A subtractive process planning method, device, equipment and storage medium

Abstract

The application discloses a subtractive process planning method, device and equipment and a storage medium. The method comprises the following steps: acquiring contour information of each layer of a structure to be subtracted; acquiring a topological relationship between all contours contained in each layer; and identifying a corresponding relationship between contours of different layers to perform contour matching search. The contour matching search comprises finding two or more contours between different layers to establish a connection, so that the connection conforms to a structural feature of an STL model. The method is simple to operate, requires a small number of parameters input by a user, and can reduce the operation difficulty of the user. Meanwhile, NC code generation is rapid and accurate. In addition, the method is easy to integrate with a system, is used for rapidly and accurately generating subtractive process code of composite additive and subtractive machining, and controls accurate execution of a subtractive process.

Description

Technical Field

[0001] This invention relates to the field of additive and subtractive manufacturing technology, and in particular to a method, apparatus, equipment and storage medium for subtractive manufacturing process planning of composite additive and subtractive manufacturing systems. Background Technology

[0002] Additive-subtractive composite machine tools are machine tools that combine 3D printing technology. These machine tools can achieve integrated manufacturing and play a key role in the aerospace and military industries. In composite additive-subtractive systems, synchronous powder feeding laser forming technology is used to form metal structures, while subtractive techniques such as milling and grinding are used to improve the dimensional and surface accuracy of the formed parts.

[0003] During the process of increasing and decreasing material, it is necessary to continuously perform NC planning for the subtractive machining process (STEP-NC is a new CNC interface standard proposed by Europe and the United States to replace ISO 6983 (ISO1 4649). The STEP-NC data model and its impact on the CNC system are analyzed. Based on the basic idea of ​​STEP-NC, the process planning in CNC machining is divided into offline planning, online planning and real-time planning).

[0004] The existing methods for performing subtractive manufacturing processes are as follows:

[0005] 1. Import the solid model into the CAM software;

[0006] 2. Cut out corresponding sliced ​​solid models based on the machined parts of the workpiece;

[0007] 3. Define CAM parameters and generate NC code for the sliced ​​solid model;

[0008] 4. Use specialized software to convert the CAM's NC code into the NC code file required by the device;

[0009] 5. Transfer the device NC file to the device for execution using a specified protocol, such as FTP.

[0010] In existing technologies, the use of CAM software for subtractive material planning is not only cumbersome and time-consuming, but also prone to errors and not integrated with the system, so it urgently needs improvement. Summary of the Invention

[0011] In view of the above problems, the present invention provides a subtractive manufacturing process planning method, apparatus, equipment and storage medium for overcoming the above problems or at least partially solving the above problems.

[0012] This invention provides the following solution:

[0013] A subtractive manufacturing process planning method, comprising:

[0014] Obtain the contour information of each layer of the structural component to be subtracted;

[0015] Obtain the topological relationships between all contours contained in each layer;

[0016] Identify the correspondence between contours in different layers and perform contour matching search. The contour matching search includes finding two or more contours between different layers and establishing a connection so that the connection conforms to the structural features of the STL model.

[0017] Analyze each contour feature and perform two contour segment / point matching searches;

[0018] The derived steps are processed by a target step processing strategy. The target step processing strategy includes taking the contour of the bottom of the step as the source contour and the upper and lower contours of the new cutting layer as two reference contours. When calculating the tool path, the tool position of each reference is calculated separately, and the tool position with the highest safety is selected as the result.

[0019] Analyze the features of the contour and the reference contour, find the inflection points of each contour, and perform matching analysis. If no match can be found, draw a perpendicular bisector from the contour vertex to find the intersection point. If there is no intersection point, find the nearest point and use the direction of the line connecting the intersection point or the nearest point to the vertex as the direction of the cutting edge tangent vector. If a match can be found, divide the contour and the reference contour into multiple corresponding segments. At the inflection point, use the inflection point as the basis for the direction of the cutting edge tangent vector. For the remaining points, find the intersection point of the perpendicular bisector of the contour vertex and the reference contour or the nearest point in each corresponding segment as the basis for the direction of the cutting edge tangent vector. Based on the cutting edge tangent vector and the bottom tangent point, offset the tool radius radially outward from the solid. Then, based on the tool structure features, obtain the tool center position and axial vector.

[0020] Based on the tool center position and the axial vector, and according to the characteristics of the NC device, the corresponding NC code is output;

[0021] Establish an FTP protocol to enable direct NC code transfer with the device.

[0022] Preferably, the contour information is obtained from any one of the following: STL model file slices, CLI slice files, or existing additive manufacturing process files. The contour information includes polygonal information of arcs represented by multiple line segments according to the target precision.

[0023] Preferably: the topological relationships between all contours contained in each layer are obtained after optimizing the contour information;

[0024] The optimization includes obtaining the contour points contained in the contour information and removing contour points whose adjacent contour points are smaller than the target spacing and whose contour deviation is smaller than the accuracy threshold.

[0025] Preferably, the principles of contour matching search include the principle of identical contour nesting relationship and the principle of closest contour centroid distance.

[0026] Preferably: the principle of identical contour nesting relationship includes that a contour is represented by a level in the relationship network; contour matching of different layers must be at the same level; the principle of closest contour centroid distance includes that the two contours are matched if their geometric centers are closest; if there is a certain twist angle between two layers, one layer is first rotated around the specified center by the specified angle, and then matched by the principle of closest contour centroid distance.

[0027] Preferably: the analysis of each contour feature involves two contour segment / point matching searches; including:

[0028] Analyze each contour feature: if the direction is not as expected, reverse its order to obtain the inflection point;

[0029] Determine whether the inflection point is a concave point, and whether there are concave points in the region after the inflection point;

[0030] If the number of inflection points in a contour is 0, a match cannot be made, and a match failure is returned.

[0031] If the number of inflection points is not equal, then match according to the shortest distance and return the matching results;

[0032] If all inflection point attributes are the same, then match based on the shortest distance and return the matching results;

[0033] Match based on attribute features; if a match is found, return the matching result.

[0034] Matches are performed based on the shortest distance, and the matching results are returned.

[0035] Preferably, the target step processing strategy further includes, for structures with a nearly straight longitudinal section, merging the derived steps with the upper layer and cutting them together; for structures with a concave longitudinal section, scraping the derived steps layer by layer.

[0036] A subtractive manufacturing process planning apparatus, the apparatus comprising:

[0037] The contour information acquisition unit is used to acquire the contour information of each layer of the structural component to be reduced in material.

[0038] Layer contour topology analysis unit, used to obtain the topological relationships between all contours contained in each layer;

[0039] A contour matching search unit for different layers is used to identify the correspondence between contours in different layers and perform contour matching search. The contour matching search includes finding two or more contours in different layers to establish a connection, so that the connection conforms to the structural features of the STL model.

[0040] Two contour segment / point matching search units are used to analyze each contour feature and perform two contour segment / point matching searches.

[0041] The derived step processing unit is used to process the derived steps through the target step processing strategy. The target step processing strategy includes taking the contour of the bottom of the step as the source contour and the upper and lower contours of the new cutting layer as two reference contours. When calculating the tool path, the tool position of each reference is calculated separately, and the tool position with the highest safety is selected as the result.

[0042] The tool position and attitude calculation unit is used to analyze the features of the contour and the reference contour, find the inflection points of each contour, and perform matching analysis. If a match cannot be found, a perpendicular bisector is drawn from the contour vertex to find the intersection point. If there is no intersection point, the nearest point is obtained, and the direction of the line connecting the intersection point or the nearest point to the vertex is used as the direction of the tangent vector. If a match can be found, the contour and the reference contour are divided into multiple corresponding segments. At the inflection point, the inflection point is used as the basis for the direction of the tangent vector. For the remaining points, the intersection point of the perpendicular bisector of the contour vertex and the reference contour or the nearest point is found in each corresponding segment as the basis for the direction of the tangent vector. Based on the tangent vector and the bottom tangent point, the tool radius is offset radially outward from the solid. Then, based on the tool structural features, the tool center position and axial vector are obtained.

[0043] The NC code output unit is used to output the corresponding NC code based on the characteristics of the NC device according to the tool center position and the axial vector.

[0044] The NC code transmission unit is used to establish an FTP protocol to enable direct NC code transmission with the device.

[0045] A subtractive manufacturing process planning device, the device comprising a processor and a memory:

[0046] The memory is used to store program code and transmit the program code to the processor;

[0047] The processor is used to execute the steps of the above-described subtractive process planning method according to the instructions in the program code.

[0048] A computer-readable storage medium for storing program code for performing the steps of the above-described subtractive process planning method.

[0049] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0050] This application provides a subtractive manufacturing process planning method, apparatus, equipment, and storage medium. It is simple to operate, requires few user input parameters, and reduces the difficulty of user operation. Simultaneously, NC code generation is rapid and accurate. Furthermore, this method is easily integrated with systems to quickly and accurately generate subtractive manufacturing process codes for composite additive and subtractive machining, ensuring accurate execution of subtractive processes.

[0051] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0053] Figure 1 This is a flowchart of a subtractive manufacturing process planning method provided in an embodiment of the present invention;

[0054] Figure 2 This is a flowchart illustrating one implementation of the method provided in this embodiment of the invention;

[0055] Figure 3 This is a schematic diagram of a subtractive manufacturing process planning device provided in an embodiment of the present invention;

[0056] Figure 4 This is a structural schematic diagram of a subtractive manufacturing process planning device provided in an embodiment of the present invention. Detailed Implementation

[0057] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0058] See Figure 1 This invention provides a subtractive manufacturing process planning method, such as... Figure 1 As shown, the method may include:

[0059] S101: Obtain the contour information of each layer of the subtractive structural component; specifically, the contour information can be obtained from STL model file slices, CLI slice files, or existing additive manufacturing process files, and the contour information includes polygonal information of arcs represented by multiple line segments according to the target precision setting.

[0060] S102: Obtain the topological relationships between all contours contained in each layer; specifically, after optimizing the contour information, obtain the topological relationships between all contours contained in each layer.

[0061] The optimization includes obtaining the contour points contained in the contour information and removing contour points whose adjacent contour points are smaller than the target spacing and whose contour deviation is smaller than the accuracy threshold.

[0062] S103: Identify the correspondence between contours in different layers and perform contour matching search. The contour matching search includes finding two or more contours in different layers to establish a connection, such that the connection conforms to the structural features of the STL model. Specifically, the principles of contour matching search include the principle of identical contour nesting relationship and the principle of closest contour centroid distance. The principle of identical contour nesting relationship includes that a contour is represented by a level in the relationship network; contours in different layers must be at the same level. The principle of closest contour centroid distance includes that if the geometric center of the contour is closest, the two contours are considered to be matched. If there is a certain twist angle between two layers, one layer is first rotated around the specified center by the specified angle, and then matched according to the principle of closest contour centroid distance.

[0063] S104: Analyze each contour feature and perform two contour segment / point matching searches; specifically, this includes:

[0064] Analyze each contour feature: if the direction is not as expected, reverse its order to obtain the inflection point;

[0065] Determine whether the inflection point is a concave point, and whether there are concave points in the region after the inflection point;

[0066] If the number of inflection points in a contour is 0, a match cannot be made, and a match failure is returned.

[0067] If the number of inflection points is not equal, then match according to the shortest distance and return the matching results;

[0068] If all inflection point attributes are the same, then match based on the shortest distance and return the matching results;

[0069] Match based on attribute features; if a match is found, return the matching result.

[0070] Matches are performed based on the shortest distance, and the matching results are returned.

[0071] S105: The derived steps are processed using a target step processing strategy. The target step processing strategy includes using the contour of the bottom of the step as the source contour and the upper and lower contours of the new cutting layer as two reference contours. When calculating the tool path, the tool position of each reference is calculated separately, and the tool position with the highest safety is selected as the result. Specifically, the target step processing strategy also includes that for structures with a nearly straight longitudinal section, the derived steps can be cut together with the upper layer; while for structures with a concave longitudinal section, the derived steps can be processed by scraping layer by layer.

[0072] S106: Analyze the features of the contour and the reference contour, find the inflection points of each contour, and perform matching analysis; if they cannot be matched, draw a perpendicular bisector from the contour vertex to find the intersection point; if there is no intersection point, obtain the nearest point, and use the direction of the line connecting the intersection point or the nearest point to the vertex as the direction of the cutting edge tangent vector; if they can be matched, divide the contour and the reference contour into multiple corresponding segments, and use the inflection point as the basis for the direction of the cutting edge tangent vector at the inflection point. For the remaining points, find the intersection point or the nearest point of the perpendicular bisector of the contour vertex and the reference contour in each corresponding segment as the basis for the direction of the cutting edge tangent vector; based on the cutting edge tangent vector and the bottom tangent point, offset the tool radius radially outward from the solid, and then obtain the tool center position and axial vector based on the tool structure features;

[0073] S107: Based on the tool center position and the axial vector, output the corresponding NC code according to the characteristics of the NC device;

[0074] S108: Establish FTP protocol to enable direct NC code transmission with the device.

[0075] The method provided in this application embodiment can be integrated into a system to quickly and accurately generate subtractive process codes for composite additive and subtractive manufacturing, and control the accurate execution of subtractive manufacturing.

[0076] like Figure 2 As shown, the method provided in this application embodiment is implemented as follows:

[0077] Contour acquisition

[0078] Obtain contour information and represent the contour as a polygon, for example, representing an arc as multiple line segments with a certain precision. Read the .stl file and obtain contour information through slicing; obtain contour information from the slice file; extract contour information from the additive manufacturing process file. Such contours may contain arcs and need to be polygonized.

[0079] Contour optimization

[0080] Contour information, especially contour information obtained from slices, may contain some points that are very close to adjacent contour points (e.g., less than 0.5 mm). Removing these points does not affect the contour fitting accuracy. Removing these points has a significant impact on subtractive planning, as it can eliminate creep and crawling effects and speed up the processing execution, while having little impact on accuracy.

[0081] Layer contour topology analysis

[0082] Analyze the topological relationships between all contours in a layer. The hierarchical relationship of each contour in the layer: A layer first contains one or more outer contours, i.e., the outer contour of layer 0. Each outer contour of layer 0 may contain 0 or more inner contours of layer 1. The inner contours of layer 1 may in turn contain the outer contours of layer 2, and so on.

[0083] Different layer contour matching search

[0084] Identifying the correspondence between contours in different layers, that is, a contour in one layer corresponds to a contour in another layer. Obtaining the tool direction first requires establishing the correspondence between contours in different layers, which means finding the contour in another layer that corresponds to the contour; this is called contour matching search.

[0085] Contour matching search involves finding two or more contours and establishing relationships that conform to the structural characteristics of the model. If one layer has a spatial transformation relationship with another layer based on rotation or translation, this transformation is corrected first. A simple principle of this matching search is the principle of contours with the same nesting relationship and the principle of the closest distance between contour centroids.

[0086] Contour nesting relationships refer to the nesting relationship between contours within the same level. A contour is represented by a level in the relationship network, with the outermost contour having a level of 0. There can be multiple sibling contours at the same level. The same principle applies to contour nesting relationships: contours from different levels must first be at the same level to match.

[0087] The principle of closest centroid distance states that two contours are considered to match if their geometric centers are closest. This principle is not absolute, but rather a relatively effective reference standard.

[0088] If there is a certain twist angle between two layers, first rotate one layer around the specified center at the specified twist angle, and then match it according to the principle of the closest distance between the centroids of the contours.

[0089] Two contour segments / points matching search

[0090] First, analyze each contour feature: if the direction is not as expected, reverse its order, obtain the inflection point, whether the inflection point is a concave point, and whether there is a concave point in the area after the inflection point.

[0091] If the number of inflection points in a contour is 0, a match cannot be made, and a match failure is returned.

[0092] If the number of inflection points is not equal, then match according to the shortest distance and return the matching results;

[0093] If all inflection point attributes are the same, then match based on the shortest distance and return the matching results;

[0094] Match based on attribute features; if a match is found, return the matching result.

[0095] Matches are performed based on the shortest distance, and the matching results are returned.

[0096] Derivative step treatment

[0097] During the process of adding and subtracting materials, the subsequent additive layer will generate steps (within a certain height range) on the surface of the previous subtractive material, and these steps need to be removed in the new subtractive material process.

[0098] Step handling strategy: Use the contour at the bottom of the step as the source contour, and the upper and lower contours of the new cutting layer as two reference contours. When calculating the tool path, calculate the tool position of each reference separately, and select the safest one as the result (to ensure that the reference contour is not overcut).

[0099] For structures with nearly straight longitudinal sections, the steps can be cut together with the upper layer; while for structures with concave longitudinal sections, the steps can be scraped layer by layer to improve forming accuracy.

[0100] Tool position and attitude calculation

[0101] Analyze the features of the contour and the reference contour, find the inflection points of each contour, and perform matching analysis. If no match can be found, draw a perpendicular bisector from the contour vertex and find the intersection point. If there is no intersection point, find the nearest point, and use the direction of the line connecting the intersection point or the nearest point to the vertex as the direction of the tangent vector. If a match can be found, divide the contour and the reference contour into multiple corresponding segments. At the inflection points, use the inflection point as the reference for the direction of the tangent vector. For other points, find the intersection point of the perpendicular bisector of the contour vertex and the reference contour or the nearest point within each corresponding segment as the reference for the direction of the tangent vector.

[0102] Based on the cutting line vector and the bottom tangent point, the tool radius is offset radially outward from the solid, and then the tool center position and axial vector are obtained based on the tool structure characteristics.

[0103] NC code output

[0104] Based on the characteristics of the NC device, output its corresponding NC code.

[0105] NC code transmission

[0106] Establish an FTP protocol to enable direct NC code transfer with the device.

[0107] In summary, the subtractive manufacturing process planning method provided in this application is simple to operate, requires few user input parameters, and reduces the operational difficulty for users. Meanwhile, NC code generation is rapid and accurate. Furthermore, this method is easily integrated with systems to quickly and accurately generate subtractive manufacturing process codes for composite additive and subtractive machining, ensuring accurate execution of subtractive processes.

[0108] See Figure 3 This application embodiment can also provide a subtractive manufacturing process planning device, such as... Figure 3 As shown, the device may include:

[0109] The contour information acquisition unit 301 is used to acquire the contour information of each layer of the structural component to be subtracted from the material;

[0110] Layer contour topology analysis unit 302 is used to obtain the topological relationships between all contours contained in each layer;

[0111] The different layer contour matching search unit 303 is used to identify the correspondence between contours between different layers and perform contour matching search. The contour matching search includes finding two or more contours between different layers to establish a connection, so that the connection conforms to the structural features of the STL model.

[0112] Two contour segment / point matching search units 304 are used to analyze each contour feature and perform two contour segment / point matching searches.

[0113] The derived step processing unit 305 is used to process the derived step through a target step processing strategy. The target step processing strategy includes taking the contour of the bottom of the step as the source contour and the upper and lower contours of the new cutting layer as two reference contours. When calculating the tool path, the tool position of each reference is calculated separately, and the tool position with the highest safety is selected as the result.

[0114] The tool position and attitude calculation unit 306 is used to analyze the features of the contour and the reference contour, find the inflection points of each contour, and perform matching analysis. If a match cannot be found, a perpendicular bisector is drawn from the contour vertex to find the intersection point. If there is no intersection point, the nearest point is obtained, and the direction of the line connecting the intersection point or the nearest point to the vertex is used as the direction of the cutting edge tangent vector. If a match can be found, the contour and the reference contour are divided into multiple corresponding segments. At the inflection point, the inflection point is used as the basis for the direction of the cutting edge tangent vector. For the remaining points, the intersection point of the perpendicular bisector of the contour vertex and the reference contour or the nearest point is found in each corresponding segment as the basis for the direction of the cutting edge tangent vector. Based on the cutting edge tangent vector and the bottom tangent point, the tool radius is offset radially outward from the solid. Then, based on the tool structural features, the tool center position and axial vector are obtained.

[0115] The NC code output unit 307 is used to output the corresponding NC code based on the characteristics of the NC device according to the tool center position and the axial vector.

[0116] The NC code transmission unit 308 is used to establish an FTP protocol to enable direct NC code transmission with the device.

[0117] This application embodiment can also provide a subtractive manufacturing process planning device, characterized in that the device includes a processor and a memory:

[0118] The memory is used to store program code and transmit the program code to the processor;

[0119] The processor is used to execute the steps of the above-described subtractive process planning method according to the instructions in the program code.

[0120] like Figure 4 As shown, the subtractive manufacturing process planning equipment provided in this application embodiment may include: a processor 10, a memory 11, a communication interface 12, and a communication bus 13. The processor 10, memory 11, and communication interface 12 all communicate with each other through the communication bus 13.

[0121] In this embodiment, the processor 10 may be a central processing unit (CPU), an application-specific integrated circuit, a digital signal processor, a field-programmable gate array, or other programmable logic devices.

[0122] The processor 10 can call programs stored in the memory 11. Specifically, the processor 10 can execute operations in the embodiments of the subtractive process planning method.

[0123] The memory 11 is used to store one or more programs. The programs may include program code, which includes computer operation instructions. In this embodiment, the memory 11 stores at least a program for implementing the following functions:

[0124] Read the STL model file of the structural component to be reduced in material, and obtain the contour information of each layer by slicing;

[0125] Obtain the topological relationships between all contours contained in each layer;

[0126] Identify the correspondence between contours in different layers and perform contour matching search. The contour matching search includes finding two or more contours between different layers and establishing a connection so that the connection conforms to the structural features of the STL model.

[0127] Analyze each contour feature and perform two contour segment / point matching searches;

[0128] The derived steps are processed by a target step processing strategy. The target step processing strategy includes taking the contour of the bottom of the step as the source contour and the upper and lower contours of the new cutting layer as two reference contours. When calculating the tool path, the tool position of each reference is calculated separately, and the tool position with the highest safety is selected as the result.

[0129] Analyze the features of the contour and the reference contour, find the inflection points of each contour, and perform matching analysis. If no match can be found, draw a perpendicular bisector from the contour vertex to find the intersection point. If there is no intersection point, find the nearest point and use the direction of the line connecting the intersection point or the nearest point to the vertex as the direction of the cutting edge tangent vector. If a match can be found, divide the contour and the reference contour into multiple corresponding segments. At the inflection point, use the inflection point as the basis for the direction of the cutting edge tangent vector. For the remaining points, find the intersection point of the perpendicular bisector of the contour vertex and the reference contour or the nearest point in each corresponding segment as the basis for the direction of the cutting edge tangent vector. Based on the cutting edge tangent vector and the bottom tangent point, offset the tool radius radially outward from the solid. Then, based on the tool structure features, obtain the tool center position and axial vector.

[0130] Based on the tool center position and the axial vector, and according to the characteristics of the NC device, the corresponding NC code is output;

[0131] Establish an FTP protocol to enable direct NC code transfer with the device.

[0132] In one possible implementation, the memory 11 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function (such as file creation or data read / write). The data storage area may store data created during use, such as initialization data.

[0133] In addition, memory 11 may include high-speed random access memory, and may also include non-volatile memory, such as at least one disk storage device or other volatile solid-state storage device.

[0134] Communication interface 12 can be an interface for the communication module, used to connect with other devices or systems.

[0135] Of course, it should be noted that, Figure 4 The structure shown does not constitute a limitation on the subtractive manufacturing process planning equipment in the embodiments of this application. In practical applications, the subtractive manufacturing process planning equipment may include more advanced technologies. Figure 4 More or fewer components as shown, or combinations of certain components.

[0136] This application embodiment may also provide a computer-readable storage medium, characterized in that the computer-readable storage medium is used to store program code, the program code being used to execute the steps of the above-described subtractive process planning method.

[0137] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus 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 apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0138] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that this application can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0139] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0140] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention are included within the scope of protection of the present invention.

Claims

1. A method for planning subtractive manufacturing processes, characterized in that, The method includes: Obtain the contour information of each layer of the structural component to be subtracted; Obtain the topological relationships between all contours contained in each layer; Identify the correspondence between contours in different layers and perform contour matching search. The contour matching search includes finding two or more contours between different layers and establishing a connection so that the connection conforms to the structural features of the STL model. Analyze each contour feature and perform two contour segment / point matching searches; The derived steps are processed by a target step processing strategy. The target step processing strategy includes taking the contour of the bottom of the step as the source contour and the upper and lower contours of the new cutting layer as two reference contours. When calculating the tool path, the tool position of each reference is calculated separately, and the tool position with the highest safety is selected as the result. Analyze the features of the contour and the reference contour, find the inflection points of each contour, and perform matching analysis. If no match can be found, draw a perpendicular bisector from the contour vertex to find the intersection point. If there is no intersection point, find the nearest point and use the direction of the line connecting the intersection point or the nearest point to the vertex as the direction of the cutting edge tangent vector. If a match can be found, divide the contour and the reference contour into multiple corresponding segments. At the inflection point, use the inflection point as the basis for the direction of the cutting edge tangent vector. For the remaining points, find the intersection point of the perpendicular bisector of the contour vertex and the reference contour or the nearest point in each corresponding segment as the basis for the direction of the cutting edge tangent vector. Based on the cutting edge tangent vector and the bottom tangent point, offset the tool radius radially outward from the solid. Then, based on the tool structure features, obtain the tool center position and axial vector. Based on the tool center position and the axial vector, and according to the characteristics of the NC device, the corresponding NC code is output; Establish an FTP protocol to enable direct NC code transfer with the device.

2. The subtractive manufacturing process planning method according to claim 1, characterized in that, The contour information is obtained from any one of the STL model slice file, CLI slice file, or existing additive manufacturing process file. The contour information includes polygonal information of the arc represented by multiple line segments according to the target precision.

3. The subtractive manufacturing process planning method according to claim 1, characterized in that, After optimizing the contour information, the topological relationships between all contours contained in each layer are obtained; The optimization includes obtaining the contour points contained in the contour information and removing contour points whose adjacent contour points are smaller than the target spacing and whose contour deviation is smaller than the accuracy threshold.

4. The subtractive manufacturing process planning method according to claim 1, characterized in that, The principles of contour matching search include the principle of identical contour nesting relationships and the principle of closest contour centroid distance; the principle of identical contour nesting relationships includes a contour being represented by a level in the relationship network; Contour matching of different layers is at the same level; the principle of closest centroid distance of contours includes that if the geometric centers of contours are closest, then the two contours are matched; if there is a certain twist angle between two layers, one layer is first rotated around the specified center by the specified angle, and then matched by the principle of closest centroid distance of contours.

5. The subtractive manufacturing process planning method according to claim 1, characterized in that, The analysis of each contour feature involves two contour segment / point matching searches, including: Analyze each contour feature: if the direction is not as expected, reverse its order to obtain the inflection point; Determine whether the inflection point is a concave point, and whether there are concave points in the region after the inflection point; If the number of inflection points is not equal, then match according to the shortest distance and return the matching results; If all inflection point attributes are the same, then match based on the shortest distance and return the matching results; Match based on attribute features; if a match is found, return the matching result. Matches are performed based on the shortest distance, and the matching results are returned.

6. The subtractive manufacturing process planning method according to claim 1, characterized in that, The target step processing strategy also includes, for structures with a nearly straight longitudinal section, merging the derived steps with the upper layer and cutting them together; for structures with a concave longitudinal section, scraping the derived steps layer by layer.

7. A subtractive manufacturing process planning device, characterized in that, The device includes: The contour information acquisition unit is used to acquire the contour information of each layer of the structural component to be reduced in material. Layer contour topology analysis unit, used to obtain the topological relationships between all contours contained in each layer; A contour matching search unit for different layers is used to identify the correspondence between contours in different layers and perform contour matching search. The contour matching search includes finding two or more contours in different layers to establish a connection, so that the connection conforms to the structural features of the STL model. Two contour segment / point matching search units are used to analyze each contour feature and perform two contour segment / point matching searches. The derived step processing unit is used to process the derived steps through the target step processing strategy. The target step processing strategy includes taking the contour of the bottom of the step as the source contour and the upper and lower contours of the new cutting layer as two reference contours. When calculating the tool path, the tool position of each reference is calculated separately, and the tool position with the highest safety is selected as the result. The tool position and attitude calculation unit is used to analyze the features of the contour and the reference contour, find the inflection points of each contour, and perform matching analysis. If a match cannot be found, a perpendicular bisector is drawn from the contour vertex to find the intersection point. If there is no intersection point, the nearest point is obtained, and the direction of the line connecting the intersection point or the nearest point to the vertex is used as the direction of the tangent vector. If a match can be found, the contour and the reference contour are divided into multiple corresponding segments. At the inflection point, the inflection point is used as the basis for the direction of the tangent vector. For the remaining points, the intersection point of the perpendicular bisector of the contour vertex and the reference contour or the nearest point is found in each corresponding segment as the basis for the direction of the tangent vector. Based on the tangent vector and the bottom tangent point, the tool radius is offset radially outward from the solid. Then, based on the tool structural features, the tool center position and axial vector are obtained. The NC code output unit is used to output the corresponding NC code based on the characteristics of the NC device according to the tool center position and the axial vector. The NC code transmission unit is used to establish an FTP protocol to enable direct NC code transmission with the device.

8. A subtractive manufacturing process planning device, characterized in that, The device includes a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the steps of the subtractive process planning method according to any one of claims 1-6 according to the instructions in the program code.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium is used to store program code for performing the steps of the subtractive process planning method according to any one of claims 1-6.

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