Additive manufacturing trajectory planning method based on isotropic constraint

Abstract

The invention discloses an additive manufacturing trajectory planning method based on isotropic constraint, and relates to the technical field of additive manufacturing and intelligent path planning, and the method comprises the steps: generating a geometric mask; generating discrete layer basic data which can be used for intra-layer diagonal dominant path planning; generating in-layer path data conforming to the geometric constraint of the part and with balanced heat input; obtaining an interlayer path sequence; generating a trimmed in-layer path sequence; generating path data after heat input balance; in combination with the heat input balance path data, generating feature region path data meeting a global tolerance requirement; and automatically adjusting the line spacing, the segment sequence, the starting and ending point distribution and the compensation segment until final trajectory data meeting the isotropic constraint is generated. The method solves the problems of inconsistent three-direction thermal response, residual stress concentration and forming deformation caused by lack of path level isotropic constraint and thermal input balance mechanism in the prior art, and achieves the technical effects of improving forming stability, structural precision and thermal field uniformity.

Description

Technical Field

[0001] This invention relates to the field of additive manufacturing and intelligent path planning technology, specifically to an additive manufacturing trajectory planning method based on isotropic constraints. Background Technology

[0002] Existing additive manufacturing path planning methods typically prioritize geometric infill efficiency or interlayer overlap uniformity as optimization objectives, neglecting the coupled influence of path configuration on triaxial heat input distribution and orientation evolution. As a result, in the printing of complex parts or large structures, uneven local heat accumulation and interlayer thermal-mechanical mismatch can easily occur, inducing problems such as warping, residual stress concentration, and assembly errors. Furthermore, traditional methods lack a global constraint mechanism on path topology, failing to achieve consistent control of equivalent heat input and anisotropic response during the planning stage. This makes it difficult to suppress triaxial thermal expansion differences during the forming process at its source, and thus cannot meet the requirements of high-precision, high-stability additive manufacturing for dimensional consistency and service reliability. Summary of the Invention

[0003] This application provides an additive manufacturing trajectory planning method based on isotropic constraints, which addresses the problem that existing technologies only focus on geometric path discretization and material deposition accuracy, lacking isotropic constraints on three-dimensional heat input and orientation structure, resulting in significant thermal mismatch and mechanical anisotropy in the thickness direction of the formed component.

[0004] In view of the above problems, this application provides an additive manufacturing trajectory planning method based on isotropic constraints.

[0005] This application provides an additive manufacturing trajectory planning method based on isotropic constraints, the method comprising:

[0006] Based on the 3D model of the part, the minimum bounding cube is determined and set as the reference domain. The part model is embedded into this reference domain using proportional or affine mapping to generate a geometric mask for subsequent layer segmentation and feature identification. Layer thickness and line spacing are set according to material properties and process parameters, and a layered sequence is constructed within the reference domain to generate discrete layer-based basic data that can be used for intra-layer diagonal dominant path planning. Based on the geometric mask and layered sequence, equidistant paths are generated in each layer along the diagonal direction of the reference domain space, and the part boundary is trimmed. A final diagonal fill is performed along the outer contour to generate intra-layer path data that conforms to the part's geometric constraints and has balanced thermal input. Using an alternating inter-layer direction strategy, the intra-layer path data is grouped and arranged in rows to obtain an inter-layer path sequence. Based on the inter-layer path sequence, start-end point decorrelation and time balancing are performed on each layer path to generate a balanced intra-layer path sequence. Using the balanced intra-layer path sequence, the equivalent heat input in the x, y, and z directions is statistically analyzed within multiple time windows. When the z-axis deviation exceeds a preset threshold, a short-range compensation segment is inserted or the layer pair order is adjusted to generate path data after heat input balance. Combining the heat input balance path data, the characteristic regions of hole edges, sharp corners, and rib positions are subjected to uniformization processing. The uniformization processing includes generating an envelope tool path along the nearest diagonal direction and performing equidistant trimming, as well as inserting short vector completion segments when significant three-dimensional offsets are introduced by local geometry, to generate characteristic region path data that meets global tolerance requirements. Using the generated characteristic region path data, a trajectory file is output and a statistical report on the three-dimensional cumulative projection, equivalent heat input, and seam distribution is generated. When the deviation of any statistical window exceeds the preset tolerance, the line spacing, segment order, start and end point distribution, and compensation segments are automatically adjusted until the final trajectory data that meets the isotropic constraints is generated.

[0007] One or more technical solutions provided in this application have at least the following technical effects or advantages:

[0008] This application determines the minimum bounding cube based on the 3D model of the part and sets it as the reference domain. The part model is embedded into this reference domain using proportional or affine mapping to generate a geometric mask for subsequent layer segmentation and feature identification. Layer thickness and line spacing are set based on material properties and process parameters, and a layered sequence is constructed within the reference domain to generate discrete layer-based basic data that can be used for intra-layer diagonal dominant path planning. Based on the geometric mask and layered sequence, equidistant paths are generated in each layer along the diagonal direction of the reference domain space, and the part boundary is trimmed. A final diagonal fill is performed along the outer contour to generate intra-layer path data that conforms to the part's geometric constraints and has balanced thermal input. A layer-by-layer direction alternation strategy is used to group the intra-layer path data into rows to obtain an inter-layer path sequence. Based on the inter-layer path sequence, start-end point decorrelation and time balancing are performed on each layer path to generate a balanced intra-layer path sequence. Using the balanced intra-layer path sequence, the equivalent heat input in the x, y, and z directions is statistically analyzed within multiple time windows. When the z-axis deviation exceeds a preset threshold, a short-range compensation segment is inserted or the layer pair order is adjusted to generate path data after heat input balance. Combining the heat input balance path data, the characteristic regions of hole edges, sharp corners, and rib positions are subjected to uniformization processing. The uniformization processing includes generating an envelope tool path along the nearest diagonal direction and performing equidistant trimming, as well as inserting short vector completion segments when significant three-dimensional offsets are introduced by local geometry, to generate characteristic region path data that meets global tolerance requirements. Using the generated characteristic region path data, a trajectory file is output and a statistical report on the three-dimensional cumulative projection, equivalent heat input, and seam distribution is generated. When the deviation of any statistical window exceeds the preset tolerance, the line spacing, segment order, start and end point distribution, and compensation segments are automatically adjusted until the final trajectory data that meets the isotropic constraints is generated. By introducing alternating path directions, time balancing, and heat input balance control mechanisms within and between layers, the equivalent heat input along the x, y, and z directions is statistically consistent, significantly reducing warping and residual stress caused by thermal-mechanical imbalance. Employing "layer pair alternation" and "thickness direction isotropic constraint" strategies, the layer pair sequence and compensation segment distribution are dynamically adjusted to effectively stabilize the average heat input in the thickness direction, achieving high-dimensional accuracy in interlayer construction. For local geometric features such as hole edges, sharp corners, and rib locations, envelope tooling and equidistant trimming are performed, and short vector completion segments are automatically inserted when three-dimensional offsets occur, ensuring consistency between the feature area and the main path within statistical tolerances. Statistical reports on three-dimensional cumulative projection, equivalent heat input, and seam distribution are generated simultaneously with the output trajectory file. When any statistical window exceeds the limit, the line spacing, segment sequence, and compensation segments are automatically adjusted, forming a closed-loop optimization process.This invention addresses the technical problems of existing technologies lacking triaxial heat input constraints, interlayer path statistical balancing mechanisms, and characteristic region consistency processing, which lead to uneven heat accumulation, residual stress concentration, and component warping and deformation during the forming process. By constructing an intralayer / interlayer path planning model under isotropic constraints, combined with heat input statistical balancing and characteristic region consistency correction mechanisms, the invention achieves the technical effects of improving the consistency of triaxial thermal response during the forming process, reducing residual stress and deformation, and improving component dimensional stability and forming accuracy. Attached Figure Description

[0009] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0010] Figure 1 This is a schematic flowchart of an additive manufacturing trajectory planning method based on isotropic constraints, provided as an embodiment of this application. Detailed Implementation

[0011] This application provides an additive manufacturing trajectory planning method based on isotropic constraints to address the technical problems in existing technologies that lack triaxial heat input constraints, interlayer path statistical balancing mechanisms, and feature region consistency processing, leading to uneven heat accumulation, residual stress concentration, and component warping deformation during the forming process. By constructing an intralayer / interlayer path planning model under isotropic constraints, combined with heat input statistical balancing and feature region consistency correction mechanisms, the method achieves the technical effects of improving the consistency of triaxial thermal response during the forming process, reducing residual stress and deformation, and improving component dimensional stability and forming accuracy.

[0012] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0013] It should be noted that any variation of the terms "comprising" and "having" is intended to cover non-exclusive inclusion, for example, a process, method, system, product, or server that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or modules that are not explicitly listed or that are inherent to such processes, methods, products, or devices.

[0014] Examples, such as Figure 1As shown, this application provides an additive manufacturing trajectory planning method based on isotropic constraints, the method comprising:

[0015] S100: Determine the minimum bounding cube based on the 3D model of the part and set it as the reference domain. Embed the part model into the reference domain using proportional or affine mapping to generate a geometric mask for subsequent layer segmentation and feature identification.

[0016] Furthermore, step S100 of this application also includes:

[0017] Based on the 3D model data of the part, a minimum bounding cube is determined, and the geometric center of the cube is set as the origin of the workpiece coordinate system. This cube is defined as a reference domain. The 3D model is embedded into the reference domain using proportional or affine mapping to generate a geometric mask for subsequent layer segmentation and feature identification. Affine mapping includes scaling, translation, and rotation operations to ensure the part model maintains consistent geometric proportions within the reference domain. Based on the geometric mask and machining requirements, layer slicing is performed on the 3D model of the part to obtain a layered model with corresponding layer thickness and number of layers. The layer slicing process includes slicing the outer contour region and the inner cavity region of the model separately to ensure the continuity of the generated path and the uniformity of the filling. According to the layer thickness parameters, material properties, and machining strategy of the layered model, a corresponding machining trajectory segment is generated for each layer. The trajectory segment includes a G-code instruction sequence to describe the spatial path and motion parameters of the tool or nozzle. During trajectory segment generation, the in-layer path type is further set according to the machining strategy, including equidistant filling, contour following, or spiral scanning paths. Control parameters for speed, acceleration, nozzle opening and closing, and interlayer cooling delay are integrated into the G-code instructions.

[0018] Specifically, based on the 3D model data of the part to be additively manufactured, its smallest bounding cube is first determined, and the geometric center of this cube is set as the origin of the workpiece coordinate system. This cube is denoted as the cube reference domain. Through proportional or affine mapping, part voxels or meshes are embedded into the reference domain, thereby generating a geometric mask. Affine mapping includes scaling, translation, and rotation operations to maintain the consistent geometric proportions of the part model within the reference domain. The geometric mask is used for subsequent layer segmentation, path trimming, and feature identification, while also providing a unified spatial reference for statistical verification. This process enables the spatial standardization mapping of the part model, allowing subsequent in-layer path generation, feature region processing, and heat input statistics to be performed in a unified coordinate system, which is beneficial for improving path planning accuracy and the consistency of additively manufactured components. For example, when generating 3D printing trajectories, layer segmentation and diagonal dominant path planning can be directly performed based on this reference domain, ensuring the comparability and traceability of statistical analysis of heat input and seam distribution in each layer. Based on the geometric mask and part processing requirements, layer slicing is performed on the 3D model of the part to obtain a layered model with corresponding layer thickness and number of layers. Layer slicing involves slicing the outer contour region and the inner cavity region of the model separately to ensure the continuity of the generated path and the uniformity of filling. Based on the layer thickness parameters, material properties, and processing strategy of the layered model, a corresponding processing trajectory segment is generated for each layer. The trajectory segment includes a G-code instruction sequence used to describe the movement path of the tool or nozzle in space and related motion parameters. During trajectory segment generation, the type of path within the layer is further set according to the processing strategy, including equidistant filling, contour following, or spiral scanning paths. Control parameters such as speed, acceleration, nozzle opening and closing, and interlayer cooling delay are integrated into the G-code instructions. Through this process, the continuity and uniform filling of each layer's path can be achieved, ensuring a reasonable distribution of heat input during additive manufacturing, thereby reducing uneven heat accumulation between layers and improving the forming accuracy and dimensional stability of the component. For example, when printing complex internal cavity structures, the contour region prioritizes following the outer contour for path planning, while the inner cavity region uses equidistant or spiral filling paths to balance structural support and heat input balance.

[0019] S200: By combining material properties and process parameters to set layer thickness and line spacing, a layered sequence is constructed within the reference domain to generate discrete layer basic data that can be used for intra-layer diagonal dominant path planning.

[0020] Furthermore, step S200 of this application also includes:

[0021] Based on the thermal properties of the part material and the process window parameters of the selected additive manufacturing process, the appropriate layer thickness h and line spacing p are determined. The thermal properties include thermal conductivity, specific heat capacity, and coefficient of thermal expansion. The process window parameters include energy density, scanning speed, forming power, and interlayer cooling time. Within a preset reference domain, a layer sequence is constructed along the Z-axis with a step size of layer thickness h, and the position of each layer is defined as z = k × h, where k is the layer number. The layer sequence is spatially intersected with the part geometric mask to extract the effective cross-sectional contour and its feature markers of each layer, generating discrete layer basic data within the layer. This discrete layer basic data is used for subsequent diagonal dominant path planning and thermal input consistency control.

[0022] Specifically, by combining the material properties and additive manufacturing process parameters, a suitable layer thickness *h* and line spacing *p* are determined. The material properties include thermal conductivity, specific heat capacity, and coefficient of thermal expansion. The additive manufacturing process parameters include energy density, scanning speed, forming power, and interlayer cooling time. Based on the layer thickness *h*, a layered sequence is constructed along the Z-axis within a preset reference domain, and the position of each layer is defined as *z = k × h*, where *k* is the layer number. This layered sequence can be used to discretize each layer, providing a basis for subsequent diagonal dominant path planning within each layer. The layered sequence is spatially intersected with the part's geometric mask to extract the effective cross-sectional contour and feature markers of each layer, generating basic data for discrete layers within the layer. This basic data for discrete layers is used not only for path generation but also for thermal input consistency control, ensuring that the generated path spatially matches the part's geometry and balances the thermal input rhythm. This process ensures that the path density and thermal input rhythm are adapted to the target geometry and forming stability requirements. For example, in high thermal conductivity materials or thin-walled structural parts, by reasonably setting the layer thickness and line spacing, it is possible to reduce local heat accumulation and residual stress while ensuring printing continuity, thereby improving the dimensional accuracy and structural reliability of the forming.

[0023] S300. Based on the geometric mask and layer sequence, generate equidistant paths in each layer according to the diagonal direction of the reference domain space and trim the part boundary. After finishing around the outer contour, perform diagonal filling to generate in-layer path data that conforms to the geometric constraints of the part and has balanced thermal input.

[0024] Furthermore, step S300 of this application also includes:

[0025] Based on the obtained geometric mask and layer sequence, the projection results of the diagonal direction of the reference domain space are extracted for each layer to determine two sets of dominant intra-layer direction vectors that are 90° apart. Equidistant line columns are generated in the layer according to the dominant intra-layer direction vectors and the preset line spacing, and boundary clipping is performed according to the geometric mask to obtain a preliminary path set that conforms to the shape of the part. In the preliminary path set, a ring of edge-reducing path is generated along the outer contour direction of the part to balance the heat input of the boundary area. Then, diagonal filling is performed according to the dominant intra-layer direction to complete the internal path of the layer and form complete intra-layer path data.

[0026] Specifically, based on the obtained geometric mask and layer sequence, the projection results of the diagonal direction of the reference domain space are extracted for each layer to determine two sets of dominant intra-layer direction vectors at 90° to each other. According to the dominant intra-layer direction vectors and the preset line spacing, equidistant line arrays are generated within the layer, and the path boundaries are trimmed using the geometric mask to obtain a preliminary path set conforming to the part's shape. In this preliminary path set, a ring of edge-reducing paths is generated along the outer contour of the part to balance the heat input distribution in the boundary region. Subsequently, diagonal filling is performed according to the dominant intra-layer direction to complete the internal paths of the layer, forming complete intra-layer path data. This intra-layer path data not only satisfies the geometric constraints of the part but also achieves balanced intra-layer heat input through the dominant direction and edge-reducing strategy, thereby reducing the difference in thermal gradient between the boundary and internal regions, improving forming quality and structural stability. Through this process, local heat input balance can be achieved in high aspect ratio or complex contour parts through diagonal dominant paths and boundary edge-reducing strategies, effectively suppressing local warping and thermal stress concentration within layers. For example, in thin-walled parts or areas with dense holes, the in-layer paths generated using this method can ensure printing continuity and uniform filling, while providing a basis for subsequent interlayer thermal input balance.

[0027] S400. Using an inter-layer direction alternation strategy, the intra-layer path data is grouped and arranged in rows to obtain an inter-layer path sequence.

[0028] Furthermore, step S400 of this application also includes:

[0029] Based on the obtained path data within each layer, two sets of dominant direction vectors within the layer, each at 90° to the other, are determined according to the diagonal direction of the reference domain space. An alternating strategy of two layers per pair is adopted, assigning the path of layer k to the first diagonal direction and the path of layer k+1 to the second diagonal direction, with this assignment repeated for adjacent layers. The path data of two consecutive layers are grouped to generate an inter-layer path sequence. The cumulative projection length and corresponding execution time of the paths of two consecutive layers along the x and y directions are statistically analyzed to ensure that the difference between the cumulative projection length and execution time of the two layers in the x and y directions does not exceed a preset tolerance, thereby stabilizing the average heat input in the thickness direction. The inter-layer path sequence is output for subsequent start-endpoint decorrelation and time balancing processing.

[0030] Specifically, based on the obtained path data within each layer, the path direction of each layer is analyzed using the spatial diagonal direction of the reference domain as the reference direction to determine two sets of dominant direction vectors within the layer that are 90° apart in the plane. These dominant direction vectors characterize the overall orientation of the path within that layer. A strategy of alternating directions between layers is adopted, with two consecutive layers forming a pair. The path within the k-th layer is uniformly assigned to the first set of dominant direction vectors, and the path within the (k+1)-th layer is uniformly assigned to the second set of dominant direction vectors. This process is repeated for subsequent adjacent layers to avoid the continuous superposition of path orientations in the same direction between adjacent layers. After completing the inter-layer direction assignment, the path data of two consecutive layers are grouped according to the layer pair relationship to form corresponding inter-layer path sequences. For each inter-layer path sequence, the projected lengths of all path segments in the two layers along the x and y directions in the workpiece coordinate system are accumulated and statistically analyzed, and the corresponding path execution time is simultaneously calculated. Based on the statistical results of the cumulative projection length and execution time, the differences in path distribution in the x and y directions between the k-th layer and the (k+1)-th layer are determined. This ensures that the differences in cumulative projection length and execution time between two consecutive layers in the x and y directions are controlled within a preset tolerance range, thereby statistically stabilizing the average heat input distribution in the thickness direction. Finally, the interlayer path sequence, after alternating interlayer directions, grouping, and directional statistical verification, is output. This interlayer path sequence serves as input data for subsequent start-end point decorrelation and time balancing steps, further reducing directional heat accumulation and interlayer heat input fluctuations. For example, in multi-layer thin-walled parts or complex hole areas, this strategy can effectively adjust interlayer heat input, making the overall forming process more stable.

[0031] S500. Based on the inter-layer path sequence, perform start-end point decorrelation and time balancing on each layer path to generate a balanced intra-layer path sequence.

[0032] Furthermore, step S500 of this application also includes:

[0033] Based on the inter-layer path sequence, the start and end points of each layer path are decorated and time-balanced, including: finite-domain jittering and misalignment of the start and end points within each layer; and the execution of round-trip or equivalent reverse strategies for line segments to ensure that the difference between the cumulative projection length along x and y and the execution time per unit time does not exceed the preset tolerance, thereby generating a balanced intra-layer path sequence.

[0034] Specifically, the generated inter-layer path sequence undergoes start-end point decorrelation and time balancing processing for each layer path to optimize the intra-layer heat input distribution and suppress directional heat accumulation. This includes the following operations: within each layer path, finite-domain jittering and misalignment are applied to the start and end points to prevent adjacent paths or adjacent layer seams from stacking in the same direction, reducing the risk of local heat accumulation and warping; a zig-zag strategy or an equivalent reverse motion strategy is applied to each path segment to ensure that the difference between the cumulative projected length and execution time along the two main x and y directions per unit time does not exceed a preset tolerance, thereby achieving time balance of path movement and reducing heat input bias in the thickness direction; through the above processing, a balanced intra-layer path sequence is generated, which can be used for subsequent thickness direction heat input balancing control and can also directly provide basic path data for feature region consistency processing. This process, through start-end point jittering and time balancing strategies, makes the heat input along the x and y directions of the additive component more uniform during continuous layer construction, significantly reducing local residual stress concentration caused by seam overlap or unidirectional stacking, thereby improving forming accuracy and component dimensional stability. For example, this strategy can effectively improve local warping and thermal deformation problems in the printing of thin-walled structures or porous parts.

[0035] S600: Using the balanced intra-layer path sequence, the equivalent heat input in the x, y, and z directions is statistically analyzed in the multi-layer time window. When the z-direction deviation exceeds the preset threshold, a short-range compensation segment is inserted or the layer pair order is adjusted to generate path data after heat input balance.

[0036] Furthermore, step S600 of this application also includes:

[0037] S601: Using the balanced intra-layer path sequence, perform time window statistics on multiple layers and calculate the equivalent heat input and path projection in the x, y, and z directions. The multiple layers include single layers, layer pairs, and sliding multi-layer time windows. S602: Determine whether the equivalent heat input in the z direction exceeds the preset tolerance. If it does, insert short-range compensation segments at the diagonal ends or adjust the layer pair order to generate path data after the heat input balance is within the preset tolerance range for the equivalent heat input difference in the x, y, and z directions.

[0038] Furthermore, step S601 of this application also includes:

[0039] S601-1, Utilizing the balanced intra-layer path sequence Time window statistics were performed on the multi-layer structure, and the equivalent heat input Q in the x, y, and z directions was calculated. x Q y Q z and path projection L x ,L y ,L z The multilayer includes single-layer, layer-to-layer, and sliding multilayer time windows;

[0040] S601-2, For each path segment The projection of the i-th path segment in the x, y, and z directions, i.e., the projection length, is given by the formula:

[0041]

[0042] Among them, L d L is the cumulative projected length along direction d within a certain time window. i,d is the geometric projection length of the i-th path segment in direction d, and n is the total number of path segments in the current statistical object;

[0043] S601-3, The equivalent heat input in direction d for the i-th time window is calculated using the following formula:

[0044]

[0045] in, N represents the equivalent heat input in direction d for the i-th time window. i E represents the number of path segments within the i-th time window. j For the unit heat input of path segment j, L d,j Let v be the projection length of path segment j in direction d. j Let Δt be the scanning speed of path segment j. j f is the deposition time of path segment j. d (v j ,Δt j () is a weighting function used to adjust the contribution of speed and time to heat input;

[0046] S601-4. Statistical analysis is performed on the path projection and equivalent heat input within the sliding multi-layer time window [k,k+m] to determine the heat input deviation in the z-direction or other directions.

[0047] Specifically, based on the balanced intra-layer path sequence generated in step S500, the heat input distribution of the multi-layer paths in the thickness direction is statistically analyzed and corrected to reduce the impact of thermal deviation in the z-direction on the component forming quality. The specific operations include: using the balanced intra-layer path sequence, performing time window statistics on multiple layers, including single-layer, layer-pair, and sliding multi-layer time windows. These multi-layer components, including single-layer, layer-pair, and sliding multi-layer time windows, are used to statistically analyze and evaluate the heat input distribution during path execution at different time scales. A single layer characterizes the uniformity of heat input within the layer, a layer pair depicts the superposition relationship of heat input between adjacent layers, and the sliding multi-layer time window reflects the overall trend of heat input variation during the cumulative manufacturing process of multiple layers, thereby achieving coordinated identification and control of high-frequency, mid-frequency, and low-frequency thermal imbalance problems. Calculate the equivalent heat input and path projection in the x, y, and z directions; determine if the equivalent heat input in the z direction exceeds the preset tolerance. If it does, balance the equivalent heat input in the x, y, and z directions in a statistical sense by inserting short-range compensation segments at the diagonal ends or fine-tuning the layer pair order; generate an in-layer path sequence after heat input balance to stabilize the average heat input in the thickness direction, thereby reducing local heat accumulation, warping, and residual stress concentration; utilize the balanced in-layer path sequence. Time window statistics were performed on the multi-layer structure, and the equivalent heat input Q in the x, y, and z directions was calculated. x Q y Q z and path projection L x ,L y ,L z The multi-layer structure includes single-layer, layer-to-layer, and sliding multi-layer time windows; for each path segment The projection length of the i-th path segment in the x, y, and z directions is a fundamental quantity for calculating the triaxial heat input and isotropic constraints. The formula is: Among them, L d L is the cumulative projected length along direction d within a certain time window. i,d S601-3 represents the geometric projection length of the i-th path segment in direction d; S601-3 represents the equivalent heat input of the i-th time window in direction d, calculated using the following formula: Where i is the time window number, and j is the path segment number within the time window. N represents the equivalent heat input in direction d for the i-th time window. i E represents the number of path segments within the i-th time window, dynamically determined by the time window type and span, and is used to characterize the number of path segments actually participating in heat input statistics within the current time window. j For the unit heat input of path segment j, L d,jLet v be the projection length of path segment j in direction d. j Let Δt be the scanning speed of path segment j. j f is the deposition time of path segment j. d (v j ,Δt j The weighting function is used to adjust the contribution of velocity and time to heat input. The path projection and equivalent heat input within the sliding multi-layer time window [k, k+m] are statistically analyzed to determine heat input deviations in the z-direction or other directions. `k` represents the starting layer number (layer index) of the sliding multi-layer time window. The k-th layer is used as the starting layer of the time window, and it, along with the subsequent `m` consecutive layers, constitutes a sliding multi-layer time window. `m` is the number of consecutive layers selected after the k-th layer, used to determine the layer span of the sliding multi-layer time window. Within this time window, the length and deposition state information of each path segment in the x, y, and z directions are acquired, and the path projection in each direction is calculated cumulatively. Simultaneously, combining the unit heat input of the path segment, scanning velocity, and deposition time, the corresponding equivalent heat input in the x, y, and z directions is calculated, thereby obtaining the heat distribution during the multi-layer material deposition process. As the manufacturing process progresses, the statistical window is slid along the layer sequence direction, and the above statistical process is repeated for the next set of consecutive layers, ensuring that the heat input assessment has temporal continuity and spatial correlation. Based on statistical results, the system determines whether the equivalent heat input in the z-direction and other directions deviates from the preset tolerance threshold. This includes whether the heat input is consistently higher or lower than the x and y directions within consecutive multi-layer structures, or whether directional heat input imbalance is caused by path repetition, layer overlap, or concentrated start and end points. When the system determines that the heat input deviation in the z-direction or other directions exceeds the tolerance range, a heat input compensation strategy is triggered. The compensation strategy includes: first, inserting short-range compensation segments at the diagonal end of the current layer or in areas with insufficient local heat, adjusting the heat input distribution by locally increasing or decreasing the deposition amount; second, adjusting the layer pair sequence within the sliding time window to balance the heat input in space and time, avoiding local overheating or undercooling. After completing the compensation or sequence adjustment, the system generates new path data and re-statistically calculates the equivalent heat input in the three directions to confirm that the heat input deviation in each direction has been controlled within the preset tolerance range. If there is still a deviation, the compensation operation is repeated to form a closed-loop control until heat input balance is achieved. Finally, the balanced path data is used for subsequent additive manufacturing trajectory execution and can generate a heat input statistical report to verify and record the thermal management effect of the entire additive manufacturing process. This implementation process can significantly reduce heat input fluctuations in the z-direction, improve the consistency between parts layers, dimensional accuracy and structural stability, and effectively avoid forming defects caused by local warping, deformation and uneven heat accumulation.

[0048] S700: Combining the heat input balance path data, perform uniformization processing on the feature regions of hole edges, sharp corners, and rib positions. The uniformization processing includes generating an envelope tool path along the nearest diagonal direction and performing equidistant trimming, and inserting short vector completion segments when significant three-dimensional offsets are introduced by local geometry, to generate feature region path data that meets global tolerance requirements.

[0049] Furthermore, step S700 of this application also includes:

[0050] After obtaining the path data with balanced thermal input, local feature regions such as hole edges, sharp corners, and ribs are identified in the path data. An envelope tool path is generated in each local feature region along the nearest diagonal direction, and the path segments are trimmed at equal intervals to ensure coverage of the feature region and balanced local thermal input. When the geometry of a local feature region causes a significant three-dimensional thermal input bias, a short vector completion segment is inserted into the feature region path to adjust the local path projection and generate feature region path data that meets the global tolerance requirements.

[0051] Specifically, based on the path data obtained after achieving thermal input balance, to further ensure the path continuity and thermal input balance of local feature areas such as hole edges, sharp corners, and ribs, a consistency processing method is applied to these feature areas. This includes the following steps: identifying local feature areas such as hole edges, sharp corners, and ribs in the path data; generating an envelope toolpath in each feature area along the nearest diagonal dominant direction, and trimming the path segments at preset equidistant intervals to ensure the envelope path completely covers the feature area and achieves a uniform distribution of local thermal input; automatically inserting short vector completion segments into the feature area path when the geometry of a local feature area causes a significant three-dimensional thermal input bias to adjust the local path projection and balance the three-dimensional thermal input difference; and generating feature area path data that meets global tolerance requirements for subsequent path integration and trajectory output processing. Through this feature area consistency processing, while maintaining the geometric accuracy of the part, problems such as hole edge ablation, sharp corner overheating, and rib heat accumulation can be effectively avoided, thereby improving the thermal field uniformity and overall stability during the forming of complex structures. For example, for metal parts with high-density ribs or local hole groups, this method can automatically insert compensation paths locally according to the thermal input deviation, so as to achieve simultaneous protection of thermal input self-balancing and forming accuracy in the feature area.

[0052] S800: Using the generated feature region path data, output trajectory files and generate statistical reports on three-dimensional cumulative projection, equivalent heat input, and seam distribution. When any statistical window deviation exceeds the preset tolerance, automatically adjust the line spacing, segment sequence, start and end point distribution, and compensation segment until the final trajectory data that meets the isotropic constraints is generated.

[0053] Furthermore, step S800 of this application also includes:

[0054] S801: Obtain the feature region path data after heat input balance; S802: Generate a trajectory file or directly executable trajectory segment based on the feature region path data for execution by additive manufacturing equipment; S803: During trajectory generation, statistically analyze the cumulative projection length, equivalent heat input, and seam distribution in the x, y, and z directions for each layer and sliding multi-layer time window, and generate corresponding heat maps or statistical reports; S804: Determine whether the cumulative projection, equivalent heat input, and seam distribution in the x, y, and z directions within any statistical window exceed the preset tolerance; S805: When the statistical value exceeds the preset tolerance, automatically adjust the line spacing, path segment sequence, start and end point distribution, and local compensation segments, and return to regenerate the path; S806: Repeat steps S802 to S805 until the deviation of all statistical windows is within the preset tolerance range, generating final trajectory data that satisfies isotropic constraints; S807: Output the final trajectory file and corresponding statistical report to provide a unified data foundation for additive manufacturing execution and quality control.

[0055] Specifically, after completing the characteristic region path consistency processing, this embodiment further utilizes the generated characteristic region path data to output a trajectory file and perform multi-dimensional statistical verification to ensure the balance of the final path data in terms of three-dimensional equivalent heat input and seam distribution, thereby generating final trajectory data that meets the isotropic constraints. The process involves: acquiring characteristic region path data after heat input balance; generating a trajectory file or directly executable trajectory segment based on the characteristic region path data, whereby the trajectory file includes position, attitude, and process control instructions for path execution by the additive manufacturing equipment; performing statistics on each layer and sliding multi-layer time windows during trajectory generation, calculating the cumulative projection length, equivalent heat input, and seam distribution in the x, y, and z directions, and generating corresponding heat maps or statistical reports to evaluate the energy input balance and structural consistency of the path planning; determining whether the cumulative projection, equivalent heat input, and seam distribution in the x, y, and z directions within any statistical window exceed a preset tolerance range; and automatically adjusting the line spacing, path segment sequence, start and end point distribution, and local compensation segments when the statistical value exceeds the preset tolerance, and then regenerating the path data. Repeat steps S802 to S805 until the deviations of all statistical windows are within the preset tolerance range, generating final trajectory data that meets isotropic constraints. Simultaneously with generating G-codes or trajectory segments, output layered and sliding window statistical reports, including three-dimensional cumulative projection, equivalent heat input, and seam distribution heatmaps, providing a unified data foundation for the execution and quality control of the additive manufacturing process. Through the trajectory output and statistical verification process of this workflow, multi-layered closed-loop optimization of the path planning stage can be achieved. While generating the trajectory, the system automatically monitors the three-dimensional energy input and path balance within each layer and multi-layer sliding windows. When local directional heat input deviations or seam stacking effects exceed the tolerance, it can automatically adjust the path density, segment sequence, and local compensation segment strategy until a final trajectory file that meets statistical isotropic requirements is formed. For example, when forming complex shell or ribbed structures, this embodiment can dynamically analyze the equivalent heat input in the x, y, and z directions through sliding time windows, preventing local warping, residual stress concentration, and dimensional drift caused by a single path direction or uneven energy distribution. Through the layered and sliding window verification mechanism, the verification of three-dimensional energy balance and structural consistency can be completed in the generation stage, realizing process traceability and result quantification, thereby significantly improving the stability and forming accuracy of additive manufacturing.

[0056] In this embodiment, a path partitioning strategy and initial forming parameters suitable for the target area are determined through comprehensive analysis of the part's geometric model and material thermal properties. Multi-layer time window statistics and dynamic analysis are performed on each layer path during additive manufacturing to determine the three-dimensional heat input and path projection distribution, achieving heat input balance in the thickness and spatial directions. In each printed layer or layer pair, the length and deposition state information of each path segment in the x, y, and z directions are acquired, while process parameters such as unit heat input, scanning speed, and deposition time are recorded. The corresponding three-dimensional equivalent heat input and cumulative path projection are calculated to form multi-layer path and heat input statistics, used to evaluate the local and overall heat input distribution. Subsequently, by repeating this statistical process within continuously sliding multi-layer time windows, the continuity and correlation of heat input in time and space can be analyzed, thereby identifying heat input deviations in the z-direction or other directions, including local heat input imbalances caused by path direction repetition, inter-layer path superposition, or concentration of start and end points. When the thermal input deviation exceeds the preset tolerance threshold, this application corrects the path data by inserting short-range compensation segments or adjusting the layer pair sequence, ensuring that the equivalent thermal input difference in the x, y, and z axes is controlled within a set range, thus achieving spatial balance of thermal input. It can obtain a deposition path that meets the interlayer consistency requirements while maintaining the workpiece clamping state and coordinate system, and forms path data after thermal input balance, providing a reference for subsequent additive or subtractive processing. Furthermore, by combining multi-zone temperature control data, melt temperature and pressure monitoring information, and workpiece temperature field data, the extrusion rate, feed rate, and conformal roller pressure parameters can be dynamically adjusted to obtain stable layer thickness and uniform deposition quality. It can effectively determine the thermal input distribution, deposition consistency, and possible local defect locations of parts during additive manufacturing, providing a guarantee for manufacturing fiber-reinforced composite material parts with high precision, high dimensional stability, and structural reliability.

[0057] In summary, the embodiments of this application have at least the following technical effects:

[0058] This application determines the minimum bounding cube based on the 3D model of the part and sets it as the reference domain. The part model is embedded into this reference domain using proportional or affine mapping to generate a geometric mask for subsequent layer segmentation and feature identification. Layer thickness and line spacing are set based on material properties and process parameters, and a layered sequence is constructed within the reference domain to generate discrete layer-based basic data that can be used for intra-layer diagonal dominant path planning. Based on the geometric mask and layered sequence, equidistant paths are generated in each layer along the diagonal direction of the reference domain space, and the part boundary is trimmed. A final diagonal fill is performed along the outer contour to generate intra-layer path data that conforms to the part's geometric constraints and has balanced thermal input. A layer-by-layer direction alternation strategy is used to group the intra-layer path data into rows to obtain an inter-layer path sequence. Based on the inter-layer path sequence, start-end point decorrelation and time balancing are performed on each layer path to generate a balanced intra-layer path sequence. Using the balanced intra-layer path sequence, the equivalent heat input in the x, y, and z directions is statistically analyzed within multiple time windows. When the z-axis deviation exceeds a preset threshold, a short-range compensation segment is inserted or the layer pair order is adjusted to generate path data after heat input balance. Combining the heat input balance path data, the characteristic regions of hole edges, sharp corners, and rib positions are subjected to uniformization processing. The uniformization processing includes generating an envelope tool path along the nearest diagonal direction and performing equidistant trimming, as well as inserting short vector completion segments when significant three-dimensional offsets are introduced by local geometry, to generate characteristic region path data that meets global tolerance requirements. Using the generated characteristic region path data, a trajectory file is output and a statistical report on the three-dimensional cumulative projection, equivalent heat input, and seam distribution is generated. When the deviation of any statistical window exceeds the preset tolerance, the line spacing, segment order, start and end point distribution, and compensation segments are automatically adjusted until the final trajectory data that meets the isotropic constraints is generated. By introducing alternating path directions, time balancing, and heat input balance control mechanisms within and between layers, the equivalent heat input along the x, y, and z directions is statistically consistent, significantly reducing warping and residual stress caused by thermal-mechanical imbalance. Employing "layer pair alternation" and "thickness direction isotropic constraint" strategies, the layer pair sequence and compensation segment distribution are dynamically adjusted to effectively stabilize the average heat input in the thickness direction, achieving high-dimensional accuracy in interlayer construction. For local geometric features such as hole edges, sharp corners, and rib locations, envelope tooling and equidistant trimming are performed, and short vector completion segments are automatically inserted when three-dimensional offsets occur, ensuring consistency between the feature area and the main path within statistical tolerances. Statistical reports on three-dimensional cumulative projection, equivalent heat input, and seam distribution are generated simultaneously with the output trajectory file. When any statistical window exceeds the limit, the line spacing, segment sequence, and compensation segments are automatically adjusted, forming a closed-loop optimization process. The above technical solution can a priori homogenize the triaxial equivalent heat input and constraint in the path topology layer, weaken the directional heat accumulation and joint superposition effect, thereby effectively suppressing thermal warping, residual stress concentration and assembly dimension drift.As a material and equipment-neutral upper-level planning strategy, this invention can be directly embedded into existing slicing and path generation processes and is compatible with multiple types of controllers. Simultaneously, it provides quantifiable and traceable process quality criteria through multi-window statistical verification and report output. This invention addresses the technical problems in existing technologies that lack three-dimensional thermal input constraints, inter-layer path statistical balancing mechanisms, and feature region consistency processing, leading to uneven thermal accumulation, residual stress concentration, and component warping deformation during the forming process. By constructing an intra-layer / inter-layer path planning model under isotropic constraints, combined with thermal input statistical balancing and feature region consistency correction mechanisms, it achieves the technical effects of improving the consistency of three-dimensional thermal response during the forming process, reducing residual stress and deformation, and improving component dimensional stability and forming accuracy.

[0059] It should be noted that the order of the embodiments described above is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some implementations, multitasking and parallel processing are possible or may be advantageous.

[0060] The above description is only a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0061] This specification and accompanying drawings are merely illustrative examples of this application and are intended to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Therefore, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. An additive manufacturing trajectory planning method based on isotropic constraints, characterized in that, include: S100. Based on the 3D model of the part, determine the minimum bounding cube and set it as the reference domain. Use proportional or affine mapping to embed the part model into the reference domain to generate a geometric mask for subsequent layer segmentation and feature identification. S200: By combining material properties and process parameters to set layer thickness and line spacing, a layered sequence is constructed within the reference domain to generate discrete layer basic data that can be used for intra-layer diagonal dominant path planning. S300. Based on the geometric mask and layer sequence, generate equidistant paths in each layer according to the diagonal direction of the reference domain space and trim the part boundary. After finishing around the outer contour, perform diagonal filling to generate in-layer path data that conforms to the geometric constraints of the part and has balanced thermal input. S400. Using an inter-layer direction alternation strategy, the intra-layer path data is grouped and arranged in rows to obtain an inter-layer path sequence. S500. Based on the inter-layer path sequence, perform start and end point decorrelation and time balancing on each layer path to generate a balanced intra-layer path sequence. S600: Using the balanced intra-layer path sequence, the equivalent heat input in the x, y, and z directions is statistically analyzed in the multi-layer time window. When the z-direction deviation exceeds the preset threshold, a short-range compensation segment is inserted or the layer pair order is adjusted to generate path data after heat input balance. S700, combined with the heat input balance path data, performs uniformization processing on the feature regions of hole edge, sharp corner, and rib position. The uniformization processing includes generating envelope tooling along the nearest diagonal direction and performing equidistant trimming, and inserting short vector completion segments when significant three-dimensional offset is introduced by local geometry, to generate feature region path data that meets global tolerance requirements. S800: Using the generated feature region path data, output trajectory files and generate statistical reports on three-dimensional cumulative projection, equivalent heat input, and seam distribution. When any statistical window deviation exceeds the preset tolerance, automatically adjust the line spacing, segment sequence, start and end point distribution, and compensation segment until the final trajectory data that meets the isotropic constraints is generated.

2. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 1, characterized in that, The process of determining the minimum bounding cube based on the 3D model of the part and setting it as a reference domain, then embedding the part model into the reference domain using proportional or affine mapping to generate a geometric mask includes: The minimum bounding cube is determined based on the 3D model data of the part, the geometric center of the cube is set as the origin of the workpiece coordinate system, and the cube is defined as the reference domain. The 3D model is embedded into the reference domain and a geometric mask is generated by proportional or affine mapping, which is used for subsequent layer segmentation and feature identification. Affine mapping includes scaling, translation and rotation operations to keep the geometric proportions of the part model consistent within the reference domain. Based on the geometric mask and processing requirements, the three-dimensional model of the part is subjected to layer slicing to obtain a layered model with corresponding layer thickness and number of layers. The layer slicing process includes slicing the outer contour area and the inner cavity area of ​​the model respectively to ensure the continuity of the generation path and the uniformity of filling. Based on the layer thickness parameters, material properties, and processing strategies of the layered model, a corresponding processing trajectory segment is generated for each layer; the trajectory segment includes a G-code instruction sequence, which is used to describe the spatial path and motion parameters of the tool or nozzle; In the trajectory segment generation process, the in-layer path type is further set according to the processing strategy, including equidistant filling, contour following or spiral scanning path, and the control parameters of speed, acceleration, nozzle opening and closing and interlayer cooling delay are integrated in the G-code instruction.

3. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 1, characterized in that, The process involves setting layer thickness and line spacing based on material properties and process parameters, constructing a layered sequence within a reference domain, and generating discrete layer-based data that can be used for intra-layer diagonal dominant path planning, including: Based on the thermal properties of the part material and the process window parameters of the selected additive manufacturing process, the appropriate layer thickness h and line spacing p are determined. The thermal properties include thermal conductivity, specific heat capacity, and coefficient of thermal expansion. The process window parameters include energy density, scanning speed, forming power, and interlayer cooling time. Within a preset reference domain, a layered sequence is constructed along the Z-axis with a step size of layer thickness h, and the position of each layer is defined as z = k × h, where k is the layer number; The layered sequence is spatially intersected with the part geometry mask to extract the effective cross-sectional contour and its feature markers of each layer, generating discrete layer basic data within the layer. This discrete layer basic data is used for subsequent diagonal dominant path planning and thermal input consistency control.

4. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 1, characterized in that, Based on the geometric mask and layer sequence, equidistant paths are generated in each layer along the diagonal direction of the reference domain space, and the part boundaries are trimmed. After circling the outer contour, diagonal fill is performed to generate in-layer path data that conforms to the part's geometric constraints and has balanced thermal input. This includes: Based on the obtained geometric mask and layer sequence, the projection results of the diagonal direction of the reference domain space are extracted for each layer to determine two sets of dominant intra-layer direction vectors that are 90° apart. Equidistant line arrays are generated within the layer according to the dominant direction vector within the layer and the preset line spacing, and boundary clipping is performed according to the geometric mask to obtain a preliminary set of paths that conform to the shape of the part. In the initial path set, a ring edge path is generated along the outer contour of the part to balance the heat input in the boundary area. Then, diagonal filling is performed according to the dominant direction within the layer to complete the internal path of the layer and form complete internal path data.

5. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 1, characterized in that, The method employs an inter-layer direction alternation strategy to group and arrange the intra-layer path data into rows to obtain an inter-layer path sequence, including: Based on the path data within each layer, two sets of dominant direction vectors within the layer, which are 90° apart, are determined according to the diagonal direction of the reference domain space. An alternating strategy of two layers as a pair is adopted, in which the path of the kth layer is assigned to the first diagonal direction, the path of the (k+1)th layer is assigned to the second diagonal direction, and the adjacent layer pairs are assigned in this order. Group the path data of two consecutive layers to generate an inter-layer path sequence; The cumulative projection length and corresponding execution time of two consecutive paths along the x and y directions are statistically analyzed to ensure that the difference between the cumulative projection length and execution time of the two paths in the x and y directions does not exceed the preset tolerance, thereby stabilizing the average heat input in the thickness direction. The inter-layer path sequence is output for subsequent start-end point decorrelation and time balancing processing.

6. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 1, characterized in that, Based on the inter-layer path sequence, the process of decorrelation of start and end points and time balancing is performed on each layer path to generate a balanced intra-layer path sequence, including: Finite-domain jittering and misalignment are applied to the start and end points within each layer; Apply a round-trip or equivalent reverse strategy to the line segment to ensure that the difference between the cumulative projection length along x and y per unit time and the execution time does not exceed the preset tolerance, and generate a balanced intra-layer path sequence.

7. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 1, characterized in that, The method involves using the balanced intra-layer path sequence to statistically analyze the equivalent heat input in the x, y, and z directions within a multi-layer time window. When the z-axis deviation exceeds a preset threshold, a short-range compensation segment is inserted or the layer pair order is adjusted to generate path data after heat input balance. This includes: S601. Using the balanced intra-layer path sequence, perform time window statistics on the multi-layer, and calculate the equivalent heat input and path projection in the x, y, and z directions. The multi-layer includes single-layer, layer pairs, and sliding multi-layer time windows. S602. Determine whether the equivalent heat input in the z direction exceeds the preset tolerance, and if it does, generate path data after the heat input balance is achieved by inserting short-range compensation segments at the diagonal ends or adjusting the layer pair order, so that the equivalent heat input difference in the x, y, and z directions is within the preset tolerance range.

8. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 7, characterized in that, Using the balanced intra-layer path sequence, time window statistics are performed on multiple layers, and the equivalent heat input and path projection in the x, y, and z directions are calculated. The multiple layers include single layers, layer pairs, and sliding multi-layer time windows, including: S601-1, Utilizing the balanced intra-layer path sequence Time window statistics were performed on the multi-layer structure, and the equivalent heat input Q in the x, y, and z directions was calculated. x Q y Q z and path projection L x ,L y ,L z The multi-layer structure includes single-layer, layer-to-layer, and sliding multi-layer time windows. For each path segment The components in the x, y, and z directions are statistically analyzed using the following formula: Among them, L d L is the cumulative projected length along direction d within a certain time window. i,d Let be the geometric projection length of the i-th path segment in direction d; S601-2, The equivalent heat input in direction d for the i-th time window is calculated using the following formula: in, N represents the equivalent heat input in direction d for the i-th time window. i E represents the number of path segments within the i-th time window. j For the unit heat input of path segment j, L d,j Let v be the projection length of path segment j in direction d. j Let Δt be the scanning speed of path segment j. j f is the deposition time of path segment j. d (v j ,Δt j () is a weighting function used to adjust the contribution of speed and time to heat input; S601-3. Statistical analysis is performed on the path projection and equivalent heat input within the sliding multi-layer time window [k,k+m] to determine the heat input deviation in the z-direction or other directions.

9. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 1, characterized in that, The process combines thermal input balance path data to perform uniformization processing on the feature regions of hole edges, sharp corners, and rib positions. This uniformization processing includes generating an envelope toolpath along the nearest diagonal direction and performing equidistant trimming, as well as inserting short vector completion segments when significant triaxial biases are introduced by local geometry, generating feature region path data that meets global tolerance requirements. After obtaining the path data after heat input balance, identify the local feature areas of hole edges, sharp corners, and ribs in the path data; An envelope tool is generated in each local feature region along the nearest diagonal direction, and the path segments are trimmed at equal intervals to ensure coverage of the feature region and balanced local heat input. When the geometry of a local feature region causes a significant three-dimensional thermal input bias, a short vector completion segment is inserted into the feature region path to adjust the local path projection and generate feature region path data that meets the global tolerance requirements.

10. The additive manufacturing trajectory planning method based on isotropic constraints as described in claim 1, characterized in that, The process utilizes the generated feature region path data to output a trajectory file and generate statistical reports on three-dimensional cumulative projection, equivalent heat input, and seam distribution. When any statistical window deviation exceeds the preset tolerance, the line spacing, segment sequence, start and end point distribution, and compensation segments are automatically adjusted until final trajectory data satisfying isotropic constraints is generated, including: S801. Obtain the feature region path data after thermal input balance; S802. Generate a trajectory file or a directly executable trajectory segment based on the path data of the feature region for execution by the additive manufacturing equipment; S803. During the trajectory generation process, the cumulative projection length, equivalent heat input, and seam distribution in the x, y, and z directions are statistically analyzed for each layer and sliding multi-layer time window, and corresponding heat maps or statistical reports are generated. S804. Determine whether the cumulative projection of x, y, and z axes, equivalent heat input, and seam distribution within any statistical window exceed the preset tolerance. S805. When the statistical value exceeds the preset tolerance, automatically adjust the line spacing, path segment sequence, start and end point distribution, and local compensation segment, and return to regenerate the path. S806. Repeat steps S802 to S805 until the deviation of all statistical windows is within the preset tolerance range, and generate the final trajectory data that satisfies the isotropic constraint. S807. Output the final trajectory file and corresponding statistical report to provide a unified data foundation for additive manufacturing execution and quality control.

Images