An automatic fiber placement trajectory design method for laying edges of large-thickness product plies
By designing specific trajectories for the edge of thick product layups, problems such as collision between pressure rollers and edges and ribbon buckling in the automatic yarn layup process were solved, thus improving the quality of yarn layup.
Patent Information
- Application Number
- CN202411556464.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-04
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2044-11-04
AI Technical Summary
When using automated yarn placement technology to lay thick products, existing technologies suffer from problems such as collisions between the pressure roller and the product edge, yarn bending, wrinkles, overlaps, and excessive gaps, which affect product quality.
By designing specific trajectories for the layup edges, including dividing the layup, designing the outline and the yarn laying trajectory, adjusting the center line of the yarn laying trajectory and the position of the yarn exit bundle, adjusting the starting point and ending point of the yarn laying trajectory for different angle positions, and adopting a stepped slope method, problems such as pressure rollers detaching from the layup surface and ribbon buckling are avoided.
It effectively solves the problems of collision between the pressure roller of the yarn laying machine and the edge of the ribbon, ribbon bending, overlap and excessive gap, and improves the yarn laying quality of thick products.
Smart Images
Figure CN119427787B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of carbon fiber composite material production technology, and in particular relates to an automatic fiber placement trajectory design method for laying the edge of thick product layers. Background Technology
[0002] Carbon fiber composites possess excellent mechanical properties and high designability, leading to their widespread application in recent years. The most common method for laying composite materials is manual placement, but this results in inconsistent product quality. Utilizing automated equipment to replace manual labor in composite material placement is a crucial direction for the development of composite materials. Employing automated fiber placement processes to complete the placement of composite material products has become an inevitable trend.
[0003] Automated yarn placement, as a process using automated equipment, directly impacts product performance through the design of the yarn layup trajectory. It offers significant advantages for laying large-size products. Currently, the structure of yarn placement machines at the front exit point is largely similar both domestically and internationally, with cylindrical pressure rollers handling the laying and compaction of the yarn. Since the diameter of the pressure rollers on the equipment is usually fixed, when laying thick products, the thickness of the "step" traversed by the pressure roller from the mold plane to the laying plane increases progressively. This can lead to defects such as delamination and wrinkles caused by the collision between the pressure roller and the edge of the "step." Currently, a stepped ramp method is commonly used to avoid this problem. However, this method subsequently results in insufficient yarn pressure, yarn buckling, wrinkles, overlaps, and excessive gaps, affecting the yarn placement quality. This patent provides a yarn placement trajectory design method for laying thick products using an automated yarn placement process where the layup edge is a variable thickness region, which can solve the aforementioned quality problems encountered when using the stepped ramp method. Summary of the Invention
[0004] The purpose of this invention is to provide an automatic yarn placement trajectory design method for laying out the edge of thick products, in order to solve the above-mentioned problems. This method can effectively solve the problem of yarn edge collision when laying out thick products using automatic yarn placement process. By specifically designing different trajectories involved in the edge of the lay-up, it can effectively avoid problems such as insufficient pressure, pressure roller detachment from the laying surface, yarn buckling, wrinkles, overlaps, and excessive gaps that occur when the edge of the lay-up is a variable thickness area.
[0005] To achieve the above objectives, the present invention provides the following solution: an automatic yarn placement trajectory design method for laying out the edge of a thick product layer, the operation steps of which include:
[0006] Divide the product layup into several groups, from the first layer to the last layer.
[0007] Design the profile by calculating the slope of the stepped slope of the product edge and the profile of each ply, and then plan the profile of several ply groups.
[0008] Design the yarn layup trajectory. Design the yarn layup trajectory for each group of layups. For the following cases where the layup edge is a variable thickness area, provide a layup trajectory planning method: For positions where the layup edge contour is parallel to the layup angle direction, adjust the center line of the yarn layup trajectory and the position of the yarn exit bundle to solve the problems of insufficient pressure on the yarn bundle at the edge trajectory and the pressure roller detaching from the layup profile; For positions where the layup edge contour is neither perpendicular nor parallel to the layup angle direction, adjust the start and end points of the yarn layup trajectory to solve the problems of ribbon buckling, wrinkles, overlaps, and excessive gaps within the layup contour.
[0009] Preferably, the slope α of the stepped slope formed by the edge of the product is calculated using the following formula:
[0010]
[0011] In the formula, L is the width of the pressure roller, β is the angle between the trajectory direction and the perpendicular line of the product contour, and Y is the compression amount of the pressure roller.
[0012] In practice, the slope angle α is less than or equal to the calculated value of the above formula.
[0013] Preferably, the formula for calculating the thickness H of one of the ply layers and the corresponding increase in side length X at the bottom is as follows:
[0014]
[0015] In the formula, L is the width of the pressure roller, β is the angle between the trajectory direction and the perpendicular line of the product outline, Y is the compression amount of the pressure roller, and α is the slope.
[0016] In application, the increased side length can be calculated based on the slope α of the stepped slope and the thickness H of each step ply, and finally the outline of each step ply can be obtained.
[0017] Preferably, when the filament placement machine places filaments at an angle parallel to the edge of the layup contour, the position of the filament bundle exiting the filament placement head and the center line of the filament placement trajectory is adjusted so that the outer end point of the pressure roller of the filament placement head of the filament placement machine coincides with the boundary of the variable thickness region and the equal thickness region, so that the pressure roller is always located within the equal thickness region when the filament placement machine is laid on one side of the equal thickness region.
[0018] Preferably, when the outline of the layup includes a variable thickness region and a constant thickness region, the layup needs to be laid on both the stepped slope of the product edge and the plane of constant thickness. In this case, the layup is laid separately on both sides according to the boundary of the variable thickness region and the constant thickness region.
[0019] Preferably, when the laying angle of the filament placement machine is not perpendicular or parallel to the edge of the layup profile, and the boundary between the variable thickness region and the equal thickness region is the layup profile, for layup trajectory length greater than or equal to the shortest filament pitch, the serrated edge control strategy of the start and end points is selected to be entirely within the profile.
[0020] For paving tracks shorter than the minimum lead length, the track length should be extended so that one of the start and end points is located in the bottom equal-thickness area of the variable-thickness zone, and the other is located in either the bottom or top equal-thickness area of the variable-thickness zone. In other words, by adjusting the track length and using a serrated edge control strategy, the start and end points cannot be located in the variable-thickness zone.
[0021] Preferably, for the case where the layup edge contour is a corner where the layup trajectory length is less than the shortest lead-out filament distance, the layup trajectory is split along the direction of the layup angle using a straight line passing through the vertex of the corner, and the two sides are laid separately.
[0022] Compared with the prior art, the present invention has the following advantages and technical effects:
[0023] 1. By utilizing the laying design method of the present invention, when laying thick products, the edge is treated with a stepped slope, which effectively solves the problem of collision between the pressure roller of the yarn laying machine and the edge of the ribbon.
[0024] 2. Furthermore, regarding the stepped slope treatment method, this invention solves problems such as overlap, bending, inadequate pressing, and yarn slippage that occur in various edge situations when using this method by adjusting the trajectory planning scheme, including the yarn exit starting point and the center line of the pressure roller trajectory. This provides a method and reference for the application of automated yarn placement technology in thick products. Attached Figure Description
[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0026] Figure 1 This is a schematic diagram illustrating how the product edge is divided into multiple steps according to the present invention;
[0027] Figure 2 This is a schematic diagram of the layup edge state during automatic filament layup at 45 degrees according to the present invention;
[0028] Figure 3 This is a schematic diagram showing the position of the ear piece during automatic wire laying at a 45-degree angle according to the present invention;
[0029] Figure 4This is a schematic diagram showing the comparison before and after optimization of the pressure roller position and yarn exit position when the yarn is laid at 0 degrees to the edge of the product according to the present invention;
[0030] Figure 5 This is a schematic diagram showing the comparison between the pressure roller and the product edge before and after optimization when laying yarn at a 90-degree angle to the product edge according to the present invention;
[0031] Figure 6 This is a schematic diagram of the slope variables of the steps in this invention;
[0032] Figure 7 This is a schematic diagram of the climbing direction of the pressure roller of the present invention. Detailed Implementation
[0033] 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.
[0034] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0035] Example 1:
[0036] Reference Figures 1-7 This invention provides an automatic yarn-laying trajectory design method for laying out thick product layers at their edges, the operation steps of which include:
[0037] Divide the product layup into several groups, from the first layer to the last layer.
[0038] Design the profile by calculating the slope of the stepped slope of the product edge and the profile of each ply, and then plan the profile of several ply groups.
[0039] Design the yarn layup trajectory. Design the yarn layup trajectory for each group of layups. For the following cases where the layup edge is a variable thickness area, provide a layup trajectory planning method: For positions where the layup edge contour is parallel to the layup angle direction, adjust the center line of the yarn layup trajectory and the position of the yarn exit bundle to solve the problems of insufficient pressure on the yarn bundle at the edge trajectory and the pressure roller detaching from the layup profile; For positions where the layup edge contour is neither perpendicular nor parallel to the layup angle direction, adjust the start and end points of the yarn layup trajectory to solve the problems of ribbon buckling, wrinkles, overlaps, and excessive gaps within the layup contour.
[0040] By dividing the layup into several groups, the layup outline gradually shrinks between adjacent groups during the actual yarn laying process, thus forming a stepped slope. This facilitates the climbing of the pressure roller and effectively avoids strong collisions between the pressure roller and the edge of the layup by utilizing the thinness of each layup layer.
[0041] With further optimization, the trajectory design method of the present invention is applicable not only to whole plies, but also to sub-palies within a product.
[0042] Further optimizing the scheme, the formula for calculating the slope α of the stepped slope formed at the product edge is:
[0043] (1)
[0044] In the formula, L is the width of the pressure roller, β is the angle between the trajectory direction and the perpendicular line of the product contour, and Y is the compression amount of the pressure roller.
[0045] In practice, the slope angle α is less than or equal to the calculated value of the above formula.
[0046] like Figure 6 and Figure 7 As shown, the above calculation formula applies to laying trajectories at any angle to the product edge contour.
[0047] Further optimization of the scheme, the calculation formula between the thickness H of a single layer and the corresponding increase in the bottom side length X is as follows:
[0048] (2)
[0049] In the formula, L is the width of the pressure roller, β is the angle between the trajectory direction and the perpendicular line of the product outline, Y is the compression amount of the pressure roller, and α is the slope.
[0050] In application, the increased side length can be calculated based on the slope α of the stepped slope and the thickness H of each step ply, and finally the outline of each step ply can be obtained.
[0051] like Figure 1 As shown, when using the stepped ramp method to process edges, the total thickness is divided into n steps according to requirements, with one or more plies considered as one step, and the height H of each small step... n An X can be calculated from all of them. n This creates a stepped slope at the edge of the product.
[0052] The product layup is divided into several groups from the first layer to the last layer. The number of layup layers in each group, i.e. the number of layers, combined with the thickness of a single layer, is the thickness H of the step of that group. The increased side length X can be obtained from the corresponding formula (2), and the distance by which the outline of that group expands outward can be obtained.
[0053] like Figure 1 As shown, according to equations (1) and (2), the vertices of the steps at the ply edges can be kept on a straight line. As long as the thickness of each ply does not exceed the level that would cause an impact problem, multiple thicknesses are allowed for each step to ensure the flexibility of trajectory planning.
[0054] For products with quality requirements in sloping areas, such as those with a full paving layer covering a slope, the thickness of each group should be minimized, and it is even possible to use one or two paving layers as a step.
[0055] Further optimization of the scheme: when the filament placement machine places filaments at a 90-degree angle to the edge of the product contour, such as... Figure 5 As shown, the position where the layup direction is at a 90-degree angle to the edge is usually located at the start and end points of the layup trajectory. When the yarn layup head travels at a 90-degree angle to the edge, a stepped ramp treatment is used to create a ramp. This allows the pressure roller to complete the transition from the mold plane to the layup plane via the ramp, avoiding the increasingly thick "steps" that the pressure roller crosses in traditional processes. This avoids defects such as the yarn start point shifting backward, the sharp corners of the "steps" collapsing, and delamination and wrinkles on the sides of the laid-up layer due to impact.
[0056] To further optimize the scheme, when the filament placement machine places filaments at an angle parallel to the edge of the layup contour, the position of the filament bundle exiting the filament placement head and the center line of the filament placement trajectory is adjusted so that the outer end point of the pressure roller of the filament placement head of the filament placement machine coincides with the boundary between the variable thickness area and the equal thickness area, so that the pressure roller is always located within the equal thickness area when the filament placement machine is laid on one side of the equal thickness area.
[0057] When the filament laying machine lays filaments at an angle that is neither perpendicular nor parallel to the edge of the product contour, due to the influence of the shortest filament exit distance, ear-like structures exist in the filament at the edge of the product contour. Figure 2 As shown, taking 45 degrees as an example, the edge coverage methods from left to right are: the upper endpoint of the short side of the ribbon is located on the outline of the ply edge; the midpoint of the short side of the ribbon is located on the outline of the ply edge; and the lower endpoint of the ribbon is located on the outline of the ply edge. For thick products using stepped slope ply, the following should be selected: Figure 2 The rightmost ribbon with its short side lower end positioned on the layup edge outline ensures the ribbon falls on a flat surface, not a slope. If the other two methods are chosen, during the layup process, the corner of each ribbon closest to the slope will first come into contact with the slope, causing overlap and bending of the laid ribbons, affecting product quality.
[0058] To further optimize the scheme, when the outline of the ply includes areas of varying thickness and areas of equal thickness, the ply needs to be laid on the stepped slopes at the product edge and on the plane of equal thickness. In this case, the ply is laid separately on both sides according to the boundary between the areas of varying thickness and areas of equal thickness.
[0059] In the planning of the yarn laying trajectory, by separating the variable thickness area and the equal thickness area and laying them separately, it is possible to effectively avoid defects in yarn laying caused by height differences in the yarn on the trajectory.
[0060] Further optimization of the scheme: when the laying angle of the filament placement machine is not perpendicular or parallel to the edge of the layup contour, and the boundary between the variable thickness area and the equal thickness area is the layup contour, for layup trajectory length greater than or equal to the shortest filament pitch, the serrated edge control strategy of the start and end points is selected to be all within the contour.
[0061] For paving tracks shorter than the minimum lead length, the track length should be extended so that one of the start and end points is located in the bottom equal-thickness area of the variable-thickness zone, and the other is located in either the bottom or top equal-thickness area of the variable-thickness zone. In other words, by adjusting the track length and using a serrated edge control strategy, the start and end points cannot be located in the variable-thickness zone.
[0062] like Figure 3 As shown, when the yarn laying machine lays yarn at an angle that is not perpendicular or parallel to the edge of the product contour, when laying yarn at the corner of the product edge, the yarn laying machine controls the end of the yarn to be on a platform to avoid the starting point of the yarn being on a stepped slope.
[0063] Specifically, taking a 45-degree angle layup as an example, due to the limitation of the shortest yarn feed distance, two situations may occur: the ribbon crosses the slope and lays on the mold, or the ribbon's starting point is located on the slope. For the case where the ribbon's starting point is on the slope, the trajectory of the yarn spreader should be controlled to actively extend the ribbon feed starting point, ensuring the ribbon's starting point is on the mold platform. This avoids problems such as overlapping, bending, and insufficient pressing that occur when the starting point is on the slope. Simultaneously, for the case where the starting point is on the mold platform and the ribbon crosses the slope, the feed starting point should be extended. The extension distance should take into account the width of the pressure roller and the uphill angle to avoid bridging between the pressure roller and the slope due to one end pressing onto the slope first during the roller's advance. This prevents a significant gap between the pressure roller and the mold plane, which would cause the ribbon to slip when it is not pressed onto the platform by the pressure roller during yarn feed.
[0064] To further optimize the solution, when the filament placement machine is placing filaments at a 0-degree angle to the edge of the product contour, the pressure roller of the filament placement machine must be kept inside the edge of the product contour.
[0065] like Figure 4 As shown, when laying along an edge trajectory at a 0-degree angle to the edge, the pressure roller may cross the edge contour. In this state, within the width of the same laying trajectory, the laid surface is not a flat plane, resulting in height differences. The wider the pressure roller, the greater the impact.
[0066] When using the VCP programming tool to program the trajectory of the filament placement machine, the VCP programming tool can accumulate and calculate the shape of the previous layup, and adjust the next layup based on the calculated shape. This means that when using a stepped slope layup for thick products, the filament placement head will tilt to apply pressure to the slope. Taking a filament placement head with 16 filament bundles and 12.7mm as an example, the width of the pressure roller reaches 203.2mm, which can easily lead to problems such as insufficient pressure within the contour and the far end detaching from the laying surface and being unable to place filaments.
[0067] Therefore, when programming the yarn exit position of the yarn spreader, the layup can be adjusted by adjusting the yarn exit position of the yarn spreader and the center line position of the yarn spread trajectory, so as to avoid the problems mentioned above, such as insufficient pressure within the contour and failure to lay yarn at the far end due to the pressure roller crossing the contour line during the layup.
[0068] Further optimization of the scheme: For the case where the layup edge profile is a corner where the layup trajectory length is less than the shortest yarn pitch, the trajectory is split along the layup angle direction using a straight line passing through the vertex of the aforementioned corner, and the two sides are laid separately. The design method for the positions of the start and end points on both sides conforms to the design method described above when the yarn laying machine layup angle is not perpendicular or parallel to the edge of the layup profile, and the boundary between the variable thickness region and the equal thickness region is the layup profile.
[0069] Specifically, when both the stepped slope at the edge of the product and the flat surface of the product need to be covered with layers, the layers on the stepped slope and the layers on the flat surface are separated and laid separately.
[0070] If it is necessary to lay up layers on a slope, the up layers on the slope can be separated from the up layers on the flat surface and laid up separately. This can effectively avoid defects in the uplay due to the difference in height on the ribbon track. By laying up layers on the slope separately from the uplay on the flat surface, the uplay can be separated from the uplay.
[0071] Further optimize the plan, such as Figure 1 As shown, the number of groups is set according to the actual production situation, and the number of layers in each group is as consistent as possible so that the thickness of each layer is not too thick. This ensures that the pressure roller can smoothly transition from the mold surface to the laying surface, avoiding delamination, wrinkles, and other defects on the laying side due to the impact of the pressure roller.
[0072] Example 2:
[0073] An automated filament placement process utilizing an automated filament placement machine and based on an automated filament placement trajectory design method for the edge of layup layers of thick products includes the following steps:
[0074] Divide the product layup from the first layer to the last layer into several groups;
[0075] The yarn laying trajectory of the yarn laying machine is planned. After laying one set of layers, when laying the next set of layers, the position of the yarn at the edge of the layer is controlled so that the outer contour of each set of layers is smaller than the contour of the next set of layers. This makes the contour allowance of each set of layers gradually decrease from bottom to top, forming a stepped slope at the edge of the product, thus forming the layer contour.
[0076] Specifically, when the filament placement machine places filaments at a 90-degree angle to the edge of the product contour, it is usually located at the beginning and end points of the layup trajectory, such as... Figure 5 As shown, using a stepped ramp treatment scheme to create a ramp allows the pressure roller to complete the transition from the mold plane to the laying plane via the ramp. This avoids the problem that the thickness of the "steps" crossed by the pressure roller in the traditional process becomes larger and larger, which can cause defects such as the ribbon starting point shifting backward, the sharp corners of the "steps" collapsing, and the side of the already laid layer being delaminated and wrinkled due to impact.
[0077] When the yarn laying machine lays yarn at an angle that is not perpendicular or parallel to the edge of the product outline, ear-like pieces of yarn will be present at the edge of the product outline. Figure 2 As shown, it should be done in accordance with Figure 2 The ribbon on the far right is laid with its lower end point on the edge outline of the layup, ensuring that the ribbon falls on a flat surface, not a slope. However, due to the minimum yarn exit distance, there are two possibilities: the ribbon may cross the slope and be laid on the mold, or the ribbon's starting point may be on the diagonal layup.
[0078] For layup tracks shorter than the minimum lead pitch, the track length should be extended. Since the layup profile includes variable thickness and constant thickness regions, one of the start and end points should be located in the bottom constant thickness region of the variable thickness region, and the other in either the bottom or top constant thickness region of the variable thickness region. For example... Figure 3 As shown, when the yarn laying machine lays yarn at an angle that is not perpendicular or parallel to the edge of the product contour, when laying yarn at the corner of the product edge, the yarn laying machine controls the end of the yarn to be on a platform to avoid the starting point of the yarn being on a stepped slope.
[0079] Specifically, taking a 45-degree angle layup as an example, if the ribbon's starting point is on an inclined surface, the trajectory of the yarn spreader should be controlled to actively extend the ribbon's starting point, ensuring it's positioned on the mold platform. This avoids issues like overlapping, bending, and insufficient pressing that can occur when the starting point is on the slope. Simultaneously, for cases where the ribbon crosses the slope after starting on the mold platform, the starting point should be extended. The extension distance should consider the pressure roller width and the uphill angle to prevent bridging between the pressure roller and the slope due to one end pressing against it first. This avoids a significant gap between the pressure roller and the mold plane, preventing the ribbon from being pressed firmly onto the platform during yarn exit, resulting in slippage.
[0080] When the yarn spreader is spreading yarn at a 0-degree angle to the edge of the product contour, the pressure roller of the yarn spreader must be kept inside the edge of the product contour. The layering is adjusted by adjusting the yarn exit position of the yarn spreader head and the position of the center line of the yarn spread trajectory, etc., to avoid the above-mentioned problems such as insufficient pressure within the contour and failure to spread yarn at the far end due to the pressure roller crossing the contour line during the laying process.
[0081] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.
[0082] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for designing an automatic yarn-lay trajectory for laying out the edge of a thick product layer, characterized in that, The operating steps include: Divide the product layup into several groups, from the first layer to the last layer. Design the profile by calculating the slope of the stepped slope of the product edge and the profile of each ply, and then plan the profile of several ply groups. Design the yarn layup trajectory. Design the yarn layup trajectory for each group of layups. For the following cases where the layup edge is a variable thickness area, provide a layup trajectory planning method: For positions where the layup edge contour is parallel to the layup angle direction, adjust the center line of the yarn layup trajectory and the position of the yarn exit bundle to solve the problems of insufficient pressure on the yarn bundle at the edge trajectory and the pressure roller detaching from the layup profile; For positions where the layup edge contour is neither perpendicular nor parallel to the layup angle direction, adjust the start and end points of the yarn layup trajectory to solve the problems of ribbon buckling, wrinkles, overlaps, and excessive gaps within the layup contour. The formula for calculating the slope α of the stepped slope formed by the edge of the product is: In the formula, L is the width of the pressure roller, β is the angle between the trajectory direction and the perpendicular line of the product contour, and Y is the compression amount of the pressure roller. In practice, the slope angle α is less than or equal to the calculated value of the above formula.
2. The automatic yarn placement trajectory design method for laying out thick product layers according to claim 1, characterized in that: The formula for calculating the relationship between the thickness H of the ply and the corresponding increase in the bottom side length X is as follows: In the formula, L is the width of the pressure roller, β is the angle between the trajectory direction and the perpendicular line of the product outline, Y is the compression amount of the pressure roller, and α is the slope. In application, the increased side length can be calculated based on the slope α of the stepped slope and the thickness H of each step ply, and finally the outline of each step ply can be obtained.
3. The automatic yarn placement trajectory design method for laying out thick product layers according to claim 1, characterized in that: When the filament placement machine places filaments at an angle parallel to the edge of the layup contour, adjust the position of the filament bundle exiting the filament placement head and the center line of the filament placement trajectory so that the outer end point of the pressure roller of the filament placement machine coincides with the boundary of the variable thickness region and the equal thickness region, so that the pressure roller is always located within the equal thickness region when the filament placement machine is laid on one side.
4. The automatic yarn placement trajectory design method for laying out thick product layers according to claim 3, characterized in that: When the outline of the ply includes a variable thickness region and a constant thickness region, the ply needs to be laid on the stepped slope of the product edge and the plane of constant thickness. In this case, the ply is laid separately on both sides according to the boundary of the variable thickness region and the constant thickness region.
5. The automatic yarn placement trajectory design method for laying out thick product layers according to claim 4, characterized in that: When the layup angle of the filament placement machine is not perpendicular or parallel to the edge of the layup profile, and the boundary between the variable thickness region and the equal thickness region is the layup profile, for layup trajectory length greater than or equal to the shortest filament pitch, the serrated edge control strategy for the start and end points is to select all within the profile. For paving tracks shorter than the minimum lead length, the track length should be extended so that one of the start and end points is located in the bottom equal thickness area of the variable thickness zone, and the other is located in the bottom or top equal thickness area of the variable thickness zone. In other words, by adjusting the track length and using a serrated edge control strategy, the start and end points cannot be located in the variable thickness zone.
6. The automatic yarn placement trajectory design method for laying out thick product layers according to claim 5, characterized in that: For cases where the edge contour of the ply is a corner where the length of the ply trajectory is less than the shortest filament pitch, the trajectory is split along the direction of the ply angle using a straight line passing through the vertex of the corner, and the two sides are laid separately.
Citation Information
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