Array plane slicing based curved surface additive path planning method, device and medium

Abstract

The application discloses a curved surface additive path planning method and device based on array plane slicing and a medium, and belongs to the technical field of additive manufacturing. The method comprises the following steps: obtaining a three-dimensional model of a part to be formed; selecting a plane normal vector in the three-dimensional model, constructing a plurality of slicing planes based on the plane normal vector and a preset initial offset; determining a reference offset curve in the slicing planes; offsetting the reference offset curve in the slicing planes with a preset slicing layer thickness as an offset interval to obtain a local additive path in each slicing plane; and connecting the local additive paths to form a global additive reciprocating path from the bottom of the three-dimensional model. The application achieves the technical effect of improving the forming efficiency of curved surface additive manufacturing.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing technology, and in particular to a method, equipment and medium for curved surface additive manufacturing path planning based on arrayed planar slices. Background Technology

[0002] Currently, various additive manufacturing technologies are flourishing, including powder-laying additive manufacturing such as Selective Laser Melting (SLM) and Electron Beam Selective Melting (EBSM), as well as powder-feeding or wire-feeding additive manufacturing such as Wire Arc Additive Manufacturing (WAAM) and Laser Engineered Net Shaping (LENS). The latter two can be categorized under the field of Directed Energy Deposition (DED). DED technology is often based on robotic platforms, possessing higher degrees of freedom and capable of conforming to the shape of parts. Therefore, it is increasingly being applied to surface repair, cladding, and additive manufacturing of components such as automotive molds.

[0003] Additive manufacturing of automotive mold surfaces often involves curved substrates. The planar slicing method results in a step effect, which can easily lead to significant forming errors. Furthermore, the large number of layers in the parts also contributes to low forming efficiency. Therefore, applying DED technology to the mold market still faces considerable challenges. Summary of the Invention

[0004] The main objective of this invention is to provide a method, device, and medium for path planning in surface additive manufacturing based on arrayed planar slices, aiming to solve the problem of low forming efficiency caused by multiple parts layers in surface additive manufacturing.

[0005] To achieve the above objectives, this invention provides a surface additive manufacturing path planning method based on arrayed planar slices, the method comprising:

[0006] Obtain a 3D model of the part to be formed;

[0007] In the three-dimensional model, a plane normal vector is selected, and multiple slicing planes are constructed based on the plane normal vector and a preset initial offset.

[0008] Determine the reference offset curve in the slice plane;

[0009] Using a preset slice layer thickness as the offset interval, the reference offset curve is offset in the slice plane to obtain the local additive path in each slice plane;

[0010] Starting from the bottom of the 3D model, the local additive paths are connected to form a global additive reciprocating path.

[0011] Optionally, the step of selecting a plane normal vector in the three-dimensional model and constructing multiple slicing planes based on the plane normal vector and a preset offset includes:

[0012] The direction of the longer side in the three-dimensional model is selected as the plane normal vector;

[0013] Calculate the projection value of each vertex in the three-dimensional model onto the plane normal vector, and determine the maximum and minimum projection values ​​among the projection values;

[0014] The number of slice planes is determined based on the difference between the maximum projection value and the minimum projection value;

[0015] The slice planes are arranged in parallel with the preset initial offset as the spacing.

[0016] Optionally, the step of determining the reference offset curve in the slice plane includes:

[0017] Construct a reference surface in the three-dimensional model;

[0018] The reference surface and the slice plane are intersected to obtain the reference offset curve.

[0019] Optionally, the step of offsetting the reference offset curve in the slice plane with a preset slice layer thickness as the offset interval to obtain the local additive path in each slice plane includes:

[0020] Transform the reference offset curve into the two-dimensional plane containing the slice plane;

[0021] Calculate the curve offset reference direction of the reference offset curve;

[0022] Offset the reference direction along the curve, with a preset slice layer thickness as the interval, and offset the reference offset curve to obtain each of the local additive paths.

[0023] Optionally, the step of converting the reference offset curve to the two-dimensional plane containing the slice plane includes:

[0024] Using the starting point of the reference offset curve as the origin of the coordinate system, the direction of the contour line segment where the starting point is located as the direction of the first coordinate axis, and the direction of the second coordinate axis is determined based on the direction of the first coordinate axis to establish a local two-dimensional coordinate system;

[0025] Each curve point in the reference offset curve is transformed into the local two-dimensional coordinate system for representation.

[0026] Optionally, the step of calculating the curve offset reference direction of the reference offset curve includes:

[0027] Calculate the minimum bounding box of the reference offset curve, and take the long side direction of the minimum bounding box as the main direction of the reference offset curve;

[0028] The curve offset reference direction is determined based on the main direction.

[0029] Optionally, the step of connecting the local additive paths to form a global additive reciprocating path, starting from the bottom of the 3D model, includes:

[0030] Taking the local additive path located at the bottom of the three-dimensional model as the target local additive path, starting from the first layer of the slicing plane, the target local additive paths are connected in a serpentine manner to form the first layer of additive reciprocating path;

[0031] The target local additive path is updated to the next local additive path of the target local additive path, and the step of connecting each target local additive path in a serpentine manner starting from the first layer slice plane is executed until the global additive reciprocating path is formed.

[0032] Optionally, after the step of offsetting the reference offset curve in the slicing plane with a preset slice layer thickness as the offset interval to obtain the local additive path in each slice plane, the method further includes:

[0033] Select any point in the local additive manufacturing path as a trajectory point, and form the outer angle of the trajectory point by combining two adjacent points of the trajectory point with the trajectory point itself.

[0034] The angle bisector of the exterior angle is taken as the surface normal vector of the trajectory point;

[0035] The surface normal vector is represented in three-dimensional space to serve as the attitude parameter of the deposition head during surface additive manufacturing.

[0036] Furthermore, to achieve the above objectives, the present invention also provides an electronic device, the electronic device comprising: a memory, a processor, and a surface additive manufacturing path planning program based on array planar slices stored in the memory and executable on the processor, the surface additive manufacturing path planning program based on array planar slices being configured to implement the steps of the surface additive manufacturing path planning method based on array planar slices as described above.

[0037] Furthermore, to achieve the above objectives, the present invention also provides a storage medium, which is a computer-readable storage medium storing a surface additive manufacturing path planning program based on array planar slices. When the surface additive manufacturing path planning program based on array planar slices is executed by a processor, it implements the steps of the surface additive manufacturing path planning method based on array planar slices as described above.

[0038] The present invention provides a surface additive manufacturing path planning method based on arrayed planar slicing. First, a three-dimensional model of the part to be formed is obtained. Plane normal vectors are selected in the three-dimensional model. Multiple slicing planes are constructed based on these plane normal vectors and a preset initial offset. The direction of the slicing planes is determined by the plane normal vectors in the three-dimensional model, rather than directly using horizontal slicing planes. This reduces the number of slicing planes for three-dimensional models where the vertical dimension is greater than the horizontal dimension. A reference offset curve is determined in each slicing plane, which can serve as the shape reference for the additive manufacturing path. Using a preset slice layer thickness as the offset interval, the reference offset curve is offset in each slicing plane to obtain a local additive manufacturing path. Starting from the bottom of the three-dimensional model, the local additive manufacturing paths are connected to form a global additive reciprocating path. The deposition head performs deposition from bottom to top according to the global additive reciprocating path to manufacture a part with a curved surface. The embodiments of the present invention transform the surface slicing and path planning problem into a planar problem through the above steps, simplifying the algorithm complexity, improving computational efficiency, and reducing the number of slice layers compared to horizontal planar slicing, thus improving forming efficiency. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of an electronic device in the hardware operating environment involved in the embodiments of the present invention;

[0040] Figure 2 This is a flowchart illustrating the first embodiment of the surface additive manufacturing path planning method based on arrayed planar slices of the present invention.

[0041] Figure 3 This is a schematic diagram showing the positional relationship between the basic component and the additive component after they are combined according to an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram showing the positional relationship between the basic component and the additive component before assembly, according to an embodiment of the present invention.

[0043] Figure 5 This is a schematic diagram illustrating the positional relationship between the slicing plane and the three-dimensional model in an embodiment of the present invention;

[0044] Figure 6This is a schematic diagram illustrating the reference offset curve in a slice plane according to an embodiment of the present invention;

[0045] Figure 7 This is a schematic diagram of a local additive manufacturing path in a slice plane according to an embodiment of the present invention;

[0046] Figure 8 This is a schematic diagram of the global additive manufacturing path after connection according to an embodiment of the present invention.

[0047] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0048] It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0049] 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 the present invention.

[0050] like Figure 1 As 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.

[0051] 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.

[0052] like Figure 1As 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 surface additive manufacturing path planning program based on array planar slices.

[0053] 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 the memory 1005 in the electronic device of the present invention can be disposed in the electronic device, and the electronic device calls the surface additive manufacturing path planning program based on array planar slices stored in the memory 1005 through the processor 1001, and executes the surface additive manufacturing path planning method based on array planar slices provided in the embodiment of the present invention.

[0054] This invention provides a method for path planning in surface additive manufacturing based on arrayed planar slices, referring to... Figure 2 , Figure 2 This is a flowchart illustrating the first embodiment of a surface additive manufacturing path planning method based on arrayed planar slices according to the present invention.

[0055] In this embodiment, the surface additive manufacturing path planning method based on array planar slices includes:

[0056] Step S10: Obtain the three-dimensional model of the part to be formed.

[0057] The embodiments of the present invention can be applied to additive manufacturing of parts with curved surfaces, especially in the scenario of additive manufacturing of automotive mold surfaces. In many cases, automotive molds have curved substrates, and in the scenario of mold repair, it is necessary to perform curved additive manufacturing on the curved substrate, the shape of which includes a cylindrical surface or a conical surface. Figure 3 A schematic diagram showing the positional relationship between the base part and the additive part after assembly, such as... Figure 3 As shown, the solid outline represents the base part, and the dashed outline represents the additive part. The base part is the part to be repaired with a curved base, and the additive part is located above the curved base of the base part and matches the shape of the curved base.

[0058] The part to be formed refers to the part ultimately obtained through additive manufacturing. A 3D model is a virtual model designed based on the shape of the part to be formed, which can be designed and displayed using 3D software. In this embodiment, a 3D model in STL (S-Tereo Lithography) format is used, denoted by Ω.

[0059] Step S20: Select a plane normal vector in the three-dimensional model, and construct multiple slicing planes based on the plane normal vector and a preset initial offset.

[0060] A plane normal vector is a vector that serves as the basis for the plane direction of a slicing plane. A slicing plane is a plane used to slice a 3D model, dividing it into 2D planes for path planning. The preset initial offset refers to the pre-set offset between slicing planes during the construction process.

[0061] The plane normal vectors selected in the 3D model can be randomly chosen. In some embodiments, the side length of the 3D model or the normal vector of a flat surface of the 3D model can also be used as the selection criterion. After determining the plane normal vectors, the orientation of the slicing planes can also be determined. By moving the slicing planes to positions that intersect with the 3D model and using a preset initial offset as the spacing, an array of slicing planes can be formed.

[0062] For example, determining the initial offset o init and plane normal vector V t slice thickness h slice and trajectory spacing d path Construct n planar arrays Plane = {plane} i The planar array, i = 1, 2, ..., n, is a set of arrays with a spacing of d. path Parallel planes.

[0063] As an example, step S20 includes:

[0064] Step S21: Select the direction of the long side in the three-dimensional model as the plane normal vector.

[0065] In this embodiment, the long side of the outline of the three-dimensional model can be determined first, and the direction of the long side can be taken as the plane normal vector. The direction of the plane normal vector can be consistent with the deposition direction in the actual forming process.

[0066] Step S22: Calculate the projection value of each vertex in the three-dimensional model onto the plane normal vector, and determine the maximum and minimum projection values ​​among the projection values.

[0067] Calculate the dot of each vertex in the 3D model i (i = 1, 2, ..., n) in direction V t The projection value on the dot, i.e. i =v i ·V t =v i .x*V t .x+v i .y*V t .y, thus finding the maximum point v max and minimum point v min , respectively corresponding to min{dot i} and max{dot i}

[0068] Step S23: Determine the number of slice planes based on the difference between the maximum projection value and the minimum projection value.

[0069] Subtracting the maximum and minimum projection values ​​yields the projection length: length = max{dot} i}-min{dot i The number of slice planes can be calculated by dividing the projected length by the plane spacing.

[0070] The residual value δ = length - n * d after arranging the slice planes according to the plane spacing can be further calculated. path If the residual value δ < 0.6*d path Then n = n-1. Finally, let o init =(δ+d) path ) / 2, adjust the offset.

[0071] Step S24: Arrange the slice planes in parallel with the preset initial offset as the spacing.

[0072] If the offset is adjusted, the adjusted offset is used as the spacing, and the slice planes are arranged in parallel to obtain a planar array. Any slice plane can be represented as a set of spatial points p, plane. i ={(p-(v)} min +(i*d path +o init )*V t )·V t =0}.

[0073] Step S30: Determine the reference offset curve in the slice plane.

[0074] The reference offset curve can be regarded as the shape basis of each additive path in surface additive manufacturing. By offsetting the reference offset curve in the slicing plane, the additive path in the slicing plane can be obtained. In the scenario of this embodiment, the part to be formed has a shape similar to the curved substrate. Therefore, there is a curved surface in the three-dimensional model. This curved surface is regarded as a surface obtained by rotating the curve around a certain rotation axis or translating it in space. Then, the curve can be used as the reference offset curve, and the reference offset curve intersects with the slicing plane.

[0075] As an example, step S30 includes:

[0076] Step S31: Construct a reference surface in the three-dimensional model.

[0077] By finding the intersection of the planar array Plane and the 3D model Ω, the intersecting contour line C = {c i , i = 1, 2, ..., n}, each contour line c i Located in the corresponding slice plane i Above. On the three-dimensional model Ω, select a reference surface Surf = {t}. j The reference surface consists of a set of triangular facets t j constitute.

[0078] The reference surface can be constructed by interacting with a triangular mesh model. First, control vertices on the mesh are selected, and the shortest path algorithm is used to find the other vertices along the shortest path between two vertices, thus constructing the boundary surrounding the reference surface. Next, a triangle within the reference surface is selected, and a seed search algorithm is used to search towards the boundary to determine all triangles that make up the reference surface.

[0079] Step S32: Intersect the reference surface and the slice plane to obtain the reference offset curve.

[0080] By intersecting the planar array Plane with the reference surface Surf, the reference offset curve on each slice plane can be obtained. After obtaining the reference offset curve, it can be converted into a two-dimensional plane for additive path planning, simplifying the algorithm process.

[0081] Step S40: Using a preset slice layer thickness as the offset interval, the reference offset curve is offset in the slice plane to obtain the local additive path in each slice plane.

[0082] The preset slice layer thickness refers to the pre-set thickness of the slice plane. The local additive path refers to the additive path within each slice plane. Compared to the control parameters in the actual deposition process, the spacing between slice planes in this embodiment is actually the trajectory spacing, while the in-plane trajectory offset spacing is the slice layer thickness. Therefore, using the preset slice layer thickness as the offset spacing, the reference offset curve is offset within the slice plane. If the reference offset curve is too short and does not intersect the slice plane, both ends of the reference offset curve are extended to intersect the slice plane. If the reference offset curve is too long, the portion within the slice plane is taken to obtain the local additive path.

[0083] Step S50: Starting from the bottom of the three-dimensional model, connect the local additive paths to form a global additive reciprocating path.

[0084] The general process of surface additive manufacturing adopts a bottom-to-top forming sequence. However, in this embodiment, the direction of the slice plane is not horizontal. Therefore, instead of forming the slice plane layer by layer, the local additive manufacturing paths located at similar horizontal positions in each slice plane are connected to form a global additive reciprocating path, and then the bottom-to-top forming process is carried out.

[0085] As an example, step S50 includes:

[0086] Step S51: Taking the local additive path located at the bottom of the three-dimensional model as the target local additive path, starting from the first layer of the slicing plane, connect each target local additive path in a serpentine manner to form the first layer of additive reciprocating path.

[0087] The target local additive manufacturing path includes multiple trajectory points, and the storage order of these trajectory points can serve as the deposition order during the forming process. The storage order of the first target local additive manufacturing path can be clockwise or counterclockwise. After determining the storage order of the first target local additive manufacturing path, the storage order of the second target local additive manufacturing path is the opposite of the first, and the storage order of the third target local additive manufacturing path is also the opposite of the second. For example, if the first target local additive manufacturing path is clockwise, then the second target local additive manufacturing path is counterclockwise, and the third target local additive manufacturing path is clockwise, and so on, connected in a serpentine pattern. After the local additive manufacturing paths at the bottom of all slice planes are connected, the first layer of additive reciprocating path is formed.

[0088] Step S52: Update the target local additive path to the next local additive path of the target local additive path, and execute the step of connecting each target local additive path in a serpentine manner starting from the first layer of the slice plane until the global additive reciprocating path is formed.

[0089] After the first local additive manufacturing path in the first slice plane is connected, the second local additive manufacturing path adjacent to the first local additive manufacturing path is used as the target local additive manufacturing path. The connection process of the first local additive manufacturing path is repeated to form the second layer of additive reciprocating paths. After each layer of additive reciprocating paths is connected, a global additive reciprocating path is formed. Using a deposition modeling additive manufacturing process, the deposition head can perform deposition modeling according to the global additive reciprocating path and the path sequence therein to manufacture the part to be formed.

[0090] The global additive reciprocating path can also be constructed using path indexing. The construction process includes:

[0091] Step a, initial path index k = 1, search direction dir = 1, trajectory segment index s = 1, plane index i = 1, current path Path collection

[0092] Step b, when PolyV i The s-th segment of the k-th path If it does not exist, Store the path into Path, and let Proceed to step d.

[0093] Step c, when If it exists: If dir=1, then Store the points sequentially into path, and set dir = 0; if dir = 0, store the points in path in reverse order, and set dir = 1. Proceed to the next step.

[0094] In step d, if i < n, let i = i + 1 and return to step b.

[0095] Step e, let i = 1. If Store the path into Path, and let If s < N s If s = s + 1, return to step b; otherwise, proceed to the next step.

[0096] Step f, if k == M k If the condition is met, then all trajectories have been processed and the algorithm ends; otherwise, let k = k + 1, s = 1, return to step b, and process the next layer of trajectories.

[0097] In this embodiment, a three-dimensional model of the part to be formed is first obtained. A plane normal vector is selected in the three-dimensional model, and multiple slicing planes are constructed based on the plane normal vector and a preset initial offset. The direction of the slicing plane is determined by the plane normal vector in the three-dimensional model, rather than directly using a horizontal slicing plane. This reduces the number of slicing planes for three-dimensional models where the vertical dimension is greater than the horizontal dimension. A reference offset curve is determined in the slicing plane, which can serve as the shape reference for the additive path. Using a preset slice layer thickness as the offset interval, the reference offset curve is offset in the slicing plane to obtain local additive paths in each slicing plane. Starting from the bottom of the three-dimensional model, the local additive paths are connected to form a global additive reciprocating path. The deposition head performs deposition forming from bottom to top according to the global additive reciprocating path, manufacturing a part with a curved surface. This embodiment of the invention transforms the curved surface slicing and path planning problem into a planar problem through the above steps, simplifying the algorithm complexity, improving computational efficiency, and reducing the number of slice layers compared to horizontal planar slicing forming, thus improving forming efficiency.

[0098] Furthermore, in a second embodiment of the surface additive path planning method based on arrayed planar slices of the present invention, the method includes:

[0099] Step S41: Convert the reference offset curve to the two-dimensional plane where the slice plane is located.

[0100] The determination of the reference offset curve is related to the 3D model and is performed in 3D space. The subsequent path planning process can be converted to a 2D plane, where the contour line C in 3D space and the reference offset curve C are compared. 0 Converted to the corresponding two-dimensional contour line C on the slice plane z and the two-dimensional reference offset curve C z0 The contour vertices can be stored counterclockwise, and then the vertex order and curve offset reference direction of the reference offset curve can be calculated.

[0101] As an example, step S41 includes:

[0102] Step S411: Taking the starting point of the reference offset curve as the origin of the coordinate system, the direction of the contour line segment where the starting point is located as the direction of the first coordinate axis, and determining the direction of the second coordinate axis based on the direction of the first coordinate axis, a local two-dimensional coordinate system is established.

[0103] Let p0 be the origin of the local two-dimensional coordinate system, and let the direction of the contour line segment containing the origin be the x-axis of the coordinate system. x = (p1-p0) / |p1-p0|. Therefore, the y-axis of the coordinate system is the cross product of the plane normal vector and the x-axis, v y =(v t ×v x ) / |v t ×v x |. Determine a local two-dimensional coordinate system with the starting point of the reference offset curve in the slice plane as the reference.

[0104] Step S412: Transform each curve point in the reference offset curve into the local two-dimensional coordinate system.

[0105] For any curve point p in the reference offset curve i (x i y i , z i ), calculate its dot product X with the two coordinate axes. i2 =(p i -p0)·v x y i2 =(p i -p0)·v y This three-dimensional point can be converted into a two-dimensional representation p in the local coordinate system. i2 (Xi2 y i2 The problem is solved using a two-dimensional algorithm.

[0106] Step S42: Calculate the curve offset reference direction of the reference offset curve.

[0107] The curve offset reference direction refers to the offset direction of the reference offset curve in the slice plane. By offsetting the reference offset curve according to the curve offset reference direction, a local additive manufacturing path can be obtained. Multiple curve points can be selected in the reference offset curve as reference points for calculating the curve offset reference direction. After calculating the position of the offset curve points based on the offset distance, the offset position is fitted with the initial position to determine the curve offset reference direction.

[0108] As an example, step S42 includes:

[0109] Step S421: Calculate the minimum bounding box of the reference offset curve, and take the long side direction of the minimum bounding box as the main direction of the reference offset curve.

[0110] Calculate the minimum bounding box of the reference offset curve, with the center point p of the bounding box. c The main direction of the offset curve is v, with the long side as the reference. long The curve points from the starting point of the baseline offset curve to its ending point.

[0111] Step S422: Determine the curve offset reference direction based on the main direction.

[0112] Determine the distance p to the contour line c The farthest point p far Calculate vector v = p far -p c With v long The cross product value between them is cz = v long .x*v. y -v long . y *vx. If cz < 0, then reverse the vertices of the baseline offset curve. (The last part, "v," appears to be a typo and can be left as is.) long Rotate 90° counterclockwise to obtain the curve offset reference direction v offset .

[0113] Step S43: Offset the reference direction along the curve, with a preset slice layer thickness as the interval, and offset the reference offset curve to obtain each of the local additive paths.

[0114] The reference offset curve C can be calculated first using polynomial or cubic spline interpolation. z0 The fitted curve F={f i , i = 1, 2, ..., n}, and extend both ends of the reference offset curve by ls =l e =1.0e9, take a larger value to ensure that both ends of the subsequent reference offset curve intersect with the contour.

[0115] In plane i Above, with a slice layer thickness h slice Distance along v offset Continuous offset curve f i The k-th offset curve f i k The offset distance is dist = k * h slice Calculate f i k With two-dimensional contours intersection As a fill path. Calculation stops when the offset curve no longer intersects the contour, plane. i The set of trajectories is PolyV i Perform this operation on all planes to obtain all local additive paths: Poly = {PolyV} i , i = 1, 2, ..., n}.

[0116] Due to the concavity and convexity of the contour, the reference offset curve may form several intersecting lines with the contour line. The number of these intersecting lines is indefinite and can be distinguished by the superscript 's', indicating that they belong to discontinuous portions of the same offset curve. The maximum number of offsets of the trajectory curve in all planes is denoted as M. k The maximum number of segments is denoted as M. s .

[0117] In this embodiment, the reference offset direction is used as the direction basis, and the reference offset curve is offset in the slice plane to obtain the local additive path. The path is planned in the two-dimensional plane, which simplifies the planning process and enables a fast response in surface repair additive manufacturing.

[0118] Furthermore, in a third embodiment of the surface additive path planning method based on arrayed planar slices of the present invention, the method includes:

[0119] Step A10: Select any point in the local additive path as a trajectory point, and form the outer angle of the trajectory point by combining two adjacent points of the trajectory point and the trajectory point.

[0120] For local additive manufacturing paths Any trajectory point p in the local additive manufacturing path i2 Its two adjacent points are (p) i2-1 p i2+1 The exterior angle formed by these two angles can be represented as ∠p. i2-1 Pi2 P i2+1 .

[0121] Step A20: Use the angle bisector of the exterior angle as the surface normal vector of the trajectory point.

[0122] In a two-dimensional plane, p i The surface normal vector v i2 Let v be the angle bisector of the exterior angle. The surface normal vector of the trajectory point can be determined based on the offset direction. If the dot product v i2 ·v offset <0, v can be i2 In reverse, ensure that the surface normal vector points to the outside of the reference surface.

[0123] Step A30: Represent the surface normal vector in three-dimensional space as the attitude parameter of the deposition head during the surface additive manufacturing process.

[0124] Attitude parameters refer to parameters related to the attitude that the deposition head should achieve during the deposition process. For any two-dimensional point p i2 In a three-dimensional coordinate system, p i =p0+v x *P i2 .x+v y *p i2 .y, the corresponding two-dimensional vector v i2 Transform into v i =p0+v x *v i2 .x+v y *v i2 The above process can be used to transform the surface normal vector into its representation in three-dimensional space. The direction of the surface normal vector is the position direction of the deposition head.

[0125] In this embodiment, a conformal additive trajectory along the surface of the three-dimensional model is constructed, and a surface normal vector is provided at each trajectory point, thereby ensuring that the deposition head is perpendicular to the surface at all times, thus improving the forming accuracy.

[0126] Furthermore, in the fourth embodiment of the surface additive manufacturing path planning method based on array planar slices of the present invention, Figure 4 This is a schematic diagram showing the positional relationship between the basic component and the additive component before assembly. Figure 4 In the model, the base part Ω1 to be repaired requires an additive part Ω2 based on surface S1 to form the final part. The direction represented by edge AB is chosen as the plane normal vector of the array slicing plane, and all vertices of the 3D model are projected onto the unit vector. Above, the two vertices with maximum and minimum values ​​in this direction are P. C and P DThe projection length of the line connecting the two points onto the vector is |CD|.

[0127] Based on general laser cladding processes, the slice layer thickness h can be specified. slice =0.5~1.0mm, track spacing d path =1.0~2.0mm. Figure 5 This is a schematic diagram illustrating the positional relationship between the slicing plane and the 3D model. Figure 5 In this context, the slice planes forming the array intersect with the model and the reference plane.

[0128] In this embodiment of the invention, the spacing between the slice planes is actually the trajectory spacing, while the trajectory offset spacing within the plane is the slice layer thickness. Therefore, d path along Directional array plane, number of If the residual value is too large, then n = n-1, and finally set the initial offset distance. The plane equation is expressed as After the slice plane intersects with the 3D model, a contour line is obtained for each.

[0129] Then, the intersection lines of each slice plane and the base surface S1 can be calculated as the reference offset curves. Using plane1, its contour c1, and the reference offset curves... For the object of study, the same applies to other planar methods. Figure 6 A schematic diagram showing the reference offset curve in the slice plane, as shown below. Figure 6 As shown, vertex v1 on c1 is taken as the origin of the local coordinate system, and the direction of edge v1v2 is taken as the x-axis. The y-axis is calculated using the cross product. After determining the local coordinate system, coordinate transformation is performed on the vertices. Taking vertex v3 as an example, the projection lengths of line segment |v1v3| on the two local coordinate axes are v1v2v ... 3x and v 3y Therefore, its two-dimensional coordinates are (v 3x v 3y ).

[0130] After completing the 2D model, path planning is performed. Figure 7 This is a schematic diagram of a local additive manufacturing path in the slice plane, such as... Figure 7 As shown, the reference offset curve A s Extend both ends to a maximum value, then according to the slice layer thickness h slice An offset curve intersects the contour, and the curve inside the contour serves as the forming trajectory. Furthermore, each vertex is represented by its angle bisector as a two-dimensional normal vector. After completing the planar path planning, the two-dimensional points and vectors are transformed into a three-dimensional coordinate space using the method described above.

[0131] at last, Figure 8This is a schematic diagram of the global additive manufacturing path after connection, such as... Figure 8 As shown, starting from plane1, the first trajectory path1 is selected, then the first trajectory of plane2 is selected and stored in reverse order, followed by the first trajectory of plane3 and stored sequentially, and so on, traversing all planes to obtain the global shaping trajectory for the first layer. Then, starting from plane1 again, the planes are traversed, and the second trajectory of each plane is selected to construct the global shaping trajectory for the second layer. In the fifth layer, each trajectory line is divided into two segments. First, the first segment of the fifth trajectory on each plane is connected sequentially. Construct the first global trajectory path 5_1 Then, construct the second global trajectory path. 5_2 This process is repeated until all trajectories are planned.

[0132] This invention also provides a medium, which is a computer-readable storage medium storing a surface additive manufacturing path planning program based on array planar slices. When executed by a processor, the surface additive manufacturing path planning program based on array planar slices implements the steps of the surface additive manufacturing path planning method based on array planar slices described above. Specific implementation methods of the storage medium in this invention are detailed in the above embodiments of the surface additive manufacturing path planning method based on array planar slices, and will not be repeated here.

[0133] 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.

[0134] The sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0135] 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 the present invention, 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 the present invention.

[0136] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A path planning method for surface additive manufacturing based on arrayed planar slices, characterized in that, The surface additive manufacturing path planning method based on arrayed planar slices includes the following steps: Obtain a 3D model of the part to be formed; The direction of the longer side in the three-dimensional model is selected as the plane normal vector; Calculate the projection value of each vertex in the three-dimensional model onto the plane normal vector, and determine the maximum and minimum projection values ​​among the projection values; The number of slice planes is determined based on the difference between the maximum projection value and the minimum projection value; Each slice plane is arranged in parallel with a preset initial offset as the spacing. Construct a reference surface in the three-dimensional model; The reference surface and the slice plane intersect to obtain the reference offset curve; Using a preset slice layer thickness as the offset interval, the reference offset curve is offset in the slice plane to obtain the local additive path in each slice plane; Taking the local additive path located at the bottom of the three-dimensional model as the target local additive path, starting from the first layer of the slicing plane, the target local additive paths are connected in a serpentine manner to form the first layer of additive reciprocating path; The target local additive path is updated to the next local additive path of the target local additive path, and the step of connecting each target local additive path in a serpentine manner starting from the first layer slice plane is executed until a global additive reciprocating path is formed.

2. The surface additive manufacturing path planning method based on arrayed planar slices as described in claim 1, characterized in that, The step of offsetting the reference offset curve in the slice plane with a preset slice layer thickness as the offset interval to obtain the local additive path in each slice plane includes: Transform the reference offset curve into the two-dimensional plane containing the slice plane; Calculate the curve offset reference direction of the reference offset curve; Offset the reference direction along the curve, with a preset slice layer thickness as the interval, and offset the reference offset curve to obtain each of the local additive paths.

3. The surface additive manufacturing path planning method based on arrayed planar slices as described in claim 2, characterized in that, The step of converting the reference offset curve to the two-dimensional plane containing the slice plane includes: Using the starting point of the reference offset curve as the origin of the coordinate system, the direction of the contour line segment where the starting point is located as the direction of the first coordinate axis, and the direction of the second coordinate axis is determined based on the direction of the first coordinate axis to establish a local two-dimensional coordinate system; Each curve point in the reference offset curve is transformed and represented in the local two-dimensional coordinate system.

4. The surface additive manufacturing path planning method based on arrayed planar slices as described in claim 2, characterized in that, The step of calculating the curve offset reference direction of the reference offset curve includes: Calculate the minimum bounding box of the reference offset curve, and take the long side direction of the minimum bounding box as the main direction of the reference offset curve; The curve offset reference direction is determined based on the main direction.

5. The surface additive manufacturing path planning method based on arrayed planar slices as described in any one of claims 1 to 4, characterized in that, After the step of offsetting the reference offset curve in the slice plane with a preset slice layer thickness as the offset interval to obtain the local additive path in each slice plane, the method further includes: Select any point in the local additive manufacturing path as a trajectory point, and form the outer angle of the trajectory point by combining two adjacent points of the trajectory point and the trajectory point itself. The angle bisector of the exterior angle is taken as the surface normal vector of the trajectory point; The surface normal vector is represented in three-dimensional space to serve as the attitude parameter of the deposition head during surface additive manufacturing.

6. A device, characterized in that, The device is an electronic device, which includes: a memory, a processor, and a surface additive manufacturing path planning program based on array planar slices stored in the memory and executable on the processor. The surface additive manufacturing path planning program based on array planar slices is configured to implement the steps of the surface additive manufacturing path planning method based on array planar slices as described in any one of claims 1 to 5.

7. A medium, characterized in that, The medium is a computer-readable storage medium, on which a surface additive manufacturing path planning program based on array planar slices is stored. When the surface additive manufacturing path planning program based on array planar slices is executed by a processor, it implements the steps of the surface additive manufacturing path planning method based on array planar slices as described in any one of claims 1 to 5.

Images