Method for measuring maximum printing curvature of continuous fiber reinforced composite material
By controlling the curvature characteristics of the radial spiral trajectory and the curvature growth rate, the maximum printing curvature of continuous fiber reinforced composite materials can be quickly and accurately determined, solving the problems of low measurement efficiency and poor accuracy in existing technologies, optimizing the printing trajectory, and avoiding printing defects.
Patent Information
- Application Number
- CN202610030562.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-12
- Publication Date
- 2026-02-10
AI Technical Summary
Existing technologies cannot quickly and accurately determine the maximum printing curvature of continuous fiber reinforced composite materials, resulting in printing quality defects. Furthermore, the measurement efficiency is low and the accuracy is poor, making it difficult to apply to practical application scenarios.
By utilizing the linear growth characteristic of the curvature of a radial spiral trajectory with arc length, and by establishing the relationship functions of "curvature-arc length" and "tangent vector-arc length", combined with the curvature growth rate control parameter, the radial spiral trajectory curve is plotted, a printing execution file is generated, the actual printing endpoint is determined, and the maximum printing curvature is calculated.
It enables rapid and accurate measurement of the maximum printing curvature of continuous fiber reinforced composite materials, improving measurement efficiency and accuracy, avoiding defects such as fiber bundle dragging and peeling, and optimizing the printing trajectory.
Smart Images
Figure CN121492350A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of 3D printing technology, and more specifically to a method for determining the maximum printing curvature of continuous fiber reinforced composite materials. Background Technology
[0002] Continuous fiber reinforced composite material 3D printing (CFRC-3DP) can not only customize structural parts of various shapes and functions, but also has excellent advantages in high efficiency and low cost, making it an effective way for miniaturization, integration, and lightweighting in high-end manufacturing fields such as aerospace and shipbuilding. However, due to the influence of printing process parameters such as printing speed, printing materials, and printing temperature, CFRC-3DP cannot print large curvature trajectories. This is because there is a gap between the printing nozzle and the fiber bundle, such as... Figure 1 As shown, time t0 is the initial state, time t1 is horizontal printing to the right, the printing trajectory is a straight line, the fiber bundle is against the side wall of the printing nozzle and is dragged along the straight line, time t2 is the turning state, time t3 is the turning printing completed, the printing trajectory changes direction, the fiber bundle will change direction and move in the printing nozzle, the side wall of the printing nozzle at different positions is against the fiber bundle and drags it. When the curvature of the printing trajectory is too large, the printing nozzle often spins around the fiber bundle, the printing nozzle cannot be against the fiber bundle and drag the fiber bundle, and cannot print with the expected trajectory curvature, which will cause defects such as material accumulation, seriously affecting the printing quality. Therefore, before printing, it is necessary to measure the maximum printing curvature of the current model of printing nozzle and the current size of fiber bundle in advance, so as to optimize the printing trajectory according to the maximum printing curvature and avoid defects such as fiber bundle dragging and peeling at the point where the trajectory curvature is too large.
[0003] Existing methods for determining the maximum printing curvature of continuous fiber reinforced composite materials generally involve printing arc trajectories with different curvatures and observing the printing results to determine the maximum printing curvature. The curvature corresponding to the point where the printed trajectory shows accumulation is considered the maximum printing curvature. The trajectory curvature of this method is manually set, and multiple printing attempts are required to approximate the maximum printing curvature. This method has disadvantages such as low measurement efficiency, poor accuracy, and high cost, making it difficult to apply to practical application scenarios.
[0004] Therefore, a method for determining the maximum printing curvature of continuous fiber reinforced composite materials is needed, which can achieve a one-time, rapid, and accurate measurement of the maximum printing curvature of CFRC-3DP, so as to improve the detection efficiency and accuracy of the maximum printing curvature of CFRC-3DP. Summary of the Invention
[0005] To address the aforementioned problems, this invention provides a method for determining the maximum printing curvature of continuous fiber reinforced composite materials, thereby resolving the technical issues raised in the background section.
[0006] The technical solution adopted by this invention to solve its technical problem is as follows:
[0007] A method for determining the maximum printing curvature of a continuous fiber reinforced composite material includes the following steps:
[0008] S1: Obtain the current basic printing parameters and calculate the fiber bundle printing width;
[0009] S2: Establish a curve model of the radial spiral trajectory, and calculate the curvature at the end of the radial spiral trajectory based on the current printing base parameters and fiber bundle printing width;
[0010] S3: Based on the curve model of the radial spiral trajectory, the curvature growth rate control parameters are determined according to the fiber bundle printing width and the curvature at the end of the radial spiral trajectory.
[0011] S4: Combining the curvature growth rate control parameter and the curvature at the end of the radial spiral trajectory, plot the radial spiral trajectory curve and generate the printable executable file;
[0012] S5: Under the set printing process parameters, based on the generated printing execution file, use the test model of printing radial spiral trajectory with fiber bundles to determine the actual printing endpoint;
[0013] S6: Calculate the curvature of the actual printing endpoint to obtain the maximum printing curvature corresponding to the current printing base parameters.
[0014] Furthermore, the method for establishing the curve model of the radial spiral trajectory described in S2 is as follows: based on the curvature of the radial spiral trajectory... With arc length The curvature characteristics of linear growth are used to establish a "curvature-arc length" relationship function, i.e. ,in, This is a parameter for controlling the rate of curvature growth. Based on the curvature and arc length and the tangent vector of the trajectory Differential geometric relations are used to establish the "tangent vector-arc length" relationship function, i.e. The trajectory tangent vector is the angle between the tangent line of the radial spiral trajectory and the horizontal axis; the parametric equation of the radial spiral trajectory is established through Fresnel integration, namely:
[0015]
[0016] In the formula, t represents the parameter of the trajectory parametric equation. The coordinates are the coordinates of the radial spiral trajectory.
[0017] Furthermore, the current basic printing parameters mentioned in S1 include the nozzle inner wall diameter D, the fiber bundle diameter d, and the printing layer height h. Under the assumption that the cross-section of the printed fiber bundle is approximately rectangular, the fiber bundle printing width b is calculated. .
[0018] Furthermore, the method for calculating the curvature at the end of the radial spiral trajectory described in S2 is as follows: It is determined whether the fiber bundle will spin freely inside the nozzle during the printing process along the radial spiral trajectory from its initial pose. If spinning occurs, the fiber bundle is printed to the end of the radial spiral trajectory, and the curvature at the end of the radial spiral trajectory is calculated. , ,in, This is the curvature scaling factor, with a value ranging from 0.1 to 0.3. This is the difference in radius between the inner wall of the nozzle and the fiber bundle. .
[0019] Furthermore, the specific method for determining the curvature growth rate control parameter described in S3 includes: establishing the center point of the trajectory end when the fiber bundle printed using the radial spiral trajectory overlaps at the trajectory end. Center point of the previous radial spiral trajectory Overlap parameter relationship: ,in, and Points and points Curvature; Establish the center point at the end of the trajectory Center point of the previous radial spiral trajectory Tangent vector relationship: In the formula, and Points and points The trajectory tangent vector.
[0020] Furthermore, the specific method for determining the curvature growth rate control parameters described in S3 also includes: establishing the relationship between the curvature of the radial spiral trajectory and the tangent vector during the printing of the fiber bundle from its initial pose along the radial spiral trajectory to its end, based on the "curvature-arc length" relationship function and the "tangent vector-arc length" relationship function.
[0021]
[0022] Junction point and Based on the tangent vector relationship and overlap parameter relationship, determine the curvature growth rate control parameters. ,Right now:
[0023]
[0024] in, This is the resolution scaling factor, and its value ranges from 1 to 2.
[0025] Furthermore, the specific method for drawing the radial spiral trajectory curve described in S4 is as follows: based on the "curvature-arc length" relationship function, calculate the arc length at the end of the radial spiral trajectory according to the curvature at the end of the radial spiral trajectory; based on the parametric equation of the radial spiral trajectory, draw the radial spiral trajectory curve according to the arc length at the end of the radial spiral trajectory.
[0026] Furthermore, the specific method for calculating the curvature of the actual printing endpoint described in S6 is as follows: determine the trajectory tangent vector of the actual printing endpoint, calculate the actual arc length from the printing start point to the actual printing endpoint based on the "tangent vector-arc length" relationship function; and calculate the maximum printing curvature based on the "curvature-arc length" relationship function and the actual arc length from the printing start point to the actual printing endpoint.
[0027] Furthermore, the printing process parameters mentioned in S5 include printing speed, printing temperature, and ambient temperature.
[0028] Compared with the prior art, the beneficial effects of the present invention are:
[0029] 1. The present invention provides a method for determining the maximum printing curvature of continuous fiber reinforced composite materials. By utilizing the curvature characteristic that the curvature of a radial spiral trajectory increases linearly with the arc length, the maximum printing curvature of the continuous fiber reinforced composite material can be quickly determined in one go by printing only one test model with a radial spiral trajectory curve. This greatly improves the measurement efficiency and allows for optimization of the printing trajectory based on the maximum printing curvature before printing, avoiding defects such as fiber bundle dragging and peeling at points where the trajectory curvature is too large.
[0030] 2. The present invention provides a method for determining the maximum printing curvature of continuous fiber reinforced composite materials. The measurement accuracy is determined by the curvature growth rate control parameter. Compared with the traditional discrete sampling measurement method, it does not require much human experience and the measured maximum printing curvature is more accurate, which can provide strong support for the precision printing of continuous fiber reinforced composite materials. Attached Figure Description
[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a schematic diagram showing the state of the fiber bundle at the nozzle exit under different printing trajectories.
[0033] Figure 2 This is a schematic diagram of the process for determining the maximum printing curvature of a continuous fiber reinforced composite material as described in this embodiment;
[0034] Figure 3 This is a schematic diagram showing the overlap at the end of the trajectory of the fiber bundle printed using the radial spiral trajectory as described in this embodiment;
[0035] Figure 4 This is a schematic diagram of the radial spiral trajectory curve described in this embodiment;
[0036] Figure 5 This is a schematic diagram of the actual printed test model described in this embodiment. Detailed Implementation
[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0038] This invention provides a method for determining the maximum printing curvature of continuous fiber reinforced composite materials, such as... Figure 2 As shown, the method includes the following steps:
[0039] S1: Obtain the current basic printing parameters and calculate the fiber bundle printing width;
[0040] Furthermore, the current basic printing parameters include the nozzle inner wall diameter D, the fiber bundle diameter d, and the printing layer height h. Assuming the cross-section of the printed fiber bundle is approximately rectangular, the fiber bundle printing width b is calculated. In this embodiment, the nozzle inner wall diameter is 1.2 mm, the fiber bundle diameter is 0.4 mm, the printing layer height is 0.2 mm, and the calculated fiber bundle printing width is 0.628 mm.
[0041] S2: Establish a curve model of the radial spiral trajectory, and calculate the curvature at the end of the radial spiral trajectory based on the current printing base parameters and fiber bundle printing width;
[0042] Furthermore, the method for establishing the curve model of the radial spiral trajectory is as follows: based on the curvature of the radial spiral trajectory... With arc length The curvature characteristics of linear growth are used to establish a "curvature-arc length" relationship function, i.e. ,in, The curvature growth rate control parameter controls the resolution of the radial spiral trajectory. With a constant printed trajectory curvature, a smaller curvature growth rate control parameter results in a smaller rate of change of printed trajectory curvature, a larger printed arc length, and thus a higher printed trajectory resolution and higher maximum printed curvature detection accuracy. This is based on the curvature and arc length in relation to the trajectory tangent vector. Differential geometric relations are used to establish the "tangent vector-arc length" relationship function, i.e. The trajectory tangent vector is the angle between the tangent line of the radial spiral trajectory and the horizontal axis; the parametric equation of the radial spiral trajectory is established through Fresnel integration, namely:
[0043]
[0044] In the formula, t represents the parameter of the trajectory parametric equation. The coordinates are the coordinates of the radial spiral trajectory.
[0045] Furthermore, the method for calculating the curvature at the end of the radial spiral trajectory is as follows: Since the biggest factor limiting the printing curvature is that the fiber bundle spins freely inside the nozzle due to the gap between the nozzle and the fiber bundle diameter, it is determined whether the fiber bundle spins freely inside the nozzle during the printing process along the radial spiral trajectory from the initial pose. If it does spin freely, the fiber bundle is printed to the end of the radial spiral trajectory, and the curvature at the end of the radial spiral trajectory is calculated. The curvature at the end of the radial spiral trajectory should satisfy: The curvature at the point of maximum stroke when the nozzle is idling is taken as the curvature at the end of the radial spiral trajectory, i.e. ,in, This is the curvature scaling factor, with a value ranging from 0.1 to 0.3. This is the difference in radius between the inner wall of the nozzle and the fiber bundle. In this embodiment, the curvature scaling factor Calculations yielded , .
[0046] S3: Based on the curve model of the radial spiral trajectory, the curvature growth rate control parameters are determined according to the fiber bundle printing width and the curvature at the end of the radial spiral trajectory.
[0047] Furthermore, the determination of the curvature growth rate control parameters The specific methods include: establishing the center point of the trajectory end when the fiber bundles printed using radial spiral trajectories overlap at the trajectory end. Center point of the previous radial spiral trajectory The relationship of overlapping parameters, such as Figure 3 As shown, point With point When fiber bundles overlap at a point, the fiber bundle at the end of the trajectory contacts the fiber bundle of the previous radial spiral trajectory at that point. Due to the center point at the end of the trajectory Center point of the previous radial spiral trajectory The distance is the fiber bundle printing width b, from which we can obtain... , that is ,in, and Points and points The curvature;
[0048] Establish the center point at the end of the trajectory Center point of the previous radial spiral trajectory Tangent vector relationship: due to the center point of the trajectory end The trajectory tangent vector relative to the center point of the previous radial spiral trajectory The tangent vector of the trajectory is approximately the angle rotated counterclockwise around the printing starting point O. , can be obtained In the formula, and Points and points The trajectory tangent vector;
[0049] Based on the curvature-arc length and tangent vector-arc length functions, the relationship between the curvature of the radial spiral trajectory and the tangent vector is established during the printing of the fiber bundle from its initial pose along the radial spiral trajectory to its end, namely:
[0050]
[0051] Junction point and By considering the tangent vector relationship and the overlap parameter relationship, we can obtain the condition that the curvature growth rate control parameter should satisfy during the process of printing the fiber bundle along the radial spiral trajectory to the end of the trajectory.
[0052]
[0053] The constraint is that the fiber bundles printed with the radial spiral trajectory overlap at the end of the trajectory; therefore, the curvature growth rate control parameter is determined as follows:
[0054]
[0055] in, This is the resolution scaling factor, which ranges from 1 to 2. In this embodiment, the resolution scaling factor is... The calculated curvature growth rate control parameters .
[0056] S4: Combining the curvature growth rate control parameter and the curvature at the end of the radial spiral trajectory, plot the radial spiral trajectory curve and generate the printable executable file;
[0057] Furthermore, the specific method for drawing the radial spiral trajectory curve is as follows: based on the "curvature-arc length" relationship function. Based on the curvature of the end of the radial spiral trajectory Calculate the arc length at the end of the radial spiral trajectory. Based on the parametric equation of the radial spiral trajectory, according to the arc length of the end of the radial spiral trajectory... The radial spiral trajectory curve is plotted. The radial spiral trajectory curve plotted in this embodiment is as follows: Figure 4 As shown, post-processing of the radial spiral trajectory curve can generate an executable file for CFRC-3DP printing.
[0058] S5: Under the set printing process parameters, based on the generated printing execution file, use the test model of printing radial spiral trajectory with fiber bundles to determine the actual printing endpoint;
[0059] Furthermore, the printing process parameters include printing speed, printing temperature, and ambient temperature. In this embodiment, the printing speed is 600 mm / min, the printing temperature is 270°C, and the ambient temperature is 25°C. The actual printed test model is as follows: Figure 5 As shown, a planar coordinate system is established with the actual printing endpoint as the origin, and the axis parallel to the starting printing direction as the reference axis (labeled in the figure). Based on the number of times the fiber bundle passes through the reference axis during printing to the actual printing endpoint, and the angle between the actual printing endpoint and the reference axis, the trajectory tangent vector at the actual printing endpoint is determined. For each revolution of the fiber bundle through the reference axis, the trajectory tangent vector at the actual printing endpoint increases. In this embodiment, the fiber bundle passes through the reference axis twice, and the tangent line of the trajectory at the actual printing endpoint is perpendicular to the reference axis. The angle between the tangent line of the trajectory at the actual printing endpoint and the reference axis is... Then the actual tangent vector of the trajectory at the printed endpoint is When the printing reaches the actual printing endpoint, the printing curvature reaches its maximum. At this point, due to the gap between the nozzle and the fiber bundle, the excessive printing curvature causes the nozzle to spin around the fiber bundle without moving it. The nozzle cannot drag the fiber bundle and cannot continue printing along the drawn radial spiral trajectory curve.
[0060] S6: Calculate the curvature of the actual printing endpoint to obtain the maximum printing curvature corresponding to the current printing base parameters.
[0061] Furthermore, the specific method for calculating the curvature of the actual printing endpoint is as follows: determine the actual printing endpoint. Trajectory Tangent Vector Based on the "tangent vector-arc length" relationship function Calculate the actual arc length from the starting point of printing to the actual ending point of printing. In this embodiment, the calculated actual arc length is 83.135 mm; based on the "curvature-arc length" relationship function. Based on the actual arc length from the starting point to the actual ending point of the print. Calculate the maximum printed curvature In this embodiment, the calculated maximum printing curvature is After obtaining the maximum printing curvature, the printing trajectory can be optimized based on the maximum printing curvature before printing to avoid defects such as fiber bundle dragging and peeling at points of excessive curvature. In this embodiment, under the set printing process parameters, the maximum printing curvature of continuous fiber reinforced composite materials can be quickly determined in one go by printing only one radial spiral trajectory curve. At the same time, the measurement accuracy of this embodiment is determined by the curvature growth rate control parameter. Compared with the traditional discrete sampling measurement method, it does not require too much human experience, and the measured maximum printing curvature is more accurate, effectively improving measurement efficiency and accuracy, and providing strong support for the precision printing of continuous fiber reinforced composite materials.
[0062] In other embodiments, if the current printing base parameters change, such as the fiber bundle diameter, the corresponding maximum printing curvature will also change. Therefore, according to the above measurement method, the maximum printing curvature can be determined quickly and accurately, which makes it convenient to optimize the printing trajectory in advance and avoid the situation of nozzle idling.
[0063] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A path planning method for 3D printing of continuous fiber reinforced composite materials, characterized in that, Includes the following steps: S1: Obtain the current basic printing parameters and calculate the fiber bundle printing width; S2: Establish a curve model of the radial spiral trajectory, and calculate the curvature at the end of the radial spiral trajectory based on the current printing base parameters and fiber bundle printing width; S3: Based on the curve model of the radial spiral trajectory, the curvature growth rate control parameters are determined according to the fiber bundle printing width and the curvature at the end of the radial spiral trajectory. S4: Combining the curvature growth rate control parameter and the curvature at the end of the radial spiral trajectory, plot the radial spiral trajectory curve and generate the printable executable file; S5: Under the set printing process parameters, based on the generated printing execution file, use the test model of printing radial spiral trajectory with fiber bundles to determine the actual printing endpoint; S6: Calculate the curvature of the actual printing endpoint to obtain the maximum printing curvature corresponding to the current printing base parameters.
2. The method for path planning in 3D printing of continuous fiber reinforced composite materials according to claim 1, characterized in that, The method for establishing the curve model of the radial spiral trajectory described in S2 is as follows: based on the curvature of the radial spiral trajectory... With arc length The curvature characteristics of linear growth are used to establish a "curvature-arc length" relationship function, i.e. ,in, This is a parameter for controlling the rate of curvature growth. Based on the curvature, arc length, and trajectory tangent vector Differential geometric relations are used to establish the "tangent vector-arc length" relationship function, i.e. The trajectory tangent vector is the angle between the tangent line of the radial spiral trajectory and the horizontal axis; the parametric equation of the radial spiral trajectory is established through Fresnel integration, namely: In the formula, t represents the parameter of the trajectory parametric equation. The coordinates are the coordinates of the radial spiral trajectory.
3. The method for path planning in 3D printing of continuous fiber reinforced composite materials according to claim 2, characterized in that, The current basic printing parameters mentioned in S1 include the nozzle inner wall diameter D, the fiber bundle diameter d, and the printing layer height h. Assuming the cross-section of the printed fiber bundle is approximately rectangular, the fiber bundle printing width b is calculated. .
4. The method for 3D printing path planning of continuous fiber reinforced composite materials according to claim 3, characterized in that, The method for calculating the curvature at the end of the radial spiral trajectory described in S2 is as follows: Determine whether the fiber bundle will spin freely inside the nozzle during the printing process along the radial spiral trajectory from its initial pose. If spinning occurs, the fiber bundle is printed to the end of the radial spiral trajectory, and the curvature at the end of the radial spiral trajectory is calculated. , ,in, This is the curvature scaling factor, with a value ranging from 0.1 to 0.
3. This is the difference in radius between the inner wall of the nozzle and the fiber bundle. .
5. The method for 3D printing path planning of continuous fiber reinforced composite materials according to claim 4, characterized in that, The specific method for determining the curvature growth rate control parameters described in S3 includes: establishing the center point of the trajectory end when the fiber bundles printed using radial spiral trajectories overlap at the trajectory end. Center point of the previous radial spiral trajectory Overlap parameter relationship: ,in, and Points and points The curvature; establishing the center point at the end of the trajectory. Center point of the previous radial spiral trajectory Tangent vector relationship: In the formula, and Points and points The trajectory tangent vector.
6. The method for 3D printing path planning of continuous fiber reinforced composite materials according to claim 5, characterized in that, The specific method for determining the curvature growth rate control parameters described in S3 further includes: establishing the relationship between the curvature of the radial spiral trajectory and the tangent vector during the printing of the fiber bundle from its initial pose along the radial spiral trajectory to its end, based on the "curvature-arc length" relationship function and the "tangent vector-arc length" relationship function. Junction point and Based on the tangent vector relationship and overlap parameter relationship, determine the curvature growth rate control parameters. ,Right now: in, This is the resolution scaling factor, and its value ranges from 1 to 2.
7. The method for path planning in 3D printing of continuous fiber reinforced composite materials according to claim 6, characterized in that, The specific method for drawing the radial spiral trajectory curve described in S4 is as follows: based on the "curvature-arc length" relationship function, calculate the arc length at the end of the radial spiral trajectory according to the curvature at the end of the radial spiral trajectory; based on the parametric equation of the radial spiral trajectory, draw the radial spiral trajectory curve according to the arc length at the end of the radial spiral trajectory.
8. The method for path planning in 3D printing of continuous fiber reinforced composite materials according to claim 7, characterized in that, The specific method for calculating the curvature of the actual printing endpoint described in S6 is as follows: determine the trajectory tangent vector of the actual printing endpoint, and calculate the actual arc length from the printing start point to the actual printing endpoint based on the "tangent vector-arc length" relationship function. Based on the "curvature-arc length" relationship function, the maximum printing curvature corresponding to the current printing basic parameters is calculated according to the actual arc length from the printing start point to the actual printing end point.
9. The method for path planning in 3D printing of continuous fiber reinforced composite materials according to claim 1, characterized in that, The printing process parameters mentioned in S5 include printing speed, printing temperature, and ambient temperature.