section parts of the building model including the floor beam, ring beam and door and window openings are taken as the dividing lines to divide different printing areas; according to the positional relationship of each printing area, the printing order of each printing area is sorted, and the working position of each stage 3D printer and its extension is set to ensure that the position does not conflict with the printed wall. Referring to Figure 4 , this project is divided into A1, A2, A3, A4, B1, B2, B3, B4, a total of 8 subblocks, referring to Figures 5-11 , in the vertical direction, A1-1~A-17, A2-1~A2-2, A3-1~A3-12, A4-1~A4-2, B1-1~B-9, B2-1~B2-7, B3-1~B3-4, B4-1~B4-7, a total of 60 printing areas are obtained, and the printing order in the horizontal direction is A1, A2, A4, A3; B1, B3, B2, B4; the vertical direction is to print from bottom to top for each subblock.

[0071] Step S3: slice the inner and outer wall body determined in sequence and segmented printing, the number of slices = the printing height of a certain printing area / the printing layer thickness, the printing layer thickness is 1 / 2 nozzle diameter, and the printing order of each printing layer is determined from bottom to top. With the help of software operation, projection curve or control point, equidistant section line is selected for slicing, the slicing direction and equidistant section line spacing are selected, and the slice layer is automatically generated. The line of each layer is composed of evenly divided point coordinates. After slicing of the project, the printing layer situation of each printing area is shown in Figures 5-11 , and the single layer line length and printing time table of each printing area in the following.

[0072] Step S4: print path planning for each printing layer, the connection path along the contour between the upper and lower layers of the printing layer of each printing area corresponds to the path along the inclined web, and the lower layer can carry the upper layer; the printing end point of the adjacent lower layer of each printing layer of each printing area is the printing start point of the upper layer (i.e. the coordinates x, y are the same), and each printing area forms a continuous printing path. Referring to Figure 12 , the printing start point of the nth layer is S n , the end point is E n , the printing start point of the n+1 layer is S n+1 , the end point is E n+1 , the coordinates x, y of E n and E n+1 are the same, the continuous printing path of the nth layer and the n+1 layer is S n —E n —E n+1 —S n+1 , and each printing layer of the same printing area is the same.

[0073] Specific to the printing path inside each printing layer, first determine the local printing path of the wall body position with special requirements including the steel bar column and the segmented printing joint, see Figure 14 The column 1 of the steel bar in these positions needs to determine a square path first, so as to leave a square space for printing and filling to form a structural column.

[0074] Figures 14-18 The printing path planning schematic diagrams for the embodiment buildings A1-1 layer, A1-3 layer, A3-1 layer, B2-4 layer and B4-2 layer are respectively shown, and the printing start point arrow line is determined according to the one stroke theorem, and the printing path of each printing layer is a figure with only two singular points, and the printing path starts from one singular point and ends at the other singular point.

[0075] Referring to Figure 14 , 15, 17, for the force wall body with thickness ≥200mm, the printing path is first offset from the outer contour two sides to the inside by 0.5 times the nozzle diameter to move the coordinate point, and the connecting line is connected with the previously determined local printing path; then the truss inclined web between the printing lines on the two sides of the outer contour is made to form an angle of 30º-60º with the center line of the wall body;

[0076] Referring to Figure 16 , 18 , for the non-force wall body, the outer contour is walked, and the internal space is sufficient to make a zigzag printing path.

[0077] The printing start point position of each area first layer is selected at the intersection of the internal truss line and the external wall line in the middle of the printing wall length direction. Referring to Figure 14 the A1-1 layer printing path planning schematic diagram, the printing start point is S A1-1 , and the end point is E A1-1 , the printing start point S A1-1 is selected at the intersection of the internal truss line and the external wall line in the middle of the printing wall length direction. Referring to Figure 13 , the printing start point S n is at the intersection of the internal truss line and the external wall line in the middle of the printing wall length direction.

[0078] Referring to Figure 19 , the distance h1 between the later printed wall body indicated by the dashed line and the earlier printed wall body indicated by the solid line is 20mm.

[0079] Referring to Figure 20 , the distance h2 of the division point on the printing path curve is 0.5 times the nozzle diameter+5mm; the distance h3 between the truss inclined web and the outer contour wall body is 20mm; the angle θ / 2 of the truss inclined web and the wall body center line is preferably 45º.

[0080] Step S5: statistical analysis of each printing layer line length and printing time as follows:

[0081] A1 single layer line length and printing time

[0082]

[0083] A2 single layer line length and printing time (A4 is the same)

[0084] ;

[0085] A3 single layer line length and printing time

[0086] ;

[0087] B1 single layer line length and printing time

[0088] ;

[0089] B2 single layer line length and printing time

[0090] ;

[0091] B3 single layer line length and printing time

[0092] ;

[0093] B4 single layer line length and printing time

[0094] ;

[0095] Analysis of whether the interval time between layers exceeds the initial setting time of concrete; if there is a printing layer that does not meet the requirements, return to step S4 for adjustment; if it is difficult to solve the situation of exceeding the initial setting time by returning to step S4 to adjust the individual printing layer path planning, the mix proportion of the concrete in the printing area is changed to change the initial setting time to meet the requirements.

[0096] In this project, according to the layer thickness of 15mm and the estimated value of the printer speed of 0.15m / s, the printing time of each printing layer is less than 30min (1800s), which meets the requirement of not exceeding the initial setting time of concrete.

[0097] Step S6: The global path planning, slicing and printing path planning results are summarized, the digital model adaptation software is used to compile the printing code, and the program for building 3D printing is output. Using Rhino software and visual programming Grasshopper plug-in, the global path planning, slicing and printing path planning information are summarized, for each printing area, the printing layers to be printed are associated, the software is operated to automatically find the printing start point, and the printing program is generated.

[0098] The slicing and path planning method for 3D printing large-scale buildings in the project meets the requirements that there are no obstacles in the working radius of the printer and the structure bearing wall can be covered, the number of printer movements is minimized, the structure bearing wall is continuously printed, the end point of the adjacent lower layer printing is the start point of the upper layer printing, the interval time between adjacent upper and lower layers is less than the initial setting of the material, the number of interfaces between the printing strips is minimized, the wall is continuously printed, the concrete printing is uninterrupted, the empty walking rate is reduced, the printing head can avoid sharp turns, the amount of printing material is small, the constructability before the initial setting of the concrete is met, the appearance quality of the printing is met, and the eccentric compression strength, stiffness and stability after the final setting are met.

[0099] The above is only a preferred example of the present application, and is not a formal and substantial limitation of the present application. Any technical solution under the concept of the present application belongs to the protection scope of the present application. Any equivalent change and modification of the above example according to the substantial technology of the present application should be considered as the protection scope of the present application.

Claims

1. A practical slicing and path planning method for large-scale 3D printed buildings, characterized by: Includes the following steps: S1. Prepare the architectural model, 3D printing equipment, and digital model adaptation software: complete the detailed design of the architectural digital model, and reserve pre-embedded cable trays for water and electricity pipes; select the 3D printing equipment and robotic arm model according to the dimensions of the project plan and elevation; import the architectural digital model into the digital model adaptation software. S2, Global path planning for the building model: Global path planning is performed on the building model to avoid obstacles in the horizontal and vertical directions, the printing area is divided, and the machine position in each area must meet the working radius of the robotic arm. The printing order is determined according to the positional relationship of each printing area. S3, slice each printing area: number of slices = printing height of a printing area / printing layer thickness, the printing layer thickness is less than 1 / 2 nozzle diameter; The printing order of each layer is determined from bottom to top based on the slices; S4. Plan the printing path for each printing layer: For wall locations with specific requirements, including reinforced columns and joints of segmented printing, first determine the local printing path; for load-bearing walls with a thickness ≥200mm, create a printing path that first follows the outer contour of the wall and then the diagonal bracing of the truss inside the wall, connecting it to the pre-determined local printing path; for non-load-bearing walls, create a Z-shaped printing path that follows the outer contour and has sufficient internal space; between the upper and lower printing layers in each printing area, the connecting path along the contour and the path along the diagonal bracing correspond vertically, ensuring that the lower layer can support the upper layer; the printing end point of each printing layer in each printing area is the printing start point of the upper layer, and each printing area forms a continuous printing path; S5, analyze and optimize the slicing and path planning: perform statistics on the length of each printed layer and the printing time, and analyze whether the layer interval time exceeds the initial setting time of the concrete. If there are any non-compliant print layers, return to step S4 for adjustment; S6, Input Planning and Output 3D Printing Program: Summarize the global path planning, slicing and printing path planning results, use digital model adaptation software to compile printing code, and output a program for building 3D printing.

2. The practical slicing and path planning method for large-scale 3D printed buildings according to claim 1, characterized in that: In step S1, the digital model adaptation software includes Autodesk Revit 2018 3D architectural design software, Rhino 3D modeling design software, and Grasshopper visual programming plugin. The architectural model uses FBX format.

3. The practical slicing and path planning method for large-scale 3D printed buildings according to claim 1, characterized in that, Step S2 specifically includes the following steps: In the horizontal direction, different printing areas are divided according to the reach of the robotic arm; in the vertical direction, different printing areas are divided by the variable cross-section parts of the building model, including ground beams, ring beams, and door and window openings; according to the positional relationship of each printing area, the printing order of each printing area is sorted, and the working positions of each stage 3D printer and its extension frame are set to ensure that the machine positions do not conflict with the printed walls.

4. The practical slicing and path planning method for large-scale 3D printed buildings according to claim 1, characterized in that: Step S4 specifically includes the following steps: For load-bearing walls with a thickness of ≥200mm, first move the coordinate points in a directed manner by offsetting them inward from both sides of the outer contour by 0.4-0.6 times the nozzle diameter. Then, construct truss diagonal bracing between the printing lines on both sides of the outer contour at an angle of 30º-60º to the center line of the wall. The starting point of the printing is determined by the one-stroke drawing theorem, that is, the printing path of each printing layer is a graphic with only even points or only two odd points. A certain distance is maintained between the diagonal web members of the truss and the outer contour wall; a certain distance is maintained between the later-printed wall and the earlier-printed wall.

5. The practical slicing and path planning method for large-scale 3D printed buildings according to claim 4, characterized in that: In step S4, the printing path of each printing layer is a graphic with only two singular points. The printing path starts from one singular point and ends at the other singular point. The printing start point of the first layer in each region is selected at the middle of the length of the printed wall, at the intersection of the internal truss line and the external wall line.

6. The practical slicing and path planning method for large-scale 3D printed buildings according to claim 5, characterized in that: In step S4 The distance between the dividing points on the printing path curve is 0.5 times the nozzle diameter + 5mm; For load-bearing walls with a thickness of ≥200mm, create a printing path by moving the coordinate points inward from both sides of the outer contour by 0.5 times the nozzle diameter and connecting them in a directed manner. Construct truss diagonal braces between the printed lines on both sides of the outer contour, forming a 45º angle with the center line of the wall; A 20mm gap is maintained between the truss diagonal web members and the outer contour wall; a 20mm gap is maintained between the later-printed wall and the earlier-printed wall.

7. The practical slicing and path planning method for large-scale 3D printed buildings according to claim 1, characterized in that: Step S5 further includes the following steps: Perform statistics on the length of each printed layer and the printing time, and analyze whether the layer interval time exceeds the initial setting time of the concrete. If there are printed layers that do not meet the requirements, return to step S4 for adjustment. If it is difficult to resolve the situation of exceeding the initial setting time by returning to step S4 to adjust the individual printed layer path planning, then change the concrete mix ratio of the printed area and the initial setting time to meet the requirements.

8. The practical slicing and path planning method for large-scale 3D printed buildings according to claim 1, characterized in that: Step S6 specifically includes the following steps: Export the Revit 2018 model with the completed detailed design to FBX format, open it with Rhino software, open the Grasshopper visual programming plugin, and use the software functions to input global path planning, slicing and printing path planning information. For each printing area, the software automatically finds the starting point of the print job and generates the print program by associating the print layers to be printed with it.

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