A Collapse Compensation Method and Device for Variable-Diameter Fiber Extrusion 3D Printing

Abstract

The embodiments of this specification relate to the field of engineering technology, are applicable to the field of 3D printing technology, and particularly relate to a collapse compensation method and device for variable-diameter fiber extrusion 3D printing. The method includes: establishing a 3D model of the collapse area corresponding to each layer of variable-diameter fiber after deposition; constructing a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fiber according to the diameter change range of the variable-diameter fiber; calculating the collapse compensation model according to the 3D model of the collapse area to obtain a compensation printing trajectory composed of constant-diameter fibers corresponding to each layer of variable-diameter fiber; and compensating for the collapse of each layer of variable-diameter fiber after deposition using constant-diameter fibers according to the compensation printing trajectory. Through the embodiments of this specification, by taking the local collapse area as a breakthrough point and using constant-diameter fibers to compensate the local collapse area, the problem that the models printed by the existing variable-diameter fiber extrusion 3D printing technology have local collapse is solved.

Description

Technical Field

[0001] The embodiments of this specification relate to the field of engineering technology, applicable to the field of 3D printing technology, and particularly relate to a collapse compensation method and device for variable-diameter fiber extrusion 3D printing. Background Art

[0002] With the rapid development of the extrusion 3D printing technology, in order to meet the design and manufacturing of gradient structures, technicians in the current field have proposed the extrusion 3D printing technology of variable-diameter fibers. The extrusion 3D printing technology of variable-diameter fibers realizes the diameter or width of the deposited fibers by adjusting the feeding flow rate or the printing speed, so as to obtain a gradient structure. Although this extrusion 3D printing strategy of variable-diameter fibers can realize the processing of gradient structures in the x-axis or y-axis direction, with the increase of the processing height, the possibility of local collapse of the sample increases. This severely limits the application of this technology in the processing and manufacturing of large-size models.

[0003] Now there is an urgent need for a collapse compensation method for variable-diameter fiber extrusion 3D printing, so as to solve the problem of local collapse existing in the models printed by the existing variable-diameter fiber extrusion 3D printing technology. Summary of the Invention

[0004] To solve the problems in the prior art, the embodiments of this specification provide a collapse compensation method and device for variable-diameter fiber extrusion 3D printing. Taking the local collapse area as a breakthrough point, a method of using constant-diameter fibers to compensate the local collapse area solves the problem of local collapse existing in the models printed by the existing variable-diameter fiber extrusion 3D printing technology.

[0005] To solve the above technical problems, the specific technical solutions of the embodiments of this specification are as follows:

[0006] On the one hand, the embodiments of this specification provide a collapse compensation method for variable-diameter fiber extrusion 3D printing, including,

[0007] Establishing a 3D model of the collapse area corresponding to each layer of variable-diameter fibers after deposition;

[0008] According to the diameter change range of the variable-diameter fibers, constructing a collapse compensation model corresponding to each layer of variable-diameter fibers and composed of constant-diameter fibers;

[0009] Calculating the collapse compensation model according to the 3D model of the collapse area to obtain a compensation printing trajectory corresponding to each layer of variable-diameter fibers and composed of the constant-diameter fibers;

[0010] Compensating the collapse of each layer of variable-diameter fibers after deposition with the constant-diameter fibers according to the compensation printing trajectory.

[0011] Further, according to the diameter change range of the variable-diameter fiber, constructing a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers further includes:

[0012] Determine the diameter of the constant-diameter fiber according to the diameter change range of the variable-diameter fiber;

[0013] Determine the compensation layers of the constant-diameter fiber according to the diameter of the variable-diameter fiber and the diameter of the constant-diameter fiber;

[0014] Deploy the constant-diameter fiber on the deposited variable-diameter fiber according to the compensation layers to obtain the collapse compensation model.

[0015] Further, determining the diameter of the constant-diameter fiber according to the diameter change range of the variable-diameter fiber further includes:

[0016] Take the minimum value in the diameter change range as the diameter of the constant-diameter fiber.

[0017] Further, determining the compensation layers of the constant-diameter fiber according to the diameter of the variable-diameter fiber and the diameter of the constant-diameter fiber further includes:

[0018] Calculate the ratio between the maximum value in the diameter change range and the diameter of the constant-diameter fiber, and round the ratio to obtain the compensation layers.

[0019] Further, deploying the constant-diameter fiber on the deposited variable-diameter fiber according to the compensation layers to obtain the collapse compensation model further includes:

[0020] Deploy the first layer of constant-diameter fiber on the deposited variable-diameter fiber along the printing trajectory of the variable-diameter fiber;

[0021] Deploy the second layer of constant-diameter fiber on the first layer of constant-diameter fiber in parallel between layers and at a predetermined interlayer crossing angle;

[0022] Take the second layer of constant-diameter fiber as the first layer of constant-diameter fiber, and repeat the step of deploying the next layer of constant-diameter fiber on the first layer of constant-diameter fiber in parallel between layers and at a predetermined interlayer crossing angle until the number of deployed layers reaches the compensation layers, and take all the deployed layers of constant-diameter fiber as the collapse compensation model.

[0023] Further, establishing a 3D model of the collapse area corresponding to each layer of deposited variable-diameter fiber further includes:

[0024] For each layer of variable-diameter fiber, determine multiple fiber vertices and corner vertices of the variable-diameter fiber;

[0025] Calculate the collapsed top surface that is tangent to the multiple fiber vertices and corner vertices;

[0026] Determine the horizontal plane where the corner vertex with the highest height is located as the compensation top plane;

[0027] Form a closed space by the collapsed top surface and the compensation top plane along the vertical direction of the side boundary of the variable-diameter fiber of this layer to obtain the 3D model of the collapsed area.

[0028] Furthermore, the method further includes:

[0029] Print the constant-diameter fibers corresponding to the collapse compensation model within the 3D model of the collapsed area corresponding to each layer of variable-diameter fibers to compensate for the collapse of each layer of deposited variable-diameter fibers.

[0030] Furthermore, calculating the compensation printing trajectory composed of the constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the 3D model of the collapsed area for the collapse compensation model further includes:

[0031] Perform a Boolean intersection operation on the 3D model of the collapsed area and the collapse compensation model to obtain the constant-diameter fiber lines corresponding to the intersection;

[0032] Use the constant-diameter fiber lines whose lengths meet a predetermined threshold as the compensation printing trajectory.

[0033] On the other hand, an embodiment of this specification also provides a collapse compensation device for variable-diameter fiber extrusion 3D printing, including,

[0034] A 3D model construction unit for the collapsed area, configured to establish a 3D model of the collapsed area corresponding to each layer of deposited variable-diameter fibers;

[0035] A collapse compensation model construction unit, configured to construct a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers;

[0036] A compensation printing trajectory calculation unit, configured to calculate the compensation printing trajectory composed of the constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the 3D model of the collapsed area for the collapse compensation model;

[0037] A collapse compensation unit, configured to compensate for the collapse of each layer of deposited variable-diameter fibers according to the diameter of the constant-diameter fibers and the compensation printing trajectory.

[0038] On the other hand, an embodiment of the present invention further provides a computer device, including a memory, a processor, and a computer program stored on the memory. When the processor executes the computer program, the above method is implemented.

[0039] Using the embodiments of this specification, in 3D printing technology, first, a 3D model of the object to be printed needs to be constructed. The way to make an object by 3D printing is to divide the designed 3D model into a series of thin layers, write a printing program for 3D printing according to the size, structure, etc. of the thin layers, and then execute the printing program to build the completed object by stacking variable-diameter fibers layer by layer.

[0040] Therefore, the embodiments of this specification establish a 3D model of the collapse area of each layer of variable-diameter fibers after deposition, so as to compensate the collapse area layer by layer. Then, according to the diameter change range of the variable-diameter fibers of the printed object, a collapse compensation model constructed by constant-diameter fibers corresponding to each layer of variable-diameter fibers is constructed, that is, the collapse area of each layer of variable-diameter fibers is compensated by using constant-diameter fibers. Using constant-diameter fibers for collapse compensation can achieve the gradient void structure of the object while compensating for the collapse, and improve the performance of the printed object.

[0041] Then, the collapse compensation model is calculated according to the 3D model of the collapse area to obtain a compensation printing trajectory composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers. After obtaining the compensation printing trajectory, the embodiments of this specification can generate a printing program for the compensation printing trajectory, add the printing program of the compensation printing trajectory after the printing program of the variable-diameter fibers of the corresponding layer, and execute the printing program to automatically compensate the collapse of each layer during the 3D printing of the object, reducing the workload of collapse compensation. Description of the Drawings

[0042] In order to more clearly illustrate the technical solutions in the embodiments of this specification or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of this specification. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0043] Figure 1 Shown is a schematic flow chart of a collapse compensation method for variable-diameter fiber extrusion 3D printing in the embodiments of this specification;

[0044] Figure 2a Shown is a schematic diagram of a single-layer printing model of variable-diameter fibers in the embodiments of this specification;

[0045] Figure 2b Shown is the printing speed matching the single-layer printing model in the embodiments of this specification;

[0046] Figure 2c Shown is the printing height matching the single-layer printing model in the embodiments of this specification;

[0047] Figure 2d Shown is the fiber diameter matching the single-layer printing model in the embodiments of this specification;

[0048] Figure 3a-1 Shown is the change curve of the fiber diameter when the printing resolution is 10 mm in the embodiments of this specification;

[0049] Figure 3a-2 Shown is the change curve of the fiber diameter when the printing resolution is 5 mm in the embodiments of this specification;

[0050] Figure 3a-3 Shown is the change curve of the fiber diameter when the printing resolution is 2.5 mm in the embodiments of this specification;

[0051] Figure 3a-4 Shown is the change curve of the fiber diameter when the printing resolution is 1.25 mm in the embodiments of this specification;

[0052] Figure 3a-5 Shown is the change curve of the fiber diameter when the printing resolution is 0.625 mm in the embodiments of this specification;

[0053] Figure 3b Shown is the schematic diagram of the step effect of the fiber in the embodiments of this specification;

[0054] Figure 3c Shown is the corresponding relationship between the size of the printing code G-codes file and the printing resolution in the embodiments of this specification;

[0055] Figure 4 Shown are the steps for establishing a 3D model of the collapsed area corresponding to each layer of variable-diameter fibers after deposition in the embodiments of this specification;

[0056] Figure 5a Shown is the schematic diagram of the fiber vertex in the embodiments of this specification;

[0057] Figure 5b Shown is the schematic diagram of the corner vertex in the embodiments of this specification;

[0058] Figure 5c Shown is the schematic diagram of the point set in the embodiments of this specification;

[0059] Figure 5d Shown is the schematic diagram of the top surface in the embodiments of this specification;

[0060] Figure 5e Shown is the schematic diagram of compensating the top plane in the embodiments of this specification;

[0061] Figure 5f The figure shows a schematic diagram of the 3D model of the collapsed area in the embodiments of this specification;

[0062] Figure 6 The figure shows a schematic diagram of the collapse of variable-diameter fibers in the embodiments of this specification;

[0063] Figure 7 The figure shows the steps of constructing a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers in the embodiments of this specification;

[0064] Figure 8 The figure shows the steps of deploying the constant-diameter fibers on the deposited variable-diameter fibers according to the number of compensation layers to obtain the collapse compensation model in the embodiments of this specification;

[0065] Figure 9 The figure shows a schematic diagram of obtaining a constant-diameter support fiber model and its printing trajectory through Boolean operations in the embodiments of this specification;

[0066] Figure 10 The figure shows the steps of calculating the collapse compensation model according to the 3D model of the collapsed area to obtain a compensation printing trajectory composed of the constant-diameter fibers corresponding to each layer of variable-diameter fibers in the embodiments of this specification;

[0067] Figure 11 The figure shows a schematic structural diagram of a collapse compensation device for variable-diameter fiber extrusion 3D printing in the embodiments of this specification;

[0068] Figure 12 The figure shows a schematic diagram of constructing a horizontal gradient structure by variable-fiber-diameter extrusion 3D printing with a constant-diameter fiber compensation method in the embodiments of this specification;

[0069] Figure 13a The figure shows the printing speeds and printing head heights of the variable-diameter fiber layer and the constant-diameter fiber compensation layer in the embodiments of this specification;

[0070] Figure 13b The figure shows the key frames of processing the variable-diameter fiber layer and the constant-diameter fiber compensation layer during the variable-fiber-diameter extrusion 3D printing process in the embodiments of this specification;

[0071] Figure 14a The figure shows the horizontal gradient structure reconstructed by Micro-CT in the embodiments of this specification;

[0072] Figure 14b The figure shows using ImageJ to analyze the Micro-CT data of the sample and quantitatively evaluate the pore size of the gradient structure sample in the embodiments of this specification;

[0073] Figure 15 The figure shows a schematic diagram of a gradient structure affected by letters in the embodiments of this specification;

[0074] Figure 16 The figure shows a schematic diagram of a "cancellous bone - cortical bone" mimicking radial gradient bone tissue engineering scaffold in the embodiments of this specification;

[0075] Figure 17 The figure shows a schematic diagram of the structure of a computer device in the embodiments of this specification.

[0076]

Explanation of the reference numerals

[0077] 1101, Collapse area 3D model construction unit;

[0078] 1102, Collapse compensation model construction unit;

[0079] 1103, Compensation printing trajectory calculation unit;

[0080] 1104, Collapse compensation unit;

[0081] 1702, Computer device;

[0082] 1704, Processor;

[0083] 1706, Memory;

[0084] 1708, Driving mechanism;

[0085] 1710, Input / output module;

[0086] 1712, Input device;

[0087] 1714, Output device;

[0088] 1716, Rendering device;

[0089] 1718, Graphical user interface;

[0090] 1720, Network interface;

[0091] 1722, Communication link;

[0092] 1724, Communication bus. Detailed implementation manners

[0093] The following will clearly and completely describe the technical solutions in the embodiments of this specification with reference to the accompanying drawings in the embodiments of this specification. Obviously, the described embodiments are only a part of the embodiments of this specification, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in this specification without creative efforts belong to the scope of protection of this specification.

[0094] It should be noted that the terms "first", "second", etc. in the specification, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of this specification described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, device, product or equipment that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or equipment.

[0095] It should be noted that the acquisition, storage, use, processing, etc. of data in the technical solution of this application all comply with the relevant regulations of national laws and regulations.

[0096] In order to solve the problems existing in the prior art, the embodiments of this specification provide a collapse compensation method for variable-diameter fiber extrusion 3D printing. Taking the local collapse area as a breakthrough point, a method of using constant-diameter fibers to compensate the local collapse area solves the problem of local collapse in the models printed by the existing variable-diameter fiber extrusion 3D printing technology. Figure 1 The following shows a schematic flowchart of a collapse compensation method for variable-diameter fiber extrusion 3D printing in the embodiments of this specification. The process of compensating for the collapse of variable-diameter fiber extrusion 3D printing is described in this figure, but based on routine or non-creative labor, it may include more or fewer operation steps. The order of steps listed in the embodiments is only one way among the execution orders of numerous steps and does not represent the only execution order. When the actual system or device product is executed, it can be executed in the order shown in the embodiments or the drawings or executed in parallel. Specifically, as Figure 1 shown, the method may include:

[0097] Step 101: Establish a 3D model of the collapse area corresponding to each layer of variable-diameter fibers after deposition;

[0098] Step 102: Construct a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers;

[0099] Step 103: Calculate the collapse compensation model according to the 3D model of the collapsed area to obtain a compensation printing trajectory composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers.

[0100] Step 104: Compensate for the collapse of each layer of deposited variable-diameter fibers using the constant-diameter fibers according to the compensation printing trajectory.

[0101] Using the embodiments of this specification, in 3D printing technology, first, a 3D model of the object to be printed needs to be constructed. The way to 3D print an object is to divide the designed 3D model into a series of thin layers, write a 3D printing program according to the size, structure, etc. of the thin layers, and then execute the printing program to construct the completed object by stacking variable-diameter fibers layer by layer.

[0102] Therefore, the embodiments of this specification establish a 3D model of the collapsed area of each layer of deposited variable-diameter fibers, so as to compensate for the collapsed area layer by layer. Then, according to the diameter change range of the variable-diameter fibers of the printed object, a collapse compensation model constructed by constant-diameter fibers corresponding to each layer of variable-diameter fibers is constructed, that is, the collapsed area of each layer of variable-diameter fibers is compensated using constant-diameter fibers. Using constant-diameter fibers for collapse compensation can, while compensating for the collapse, achieve the gradient void structure of the object and improve the performance of the printed object.

[0103] Then, calculate the collapse compensation model according to the 3D model of the collapsed area to obtain a compensation printing trajectory composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers. After obtaining the compensation printing trajectory, the embodiments of this specification can generate a printing program for the compensation printing trajectory, add the printing program of the compensation printing trajectory after the printing program of the variable-diameter fibers of the corresponding layer, and execute the printing program to automatically compensate for the collapse of each layer during the 3D printing of the object, reducing the workload of collapse compensation.

[0104] In the embodiments of this specification, based on the target gradient and variable-diameter fiber extrusion 3D printing technology, a fiber layer with continuously variable diameter is designed. Based on the printing resolution, the number and positions of equally divided points on the printing path / trajectory of the variable-diameter fibers are determined, and then printing parameters matching the designed 3D model are obtained, such as extrusion air pressure, feeding speed, printing / moving speed, printing / nozzle height, etc., where the printing resolution is the manufacturing resolution of fibers with different diameters on a 3D printer. The single-layer printing model of variable-diameter fibers can be as Figure 2a shown. First, design the printing trajectory, then design the degree of diameter change of the variable-diameter fibers, and then fuse the printing trajectory and the degree of diameter change to obtain the single-layer printing model of the variable-diameter fibers.

[0105] Figure 2b - Figure 2dPrinting parameters that match the single-layer printing model, where Figure 2b is the printing speed, Figure 2c is the printing height, Figure 2d is the fiber diameter. The printing height is the height of the fiber extrusion port relative to the position of the fiber in the single-layer printing model.

[0106] Figure 3a-1 is the change curve of the fiber diameter when the printing resolution is 10 mm, Figure 3a-2 is the change curve of the fiber diameter when the printing resolution is 5 mm, Figure 3a-3 is the change curve of the fiber diameter when the printing resolution is 2.5 mm, Figure 3a-4 is the change curve of the fiber diameter when the printing resolution is 1.25 mm, Figure 3a-5 is the change curve of the fiber diameter when the printing resolution is 0.625 mm, Figure 3a-1 to 3a-5 The abscissa of is the printing track length. At a printing resolution of 10 mm (printing resolution example: on a printing distance of 40 mm, if 4 printing speeds are set, then the printing resolution = 40 mm long printing distance / 4 = 10 mm. Similarly, if 8 printing speeds are set on a 40 mm long printing distance, then the printing resolution = 40 mm long printing distance / 8 = 5 mm), there is a very obvious step effect in the obtained fiber width (as Figure 3b the position pointed by the arrow in), and it is impossible to continuously and uniformly control the fiber diameter or width. At printing resolutions of 1.25 mm and 0.625 mm, it is basically difficult to find the step effect. However, as the printing resolution increases, the size of its 3D printing code G-codes file also increases exponentially. For example Figure 3c the corresponding relationship between the size of the printing code G-codes file and the printing resolution shown. Therefore, 1.25 mm can be used as the printing resolution of the typical embodiment of the present invention.

[0107] In the embodiments of this specification, a 3D model of the collapse area corresponding to each layer of variable-diameter fibers after deposition can be established using existing 3D model simulation software. Further, as Figure 4 shown, establishing a 3D model of the collapse area corresponding to each layer of variable-diameter fibers after deposition further includes:

[0108] Step 401: For each layer of variable-diameter fibers, determine multiple fiber vertices and corner vertices of the variable-diameter fibers;

[0109] Step 402: Calculate the collapse top surface tangent to the multiple fiber vertices and corner vertices;

[0110] Step 403: Determine the horizontal plane where the corner vertex with the highest height is located as the compensation top plane;

[0111] Step 404: Form a closed space by using the collapsed top surface and the compensated top plane along the vertical direction of the side boundary of the variable-diameter fiber of this layer, to obtain the 3D model of the collapsed area.

[0112] In the embodiments of this specification, after each layer of variable-diameter fiber is deposited, based on the fibers of the current layer model, multiple fiber vertices and corner vertices of the variable-diameter are determined. Among them, the fiber vertices can be as Figure 5a shown. It can be understood that the fiber vertex is the highest point on the fiber. Among them, the corner vertices can be as Figure 5b shown. It can be understood that the coordinates of the corner vertex are the coordinates of the points where the four corners of this layer of fiber are located. Then calculate the collapsed top surface that is tangent to multiple fiber vertices and corner vertices. Specifically, the fiber vertices and corner vertices can be merged into a point set, as Figure 5c shown; then based on Figure 5c the shown point set, construct a top surface that is approximately tangent to all points of the point set to obtain the collapsed top surface, as Figure 5d shown; then determine the plane where the corner vertex with the highest height is located as the compensated top plane, as Figure 5e shown. Specifically, the corner vertex corresponding to the maximum value of the z-axis can be selected from the corner vertices, and the remaining corner vertices keep the x value and y value unchanged, and the z value is adjusted to the maximum value respectively, and then a top plane parallel to the xy plane is constructed (it should be noted that x, y, and z here represent three-dimensional coordinates). Then use Figure 5d the shown moss top surface, Figure 5e the shown compensated top plane to form a closed space along the vertical direction of the side boundary of the variable-diameter fiber of this layer, to obtain the 3D model of the collapsed area, as Figure 5f shown.

[0113] Exemplarily, Figure 6 a in represents the printing trajectory of a single layer of variable-diameter fiber, Figure 6 b in represents the object with collapse obtained after stacking multiple layers of variable-diameter fibers together, Figure 6 c in represents the 3D model of the collapsed area obtained by using the method of Figure 4 . It should be noted that Figure 6 the 3D model of the collapsed area of c is based on the stacking of multiple layers of variable-diameter fibers together. Here, only the 3D model of the collapsed area is shown exemplarily (to make the collapse more obvious), Figure 6 which is only to illustrate the collapse existing after the variable-diameter fibers are stacked together. The embodiments of this specification are for compensating the collapse of each layer of variable-diameter fiber.

[0114] According to an embodiment of this specification, the method further includes:

[0115] Print the constant-diameter fibers corresponding to the collapse compensation model within the 3D model of the collapse region corresponding to each layer of variable-diameter fibers to compensate for the collapse of each layer of deposited variable-diameter fibers.

[0116] It can be understood that after determining the 3D model of the collapse region, printing the constant-diameter fibers within the 3D model of the collapse region can compensate for the collapse of each layer of variable-diameter fibers.

[0117] In some other embodiments of this specification, such as Figure 7 shown, constructing the collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers further includes:

[0118] Step 701: Determine the diameter of the constant-diameter fibers according to the diameter change range of the variable-diameter fibers;

[0119] Step 702: Determine the compensation layers of the constant-diameter fibers according to the diameter of the variable-diameter fibers and the diameter of the constant-diameter fibers;

[0120] Step 703: Deploy the constant-diameter fibers on the deposited variable-diameter fibers according to the compensation layers to obtain the collapse compensation model.

[0121] In the embodiments of this specification, first, according to the diameter change range of the variable-diameter fibers, the diameter of the constant-diameter fibers is determined, so as to achieve the gradient void structure of the printed object. Preferably, in the embodiments of this specification, the minimum value in the diameter change range is used as the diameter of the constant-diameter fibers. It should be noted that the diameter of the constant-diameter fibers in the embodiments of this specification is a relative value, because the diameter range of the variable-diameter fibers can be adjusted by printing materials with different rheological properties, extrusion air pressure, print nozzle diameter, and printing speed. Because the parameters of the 3D printing process (such as printing materials, extrusion air pressure, print nozzle diameter, and printing speed, etc.) directly determine the minimum and maximum values of the variable-diameter fibers. Because the volume of the entire 3D printed object is fixed, according to the law of conservation of volume, the more printing material in the unit volume, the fewer pores. Therefore, in the embodiments of this specification, the minimum value in the diameter change range is used as the diameter of the constant-diameter fibers, so as to minimize the pores of the 3D printed object and improve the strength of the 3D printed object. In addition, according to the actual pore requirements, based on the diameter change range of the variable-diameter fibers, constant-diameter fibers with other diameters can be set to compensate for the collapse, and the embodiments of this specification do not limit this.

[0122] In the embodiments of this specification, determining the compensation layers of the constant-diameter fibers according to the diameter of the variable-diameter fibers and the diameter of the constant-diameter fibers further includes:

[0123] Calculate the ratio between the maximum value in the diameter change range and the diameter of the constant-diameter fiber, and round the ratio to obtain the compensation number of layers.

[0124] It can be understood that the collapse height of a single-layer variable-diameter fiber is approximately the difference between the maximum diameter and the minimum diameter of the variable-diameter fiber. In order to ensure as much as possible that the collapse of this layer of variable-diameter fiber can be better compensated, the embodiments of the specification calculate the ratio between the maximum value in the diameter change range and the diameter of the constant-diameter fiber, round the ratio to obtain the compensation number of layers. Under this compensation number of layers, the compensation height calculated in combination with the diameter of the constant-diameter fiber must be higher than the collapse height. In addition, it is also possible to first calculate the difference between the maximum diameter and the minimum diameter of the variable-diameter fiber, then calculate the ratio between this difference and the diameter of the constant-diameter fiber, and round the ratio to use the obtained value as the compensation number of layers.

[0125] According to an embodiment of the present specification, as Figure 8 shown, deploying the constant-diameter fiber on the deposited variable-diameter fiber according to the compensation number of layers to obtain the collapse compensation model further includes:

[0126] Step 801: Deploy the first layer of constant-diameter fiber on the deposited variable-diameter fiber along the printing trajectory of the variable-diameter fiber;

[0127] Step 802: Deploy the second layer of constant-diameter fiber on the first layer of constant-diameter fiber in parallel between layers and at a predetermined interlayer crossing angle;

[0128] Step 803: Take the second layer of constant-diameter fiber as the first layer of constant-diameter fiber, and repeat the step of deploying the next layer of constant-diameter fiber on the first layer of constant-diameter fiber in parallel between layers and at a predetermined interlayer crossing angle until the number of deployed layers reaches the compensation number of layers, and take all the deployed layers of constant-diameter fiber as the collapse compensation model.

[0129] Exemplarily, as Figure 9 shown, Figure 9 a in shows the 3D model of the collapse area, Figure 9 b in shows the double-layer constant-diameter fiber deployed above the variable-diameter fiber, where the first-layer diameter fiber is deployed along the printing trajectory of the variable-diameter fiber, and the second layer of constant-diameter fiber is deployed above the first layer of constant-diameter fiber in parallel between layers and at a predetermined interlayer crossing angle. The parallel between layers here means that the plane where the first layer of constant-diameter fiber is located is parallel to the plane where the second layer of constant-diameter fiber is located. The interlayer crossing angle is to rotate the deployment trajectory of the first layer of constant-diameter fiber by a predetermined crossing angle to obtain the deployment trajectory of the second layer of constant-diameter fiber, asFigure 9 as shown in c in

[0130] It should be noted that when the method of the embodiment of this specification compensates for the collapse of each layer of variable-diameter fibers, it is necessary to calculate the collapse compensation model according to the 3D model of the collapse area to obtain the compensation printing trajectory composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers. When compensating for the collapse of each layer of variable-diameter fibers, if the collapse of a certain layer of variable-diameter fibers is not large, it may be determined according to the calculation that there is no need to compensate for the collapse of this layer of variable-diameter fibers. Therefore Figure 9 the collapse of the first layer of variable-diameter fibers and the second layer of variable-diameter fibers in

[0131] is not large and does not require collapse compensation. The collapse of the third layer of variable-diameter fibers can be compensated. Therefore, collapse compensation is performed on the third layer of variable-diameter fibers.

[0132] It should be noted that all the constant execution fibers in the collapse compensation model stacked by multiple layers of constant-diameter fibers in the embodiment of this specification are not ultimately to be compensated on this layer of variable-diameter fibers. Instead, it is necessary to calculate the collapse compensation model according to the 3D model of the collapse area to obtain the compensation printing trajectory composed of the constant-diameter fibers corresponding to each layer of variable-diameter fibers.

[0133] Specifically, as Figure 10 shown, calculating the collapse compensation model according to the 3D model of the collapse area to obtain the compensation printing trajectory composed of the constant-diameter fibers corresponding to each layer of variable-diameter fibers further includes:

[0134] Step 1001: Perform a Boolean intersection operation on the 3D model of the collapse area and the collapse compensation model to obtain the constant-diameter fiber lines corresponding to the intersection;

[0135] Step 1002: Use the constant-diameter fiber lines whose lengths of the constant-diameter fiber lines meet a predetermined threshold as the compensation printing trajectory.

[0136] In the embodiment of this specification, the constant-diameter fiber lines in the collapse compensation model corresponding to the intersection obtained by the Boolean intersection operation are ultimately to be compensated in the collapse area of the variable-diameter fibers. Continuing as Figure 9 shown, Figure 9Shown in d in [the figure] is the printing trajectory obtained by a Boolean operation. That is, by printing constant-diameter fibers on variable-diameter fibers according to this printing trajectory, collapse can be compensated for.

[0137] However, since 3D printing technology cannot print arbitrarily long lengths. For example, the length of the constant-diameter fiber line obtained by a Boolean intersection operation is only 1 mm, but it is very difficult for 3D printing technology to print a line that is only 1 mm long. Therefore, in the embodiments of this specification, it is also necessary to judge the constant-diameter fiber lines obtained by the Boolean intersection operation according to a predetermined threshold, and use the constant-diameter fiber lines whose lengths meet the predetermined threshold as the compensation printing trajectory. It should be noted that the predetermined threshold can be set according to the accuracy of the 3D printer, and the embodiments of this specification do not make any restrictions.

[0138] To improve printing efficiency, the constant-diameter fiber lines that meet the predetermined threshold can also be connected end to end in sequence to obtain a continuous printing trajectory, and the continuous printing trajectory can be used as the final compensation printing trajectory, as Figure 9 shown in e and f in [the figure]. It can be understood that by printing constant-diameter fibers according to the obtained continuous printing trajectory, the 3D printer can print continuously without multiple starts and stops, and the printing efficiency is higher.

[0139] The collapse compensation method in the embodiments of this specification can also be applied to scenarios other than extrusion-based 3D printing technology, such as low-temperature deposition molding, fused deposition modeling (FDM), direct ink write (DIW), melt electrospinning writing (MEW), fiber deposition-based additive manufacturing technology, etc., and this specification does not make any restrictions. In addition, the 3D printed objects (such as gradient pore structures / samples / scaffolds, etc.) targeted by the collapse compensation method in this specification can include "cancellous-cortical" gradient pore bone scaffolds, meniscus scaffolds, superstructures, encrypted structures, functionally gradient structures, etc., and the embodiments of this specification do not make any restrictions.

[0140] The implementation tools of the collapse compensation method described in the embodiments of this specification include but are not limited to Rhino, Grasshopper, GHPython, and the execution devices used in the collapse compensation method include but are not limited to Regenovo WS extrusion 3D printer.

[0141] Furthermore, the collapse compensation method described in the embodiments of this specification can, in addition to compensating for the collapse of variable-diameter fibers, also be applicable to variable-width fibers, variable-area fibers, variable ink volume, filament width, filament area, etc., and the embodiments of this specification do not make any restrictions.

[0142] Based on the same inventive concept, an embodiment of this specification further provides a collapse compensation device for variable-diameter fiber extrusion 3D printing, as Figure 11 shown, including:

[0143] A collapse area 3D model construction unit 1101, configured to establish a 3D model of the collapse area corresponding to each layer of variable-diameter fibers after deposition;

[0144] A collapse compensation model construction unit 1102, configured to construct a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers;

[0145] A compensation printing trajectory calculation unit 1103, configured to calculate the collapse compensation model based on the collapse area 3D model to obtain a compensation printing trajectory composed of the constant-diameter fibers corresponding to each layer of variable-diameter fibers;

[0146] A collapse compensation unit 1104, configured to compensate for the collapse of each layer of variable-diameter fibers after deposition according to the diameter of the constant-diameter fibers and the compensation printing trajectory.

[0147] Since the principle of the above device for solving problems is similar to the above method, the implementation of the above device can refer to the implementation of the above method, and the repeated parts will not be elaborated.

[0148] An embodiment of this specification is described by taking the construction of a horizontal gradient structure in a cube (10 mm × 10 mm × 10 mm) based on the proposed collapse compensation method and variable fiber diameter extrusion 3D printing technology as an example.

[0149] If the collapse compensation method of the embodiment of this specification is not used, a large-scale collapse will occur in the horizontal gradient constructed in the cube based on the variable fiber diameter extrusion 3D printing technology. The software Rhino and its plug-in Grasshopper are used to complete the model design, and the collapsed area is obtained as Figure 6 shown in c of.

[0150] After using the collapse compensation method of the embodiment of this specification, a horizontal gradient 3D model is also constructed in the cube using the variable fiber diameter extrusion 3D printing technology. It is found that there is basically no significant local collapse in the horizontal gradient 3D model obtained after cross-stacking the variable-diameter fiber layer and the constant-diameter fiber compensation layer, as Figure 12 shown. As shown in a of 12, it represents a multi-layer model of variable-diameter fibers adjusted based on the collapse compensation method, Figure 12 shown in b of represents a multi-layer model of constant-diameter fibers, and as shown in c of 12 represents a non-collapsed variable fiber diameter extrusion 3D printing horizontal gradient structure model corrected using the collapse compensation method of the embodiment of this specification.

[0151] After the horizontal gradient model meets the expectations, the plug-in Grasshopper and its built-in battery GhPython are used to convert the printing trajectory and printing parameters obtained by the present invention (as Figure 13a shown) into manufacturing codes G-codes that can be recognized by an extrusion-based 3D printing device. Using polycaprolactone as the ink, JieNuofei Regenovo WS printer is used as the 3D printing device to prepare horizontal gradient samples of variable fiber diameter extrusion-based 3D printing with a constant diameter fiber compensation method (as Figure 13b shown).

[0152] The Micro-CT data of the horizontal gradient samples is obtained using the tomography device SkyScan 1176, and then the reconstruction of the samples is completed using the Bruker software package CTAn, as Figure 14a shown. The results show that the variable fiber diameter extrusion-based 3D printed samples corrected by the collapse compensation method described in the embodiments of the present specification have no collapse or negligible collapse.

[0153] Furthermore, the ImageJ software is used to quantitatively evaluate the pore size of the obtained Micro-CT data, as Figure 14b shown. The results show that the obtained gradient samples meet the requirements of the design for the horizontal gradient.

[0154] Furthermore, a gradient structure with HIT letters embedded at different positions in a cuboid (20 mm × 10 mm × 10 mm) is designed, manufactured, and evaluated using the collapse compensation method described in the embodiments of the present specification, as Figure 15 shown. The Micro-CT reconstruction model and the quantitative 3D map of the pore size obtained by ImageJ prove the feasibility of constructing a complex gradient structure in the cuboid, and the obtained gradient samples have basically no collapse or negligible collapse.

[0155] Finally, a radial gradient bone tissue engineering scaffold imitating "cancellous bone - cortical bone" is designed, manufactured, and evaluated using the collapse compensation method described in the embodiments of the present specification, as Figure 16 shown. Figure 16 In , a represents a schematic diagram of the femur, Figure 16 in , b represents the bone model after collapse compensation using the embodiments of the present specification, Figure 16 in , c represents the sample of the radial gradient bone tissue engineering scaffold prepared by variable fiber diameter extrusion-based 3D printing, Figure 16 in , d represents the quantitative evaluation result of the pore size of the radial gradient bone sample. The Micro-CT reconstruction model and the quantitative 3D map of the pore size obtained by ImageJ prove that the obtained bionic bone scaffold sample has radial gradient characteristics, and the obtained gradient samples have basically no collapse or negligible collapse.

[0156] As shown Figure 17 in the figure, a computer device provided by an embodiment of this specification is shown. In the embodiment of this specification, the device may be the computer device in this embodiment and execute the method of the embodiment of this specification. The computer device 1702 may include one or more processors 1704, such as one or more central processing units (CPUs), and each processing unit may implement one or more hardware threads. The computer device 1702 may also include any memory 1706 for storing any kind of information such as code, settings, data, etc. Non-limiting examples include any type of RAM, any type of ROM, flash memory devices, hard disks, optical disks, etc. More generally, any memory may use any technology to store information. Further, any memory may provide volatile or non-volatile retention of information. Further, any memory may represent a fixed or removable component of the computer device 1702. In one case, when the processor 1704 executes the associated instructions stored in any memory or combination of memories, the computer device 1702 may perform any operation of the associated instructions. The computer device 1702 also includes one or more drive mechanisms 1708 for interacting with any memory, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0157] The computer device 1702 may also include an input / output module 1710 (I / O) for receiving various inputs (via the input device 1712) and for providing various outputs (via the output device 1714). A specific output mechanism may include a presentation device 1716 and an associated graphical user interface (GUI) 1718. In other embodiments, the input / output module 1710 (I / O), the input device 1712, and the output device 1714 may not be included and it may only be a computer device in a network. The computer device 1702 may also include one or more network interfaces 1720 for exchanging data with other devices via one or more communication links 1722. One or more communication buses 1724 couple the components described above together.

[0158] The communication link 1722 may be implemented in any way, for example, through a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link 1722 may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc. governed by any protocol or combination of protocols.

[0159] An embodiment of this specification also provides a computer-readable storage medium on which a computer program is stored, and when the computer program is run by a processor, it executes the above steps.

[0160] The embodiments of this specification also provide a computer-readable instruction. When a processor executes the instruction, the program therein causes the processor to execute the above-mentioned method.

[0161] It should be understood that in various embodiments of this specification, the magnitudes of the serial numbers of the above processes do not imply the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of this specification.

[0162] It should also be understood that in the embodiments of this specification, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in the embodiments of this specification generally represents an "or" relationship between the associated objects before and after.

[0163] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in the embodiments of this specification can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of this specification.

[0164] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the foregoing method embodiments and will not be elaborated herein.

[0165] In several embodiments provided in this specification, it should be understood that the disclosed systems, devices, and methods can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For example, the division of the units is only a logical function division, and there may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed coupling or direct coupling or communication connection to each other can be an indirect coupling or communication connection through some interfaces, devices, or units, and can also be in an electrical, mechanical, or other form of connection.

[0166] The unit described as a separation component may or may not be physically separated. The component displayed as a unit may or may not be a physical unit, that is, it may be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiments of this specification.

[0167] In addition, each functional unit in the various embodiments of this specification may be integrated into a processing unit, may exist separately as individual physical units, or two or more units may be integrated into one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of a software functional unit.

[0168] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of this specification, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this specification. The aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0169] Specific embodiments are used in this specification to elaborate on the principles and implementation manners of this specification. The descriptions of the above embodiments are only used to help understand the method and its core idea of this specification; at the same time, for those of ordinary skill in the art, according to the idea of this specification, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to this specification.

Claims

1. A collapse compensation method for variable-diameter fiber extrusion 3D printing, characterized in that Including: Establishing a 3D model of the collapse area corresponding to each layer of variable-diameter fibers after deposition; Constructing a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers; Calculating the collapse compensation model according to the 3D model of the collapse area to obtain a compensation printing trajectory composed of the constant-diameter fibers corresponding to each layer of variable-diameter fibers; Compensating for the collapse of each layer of variable-diameter fibers after deposition using the constant-diameter fibers according to the compensation printing trajectory; Constructing a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers further includes: Determining the diameter of the constant-diameter fibers according to the diameter change range of the variable-diameter fibers; Determining the compensation number of layers of the constant-diameter fibers according to the diameter of the variable-diameter fibers and the diameter of the constant-diameter fibers; Deploying the constant-diameter fibers on the deposited variable-diameter fibers according to the compensation number of layers to obtain the collapse compensation model; Establishing a 3D model of the collapse area corresponding to each layer of variable-diameter fibers after deposition further includes: For each layer of variable-diameter fibers, determining multiple fiber vertices and corner vertices of the variable-diameter fibers; Calculating a collapse top surface tangent to the multiple fiber vertices and corner vertices; Determining the plane where the corner vertex with the highest height is located as the compensation top plane; Forming a closed space by the collapse top surface and the compensation top plane along the vertical direction of the side boundary of the variable-diameter fibers of this layer to obtain the 3D model of the collapse area; 2. The method according to claim 1, wherein Determining the diameter of the constant-diameter fibers according to the diameter change range of the variable-diameter fibers further includes: Taking the minimum value in the diameter change range as the diameter of the constant-diameter fibers; 3. The method according to claim 1, wherein Determining the compensation number of layers of the constant-diameter fibers according to the diameter of the variable-diameter fibers and the diameter of the constant-diameter fibers further includes: Calculating the ratio between the maximum value in the diameter change range and the diameter of the constant-diameter fibers, and performing rounding processing on the ratio to obtain the compensation number of layers; 4. The method according to claim 1, wherein Deploying the constant-diameter fibers on the deposited variable-diameter fibers according to the compensation number of layers to obtain the collapse compensation model further includes: Deploying the first layer of constant-diameter fibers on the deposited variable-diameter fibers along the printing trajectory of the variable-diameter fibers; Deploying the second layer of constant-diameter fibers on the first layer of constant-diameter fibers in parallel between layers and at a predetermined interlayer crossing angle; Taking the second layer of constant-diameter fibers as the first layer of constant-diameter fibers, and repeating the step of deploying the next layer of constant-diameter fibers on the first layer of constant-diameter fibers in parallel between layers and at a predetermined interlayer crossing angle until the number of deployed layers reaches the compensation number of layers, and taking all the deployed layers of constant-diameter fibers as the collapse compensation model; 5. The method according to claim 1, wherein The method further includes: Printing the constant-diameter fibers corresponding to the collapse compensation model within the 3D model of the collapse area corresponding to each layer of variable-diameter fibers to compensate for the collapse of each layer of variable-diameter fibers after deposition.

6. The method according to claim 1, wherein Calculating the collapse compensation model based on the 3D model of the collapsed area to obtain the compensation printing trajectory composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers further includes: Performing a Boolean intersection operation on the 3D model of the collapsed area and the collapse compensation model to obtain constant-diameter fiber lines corresponding to the intersection; Taking the constant-diameter fiber lines whose lengths of the constant-diameter fiber lines meet a predetermined threshold as the compensation printing trajectory.

7. A collapse compensation device for variable-diameter fiber extrusion 3D printing, characterized in that, Including: A 3D model construction unit for the collapsed area, configured to establish a 3D model of the collapsed area corresponding to each layer of variable-diameter fibers after deposition; A collapse compensation model construction unit, configured to construct a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers; A compensation printing trajectory calculation unit, configured to calculate the collapse compensation model based on the 3D model of the collapsed area to obtain a compensation printing trajectory composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers; A collapse compensation unit, configured to compensate for the collapse of each layer of variable-diameter fibers after deposition according to the diameter of the constant-diameter fibers and the compensation printing trajectory; Constructing a collapse compensation model composed of constant-diameter fibers corresponding to each layer of variable-diameter fibers according to the diameter change range of the variable-diameter fibers further includes: Determining the diameter of the constant-diameter fibers according to the diameter change range of the variable-diameter fibers; Determining the compensation number of layers of the constant-diameter fibers according to the diameter of the variable-diameter fibers and the diameter of the constant-diameter fibers; Deploying the constant-diameter fibers on the variable-diameter fibers after deposition according to the compensation number of layers to obtain the collapse compensation model; Establishing a 3D model of the collapsed area corresponding to each layer of variable-diameter fibers after deposition further includes: For each layer of variable-diameter fibers, determining multiple fiber vertices and corner vertices of the variable-diameter fibers; Calculating a collapsed top surface tangent to the multiple fiber vertices and corner vertices; Determining the surface where the corner vertex with the highest height is located as the compensation top plane; Forming a closed space by the collapsed top surface and the compensation top plane along the vertical direction of the side boundary of the variable-diameter fibers of this layer to obtain the 3D model of the collapsed area.

8. A computer device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method according to any one of claims 1 to 6.

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