Path planning methods, equipment and media for laser additive manufacturing-conformal roll forming
The laser additive manufacturing-conformal rolling composite path planning method solves the problem of low part forming quality in additive manufacturing. By constructing a straight filling trajectory and forming direction transformation strategy, the internal density and mechanical properties of the parts are improved, ensuring contour accuracy and surface flatness.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JIHUA LAB
- Filing Date
- 2022-11-02
- Publication Date
- 2026-06-30
AI Technical Summary
Existing additive manufacturing methods suffer from low part forming quality during the cladding-roll forming process, especially due to inaccurate height of the inner and outer contours and boundary collapse caused by the "high head and low tail" phenomenon, which affects the forming quality of the parts.
A path planning method combining laser additive manufacturing and conformal rolling is adopted. By acquiring the layered contour of the part to be formed, dividing the contour trajectory and constructing the straight line filling trajectory, and combining the forming direction transformation strategy, the weld can be completely rolled, eliminating the boundary flow phenomenon and improving the internal density and mechanical properties of the part.
It improves the forming quality of parts, ensures contour accuracy and surface flatness, reduces warping deformation of parts, and enhances the overall mechanical properties of parts.
Smart Images
Figure CN115673340B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of laser additive manufacturing, and in particular to a path planning method, equipment and medium for laser additive-conformal rolling composite. Background Technology
[0002] Additive manufacturing technology, based on the discrete-stack concept, transforms three-dimensional parts into layers of two-dimensional shapes, filling and stacking them from scratch to form the final part. Currently, the mainstream technologies in metal additive manufacturing include laser cladding additive manufacturing, arc wire feeding additive manufacturing, and laser / electron beam powder-laying additive manufacturing. Among these, laser cladding additive manufacturing uses a laser as a heat source to feed metal powder or wire into a molten pool, where it melts and solidifies to form weld beads. Multiple weld beads are then overlapped to form the final part. Compared to other technologies, laser cladding additive manufacturing balances high efficiency and high forming precision, and allows for precise control of various process parameters during the forming process, making it a promising technology for applications in aerospace, defense, and marine shipbuilding.
[0003] However, the mechanical properties of additively manufactured parts are often lower than those of forgings, making it difficult to meet practical application requirements, especially for load-bearing structural components. To overcome the performance bottleneck of additively manufactured parts, researchers have attempted to introduce traditional forging processes into the additive manufacturing process. However, in the cladding-roll forming process, to ensure that the rolling area can be extruded at a certain temperature, the cladding head needs to be tilted at a certain angle to minimize the distance between the molten pool and the pressure roller, thereby ensuring the temperature of the rolling area. But at the same time, the "head-high, tail-low" phenomenon of the cladding runner caused by the tilted cladding head becomes more severe, leading to the cladding runner on the inner and outer contours of the part flowing due to the lack of support from the printed solid on one side. This results in the part boundary height being lower than expected, and the pressure roller cannot roll the weld at the boundary. Furthermore, after the height error accumulates to a certain extent, the boundary cannot be formed at all, and the boundary collapse will extend further inward, resulting in the part size being smaller than expected, or even failing to complete printing. Therefore, the current cladding-roll forming method suffers from the problem of low part forming quality. Summary of the Invention
[0004] The main objective of this application is to provide a path planning method, equipment, and medium for laser additive manufacturing-conformal rolling composite, which aims to solve the problem of low forming quality of parts manufactured in the cladding-roll forming process.
[0005] To achieve the above objectives, this application provides a path planning method for laser additive manufacturing-conformal rolling composite processes, the method comprising:
[0006] Obtain the layered contour of the part to be formed, and divide the contour trajectory in the layered contour according to the preset offset distance;
[0007] Determine the outer bounding region of the contour trajectory, and obtain the forming direction transformation strategy based on the projection parameters of the contour trajectory in the outer bounding region;
[0008] A straight line filling trajectory is constructed within the contour trajectory based on the projection parameters and the preset spacing parameters;
[0009] According to the forming direction transformation strategy, the contour trajectory and the straight line filling trajectory are combined into an actual forming trajectory, so that the forming equipment can perform composite forming according to the actual forming trajectory.
[0010] Optionally, the step of obtaining the layered contour of the part to be formed and dividing the contour trajectory in the layered contour according to a preset offset distance includes:
[0011] Obtain the three-dimensional model of the part to be formed, and perform layer slicing on the three-dimensional model to obtain the layered contour;
[0012] Using the offset distance as a reference, the layered contour is moved inward to obtain the contour trajectory.
[0013] Optionally, the step of determining the circumscribed region of the contour trajectory and obtaining the forming direction transformation strategy based on the projection parameters of the contour trajectory in the circumscribed region includes:
[0014] Determine the orientation bounding box of the contour trajectory, and the direction of the short side of the orientation bounding box;
[0015] Project each side of the contour trajectory onto the direction of the short side to obtain the projection length of each short side;
[0016] The forming direction transformation strategy is determined based on the relationship between the projection length of each short side and a preset length threshold.
[0017] Optionally, the step of determining the forming direction transformation strategy based on the relationship between the projected lengths of each short side and a preset length threshold includes:
[0018] If any of the short side projection lengths is less than the length threshold, then the head-tail swap strategy is used.
[0019] If none of the short side projection lengths is less than the length threshold, then the cross-shaped strategy is used.
[0020] Optionally, the step of constructing a straight line filling trajectory within the contour trajectory based on the projection parameters and preset spacing parameters includes:
[0021] Obtain the contour projection length from the projection parameters, and the contour spacing and the first trajectory spacing from the spacing parameters;
[0022] Within the range of the contour projection length, a boundary straight line trajectory is constructed based on the contour spacing, using the contour trajectory as the boundary.
[0023] Using the boundary straight line trajectory as a reference, the internal straight line trajectory is uniformly divided according to the first trajectory spacing.
[0024] Optionally, after the step of constructing a straight line filling trajectory within the contour trajectory based on the projection parameters and preset spacing parameters, the method further includes:
[0025] When a change in the projection length of the contour is detected, the contour spacing is kept constant, and the first trajectory spacing is changed to obtain the second trajectory spacing.
[0026] If the second trajectory spacing exceeds a preset spacing threshold, the number of straight line filling trajectories or the contour spacing is changed so that the residual spacing of the contour projection length does not exceed the preset residual spacing threshold.
[0027] Optionally, the step of combining the contour trajectory and the straight line filling trajectory into an actual forming trajectory according to the forming direction transformation strategy includes:
[0028] Determine the contour starting layer in the layered contours, and the first contour starting point in the contour starting layer. Select the second contour starting point in the adjacent layer of the contour starting layer according to the preset starting point transformation rule, until the contour starting point positions of all layered contours are determined.
[0029] Obtain the first forming direction of the straight line filling trajectory in the contour starting layer, and set the second forming direction of the adjacent layers of the contour starting layer according to the first forming direction and the forming direction transformation strategy, until the forming direction of all layered contours is determined;
[0030] In each layered contour, the contour starting point position is taken as the initial forming point position, and the contour trajectory and the straight line filling trajectory are connected along the forming direction to form the actual forming trajectory.
[0031] Optionally, after the step of combining the contour trajectory and the straight line filling trajectory into an actual forming trajectory according to the forming direction transformation strategy, the method further includes:
[0032] If the forming equipment is detected to be running on the straight filling trajectory, the robot tilt parameters of the forming equipment are obtained, the robot tilt parameters are transformed into trajectory coordinate parameters, and the machine tool movement of the forming equipment is controlled according to the trajectory coordinate parameters.
[0033] If the forming device is detected to have moved to the contour trajectory, the spatial direction parameters of the trajectory points in the contour trajectory are obtained, the spatial direction parameters are converted into rotation angle parameters, and the robot movement of the forming device is controlled according to the rotation angle parameters.
[0034] In addition, to achieve the above objectives, this application also provides an electronic device, the electronic device comprising: a memory, a processor, and a laser additive-conformal rolling composite path planning program stored in the memory and executable on the processor, the laser additive-conformal rolling composite path planning program being configured to implement the steps of the laser additive-conformal rolling composite path planning method as described above.
[0035] In addition, to achieve the above objectives, this application also provides a computer-readable storage medium storing a path planning program for laser additive manufacturing-conformal rolling composite, wherein when the path planning program for laser additive manufacturing-conformal rolling composite is executed by a processor, it implements the steps of the path planning method for laser additive manufacturing-conformal rolling composite as described above.
[0036] The laser additive manufacturing-conformal rolling composite path planning method, equipment, and medium provided in this application acquire the layered contour of the part to be formed, divide the contour trajectory in the layered contour according to a preset offset distance, determine the outer enclosing region of the contour trajectory, obtain a forming direction transformation strategy based on the projection parameters of the contour trajectory in the outer enclosing region, construct a straight filling trajectory in the contour trajectory according to the projection parameters and preset spacing parameters, and combine the contour trajectory and the straight filling trajectory into an actual forming trajectory according to the forming direction transformation strategy, so that the forming equipment can perform composite forming according to the actual forming trajectory. By constructing a straight filling trajectory in the net size area of the part for laser cladding-conformal rolling composite forming filling, it is ensured that the weld can be completely rolled, thereby significantly improving the internal density and comprehensive mechanical properties of the part. By eliminating and improving the boundary flow phenomenon through free melt deposition scanning of the contour trajectory, the contour accuracy and surface flatness are ensured. Furthermore, the forming direction transformation strategy is used to change the weld direction of cladding and rolling layer by layer, reducing the warping deformation of the part, thus improving the forming quality of the part. Attached Figure Description
[0037] Figure 1 This is a schematic diagram of the structure of an electronic device in the hardware operating environment involved in the embodiments of this application;
[0038] Figure 2 This is a schematic flowchart of the first embodiment of the path planning method for laser additive manufacturing-conformal rolling composite in this application;
[0039] Figure 3a This is a schematic diagram of a three-dimensional model of the part to be formed according to an embodiment of this application;
[0040] Figure 3b This is a schematic diagram of the layered contour of the part to be formed according to an embodiment of this application;
[0041] Figure 4a This is a schematic diagram of a straight line filling trajectory distribution according to an embodiment of this application;
[0042] Figure 4b This is a schematic diagram illustrating the adjustment of straight line filling trajectory parameters according to an embodiment of this application;
[0043] Figure 4c This is a schematic diagram illustrating another method for adjusting the parameters of a straight line filling trajectory according to an embodiment of this application;
[0044] Figure 4d This is a schematic diagram illustrating another method for adjusting the straight line filling trajectory parameters according to an embodiment of this application.
[0045] Figure 5 This is a schematic diagram of the actual forming trajectory involved in the embodiments of this application;
[0046] Figure 6 This is a schematic flowchart of the second embodiment of the path planning method for laser additive manufacturing-conformal rolling composite in this application;
[0047] Figure 7 This is a schematic diagram of the straight line filling trajectory forming process involved in the embodiments of this application;
[0048] Figure 8 This is a schematic diagram of the tilted posture of the cladding head in the contour trajectory forming process involved in the embodiments of this application.
[0049] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation
[0050] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.
[0051] The mechanical properties of additively manufactured parts are often lower than those of forgings, making it difficult to meet practical application requirements, especially for load-bearing structural components. To overcome this performance bottleneck, researchers have attempted to incorporate traditional forging processes into the additive manufacturing process. One method is the use of shaped rollers, where the weld bead is rolled after the arc welding torch has formed a layer of the part. Studies on various materials, including titanium and aluminum alloys, have shown that rolling the weld bead effectively reduces stress concentration and refines the grain structure. This rolling process is a form of cold rolling, where the weld bead has completely cooled and solidified. Another method involves attaching a roller to the back of the welding torch, with both moving together to roll the weld bead while it is still semi-molten, causing plastic deformation. This method uses very little pressure to refine the weld bead grain, eliminate defects such as porosity and cracks, and achieve mechanical properties that meet or even exceed forging standards. Therefore, the combined process of micro-forging and cladding can significantly improve part quality. Furthermore, composite additive manufacturing equipment for laser cladding has emerged, which mounts the laser cladding head at the end of a robot and uses a four-axis vertical milling machine (with the milling cutter replaced by a rolling head) as an auxiliary motion platform. This equipment is used for further shape and property control during the laser cladding forming process. However, the "head-high-tail-low" and flow phenomena still exist in the composite forming process, affecting the forming quality of the parts.
[0052] The main technical solution of this application is as follows: obtaining the layered contour of the part to be formed, dividing the contour trajectory in the layered contour according to a preset offset distance; determining the outer enclosing region of the contour trajectory, obtaining a forming direction transformation strategy according to the projection parameters of the contour trajectory in the outer enclosing region; constructing a straight line filling trajectory in the contour trajectory according to the projection parameters and preset spacing parameters; combining the contour trajectory and the straight line filling trajectory into an actual forming trajectory according to the forming direction transformation strategy, so that the forming equipment can perform composite forming according to the actual forming trajectory.
[0053] Reference Figure 1 , Figure 1 This is a schematic diagram of the electronic device structure of the hardware operating environment involved in the embodiments of this application.
[0054] like Figure 1As shown, the electronic device may include: a processor 1001, such as a central processing unit (CPU), a communication bus 1002, a user interface 1003, a network interface 1004, and a memory 1005. The communication bus 1002 is used to enable communication between these components. The user interface 1003 may include a display screen or an input unit such as a keyboard; optionally, the user interface 1003 may also include a standard wired interface or a wireless interface. The network interface 1004 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 1005 may be a high-speed random access memory (RAM) or a stable non-volatile memory (NVM), such as a disk drive. The memory 1005 may also optionally be a storage device independent of the aforementioned processor 1001.
[0055] Those skilled in the art will understand that Figure 1 The structure shown does not constitute a limitation on the electronic device and may include more or fewer components than shown, or combine certain components, or have different component arrangements.
[0056] like Figure 1 As shown, the memory 1005, which serves as a storage medium, may include an operating system, a network communication module, a user interface module, and a path planning program for laser additive manufacturing-conformal rolling composite.
[0057] exist Figure 1 In the illustrated electronic device, the network interface 1004 is mainly used for data communication with other devices; the user interface 1003 is mainly used for data interaction with the user; the processor 1001 and memory 1005 in the electronic device of this application can be set in the electronic device, and the electronic device calls the path planning program of laser additive manufacturing-conformal rolling composite stored in the memory 1005 through the processor 1001, and executes the path planning method of laser additive manufacturing-conformal rolling composite provided in the embodiment of this application.
[0058] This application provides a path planning method for laser additive manufacturing-conformal rolling composite, referring to... Figure 2 , Figure 2 This is a schematic flowchart of the first embodiment of a path planning method for laser additive manufacturing-conformal rolling composite according to this application.
[0059] In this embodiment, the path planning method for laser additive manufacturing-conformal rolling composite includes:
[0060] Step S10: Obtain the layered contour of the part to be formed, and divide the contour trajectory in the layered contour according to the preset offset distance.
[0061] The path planning method for laser additive manufacturing-conformable roll forming in this application can be applied to robot-machine tool collaborative forming equipment to plan the motion paths of the robot and machine tool during the cladding-roll forming process. The robot-machine tool collaborative forming equipment may include a machine tool, a robot, and a rolling head. The robot may be a laser cladding head. Molten metal flows from the cladding head to the substrate, and after rolling and cooling, a formed metal part is obtained.
[0062] The three-dimensional part to be formed is divided into two-dimensional layered contours. The stacking of these layered contours allows the part to be formed from scratch. Since the pressure rollers cannot roll the weld beads at the contour boundaries, the contour trajectory can be set at a certain distance from the layered contours to avoid flow during contour trajectory scanning.
[0063] In some feasible implementations, the step of obtaining the layered contours of the part to be formed and dividing the contour trajectory in the layered contours according to a preset offset distance may include:
[0064] Step a: Obtain the three-dimensional model of the part to be formed, and perform layer slicing on the three-dimensional model to obtain the layered contour;
[0065] Step b: Using the offset distance as a reference, move the layered contour inward to obtain the contour trajectory.
[0066] Figure 3a A schematic diagram of a 3D model of the part to be formed, such as... Figure 3a As shown, the shape of the part to be formed can be simulated and designed using a 3D model according to actual needs, and then the three-dimensional model structure can be sliced into layers. Figure 3b The two-dimensional layered contours shown are used to obtain the set of layered contours S0 = {S 0i {i = 1, 2, ..., n}. The region enclosed by the layered contours is the inner region. The layered contours are shifted inward by an offset distance dist. i0 The contour trajectory S can be obtained. d ={S di {i = 1, 2, ..., n}. Offset distance dist i0 The thickness can be 0-2mm. The contour trajectory contains multiple trajectory points, each of which corresponds to the tilt state of the cladding head.
[0067] Step S20: Determine the outer bounding region of the contour trajectory, and obtain the forming direction transformation strategy based on the projection parameters of the contour trajectory in the outer bounding region;
[0068] When the shape of the part to be formed is highly complex, the shape of the contour trajectory is often irregular. By using the circumscribed region, a regular shape, such as a sphere or a cube, can be used to approximate the contour trajectory. The projection parameters of the contour trajectory in the circumscribed region can represent its side length distribution in different projection directions. Therefore, an appropriate forming direction transformation strategy can be selected based on the side length distribution to reduce the anisotropy of the part.
[0069] In some feasible implementations, the step of determining the outer bounding region of the contour trajectory and obtaining the forming direction transformation strategy based on the projection parameters of the contour trajectory within the outer bounding region may include:
[0070] Step c: Determine the orientation bounding box of the contour trajectory, and the direction of the short side of the orientation bounding box;
[0071] Step d: Project each side of the contour trajectory onto the direction of the short side to obtain the projection length of each short side;
[0072] Step e: Determine the forming direction transformation strategy based on the relationship between the projection length of each short side and a preset length threshold.
[0073] An Oriented Bounding Box (OBB) can be used as the outer bounding area of the contour trajectory to reflect its general direction and understand the long side's tendency, thereby reducing the number of short sides in the actual forming trajectory and improving the forming effect. The OBB can be calculated by traversing each edge e of the contour trajectory. k Project the other vertices of the contour trajectory onto e respectively. k Calculate the maximum projected length W of the point along the straight line and perpendicular direction. k and H k Calculate the area of a rectangle. k =W k ×H k Among all rectangles defined by their sides, the smallest bounding box (OBB) has the smallest area. Its four corner points are the furthest projections of the contour vertices in two directions. An OBB is a rectangle whose length direction is the direction of its longest side. The width direction is the shorter side direction. The shorter side has a significant impact on part forming. Based on the projected lengths of each side in both the long and short side directions stored in the OBB calculations, and considering whether the projected length of the shorter side exceeds a preset length threshold, different forming direction transformation strategies can be selected. These forming direction transformation strategies can be applied to the forming process of straight-line filling trajectories.
[0074] In some feasible implementations, the step of determining the forming direction transformation strategy based on the relationship between the projection lengths of each short side and a preset length threshold may include:
[0075] Step e1: If there is a short side projection length that is less than the length threshold among the short side projection lengths, then the head-tail swap strategy is used.
[0076] Step e2: If none of the short side projection lengths is less than the length threshold, then the cross-shaped strategy is used.
[0077] The initial scan direction can be set to Based on the projected lengths of each short side obtained from the OBB calculation, if there exists... The projected length in the direction is less than the preset length threshold len min For edges, a head-to-tail swap strategy can be used, that is, sequentially along... and Two directional trajectories are formed. Otherwise, a cross-shaped strategy is used, that is, sequentially along... The trajectory is formed in four directions.
[0078] Step S30: Construct a straight line filling trajectory within the contour trajectory according to the projection parameters and the preset spacing parameters;
[0079] Within the contour trajectory, cladding-rolling composite forming can be performed using straight filler trajectories. These straight filler trajectories are parallel to each other, and the straight filler trajectories in each layer of the contour are different from those in adjacent layers. The direction of the weld beads changes layer by layer, which can reduce the anisotropy and warpage of the part. The spacing between each straight filler trajectories, and the spacing between the straight filler trajectories and the contour trajectory, is determined by preset spacing parameters. The straight filler trajectories can be evenly distributed within the contour trajectory by adjusting the spacing parameters and the number of straight filler trajectories.
[0080] In some feasible implementations, the step of constructing a straight line filling trajectory within the contour trajectory based on the projection parameters and preset spacing parameters may include:
[0081] Step f: Obtain the contour projection length in the projection parameters, and the contour spacing and the first trajectory spacing in the spacing parameters;
[0082] Step g: Within the range of the contour projection length, using the contour trajectory as the boundary, construct a boundary straight line trajectory based on the contour spacing;
[0083] Step h: Using the boundary straight line trajectory as a reference, the internal straight line trajectory is evenly divided according to the first trajectory spacing.
[0084] In the process of planning the straight line filling trajectory, the contour spacing d in the spacing parameter can be obtained first. f and trajectory spacing O f Contour projection length Contour spacing represents the distance between the outermost straight fill trajectory and the contour trajectory; trajectory spacing represents the distance between adjacent straight fill trajectories; and first trajectory spacing represents the distance between adjacent straight fill trajectories within the contour trajectory of this layer. f1 The contour projection length can be the length of the contour trajectory in the scanning direction. This indicates the scanning direction, which can be either the long side direction or the short side direction. The current scanning direction will be used. With contour trajectory S d As the initial reference, the offset distance d f Construct the first straight line to intersect the contour, obtaining the first straight line filling trajectory P1, and then fill it at a distance O. f Continue offsetting the line until it intersects the contour, constructing fill segments P2, ..., P. n Boundary segment P n The distance to the profile is exactly d f .like Figure 4a As shown, the trajectory of the straight line fill satisfies the following formula 1:
[0085] Formula 1: W=2×d f +(N-2)×O f .
[0086] Where N represents the number of straight lines filling the trajectory, satisfying
[0087] exist Figure 4a In the middle, for the straight-line filling trajectory of this layer, W = 2 × d is satisfied. f1 +(N-2)×O f1 .
[0088] In some feasible implementations, after the step of constructing a straight line filling trajectory within the contour trajectory based on the projection parameters and preset spacing parameters, the method may further include:
[0089] Step i: When a change in the projection length of the contour is detected, the contour spacing is kept constant, and the first trajectory spacing is changed to obtain the second trajectory spacing;
[0090] Step j: If the second trajectory spacing exceeds a preset spacing threshold, then change the number of straight line filling trajectories or the contour spacing so that the residual spacing of the contour projection length does not exceed the preset residual spacing threshold.
[0091] The parts to be formed are often not regular three-dimensional shapes, which means that the size of each layer contour is inconsistent. When planning the straight line filling trajectory in each layer contour, the planned trajectory of the previous layer can be used as a reference. When the layer contour of the current layer is the same as that of the previous layer, the planned trajectory of the previous layer is directly used as the trajectory of the current layer. When the layer contour of the current layer is different from that of the previous layer, the contour projection length will also change, and the straight line filling trajectory is adaptively updated to satisfy the above formula 1.
[0092] During the adaptive update process, the residual spacing E can be used to evaluate the rationality of the straight-line filling trajectory planning. The expression for the residual spacing E is as follows: Formula 2:
[0093] Formula 2: E=W-2×d f -N×O f .
[0094] The trajectory spacing should meet the preset trajectory spacing threshold range [O] f ′, O f * ].if So update Otherwise, reduce the trajectory spacing. For the above O ff The value is further evaluated; if O ff ≥O f If ′, then update O f =O ff Add a straight line trajectory; otherwise, update O. f =O f ′, N, E, Increase the number of straight line trajectories and decrease the distance between the straight line trajectories and the contour trajectories on both sides.
[0095] The above adaptive update will be illustrated with an example, referring to the accompanying diagram. Figure 4a As a pre-planned straight-line filling trajectory, it can be seen that... Figure 4a In, satisfying d f1 =d f O f1 =O f The number of straight-line filling trajectories, N = 3. First, adjust the spacing of the first trajectory, such as... Figure 4b As shown, increasing the trajectory spacing while maintaining the same spacing from the contour results in d. f2 =d f O f2 >O f If the increased trajectory spacing O f2 >O f * If the threshold is exceeded, an additional trajectory needs to be added to reduce the trajectory spacing, such as... Figure 4c After adjustment, d f3 =d f O f3 <O f N = 4. However, if O f3 <O f If the trajectory spacing is too small, it will cause weld bead bulging. In this case, it is necessary to construct the internal straight trajectory with the minimum spacing and reduce the boundary trajectory spacing, such as... Figure 4d As shown, i.e., d f4 <d f O f4 =O f The residual distance being less than the residual distance threshold can be used as a basis for completing the adaptive update. In an ideal case, the residual distance is zero.
[0096] Step S40: According to the forming direction transformation strategy, the contour trajectory and the straight line filling trajectory are combined into an actual forming trajectory, so that the forming equipment can perform composite forming according to the actual forming trajectory.
[0097] In the actual part forming process, contour trajectories and straight-line filling trajectories can be formed separately, with the straight-line filling trajectory forming sequence preceding the contour trajectories. The actual forming trajectory includes all the trajectory paths and directions required for the part to be formed; that is, the actual forming trajectory can be regarded as a set of trajectory vectors. Both contour trajectories and straight-line filling trajectories have trajectory path parameters such as starting point, forming direction, and forming path. Based on the above trajectory path parameters, contour trajectories and straight-line filling trajectories can be combined into the actual forming trajectory, and the cladding head, rolling head, and machine tool can work together to perform composite forming.
[0098] In some feasible implementations, the step of combining the contour trajectory and the straight line filling trajectory into an actual forming trajectory according to the forming direction transformation strategy may include:
[0099] Step 1: Determine the contour starting layer in the layered contours, and the first contour starting point in the contour starting layer. Select the second contour starting point in the adjacent layer of the contour starting layer according to the preset starting point transformation rule, until the contour starting point positions of all layered contours are determined.
[0100] Step m: Obtain the first forming direction of the straight line filling trajectory in the contour starting layer, and set the second forming direction of the adjacent layers of the contour starting layer according to the first forming direction and the forming direction transformation strategy, until the forming direction of all layered contours is determined;
[0101] Step n: In each layered contour, taking the contour starting point position as the initial forming point position, connect the contour trajectory and the straight line filling trajectory along the forming direction to form the actual forming trajectory.
[0102] The initial contour layer can be any layer in the layered contours. In practice, the topmost layered contour can be used as the initial contour layer, and the first contour starting point is the forming starting point of the initial contour layer, which can be randomly set. The preset starting point transformation rule can be an angle transformation rule or a distance transformation rule. The angle transformation rule can be considered as taking the first contour starting point as the starting point, the edge containing the first contour starting point as the starting edge, rotating the starting edge by a preset transformation angle, and intersecting with another edge to obtain the intersection point. The corresponding position of this intersection point in the adjacent layer is the second contour starting point. The preset transformation angle can be 30°. The distance transformation rule can be that taking the first contour starting point as the starting point, moving along the length of the edge containing the starting point by a preset transformation distance to obtain the intersection point. The corresponding position of this intersection point in the adjacent layer is the second contour starting point. Starting from the initial contour layer, the above transformation steps are repeated for each adjacent layer, which can determine the contour starting point of the contour trajectory in all layered contours. The contour starting points are staggered layer by layer, avoiding printing from always starting at the same position, reducing stress concentration and starting weld bead protrusion.
[0103] In the initial contour layer, after the straight-line filling trajectory is planned, the forming direction is along the straight line. The starting end can be any end where the straight-line filling trajectory intersects the contour trajectory. The forming directions of adjacent layers are determined according to the forming direction transformation strategy. In the final layered contour, the forming directions of adjacent layers are different, and a cross-shaped strategy is adopted. During the forming process, the weld direction of cladding and rolling is changed layer by layer, which can effectively reduce the anisotropy of the part and the warping deformation of the part. The contour trajectory is usually a closed shape. After the starting position of the contour is determined, the forming direction of the contour trajectory can be the same as the imaging direction of the straight-line filling trajectory. In this way, the starting point, forming direction, and forming path are determined, and the contour trajectory and the straight-line filling trajectory are connected to form the actual forming trajectory. Figure 5 This is a schematic diagram of the actual forming trajectory. Figure 5 In the diagram, the part to be formed on the left uses a cross-shaped strategy, while the part to be formed on the right uses a head-tail exchange strategy. The arrows in the diagram indicate the forming direction, and the solid dots indicate the starting point of the contour.
[0104] Acceleration points can also be inserted into the linear filling trajectory. High-speed forming during the acceleration phase of the forming equipment can reduce the protrusion at the beginning of the linear filling trajectory. The location of the acceleration points can be found in [reference needed]. Figure 4a M represents the acceleration point, S represents the starting point, and E represents the ending point. The SM segment runs at 1.3-1.5 times the normal forming speed, and the ME segment runs at the normal forming speed. The normal forming speed can be 400-1000 mm / min, and the distance of the SM segment can be set to 3-5 mm.
[0105] In this embodiment, the layered contour of the part to be formed is obtained, and a contour trajectory is divided in the layered contour according to a preset offset distance. The outer bounding area of the contour trajectory is determined, and a forming direction transformation strategy is obtained according to the projection parameters of the contour trajectory in the outer bounding area. A straight filling trajectory is constructed in the contour trajectory according to the projection parameters and preset spacing parameters. The contour trajectory and the straight filling trajectory are combined into an actual forming trajectory according to the forming direction transformation strategy, so that the forming equipment can perform composite forming according to the actual forming trajectory. A straight filling trajectory is constructed in the net size area of the part for laser cladding-conformable rolling composite forming filling, which ensures that the weld can be completely rolled, thereby greatly improving the internal density and comprehensive mechanical properties of the part. The boundary flow phenomenon is eliminated and improved by free fusion scanning of the contour trajectory, ensuring contour accuracy and surface flatness. The forming direction transformation strategy is also used to change the weld direction of cladding and rolling layer by layer, reducing the warping deformation of the part, thus improving the forming quality of the part.
[0106] Furthermore, in the second embodiment of the path planning method for laser additive manufacturing-conformal rolling composite in this application, referring to... Figure 6 The method includes:
[0107] Step S50: If it is detected that the forming equipment has moved to the straight filling trajectory, the robot tilt parameter of the forming equipment is obtained, the robot tilt parameter is transformed into trajectory coordinate parameters, and the machine tool movement of the forming equipment is controlled according to the trajectory coordinate parameters.
[0108] In addition to the actual forming trajectory, the forming equipment has different posture parameters during the running of the forming trajectory, controlling the robot and machine tool to work together. Figure 7 This is a schematic diagram of the process of forming a straight line filling trajectory, as shown below. Figure 7 As shown, the robot tilts at a certain angle and moves to a distance of dist from the rolling head. r The position, orientation, and distance between the rolling head and the cladding head remain constant. Robot tilt parameters can include tilt angle, orientation, and distance between the rolling head and the cladding head. Based on the orientation of the rolling head and the cladding head, the trajectory undergoes coordinate transformation to obtain trajectory coordinate parameters, i.e., the rotation angle and coordinate point position in the machine tool coordinate system. The machine tool turntable rotates to the specified position according to the rotation angle, the machine tool base moves according to the coordinate point position, and the robot remains stationary. The formula used for trajectory coordinate transformation is as follows: Formula 3:
[0109] Formula 3:
[0110] Where x, y, and z represent the three coordinate axes in the coordinate system, and the rotation angle θ is the direction of the straight line filling the trajectory. and the direction of the rolling head-cladding head The included angle between them is determined by referring to the following formula 4:
[0111] Formula 4:
[0112] Wherein, δ=±1, determines the direction of the machine tool turntable along counterclockwise (1) or clockwise (-1).
[0113] When forming a straight trajectory, the cladding head is tilted at a certain angle so that it can get close to the rolling head and maintain a small rolling distance. The tilt angle can be adjusted in the range of 10°-30° and the rolling distance can be adjusted in the range of 25mm-40mm.
[0114] Step S60: If the forming device is detected to have moved to the contour trajectory, the spatial direction parameters of the trajectory points in the contour trajectory are obtained, the spatial direction parameters are converted into rotation angle parameters, and the robot movement of the forming device is controlled according to the rotation angle parameters.
[0115] Forming contour trajectory S d At that time, a safe distance can be set dist safe The robot and machine tool move synchronously within a safe distance, the cladding head moves away from the rolling head, and then returns to a vertical position. The safe distance can be set within the range of 150-250mm. The robot follows the contour trajectory S. d The robot moves according to the indicated position and orientation, while the machine tool remains stationary. After completing the trajectory shaping of one layer, the robot and the rolling head are raised, and the above movements are repeated to print subsequent contour layers. Spatial orientation parameters can include the bisector direction of the interior angle of the trajectory point and the coordinates of the trajectory point. Contour trajectory S d The tilt direction of the cladding head at each point can be considered as being obtained by rotating the vertical direction around the tangent direction of the trajectory of the point by a certain angle, and can be calculated according to the following formula 5:
[0116] Formula 5:
[0117] in, It is in the vertical direction. It is the direction of the angle bisector of the point. It is the rotation angle.
[0118] Based on the vector-to-Euler angle calculation method, the rotation angles ABC of the three axes in the spatial rectangular coordinate system required for the robot to rotate from a vertical posture to a tilted posture are calculated. The above ABC are the rotation angle parameters, calculated according to the following formula 6:
[0119] Formula 6:
[0120] Figure 8 This is a schematic diagram of the tilted posture of the cladding head during the contour trajectory forming process, as shown below. Figure 8As shown, for the contour trajectory, a local coordinate system O′X′Y′Z′ is constructed at each point. The Z′ axis is the same as the global coordinate system Z axis, the Y′ axis is the angle bisector of the vertex's interior angle, and the X′ axis is obtained by the cross product of the Y′ and Z′ vectors. The cladding head is initially in a vertical orientation, i.e., in the Z-axis direction. The cladding head is rotated by an angle θ around the local X′ axis, which can be between 20° and 45°, adjusted according to the process parameters. Then, the three posture values of the robot (A, B, and C) are calculated according to the vector-to-Euler angle conversion formula.
[0121] In this embodiment, on the robot-machine tool dual-channel collaborative platform, the collaborative operation of the robot and the machine tool is controlled according to the forming characteristics of different forming trajectories, realizing the laser cladding-conformable rolling composite forming of metal parts. Based on the geometric trajectory, the motion paths of the robot and the machine tool are planned efficiently and reasonably to avoid interference.
[0122] This application also provides an electronic device, comprising: a memory, a processor, and a path planning program for laser additive manufacturing-conformal rolling composite processing stored in the memory and executable on the processor. The path planning program is configured to implement the steps of the path planning method for laser additive manufacturing-conformal rolling composite processing as described above. Specific implementation details of the electronic device in this application can be found in the various embodiments of the path planning method for laser additive manufacturing-conformal rolling composite processing described above, and will not be repeated here.
[0123] This application also provides a computer-readable storage medium storing a path planning program for laser additive manufacturing-conformal rolling composite. When executed by a processor, the path planning program implements the steps of the path planning method for laser additive manufacturing-conformal rolling composite as described above. Specific implementation details of the computer-readable storage medium in this application can be found in the various embodiments of the path planning method for laser additive manufacturing-conformal rolling composite described above, and will not be repeated here.
[0124] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.
[0125] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.
[0126] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.
[0127] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.
Claims
1. A path planning method for laser additive manufacturing-conformal rolling composite, characterized in that, The path planning method for laser additive manufacturing-conformal rolling composite includes the following steps: A three-dimensional model of the part to be formed is obtained and sliced into layers to obtain layered contours. The layered contours are moved inward according to a preset offset distance to generate a contour trajectory. The directional bounding box of the contour trajectory is determined as the outer bounding region. The projection length of the contour trajectory in the short side direction of the outer bounding region is used as the projection parameter. The forming direction transformation strategy is obtained according to the relationship between the projection length and the preset length threshold. The directional bounding box is determined by traversing each side of the contour trajectory and projecting the other vertices on the contour trajectory, except for those constituting the current side, onto the straight line where the current side is located and its perpendicular direction. A rectangle is formed according to the maximum projection length in the two directions. Obtain the contour projection length in the projection parameters, and the contour spacing and the first trajectory spacing in the preset spacing parameters, wherein the contour projection length is the length of the contour trajectory in the scanning direction, the contour spacing is the distance between the outermost straight line trajectory and the contour trajectory, and the first trajectory spacing is the distance between adjacent straight line filling trajectories within each layer of the contour trajectory. Within the range of the contour projection length, a boundary straight line trajectory is constructed based on the contour spacing, using the contour trajectory as the boundary. Based on the boundary straight line trajectory, parallel straight line filling trajectories are evenly divided according to the first trajectory spacing; According to the forming direction transformation strategy, the contour starting layer in the layered contours and the first contour starting point in the contour starting layer are determined. According to the preset starting point transformation rule, the second contour starting point is selected in the adjacent layer of the contour starting layer until the contour starting point position of all layered contours is determined, wherein the contour starting point position of each layered contour is staggered. The first forming direction is determined by the straight line direction at either end of the intersection of the straight filling trajectory and the contour trajectory in the contour starting layer. The second forming direction of the adjacent layers of the contour starting layer is set according to the first forming direction and the forming direction transformation strategy until the forming direction of all layered contours is determined. The forming directions of the adjacent layers of each layered contour are not the same. In each layered contour, the contour starting point is taken as the initial forming point position, and the contour trajectory and the straight line filling trajectory are connected along the forming direction to form the actual forming trajectory, so that the forming equipment can perform composite forming according to the actual forming trajectory.
2. The path planning method for laser additive manufacturing-conformal rolling composite as described in claim 1, characterized in that, The steps of determining the bounding box of the contour trajectory as the outer bounding region, using the projection length of the contour trajectory along the short side of the outer bounding region as the projection parameter, and obtaining the forming direction transformation strategy based on the relationship between the projection length and a preset length threshold include: Determine the direction of the short side of the bounding box; Project each side of the contour trajectory onto the direction of the short side to obtain the projection length of each short side; If any of the short side projection lengths is less than a preset length threshold, then a head-to-tail swap strategy is used, wherein the head-to-tail swap strategy is along... and Two-directional forming trajectory, The direction of the long side of the bounding box is defined as the direction of the bounding box. If none of the short side projection lengths is less than a preset length threshold, then a cross-shaped strategy is used, wherein the cross-shaped strategy is along... , , and Four-directional forming trajectory, The direction is the direction of the short side of the bounding box.
3. The path planning method for laser additive manufacturing-conformal rolling composite as described in claim 1, characterized in that, After the step of uniformly dividing the parallel straight-line filling trajectory according to the first trajectory spacing, the method further includes: When a change in the projection length of the contour between the current layer and the previous layer is detected, the contour spacing is kept constant, and the first trajectory spacing is changed to obtain the second trajectory spacing. If the second trajectory spacing exceeds a preset spacing threshold, then the number of straight line filling trajectories or the contour spacing is changed so that the residual spacing of the contour projection length does not exceed a preset residual spacing threshold, wherein the residual spacing W is the length of the contour projection. Where N is the contour spacing, and N is the number of straight line fill trajectories. The preset spacing threshold is used.
4. The path planning method for laser additive manufacturing-conformal rolling composite as described in any one of claims 1-3, characterized in that, After the step of connecting the contour trajectory and the straight line filling trajectory along the forming direction to form the actual forming trajectory, the method further includes: If the forming equipment is detected to be running on the straight filling trajectory, the robot tilt parameters of the forming equipment are obtained. The robot tilt parameters are transformed into trajectory coordinate parameters according to the orientation of the rolling head and the cladding head. The machine tool movement of the forming equipment is controlled according to the trajectory coordinate parameters. The robot is equipped with a cladding head at its end, and the machine tool is an auxiliary motion platform of the forming equipment. If the forming device is detected to have moved to the contour trajectory, the spatial direction parameters of the trajectory points in the contour trajectory are obtained, and the spatial direction parameters are converted into rotation angle parameters according to the vector to Euler angle calculation method. The robot movement of the forming device is controlled according to the rotation angle parameters.
5. An electronic device, characterized in that, The electronic device includes: a memory, a processor, and a laser additive-conformal rolling composite path planning program stored in the memory and executable on the processor, the laser additive-conformal rolling composite path planning program being configured to implement the steps of the laser additive-conformal rolling composite path planning method as described in any one of claims 1 to 4.
6. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a path planning program for laser additive manufacturing-conformal rolling composite, which, when executed by a processor, implements the steps of the path planning method for laser additive manufacturing-conformal rolling composite as described in any one of claims 1 to 4.