Continuous fiber 3D printing method and system based on high-precision corner path design

Abstract

The invention relates to a continuous fiber 3D printing method and system based on high-precision corner path design, and the method comprises the steps: S100, obtaining Gcode features corresponding to a to-be-printed structure, and determining a continuous fiber printing path; s300, calculating an included angle between the two paths based on the two-dimensional coordinate values of the two intersected printing paths; and S500, carrying out coordinate calculation on the compensation point at the inflection point by utilizing a geometric optimization algorithm and combining the included angle between the two paths, the path vertex coordinates and the path vector direction so as to generate a compensation path Gcode, and inserting the compensation path Gcode into the original Gcode. The method does not need to manually change a corner set value, does not need to change a preset path in a large range, and only carries out local path compensation at the corner vertex. The direction of the compensation path can be determined by a mathematical expression, and the uncertainty of corner path compensation is eliminated. In addition, the compensation path calculation process is fast and simple, and printing equipment does not need to be transformed.

Description

Technical Field

[0001] The present disclosure relates to the technical field of additive manufacturing of continuous fiber reinforced composite materials, and in particular, to a continuous fiber 3D printing method and system based on high-precision corner path design. Background Art

[0002] 3D printing technology is driven by digital three-dimensional solid models and can achieve integrated rapid manufacturing of complex components. Technicians can improve the mechanical properties of the structure by adding continuous fiber reinforcements along the load path during polymer 3D printing. Therefore, the continuous fiber 3D printing process combines the rapid prototyping advantages of 3D printing with the performance advantages of continuous fiber reinforced composite materials.

[0003] During the 3D printing process of continuous fiber reinforced composite materials, the continuous fiber prepreg impregnated with the resin matrix enters the print head through the feeding extrusion system, and the matrix melts inside the print head to obtain adhesion. Then the servo mechanism controls the movement of the print head according to the preset path to achieve layer-by-layer deposition of the structure. However, to prevent clogging, the inner diameter of the print head nozzle is usually larger than the diameter of the prepreg, so the position where the print head actually compacts the molten printing filament is located at the side wall, not at the geometric center of the nozzle. In addition, due to the continuity and tension of high-rigidity fibers (such as carbon fibers), the in-plane stress along the width direction is antisymmetrically distributed, resulting in fiber torsion of the ribbon fibers at the corners. Under the combined influence of the above two situations, a significant rounding effect occurs when printing corner paths, resulting in limited corner printing accuracy, which is not conducive to the realization of the free forming potential of 3D printing. Summary of the invention

[0004] The purpose of the present disclosure is to provide a continuous fiber 3D printing method and system based on high-precision corner path design to at least partially solve the problems existing in the related art.

[0005] In order to achieve the above objectives, the present disclosure provides a continuous fiber 3D printing method based on high-precision corner path design, comprising:

[0006] S100. Obtaining Gcode features corresponding to the structure to be printed, and determining a continuous fiber printing path;

[0007] S300. Based on the two-dimensional coordinate values ​​of the two intersecting printing paths, calculate the angle between the two paths;

[0008] S500. Using a geometric optimization algorithm, combined with the angle between the two paths, the coordinates of the path vertices and the direction of the path vector, the coordinates of the compensation point at the inflection point are calculated to generate a compensation path Gcode code, and insert it into the original Gcode code.

[0009] Optionally, step S100 includes:

[0010] S100-1. Submit the 3D model to be sliced ​​to the slicing module, set the printing parameters in the slicing module, select the required path planning algorithm, and generate the Gcode code including the resin printing path and the continuous fiber printing path;

[0011] S100-2. The angle compensation judgment module reads the code line by line. If the print head code corresponding to the path is a resin print head, the path is skipped and the next line is read. If the print head code corresponding to the path is a continuous fiber print head, the angle between the two subsequent intersecting paths is calculated.

[0012] Optionally, step S300 includes:

[0013] S300-1. Since 3D printed three-dimensional models are usually composed of multiple two-dimensional triangular facets, the intersection lines of the slice plane and the three-dimensional model during the slicing process are all straight lines. When the straight line path set is projected onto the coordinate base plane, the path vertex coordinate value set can be obtained. Therefore, the angle value between any two adjacent paths can be calculated. The angle ∠ABC between two adjacent paths can be calculated as follows:

[0014]

[0015] Among them, A, B, and C are the vertices of paths AB and AC, and their coordinates are (x 1 ,y 1 ), (x 2 ,y 2 ), (x 3 ,y 3 );

[0016] S300-2. Compare the calculated included angle with the set critical angle, and determine the corner path that is smaller than the critical angle as the path to be compensated, otherwise no path compensation is required.

[0017] Optionally, the critical angle is at least 135 degrees.

[0018] Optionally, step S500 includes:

[0019] S500-1. The compensation distance is determined to be half of the outer diameter of the print head. The compensation direction is the direction of the angle bisector of the path angle to be compensated, pointing to the outside of the figure. Let the compensation distance be d, the compensation point be point P, and the intersection of the angle bisector of ∠ABC and AC be point D. According to the angle bisector theorem, the coordinates of point D are:

[0020]

[0021] Among them, |AB|, |BC| are the lengths of line segments AB and BC respectively:

[0022]

[0023] Since point P is point B along the direction The extension distance d, so the coordinates of point P (P x ,P y ) can be calculated by the following formula:

[0024]

[0025] in, is the unit direction vector of the compensation vector, which is calculated as follows:

[0026]

[0027] Substituting and simplifying, we can get the coordinates of point P (P x ,P y )as follows:

[0028]

[0029] S500-2. The printing path is A→B→P→B→C.

[0030] Optionally, in step S500-2, the print head moves from B to P, and then the print head is lowered by H. 1 , so that the side wall of the print head compacts the molten deposition line onto the substrate or the deposited layer at point B, achieving precise positioning of the path turning point;

[0031] Then raise the print head H 2 , the height after lifting must exceed the height before lowering to avoid the print head colliding with the deposited material during subsequent movement;

[0032] The print head moves from P to B, then drops to its initial height and continues to complete the subsequent printing path.

[0033] Optionally, H 1 0.1-0.5 mm, H 2 0.2-1 mm.

[0034] According to a second aspect of an embodiment of the present disclosure, a continuous fiber 3D printing system based on high-precision corner path design is provided, comprising:

[0035] A judgment module is configured to obtain Gcode features corresponding to the structure to be printed and determine a continuous fiber printing path;

[0036] An angle calculation module is configured to calculate the angle between the two paths based on the two-dimensional coordinate values ​​of the two intersecting printing paths;

[0037] The corner compensation calculation module is configured to use a geometric optimization algorithm, combined with the angle between two paths, the coordinates of the path vertices and the direction of the path vector, to calculate the coordinates of the compensation point at the turning point, and insert the compensation path Gcode code into the original Gcode code.

[0038] The technical solution provided by the embodiments of the present disclosure may have the following beneficial effects:

[0039] 1. High-precision corner compensation algorithm. The present invention proposes a high-precision compensation algorithm specifically for the corner area of ​​the continuous fiber printing path. It combines geometric analysis with path characteristics, and accurately identifies and corrects the corner path that needs to be compensated through angle judgment and compensation point coordinate calculation. This design significantly improves the printing accuracy of continuous fiber corners, effectively solves the problem of rounded corner effect at corners, and provides support for continuous fiber printing of complex geometric structures. At the same time, the algorithm uses explicit expressions to calculate the compensation path, avoiding the influence of different molding systems and material systems, and has excellent system adaptability.

[0040] 2. Measures to improve the reliability of corner compensation. In the process of generating the compensation path, the present invention combines a sophisticated print head movement strategy to propose a set of effective measures to improve the reliability of corner printing. In the compensation step, reasonable lifting and moving operations of the print head are used to avoid collision with the deposited layer, thereby preventing printing failures caused by broken wires or structural damage. This method greatly improves the reliability and safety of printing and is suitable for 3D printing needs with high precision and complex structures.

[0041] 3. Modular printing system architecture. The present invention designs a modular system architecture that can achieve high-precision corner printing. Each module has a clear division of labor and works closely together. The slicing module generates initial path data, the corner compensation judgment module intelligently identifies and selects the continuous fiber path to be compensated, the corner compensation calculation module accurately calculates the compensation path, and the slicing code integration module generates the compensation path code, which is integrated to obtain a complete printing code. The modular design can effectively simplify the compensation operation of complex paths and significantly improve the applicability, automation and intelligence level of continuous fiber 3D printing.

[0042] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0044] Figure 1 It is a flow chart of a continuous fiber 3D printing method based on high-precision corner path design according to an exemplary embodiment of the present disclosure.

[0045] Figure 2 It is a schematic diagram of the 3D printing head structure and the printing head cross section.

[0046] Figure 3 It is a schematic diagram of stress distribution at the corner.

[0047] Figure 4 Schematic diagram of the rounding effect of an uncompensated corner path.

[0048] Figure 5 It is a schematic diagram of the compensation path setting and high-precision turning angle of the present invention.

[0049] Figure 6 It is a comparison diagram of the path settings before and after 30° corner path compensation, the outermost circle contour path code, and the actual printing results.

[0050] Figure 7 It is a schematic diagram comparing the path settings before and after 45° corner path compensation, the outermost circle contour path code, and the actual printing results.

[0051] Figure 8 It is a schematic diagram comparing the path settings before and after 90° corner path compensation, the outermost circle contour path code, and the actual printing results.

[0052] Description of Reference Numerals

[0053] 1-1, continuous fiber 3D printing head; 1-2, printing head straight chamber; 1-3, continuous fiber printing filament; 1-4, set inflection point; 1-5, actual inflection point;

[0054] 2-1. Corner printing path where fiber twisting occurs; 2-2. Sectional position of corner inflection point; 2-3. Antisymmetric stress distribution at the section position of corner inflection point;

[0055] 3-1. Uncompensated corner setting path; 3-2. Uncompensated corner rounding defect;

[0056] 4-1. Setting path of the corner after compensation; 4-2. Compensation path; 4-3. High-precision corner path after compensation;

[0057] 5-1, the outermost contour of the path setting without compensation for 30° angle; 5-2, the outermost contour of the path setting after compensation for 30° angle; 5-3, the outermost contour of the actual printing path without compensation for 30° angle; 5-4, the outermost contour of the actual printing path after compensation for 30° angle;

[0058] 6-1, the outermost contour of the path setting without compensation for a 45° angle; 6-2, the outermost contour of the path setting after compensation for a 45° angle; 6-3, the outermost contour of the actual printing path without compensation for a 45° angle; 6-4, the outermost contour of the actual printing path after compensation for a 45° angle;

[0059] 7-1, the outermost contour of the path setting without compensation for 90° corner; 7-2, the outermost contour of the path setting after 90° corner compensation; 7-3, the outermost contour of the actual printing path without compensation for 90° corner; 7-4, the outermost contour of the actual printing path after 90° corner compensation; DETAILED DESCRIPTION

[0060] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0061] See also Figure 2 In the 3D printing process of continuous fiber reinforced composite materials, the continuous fiber prepreg impregnated with the resin matrix enters the print head through the feeding extrusion system. The matrix melts inside the print head to obtain adhesion. Then the servo mechanism controls the movement of the print head according to the preset path to achieve layer-by-layer deposition of the structure. To prevent clogging, the inner diameter of the print head nozzle is usually larger than the prepreg diameter, so the actual location where the print head compacts the molten printing filament is at the side wall, not at the geometric center of the nozzle. See Figure 3 In addition, due to the continuity and tension of high-rigidity fibers (such as carbon fibers), the in-plane stress at the corners along the width direction is antisymmetrically distributed, resulting in fiber torsion at the corners of the ribbon fibers. The combined influence of the above two situations leads to a significant rounding effect when printing corner paths. Please refer to Figure 4 , which limits the corner printing accuracy and is not conducive to the realization of the free forming potential of 3D printing.

[0062] See also Figure 1 The present disclosure provides a continuous fiber 3D printing method based on high-precision corner path design, including:

[0063] Step S100: Obtain the Gcode features corresponding to the structure to be printed and determine the continuous fiber printing path.

[0064] Step S300. Calculate the angle between the two paths based on the two-dimensional coordinate values ​​of the two intersecting printing paths;

[0065] Step S500. Using the geometric optimization algorithm, combined with the angle between the two paths, the coordinates of the path vertices and the direction of the path vector, the coordinates of the compensation point at the inflection point are calculated to generate the compensation path Gcode code and insert it into the original Gcode code. The start and end codes can control the actions of the 3D printer before and after the start of printing, such as returning to the original position, heating the print head and the hot bed, turning on the cooling fan, stopping heating, cutting the fiber, and turning off the motor. The Gcode code processed by the slice code integration module is the Gcode code finally submitted to the 3D printer, which can be used for high-precision printing of the model.

[0066] In one embodiment, step S100 includes:

[0067] Step S100-1. Submit the three-dimensional model to be sliced ​​to the slicing module, and set the printing parameters in the slicing module. The printing parameters include print head type, temperature, layer height, overlap rate, cooling fan speed, extrusion ratio, etc. Select the required path planning algorithm to generate Gcode code including resin printing path and continuous fiber printing path. It can be understood that when submitting the three-dimensional model to be sliced ​​to the slicing module, since the 3D printed three-dimensional model is usually composed of multiple two-dimensional triangular facets, the intersection line of the slicing plane of the slicing module and the three-dimensional model generates a contour line. The coordinate mapping algorithm is used to extract the coordinate set of the path vertices. For different materials, process parameters and filling schemes, the path planning algorithm is applied to generate the printing path and the corresponding Gcode code. Different material parts in the model to be printed correspond to different print head codes, printing parameters and printing paths.

[0068] Step S100-2. The angle compensation judgment module reads the code line by line. If the print head code corresponding to the path is a resin print head, the path is skipped and the next line is read. If the print head code corresponding to the path is a continuous fiber print head, the angle between the two subsequent intersecting paths is calculated.

[0069] In one embodiment, step S300 includes:

[0070] Step S300-1. Since a 3D printed three-dimensional model is usually composed of multiple two-dimensional triangular facets, the intersection of the slice plane and the three-dimensional model during the slicing process is a straight line. When the straight line path set is projected onto the coordinate base plane, the path vertex coordinate value set can be obtained. Figure 5 , so the angle between any two adjacent paths can be calculated. The angle ∠ABC between two adjacent paths can be calculated as follows:

[0071]

[0072] Among them, A, B, and C are the vertices of paths AB and AC, and their coordinates are (x 1,y 1 ), (x 2 ,y 2 ), (x 3 ,y 3 );

[0073] Step S300-2. Compare the calculated angle with the set critical angle, and determine the corner path less than the critical angle as the path to be compensated, otherwise no path compensation is required. Figure 4 That is, when the angle value is less than the critical angle, the corner printing will have a rounded effect and the angle accuracy will be significantly lost.

[0074] In one embodiment, the critical angle is at least 135 degrees. The selection of 135 degrees is based on multiple experiments. When the turning angle is less than 135 degrees, a rounded corner effect will occur in the corner printing, and the angle accuracy will be significantly lost.

[0075] In one embodiment, in combination Figure 5 , step S500 includes:

[0076] Step S500-1. The compensation distance is determined to be half of the outer diameter of the print head, and the compensation direction is the direction of the angle bisector of the path angle to be compensated, pointing to the outside of the figure. Let the compensation distance be d, the compensation point be point P, and the intersection of the angle bisector of ∠ABC and AC be point D. According to the angle bisector theorem, the coordinates of point D are:

[0077]

[0078] Among them, |AB|, |BC| are the lengths of line segments AB and BC respectively:

[0079]

[0080] Since point P is point B along the direction The extension distance d, so the coordinates of point P (P x ,P y ) can be calculated by the following formula:

[0081]

[0082] in, is the unit direction vector of the compensation vector, which is calculated as follows:

[0083]

[0084] Substituting and simplifying, we can get the coordinates of point P (P x ,P y )as follows:

[0085]

[0086] Step S500-2. When turning a corner, the printing path is A→B→P→B→C.

[0087] In one embodiment, see Figure 2 and 5 , Figure 2 The printing direction in refers to the continuous fiber 3D printing head 1-1 from A→B→P, point B is the actual inflection point 1-5, and point P is the fixed inflection point 1-4. In step S500-2, the printing head is from B→P, and then the printing head is lowered by H1, so that the side wall of the printing head compacts the molten deposition line to the substrate or the deposited layer at point B, and the precise positioning of the path inflection point is achieved. That is, when the printing head reaches point P through the straight chamber 1-2 (the center of the continuous fiber 3D printing head), the side wall of the printing head is at point B. At this time, the continuous fiber 3D printing head 1-1 is lowered by H1, so that the side wall of the printing head can compact the printing material at point B downward.

[0088] Then the print head is raised by H2, and the height after the raising needs to exceed the height before the lowering to prevent the print head from colliding with the deposited material during the subsequent movement.

[0089] The print head moves from P to B, and then the print head drops to the initial height to continue to complete the subsequent printing path. That is, after the print head moves to point B through the straight chamber 1-2 (the center of the continuous fiber 3D print head 1-1), the continuous fiber 3D print head 1-1 drops to the initial height. The initial height refers to the distance from the nozzle of the continuous fiber 3D print head 1-1 to the surface of the print bed when it is at point A. The distance from the nozzle of the continuous fiber 3D print head 1-1 to the surface of the print bed is the same when it moves from A to B and B to C.

[0090] In one embodiment, H1 is 0.1-0.5 mm, and H2 is 0.2-1 mm.

[0091] For example, combined with Figure 6 , the 30-degree corner path printing code is parsed line by line to illustrate the high-precision corner path optimization process. In order to specifically illustrate the optimization effect of this corner, the optimization code only contains the outermost corner contour of the visible part in the figure.

[0092] G1 Z0.2

[0093] The print head moves to the designed height of 0.2 mm (initial height).

[0094] G1 X45 Y186.7 E25

[0095] Uncompensated path, move the print head center to the starting point (45,186.7), extrusion length 25mm.

[0096] G1 X20 Y230 E49.9989

[0097] The original path to be compensated is to move the center of the print head to the designed turning point (20, 230), and the extrusion length is 49.9989 mm.

[0098] G1 X19.6118 Y231.4489 E1.5

[0099] Compensation path code, move the print head center to the compensation point (19.6118, 231.4489), extrusion length 1.5mm, to prevent fiber breakage.

[0100] G1 Z0

[0101] The print head moves downward by 0.2 mm, at which time the print head height is 0, so that the side wall of the print head compacts the molten printing filament at the designed inflection point.

[0102] G1 Z0.4

[0103] The print head moves upward a distance of 0.4 mm, at which time the print head height is 0.4 mm and is out of contact with the deposited layer.

[0104] G1 X20 Y230

[0105] The center of the print head moves to the turning point of the original path design.

[0106] G1 Z0.2

[0107] The print head moves downward 0.2mm, and the print head height is 0.2mm, returning to the designed layer height.

[0108] G1 X20 Y187.4 E42.6

[0109] Continue printing the subsequent paths.

[0110] Combination Figure 7 , the 45-degree corner path printing code is parsed line by line to illustrate the high-precision corner path optimization process. In order to specifically illustrate the optimization effect of this corner, the optimization code only contains the outermost corner contour of the visible part in the figure.

[0111] G1 Z0.2

[0112] The print head moves to the designed height of 0.2 mm.

[0113] G1 X65 Y130 E50

[0114] Uncompensated path, move the print head center to the starting point (65,130), extrusion length 50mm.

[0115] G1 X15 Y180 E70.711

[0116] The original path to be compensated is to move the center of the print head to the designed inflection point (15, 180), and the extrusion length is 70.711 mm.

[0117] G1 X14.426 Y181.3858 E1.5

[0118] Compensation path code, move the print head center to the compensation point (14.426, 181.3858), extrusion length 1.5mm, to prevent fiber breakage.

[0119] G1 Z0

[0120] The print head moves downward to a height of 0 mm from the substrate, so that the side wall of the print head compacts the molten printing filament at the designed inflection point.

[0121] G1 Z0.4

[0122] The print head moves upward to a height of 0.4 mm from the substrate and breaks contact with the deposited layer.

[0123] G1 X15 Y180

[0124] The center of the print head moves to the turning point of the original path design.

[0125] G1 Z0.2

[0126] The print head moves down to a distance of 0.2 mm from the substrate and returns to the designed layer height.

[0127] G1 X15 Y130.7 E49.3

[0128] Continue printing the subsequent paths.

[0129] Combination Figure 8 , the 90-degree corner path printing code is parsed line by line to illustrate the high-precision corner path optimization process. In order to specifically illustrate the optimization effect of this corner, the optimization code only contains the outermost corner contour of the visible part in the figure.

[0130] G1 Z1G1 Z0.3

[0131] The print head moves to the designed height of 0.3mm.

[0132] G1 X100.845 Y100.35

[0133] Uncompensated path, move the print head center to the starting point (100.845,100.35).

[0134] G1 X149.65 Y100.35 E48.805

[0135] The original path to be compensated is to move the center of the print head to the designed inflection point (149.65, 100.35), and the extrusion length is 48.805mm.

[0136] G1 X150.7107 Y99.2893 E1.5

[0137] Compensation path code, move the print head center to the compensation point (150.7107, 99.2893), extrusion length 1.5mm, to prevent fiber breakage.

[0138] G1 Z0.05

[0139] The print head moves downward by 0.25 mm, at which time the print head height is 0.05 mm, so that the side wall of the print head compacts the molten printing filament at the designed inflection point.

[0140] G1 Z0.4G1 Z0.45

[0141] The print head moves upward a distance of 0.4 mm, at which time the print head height is 0.45 mm and is out of contact with the deposited layer.

[0142] G1 X149.65 Y100.35

[0143] The center of the print head moves to the turning point of the original path design.

[0144] G1 Z0.3

[0145] The print head moves downward a distance of 0.15mm, at which point the print head height is 0.3mm, returning to the designed layer height.

[0146] G1 X149.65 Y149.155 E48.805

[0147] Continue printing the subsequent paths.

[0148] Compared with the prior art, the present invention has the following beneficial effects:

[0149] (1) The present invention does not require manual changes to the corner setting value, does not require large-scale changes to the preset path, and only performs local path compensation at the corner vertex. The direction of the compensation path can be determined by a mathematical expression, eliminating the uncertainty of corner path compensation. In addition, the compensation path calculation process is quick and simple, and there is no need to modify the printing equipment. A simple upgrade based on the existing slicing algorithm can achieve a significant improvement in corner printing accuracy.

[0150] (2) The present invention determines the compensation distance according to the geometric dimensions of the printing nozzle, without considering the difference in compensation value caused by the material system and viscoelasticity. It can effectively improve the corner printing accuracy under different printing process parameters and material systems, and has good stability and scalability.

[0151] (3) The present invention is applicable to multi-material, multi-nozzle continuous fiber 3D printers, and has a corner compensation judgment module, which realizes intelligent identification and selection of the path to be compensated. Corner path compensation is only performed on continuous fiber paths that are prone to corner defects, avoiding interference with pure resin printing and continuous fiber paths that do not require compensation.

[0152] In a second aspect, a continuous fiber 3D printing system based on high-precision corner path design is provided, comprising:

[0153] A judgment module is configured to obtain Gcode features corresponding to the structure to be printed and determine a continuous fiber printing path;

[0154] An angle calculation module is configured to calculate the angle between the two paths based on the two-dimensional coordinate values ​​of the two intersecting printing paths;

[0155] The corner compensation calculation module is configured to use a geometric optimization algorithm, combined with the angle between the two paths, the coordinates of the path vertices and the direction of the path vector, to calculate the coordinates of the compensation point at the turning point to generate a compensation path Gcode code and insert it into the original Gcode code.

[0156] The continuous fiber 3D printing system based on high-precision corner path design can have all the beneficial effects of the above-mentioned continuous fiber 3D printing method based on high-precision corner path design, which will not be repeated here.

[0157] The preferred embodiments of the present disclosure are described in detail above in conjunction with the accompanying drawings; however, the present disclosure is not limited to the specific details in the above embodiments. Within the technical concept of the present disclosure, a variety of simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0158] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0159] In addition, various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A continuous fiber 3D printing method based on high-precision corner path design, characterized in that: include: S100. Obtaining Gcode features corresponding to the structure to be printed, and determining a continuous fiber printing path; S300. Based on the two-dimensional coordinate values ​​of the two intersecting printing paths, calculate the angle between the two paths; S500. Using a geometric optimization algorithm, combined with the angle between the two paths, the coordinates of the path vertices and the direction of the path vector, the coordinates of the compensation point at the inflection point are calculated to generate a compensation path Gcode code, and insert it into the original Gcode code.

2. The 3D printing method according to claim 1, characterized in that: Step S100 includes: S100-1. Submit the 3D model to be sliced ​​to the slicing module, set the printing parameters in the slicing module, select the required path planning algorithm, and generate the Gcode code including the resin printing path and the continuous fiber printing path; S100-2. The angle compensation judgment module reads the code line by line. If the print head code corresponding to the path is a resin print head, the path is skipped and the next line is read. If the print head code corresponding to the path is a continuous fiber print head, the angle between the two subsequent intersecting paths is calculated.

3. The 3D printing method according to claim 2, characterized in that: Step S300 includes: S300-1. Since 3D printed three-dimensional models are usually composed of multiple two-dimensional triangular facets, the intersection lines of the slice plane and the three-dimensional model during the slicing process are all straight lines. When the straight line path set is projected onto the coordinate base plane, the path vertex coordinate value set can be obtained. Therefore, the angle value between any two adjacent paths can be calculated. The angle ∠ABC between two adjacent paths can be calculated as follows: Among them, A, B, and C are the vertices of paths AB and AC, and their coordinates are (x1, y1), (x2, y2), and (x3, y3) respectively; S300-2. Compare the calculated included angle with the set critical angle, and determine the corner path that is smaller than the critical angle as the path to be compensated, otherwise no path compensation is required.

4. The 3D printing method according to claim 3, characterized in that: The critical angle is at least 135 degrees.

5. The 3D printing method according to claim 3, characterized in that: Step S500 includes: S500-1. The compensation distance is determined to be half of the outer diameter of the print head. The compensation direction is the direction of the angle bisector of the path angle to be compensated, pointing to the outside of the figure. Let the compensation distance be d, the compensation point be point P, and the intersection of the angle bisector of ∠ABC and AC be point D. According to the angle bisector theorem, the coordinates of point D are: Among them, |AB|, |BC| are the lengths of line segments AB and BC respectively: Since point P is point B along the direction The extension distance d, so the coordinates of point P (P x ,P y ) can be calculated by the following formula: in, is the unit direction vector of the compensation vector, which is calculated as follows: Substituting and simplifying, we can get the coordinates of point P (P x ,P y )as follows: S500-2. The printing path is A→B→P→B→C.

6. The 3D printing method according to claim 5, characterized in that: In step S500-2, the print head moves from B to P, and then the print head is lowered by H1, so that the side wall of the print head compacts the molten deposited line on the substrate or the deposited layer at point B, thereby achieving accurate positioning of the path inflection point; Then raise the print head by H2. The height after raising must exceed the height before lowering to avoid the print head colliding with the deposited material during subsequent movement. The print head moves from P to B, then drops to its initial height and continues to complete the subsequent printing path.

7. The 3D printing method according to claim 6, characterized in that: H1 is 0.1-0.5 mm, H2 is 0.2-1 mm.

8. A continuous fiber 3D printing system based on high-precision corner path design, characterized in that: include: A judgment module is configured to obtain Gcode features corresponding to the structure to be printed and determine a continuous fiber printing path; An angle calculation module is configured to calculate the angle between the two paths based on the two-dimensional coordinate values ​​of the two intersecting printing paths; The corner compensation calculation module is configured to use a geometric optimization algorithm, combined with the angle between the two paths, the coordinates of the path vertices and the direction of the path vector, to calculate the coordinates of the compensation point at the turning point to generate a compensation path Gcode code and insert it into the original Gcode code.

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