A Process Planning Method for Additive and Subtractive Manufacturing of Complex Structural Parts

Abstract

The present invention discloses a method for planning the additive and subtractive manufacturing process of complex structural parts, including: solidifying all the hollow cavities of the complex structural parts; determining the feature segmentation positions of the complex solid structural parts after solidification, determining the overall segmentation scheme, and adjusting and merging the feature segmentation positions to obtain the optimal process plan; dividing all the hollow cavities contained in the complex structural parts into two types: hollow cylinders and hollow spheres, performing feature segmentation, determining the hollow cavity segmentation scheme, and realizing the process pre-planning of the hollow cavities; obtaining the complete segmentation scheme of the complex structural parts; obtaining the optimized additive and subtractive manufacturing process plan for the complex structural parts with hollow cavities. The present invention can realize the optimized additive and subtractive manufacturing process planning of complex structural parts with hollow cavities, solve the complex process problems in the additive and subtractive manufacturing of complex hollow structural parts, and has the advantages of improving efficiency and processing quality while ensuring high-precision requirements.

Description

Technical Field

[0001] The present invention belongs to the technical field of additive and subtractive manufacturing, and particularly relates to a method for planning the additive and subtractive manufacturing process of complex structural parts. Background Art

[0002] With the continuous improvement of people's requirements for product performance, the structure of parts has become increasingly complex, the requirements for machining accuracy have been increasing day by day, and the value of parts has become increasingly high. In many important fields such as aerospace, shipbuilding, automobiles, and energy, complex structural parts have been widely used. The manufacturing processes for such parts usually require high customization, and often involve a series of problems such as long product iteration cycles and high manufacturing costs. For the machining of complex structural parts with features such as long and narrow, narrow grooves, deep cavities, or specific requirements for machining tool path patterns, if only processed according to the optimal performance design, there will often be serious tool interference problems, resulting in the inability to machine the parts. Only by appropriately changing the design can the parts be actually machined, but it is difficult to achieve the optimal performance of the parts.

[0003] Up to now, several commercial hybrid manufacturing devices have been successfully developed in the industrial community. However, there has been little progress in the research on the process planning of additive and subtractive hybrid manufacturing for complex structural parts. Because during the machining process, the tool axis direction is restricted by environmental obstacles, and the planning of the tool axis direction must avoid interference with the already formed workpiece. The problem of additive and subtractive process planning is one of the key technologies restricting the development of complex structural part hybrid manufacturing technology. The existing additive and subtractive hybrid manufacturing methods can generally be divided into two manufacturing modes: additive first and then subtractive for the whole, and alternating additive and subtractive. However, the former is only applicable to parts with relatively simple geometric structures. For parts with complex structures and high surface accuracy requirements, a multi-stage step-by-step alternating hybrid manufacturing process of material stacking first and then cutting can be adopted. Before the interference obstacles are formed, the already formed part is finely machined and cut, which not only alleviates the tool interference problem when machining complex internal cavity features, but also can ensure the accuracy requirements of the part surface. Summary of the Invention

[0004] Object of the Invention: In order to overcome the deficiencies in the prior art, the present invention provides a method for planning the additive and subtractive manufacturing process of complex structural parts, which can realize the optimal additive and subtractive manufacturing process planning of complex structural parts containing hollow cavities, solve the complex process problems in the additive and subtractive manufacturing of complex hollow structural parts, and has the advantages of improving efficiency and machining quality under the requirement of ensuring high precision.

[0005] Technical Solution: To achieve the above object, the present invention provides a method for planning the additive and subtractive manufacturing process of complex structural parts, including the following steps:

[0006] S1: Solidify all the hollow cavities contained in the given complex structural part containing hollow cavities;

[0007] S2: Locate the position of the interference and collision junction on the solidified complex solid structural part as the feature segmentation position, determine the overall segmentation plan based on the feature segmentation position, and adjust and merge the feature segmentation positions to obtain the optimal process plan;

[0008] S3: Divide all the hollow cavities contained in the given complex structural part with hollow cavities into two types: hollow cylinders and hollow spheres;

[0009] S4: Conduct separate feature segmentation on these two types of hollow cavities, namely hollow cylinders and hollow spheres, adjust and merge the feature segmentation positions, determine the hollow cavity segmentation plan, and achieve the process pre-planning of the hollow cavities;

[0010] S5: Merge the overall segmentation plan and the hollow cavity segmentation plan to obtain the complete segmentation plan of the complex structural part with hollow cavities;

[0011] S6: Based on the complete segmentation plan, adjust and merge the execution order of the additive and subtractive manufacturing process sequences of the complex structural part with hollow cavities to reduce the switching times of the additive printing head and the subtractive cutting tool, and obtain the optimized additive and subtractive manufacturing process planning plan of the complex structural part with hollow cavities.

[0012] Further, the specific content of step S1 is as follows:

[0013] Input the STL model of the complex structural part with hollow cavities in the interactive CAD / CAM system NX. If the cavity boundaries in the complex structural part with hollow cavities are relatively clear, then use the NX synchronous modeling technology. Select "Insert" in the drop-down menu of the NX "Menu" option, select the "Delete Face" function in "Synchronous Modeling", then select "Convex Table or Cavity Face" in the "Face Rule" on the status bar, and then select the hollow cavity to be solidified for deletion; if the cavity boundaries in the complex structural part with hollow cavities are not clear, add cavity dividing lines to make the cavity boundaries in the complex structural part with hollow cavities clear, and then use the NX synchronous modeling technology. Select "Insert" in the drop-down menu of the NX "Menu" option, select the "Delete Face" function in "Synchronous Modeling", then select "Convex Table or Cavity Face" in the "Face Rule" on the status bar, and then select the hollow cavity to be solidified for deletion; solidify all the hollow cavities in the complex structural part with hollow cavities efficiently and quickly to achieve the overall process planning for the solidified complex solid structural part.

[0014] Further, step S2 includes the following process:

[0015] A1: On the solidified complex solid structural part, find the position of the interference collision junction according to the interference collision situation between the additive manufacturing head and the subtractive cutting tool generated by simulation as the feature segmentation position, and divide the complex solid structural part into multiple sub-feature structures, so as to perform finish machining and subtractive cutting on the formed part before the interference obstacles in the complex solid structural part are additively formed;

[0016] A2: Sort the operation sequences of the obtained multiple sub-feature structures to determine the overall segmentation plan and adjust and merge the multiple sub-feature structures according to the feature segmentation position, so as to ensure the minimum number of segmentation times of the complex solid structural part and obtain the optimal process plan.

[0017] Further, the step A1 is specifically: evaluate the accessibility of the additive manufacturing head and the subtractive cutting tool on the solidified complex solid structural part, analyze the interference collision situation between the additive manufacturing head and the subtractive cutting tool on the solidified complex solid structural part according to the accessibility evaluation, find n interference collisions, and use the position of the interference collision junction as the feature segmentation position, and divide the complex solid structural part into f sub-feature structures, so as to perform finish machining and subtractive cutting on the formed part before the interference obstacles in the complex solid structural part are additively formed.

[0018] Further, the step A2 is specifically:

[0019] A2-1: Sort the 2f operations of the obtained f sub-feature structures in the initial order of additive and subtractive manufacturing processing to form an initial operation sequence set Pro·seq, as shown in the following formula (1):

[0020] Pro·seq = {IN1, DE 1 , IN 2 , DE 2 , …, IN m , DE m , …, IN f , DE f |m = 1, 2, …, f} (1)

[0021] In the formula, Pro·seq refers to the initial operation sequence set on the solidified complex solid structural part, IN c refers to the additive operation of the c-th sub-feature structure in the initial operation sequence on the solidified complex solid structural part, DE c refers to the subtractive operation of the c-th sub-feature structure in the initial operation sequence on the solidified complex solid structural part, m refers to the m-th sub-feature structure in the initial operation sequence on the solidified complex solid structural part, and f refers to the number of sub-feature structures obtained after the feature segmentation of the solidified complex solid structural part;

[0022] A2 - 2: After obtaining the initial process sequence set, check whether there is still an interference collision between the additive manufacturing print head and the subtractive cutting tool when performing additive and subtractive manufacturing according to this initial process sequence. If there is an interference collision between the additive manufacturing print head and the subtractive cutting tool, return to step A1 to adjust the feature segmentation position according to the existing interference collision between the additive manufacturing print head and the subtractive cutting tool until it is checked that there is no interference collision between the additive manufacturing print head and the subtractive cutting tool when performing additive and subtractive manufacturing according to this initial process sequence; if there is no interference collision between the additive manufacturing print head and the subtractive cutting tool, the overall segmentation scheme can be determined, and the f sub - feature structures are adjusted and merged according to the feature segmentation position under the current scheme to ensure the minimum number of segmentation times for the complex solid structure part and obtain the optimal process plan.

[0023] Further, the method for obtaining the optimal process plan in step A2 - 2 is as follows:

[0024] The number of times of switching the additive manufacturing print head and the subtractive cutting tool required for sorting the initial process sequence is Swithing·T, as shown in the following formula 2:

[0025] Swithing·T = 2f - 1 (2)

[0026] In the formula, Swithing·T represents the number of times of switching the additive manufacturing print head and the subtractive cutting tool required for sorting the initial process sequence, and f represents the number of sub - feature structures obtained after feature segmentation of the complex solid structure part after solidification;

[0027] Under the condition of ensuring no interference collision between the additive manufacturing print head and the subtractive cutting tool, after adjusting and merging the f sub - feature structures according to the feature segmentation position, the minimum number of segmentation times for the complex solid structure part is ensured; the 2f processes of the obtained f sub - feature structures are re - sorted into the optimal process sequence according to the adjusted and merged order of additive and subtractive manufacturing processing sequence to form the optimal process sequence set Pro·seq*, as shown in the following formula 3:

[0028]

[0029] In the formula, Pro·seq* represents the optimal process sequence set on the complex solid structure part after solidification, IN ab represents the b - th sub - feature process in the a - th additive process of the complex solid structure part after solidification, DE ab represents the b - th sub - feature process in the a - th subtractive process of the complex solid structure part after solidification, p 1 represents the number of original sub - features in the first additive process of the complex solid structure part after solidification, pi Let \(i\) denote the number of original sub - features in the \(i\) - th additive manufacturing process of the complex solid - formed structure after solidification, and \(f\) denote the number of sub - feature structures obtained after feature segmentation of the complex solid - formed structure after solidification;

[0030] The number of times of switching the additive manufacturing head and the subtractive cutting tool required for the optimal process sequence sorting is \(Swithing\cdot T^*\), as shown in the following formula (4):

[0031] \(Swithing\cdot T^* = 2i - 1\quad(4)\)

[0032] In the formula, \(Swithing\cdot T^*\) represents the number of times of switching the additive manufacturing head and the subtractive cutting tool required for the optimal process sequence sorting, \(i\) represents the number of groups of additive and subtractive processes in the optimal process sequence sorting, and \(i\lt f\);

[0033] Obtain the optimal process sequence sorting to ensure obtaining the optimal process plan.

[0034] Furthermore, the specific feature segmentation of the two hollow cavities, namely the hollow cylinder and the hollow sphere, in step S4 is as follows:

[0035] Feature segmentation of the hollow cylinder: First, perform a vertical cut along the plane where the central axis of the hollow cylinder is located as the preliminary feature segmentation. At this time, two symmetrical parts are obtained. Select the half of the hollow cylinder close to the processing platform to perform additive manufacturing first. If the length of the hollow cylinder is short or the wall thickness of the hollow cylinder is thin, and there is no obvious interference and collision when directly performing additive manufacturing on the other half of the hollow cylinder to be additively manufactured later, then no further feature segmentation is required. If the length of the hollow cylinder is long or the wall thickness of the hollow cylinder is thick, and there is an obvious interference and collision when directly performing additive manufacturing on the other half of the hollow cylinder to be additively manufactured later, then the other half of the hollow cylinder to be additively manufactured is further segmented by a horizontal cut according to the tool reach range into equal - length cylinder segments until there is no obvious interference and collision when directly performing additive manufacturing on the other half of the hollow cylinder to be additively manufactured later;

[0036] Feature segmentation of the hollow sphere: Perform segmentation along the plane parallel to the processing platform and passing through the center of the hollow sphere as the preliminary feature segmentation (if it is an ellipsoid, first perform preliminary feature segmentation through the plane passing through the major axis). At this time, two symmetrical hollow hemispheres are obtained. Select the half of the hollow hemisphere close to the processing platform to perform additive manufacturing first, and then perform feature segmentation on the other hollow hemisphere to be additively manufactured along the plane perpendicular to the hemisphere plane and passing through the central axis of the hollow hemisphere, dividing the other hollow hemisphere into two halves, which is 1 / 4 of the original hollow sphere.

[0037] Furthermore, the method for determining the hollow cavity segmentation scheme in step S4 is:

[0038] Based on the above division, due to the incomplete regularity of the actually existing hollow cavities, and then according to the interference and collision situations still existing in the additive manufacturing heads and subtractive cutting tools simulated for the two types of hollow cavities, find the position of the interference and collision junction as the further feature segmentation position, and divide each hollow cavity into h sub-feature structures, so as to perform finish machining and subtractive cutting on the formed part before the interference obstacles in each hollow cavity are additively formed, to determine the segmentation scheme for each hollow cavity.

[0039] Furthermore, the pre-planning method for the processes of the hollow cavities in step S4 is as follows:

[0040] Pre-plan the processes of the hollow cavities in the order of the initial additive and subtractive manufacturing processing sequence for the 2h processes of the h sub-feature structures of each obtained hollow cavity, and form a pre-planning sequence set Seq of the processes, as shown in the following formula (5):

[0041] Seq = {HIN i , HDE i , HIN 2 , HDE 2 , …, HIN k , HDE k , …, HIN h , HDE h |k = 1, 2,..., h} (5)

[0042] In the formula, Seq represents the pre-planning sequence set of the processes of the hollow cavities, HIN d represents the additive process of the d-th sub-feature structure in the pre-planning sequence of the processes of the hollow cavities, HDE d represents the subtractive process of the d-th sub-feature structure in the pre-planning sequence of the processes of the hollow cavities, k represents the k-th sub-feature structure in the pre-planning sequence of the processes of the hollow cavities, and h represents the number of sub-feature structures obtained after the feature segmentation of the hollow cavities;

[0043] After obtaining the set of pre-planned process sequences for the hollow cavity, check whether there are any interference and collision situations between the additive printing head and the subtractive cutting tool when performing additive and subtractive manufacturing according to this pre-planned process sequence. If there are interference and collision situations between the additive printing head and the subtractive cutting tool, then return to the previous step and adjust the feature segmentation position according to the current interference and collision situations between the additive printing head and the subtractive cutting tool until it is checked that there are no interference and collision situations between the additive printing head and the subtractive cutting tool when performing additive and subtractive manufacturing according to this initial process sequence. If there are no interference and collision situations between the additive printing head and the subtractive cutting tool, then the segmentation scheme for each hollow cavity can be determined, and the h sub-feature structures are adjusted and merged according to the feature segmentation position under the current scheme to ensure that the number of segmentations for each hollow cavity is minimized.

[0044] The number of times the additive printing head and the subtractive cutting tool need to be switched for the pre-planned process sequence sorting of the hollow cavity is Swithing·Y, as shown in the following formula (6):

[0045] Swithing·Y = 2h - 1 (6)

[0046] In the formula, Swithing·Y represents the number of times the additive printing head and the subtractive cutting tool need to be switched for the pre-planned process sequence sorting of the hollow cavity, and h represents the number of sub-feature structures obtained after the hollow cavity is segmented by feature segmentation;

[0047] Under the condition of ensuring that there are no interference and collision situations between the additive printing head and the subtractive cutting tool, after adjusting and merging the h sub-feature structures according to the feature segmentation position to ensure that the number of segmentations for each hollow cavity is minimized; the 2h processes of the obtained h sub-feature structures are re-sorted according to the adjusted and merged order of additive and subtractive manufacturing processing sequence to form the optimal process sequence set Seq* of the hollow cavity, as shown in the following formula (7):

[0048]

[0049] In the formula, Seq* represents the optimal process sequence set of the hollow cavity, HIN rs represents the s-th sub-feature process in the r-th group of additive processes in the hollow cavity, HDE rs represents the s-th sub-feature process in the r-th group of additive processes in the hollow cavity, z 1 represents the number of original sub-features in the first group of subtractive processes in the hollow cavity, z j represents the number of original sub-features in the j-th group of additive processes in the hollow cavity, and h represents the number of sub-feature structures obtained after the hollow cavity is segmented by feature segmentation;

[0050] The number of times of switching the additive printing head and the subtractive cutting tool required for the optimal process sequence sorting of the hollow cavity is Swithing·Y*, as shown in the following formula (8):

[0051] Swithing·Y* = 2j - 1 (8)

[0052] In the formula, Swithing·Y* represents the number of times of switching the additive printing head and the subtractive cutting tool required for the optimal process sequence sorting of the hollow cavity, j represents the number of groups of additive process and subtractive process in the optimal process sequence sorting of the hollow cavity, and j < h;

[0053] Obtain the optimal process sequence sorting of the hollow cavity to ensure obtaining the optimal process plan.

[0054] Further, the specific step S5 is as follows:

[0055] Restore the solid structure part that was originally a hollow cavity in the obtained overall segmentation plan to a hollow cavity, and substitute the obtained hollow cavity segmentation plan for merging, so as to divide the complex structural part containing the hollow cavity into g sub-feature structures, and perform finish machining and subtractive cutting on the formed part before the interference obstacles in the complex structural part containing the hollow cavity are additively formed, so as to determine the complete segmentation plan of the complex structural part containing the hollow cavity.

[0056] Further, the specific step S6 is as follows:

[0057] After the final segmentation plan of the complex structural part containing the hollow cavity is established, perform the complete process planning of the complex structural part containing the hollow cavity on the 2g processes of the g sub-feature structures of the complex structural part containing the hollow cavity obtained according to the initial additive and subtractive manufacturing processing sequence, and form the complete process planning sequence set FullSeq, as shown in the following formula (9):

[0058]

[0059] In the formula, FullSeq represents the complete process planning sequence set of the complex structural part containing the hollow cavity, IN c represents the additive process of the c-th sub-feature structure in the initial process sequence on the complex solid structure part after solidification, DE c represents the subtractive process of the c-th sub-feature structure in the initial process sequence on the complex solid structure part after solidification, m represents the m-th sub-feature structure in the initial process sequence on the complex solid structure part after solidification, k represents the k-th sub-feature structure in the process pre-planning sequence of the hollow cavity, f represents the number of sub-feature structures obtained after the feature segmentation of the complex solid structure part after solidification, HIN dFor the additive process of the d-th sub-feature structure in the process pre-planning sequence representing the hollow cavity, HDE d For the subtractive process of the d-th sub-feature structure in the process pre-planning sequence representing the hollow cavity, where h is the number of sub-feature structures obtained after feature segmentation of the hollow cavity;

[0060] After obtaining the complete process planning sequence set of the complex structural part with a hollow cavity, check whether there is still interference and collision between the additive printing head and the subtractive cutting tool when performing additive and subtractive processes according to this complete process planning sequence. If there is interference and collision between the additive printing head and the subtractive cutting tool, return to the previous step and adjust the feature segmentation position according to the current interference and collision situation between the additive printing head and the subtractive cutting tool until it is checked that there is no interference and collision between the additive printing head and the subtractive cutting tool when performing additive and subtractive processes according to this complete process planning sequence of the complex structural part with a hollow cavity; if there is no interference and collision between the additive printing head and the subtractive cutting tool, adjust and merge the g sub-feature structures according to the feature segmentation position in the current scheme to ensure the minimum number of segmentation times of the complex structural part with a hollow cavity, then the final segmentation scheme of the complex structural part with a hollow cavity can be determined;

[0061] The number of times of switching the additive printing head and the subtractive cutting tool required for sorting the complete process planning sequence of the complex structural part with a hollow cavity is Swithing·W, as shown in the following formula (10):

[0062] Swithing·W = 2g - 1 (10)

[0063] In the formula, Swithing·W represents the number of times of switching the additive printing head and the subtractive cutting tool required for sorting the complete process planning sequence of the complex structural part with a hollow cavity, and g is the number of sub-feature structures obtained after feature segmentation of the complex structural part with a hollow cavity;

[0064] Under the condition of ensuring no interference and collision between the additive printing head and the subtractive cutting tool, after adjusting and merging the g sub-feature structures according to the feature segmentation position, ensure the minimum number of segmentation times of the complex structural part with a hollow cavity; re-sort the 2g processes of the obtained g sub-feature structures according to the adjusted and merged order of additive and subtractive manufacturing processes to form the final optimal process sequence set FullSeq* of the complex structural part with a hollow cavity, as shown in the following formula 11:

[0065]

[0066] Wherein, FullSeq* represents the set of final optimal process sequences of complex structural parts containing hollow cavities, and ZIN tu represents the u-th sub-feature process in the t-th additive manufacturing process of complex structural parts containing hollow cavities, and ZDE tu represents the u-th sub-feature process in the t-th subtractive manufacturing process of complex structural parts containing hollow cavities, and e 1 represents the number of original sub-features in the first additive manufacturing process of complex structural parts containing hollow cavities, and e l represents the number of original sub-features in the l-th additive manufacturing process of complex structural parts containing hollow cavities, and g represents the number of sub-feature structures obtained after feature segmentation of complex structural parts containing hollow cavities;

[0067] The number of times of switching the additive printing head and the subtractive cutting tool for the final optimal process sequence sorting of complex structural parts containing hollow cavities is Swithing·W*, as shown in the following formula (12):

[0068] Swithing·W* = 2l - 1 (12)

[0069] Wherein, Swithing·W* represents the number of times of switching the additive printing head and the subtractive cutting tool required for the final optimal process sequence sorting of complex structural parts containing hollow cavities, and l represents the number of groups of additive and subtractive processes in the final optimal process sequence sorting of complex structural parts containing hollow cavities, and l < g;

[0070] Obtain the final optimal process sequence sorting of complex structural parts containing hollow cavities to obtain the final optimal process plan, and obtain the optimized additive and subtractive manufacturing process plan for complex structural parts containing hollow cavities.

[0071] The present invention provides a method for planning the additive and subtractive manufacturing process of complex structural parts. For the currently existing conservative process division method commonly used in the application field, the part is divided into slices with uniform thickness, and then the additive-subtractive process is alternately used for each slice for manufacturing, and only the case where the part body is completely solid is considered, without considering the case where there is a hollow structure in the part body.

[0072] The method of the present invention can realize the optimized additive and subtractive manufacturing process planning of complex structural parts containing hollow cavities, and has the advantages of improving efficiency and processing quality under the requirement of ensuring high precision. According to the characteristics of high requirements for precision and efficiency in additive and subtractive manufacturing, the disclosed method of the present invention is selected to plan the additive and subtractive manufacturing process of complex structural parts containing hollow cavities, reduce the number of process switches under the premise of ensuring no tool interference, save costs and time, improve the functional characteristics of parts, and improve the universality of the additive and subtractive manufacturing process planning.

[0073] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0074] 1. On the premise of ensuring no tool interference, the number of process switches is reduced, thus saving a large amount of preparation and tool change time consumed by process alternation and improving the process efficiency.

[0075] 2. Due to the reduction of process alternation, a large number of tool marks generated on the part surface are reduced, thereby improving the surface quality and enhancing the functional characteristics of the part.

[0076] 3. It can plan the additive and subtractive manufacturing processes for complex structural parts with hollow cavities, thus improving the universality of the additive and subtractive manufacturing process planning. Description of the Drawings

[0077] Figure 1 is a schematic flow diagram of the method of the present invention;

[0078] Figure 2 is a multi-directional steel joint model diagram of a complex structural part with a hollow cavity provided by an embodiment of the present invention;

[0079] Figure 3 is a diagram of a hollow cylinder in a multi-directional steel joint model of a complex structural part with a hollow cavity provided by an embodiment of the present invention;

[0080] Figure 4 is a diagram of a hollow sphere in a multi-directional steel joint model of a complex structural part with a hollow cavity provided by an embodiment of the present invention;

[0081] Figure 5 is a characteristic segmentation diagram of the hollow cavity in a multi-directional steel joint model of a complex structural part with a hollow cavity provided by an embodiment of the present invention;

[0082] Figure 6 is a final process display diagram of a multi-directional steel joint model of a complex structural part with a hollow cavity provided by an embodiment of the present invention;

[0083] Figure 7 is a time-consuming diagram for process planning of the hollow cavity of a multi-directional steel joint model of a complex structural part with a hollow cavity according to the existing method provided by an embodiment of the present invention;

[0084] Figure 8 is a time-consuming diagram for the optimal process planning of the hollow cavity of a multi-directional steel joint model of a complex structural part with a hollow cavity provided by an embodiment of the present invention. Detailed Embodiments

[0085] The present invention will be further clarified below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. After reading the present invention, those skilled in the art's various equivalent modifications of the present invention all fall within the scope defined by the appended claims of this application.

[0086] The present invention provides a method for planning the additive and subtractive manufacturing process of complex structural parts. As Figure 1 shown, it includes the following steps:

[0087] S1: Solidify all the hollow cavities contained in the given complex structural part with hollow cavities.

[0088] S2: On the solidified complex solid structural part, find the positions of the interference and collision joints according to the interference and collision situations as the feature segmentation positions, determine the overall segmentation scheme according to the feature segmentation positions, and adjust and merge the feature segmentation positions to obtain the optimal process plan.

[0089] S3: Divide all the hollow cavities contained in the given complex structural part with hollow cavities into two types: hollow cylinders and hollow spheres.

[0090] S4: Perform separate feature segmentation on these two types of hollow cavities, namely hollow cylinders and hollow spheres, adjust and merge the feature segmentation positions, determine the hollow cavity segmentation scheme, and realize the process pre-planning of the hollow cavities.

[0091] S5: Merge the overall segmentation scheme and the hollow cavity segmentation scheme to obtain the complete segmentation scheme of the complex structural part with hollow cavities.

[0092] S6: Based on the complete segmentation scheme, adjust and merge the execution order of the additive and subtractive manufacturing process sequence of the complex structural part with hollow cavities to reduce the switching times of the additive printing head and the subtractive cutting tool, and obtain the optimized additive and subtractive manufacturing process planning scheme of the complex structural part with hollow cavities.

[0093] This embodiment also provides a system for planning the additive and subtractive manufacturing process of complex structural parts. The system includes a network interface, a memory, and a processor. Among them, the network interface is used to realize the reception and transmission of signals during the process of receiving and sending information to and from other external network elements; the memory is used to store computer program instructions that can run on the processor; the processor is used to execute the steps of the above-mentioned consensus method when running the computer program instructions.

[0094] This embodiment also provides a computer storage medium, which stores a computer program. When the processor executes the computer program, the above-described method can be implemented. The computer-readable medium can be considered tangible and non-transitory. Non-limiting examples of non-transitory tangible computer-readable media include non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital tapes or hard disk drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs), etc. The computer program includes processor-executable instructions stored on at least one non-transitory tangible computer-readable medium. The computer program may also include or rely on stored data. The computer program may include a basic input / output system (BIOS) that interacts with the hardware of a dedicated computer, device drivers that interact with specific devices of a dedicated computer, one or more operating systems, user applications, background services, background applications, etc.

[0095] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0096] The present application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, and the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a dedicated computer, an embedded processor, or other programmable data processing devices to generate a machine, such that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0097] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, such that the instructions stored in the computer-readable memory generate a manufactured article including instruction means that implement the functions specified in Figure 1 one flow or multiple flows and / or blocks Figure 1The functions specified in one or more boxes.

[0098] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process. Thus, the instructions executed on the computer or other programmable device provide for implementing the steps of the functions specified in one Figure 1 one process or multiple processes and / or boxes Figure 1 step of the functions specified in one or more boxes.

[0099] Based on the above solution, in this embodiment, the above solution is applied as an example. Specifically, a multi-directional steel joint model of a complex structural member with a hollow cavity as shown in Figure 2 is used as the application object. The specific process is as follows:

[0100] Step 1: Input the STL model of the multi-directional steel joint model of the complex structural member with a hollow cavity into the interactive CAD / CAM system NX. Since the cavity boundaries in the multi-directional steel joint model of the complex structural member with a hollow cavity are relatively clear, the NX synchronous modeling technology is adopted. Select "Insert" in the drop-down menu of the NX "Menu" option, select the "Delete Face" function in "Synchronous Modeling", then select "Boss Face or Cavity Face" in the "Face Rule" on the status bar, and then select the hollow cavity to be solidified for deletion, so as to efficiently and quickly solidify all the hollow cavities in the multi-directional steel joint model of the complex structural member with a hollow cavity, so as to realize the overall process planning for the solidified complex solid structural member.

[0101] Step 2:

[0102] 2-1) Evaluate the accessibility of the additive manufacturing head and subtractive cutting tool for the solidified multi-directional steel joint model of the complex structural member. Analyze the interference and collision conditions between the additive manufacturing head and subtractive cutting tool on the solidified complex solid structural member according to the accessibility evaluation, find n interference and collision points, use the position of the interference and collision junction as the feature segmentation position, and divide the complex solid structural member into f sub-feature structures, so as to perform finish machining and subtractive cutting on the formed part before the interference obstacles in the complex solid structural member are additively formed;

[0103] 2-2) Sort the 2f processes of the obtained f sub-feature structures in the initial order of additive and subtractive manufacturing processing to form an initial process sequence set Pro·seq, as shown in the following formula (1):

[0104] Pro·seq = {IN 1 , DE 1 , IN 2 , DE 2 , …, INm , DE m , …, IN f , DE f |m = 1, 2, …, f} (1)

[0105] In the formula, Pro·seq refers to the set of initial process sequences on the solidified complex solid structural part, IN c refers to the additive process of the c-th sub-feature structure in the initial process sequence on the solidified complex solid structural part, DE c refers to the subtractive process of the c-th sub-feature structure in the initial process sequence on the solidified complex solid structural part, m refers to the m-th sub-feature structure in the initial process sequence on the solidified complex solid structural part, and f refers to the number of sub-feature structures after the feature segmentation of the solidified complex solid structural part;

[0106] After obtaining the set of initial process sequences, check whether there is still interference and collision between the additive printing head and the subtractive cutting tool when performing additive and subtractive processes according to this initial process sequence. If there is interference and collision between the additive printing head and the subtractive cutting tool, then return to step A1 to adjust the feature segmentation position according to the current interference and collision situation between the additive printing head and the subtractive cutting tool until it is checked that there is no interference and collision between the additive printing head and the subtractive cutting tool when performing additive and subtractive processes according to this initial process sequence; If there is no interference and collision between the additive printing head and the subtractive cutting tool, then the overall segmentation scheme can be determined, and the f sub-feature structures are adjusted and merged according to the feature segmentation position under the current scheme to ensure the minimum number of segmentation times of the complex solid structural part and obtain the optimal process plan.

[0107] The method for obtaining the optimal process plan is as follows:

[0108] The number of times of switching the additive printing head and the subtractive cutting tool required for sorting the initial process sequence is Swithing·T, as shown in the following formula 2:

[0109] Swithing·T = 2f - 1 (2)

[0110] In the formula, Swithing·T refers to the number of times of switching the additive printing head and the subtractive cutting tool required for sorting the initial process sequence, and f refers to the number of sub-feature structures after the feature segmentation of the solidified complex solid structural part;

[0111] On the premise of ensuring no interference and collision between the additive printing head and the subtractive cutting tool, after adjusting and merging the f sub-feature structures according to the feature segmentation positions, the number of segmentation times of the complex solid structure part is minimized; the 2f processes of the obtained f sub-feature structures are reordered according to the adjusted and merged additive and subtractive manufacturing processing sequences to form the optimal process sequence set Pro·seq*, as shown in the following formula 3:

[0112]

[0113] In the formula, Pro·seq* represents the optimal process sequence set on the complex solid structure part after solidification, IN ab represents the b-th sub-feature process in the a-th additive process of the complex solid structure part after solidification, DE ab represents the b-th sub-feature process in the a-th subtractive process of the complex solid structure part after solidification, p 1 represents the number of original sub-features in the first additive process of the complex solid structure part after solidification, p i represents the number of original sub-features in the i-th additive process of the complex solid structure part after solidification, and f is the number of sub-feature structures formed after feature segmentation of the complex solid structure part after solidification;

[0114] The number of times of switching the additive printing head and the subtractive cutting tool required for the optimal process sequence sorting is Swithing·T*, as shown in the following formula 4:

[0115] Swithing·T* = 2i - 1 (4)

[0116] In the formula, Swithing·T* represents the number of times of switching the additive printing head and the subtractive cutting tool required for the optimal process sequence sorting, and i is the number of groups of additive and subtractive processes in the optimal process sequence sorting, and i < f;

[0117] The optimal process sequence sorting is obtained to ensure the optimal process planning.

[0118] Step 3: Divide all the hollow cavities contained in the given complex structure multi-directional steel joint model with a hollow cavity into two types: hollow cylinders and hollow spheres, specifically as Figure 3 and Figure 4 shown;

[0119] Step 4: Referring to Figure 5 , perform separate feature segmentation on these two types of hollow cavities, namely hollow cylinders and hollow spheres, specifically as:

[0120] Feature segmentation of a hollow cylinder: First, the hollow cylinder is vertically cut along the plane where the central axis of the hollow cylinder is located as the preliminary feature segmentation. At this time, two symmetrical parts are obtained. Select the half of the hollow cylinder that is close to the processing platform and perform additive manufacturing first. If the length of the hollow cylinder is short or the wall thickness of the hollow cylinder is thin, there is no obvious interference and collision when directly performing additive manufacturing on the other half of the hollow cylinder for subsequent additive manufacturing, then no further feature segmentation is required; if the length of the hollow cylinder is long or the wall thickness of the hollow cylinder is thick, there is an obvious interference and collision when directly performing additive manufacturing on the other half of the hollow cylinder for subsequent additive manufacturing, then the other half of the hollow cylinder for subsequent additive manufacturing is further segmented by flat cutting according to the reach range of the tool, divided into equal-length cylinder segments until there is no obvious interference and collision when directly performing additive manufacturing on the other half of the hollow cylinder for subsequent additive manufacturing;

[0121] Feature segmentation of a hollow sphere: Cut along the plane parallel to the processing platform and passing through the center of the sphere of the hollow sphere as the preliminary feature segmentation (if it is an ellipsoid, first perform preliminary feature segmentation through the plane passing through the major axis). At this time, two symmetrical hollow hemispheres are obtained. Select the half of the hollow hemisphere that is close to the processing platform and perform additive manufacturing first, and then perform feature segmentation on the other hollow hemisphere for subsequent additive manufacturing along the plane perpendicular to the hemisphere plane and passing through the central axis of the hollow hemisphere, dividing the other hollow hemisphere into two halves, which is 1 / 4 of the original hollow sphere.

[0122] On the basis of the above division, due to the incomplete regularity of the actual existing hollow cavity, and then according to the interference and collision situation that still exists between the additive manufacturing print head and the subtractive cutting tool simulated for the two hollow cavities, find the position of the interference and collision junction as the further feature segmentation position, so as to divide each hollow cavity into h sub-feature structures, so as to perform finish machining and subtractive cutting on the formed part before the interference obstacles in each hollow cavity are additively formed, to determine the segmentation scheme for each hollow cavity.

[0123] Pre-plan the processes of each hollow cavity according to the initial additive and subtractive manufacturing processing sequence for the 2h processes of the h sub-feature structures of each obtained hollow cavity, and form a process pre-planning sequence set Seq, as shown in the following formula (5):

[0124] Seq = {HIN 1 , HDE 1 , HIW 2 , HDE 2 , …, HIN k , HDE k , …, HIN h , HDE h |k = 1, 2, …, h} (5)

[0125] In the formula, Seq represents the set of pre-planned process sequences for the hollow cavity, and HIN d is the additive process for the d-th sub-feature structure in the pre-planned process sequence for the hollow cavity, and HDE d is the subtractive process for the d-th sub-feature structure in the pre-planned process sequence for the hollow cavity. k represents the k-th sub-feature structure in the pre-planned process sequence for the hollow cavity, and h is the number of sub-feature structures after the hollow cavity is feature-segmented;

[0126] After obtaining the set of pre-planned process sequences for the hollow cavity, check whether there is still interference and collision between the additive printing head and the subtractive cutting tool when performing additive and subtractive processes according to this pre-planned process sequence. If there is interference and collision between the additive printing head and the subtractive cutting tool, then return to the previous step and adjust the feature segmentation position according to the current interference and collision situation between the additive printing head and the subtractive cutting tool until it is checked that there is no interference and collision between the additive printing head and the subtractive cutting tool when performing additive and subtractive processes according to this initial process sequence; If there is no interference and collision between the additive printing head and the subtractive cutting tool, then the segmentation scheme of each hollow cavity can be determined, and the h sub-feature structures are adjusted and merged according to the feature segmentation position in the current scheme to ensure the minimum number of segmentations for each hollow cavity;

[0127] The number of times the additive printing head and the subtractive cutting tool need to be switched for the pre-planned process sequence sorting of the hollow cavity is Swithing·Y, as shown in the following formula (6):

[0128] Swithing·Y = 2h - 1 (6)

[0129] In the formula, Swithing·Y represents the number of times the additive printing head and the subtractive cutting tool need to be switched for the pre-planned process sequence sorting of the hollow cavity, and h is the number of sub-feature structures after the hollow cavity is feature-segmented;

[0130] Under the condition of ensuring no interference and collision between the additive printing head and the subtractive cutting tool, after adjusting and merging the h sub-feature structures according to the feature segmentation position to ensure the minimum number of segmentations for each hollow cavity; Re-sort the 2h processes of the obtained h sub-feature structures in the order of additive and subtractive manufacturing processing after adjustment and merging to form the optimal process sequence set Seq* of the hollow cavity, as shown in the following formula (7):

[0131]

[0132] In the formula, Seq* represents the set of optimal process sequences for the hollow cavity, and HIN rsIt refers to the s-th sub-feature process in the r-th additive manufacturing process in the hollow cavity, HDE rs It refers to the s-th sub-feature process in the r-th additive manufacturing process in the hollow cavity, z 1 It refers to the original number of sub-features in the first subtractive manufacturing process in the hollow cavity, z j It refers to the original number of sub-features in the j-th additive manufacturing process in the hollow cavity, and h is the number of sub-feature structures after the hollow cavity is feature-segmented;

[0133] The number of times of switching the additive printing head and the subtractive cutting tool required for the optimal process sequence sorting of the hollow cavity is Swithing·Y*, as shown in the following formula (8):

[0134] Swithing·Y* = 2j - 1 (8)

[0135] In the formula, Swithing·Y* refers to the number of times of switching the additive printing head and the subtractive cutting tool required for the optimal process sequence sorting of the hollow cavity, j is the number of groups of additive and subtractive processes in the optimal process sequence sorting of the hollow cavity, and j < h;

[0136] Obtain the optimal process sequence sorting of the hollow cavity to ensure obtaining the optimal process plan.

[0137] Step 5:

[0138] Restore the solid structure part that was originally the hollow cavity in the obtained overall segmentation plan to a hollow cavity, and substitute it into the hollow cavity segmentation plan obtained in Step 3 for merging, so as to divide the multi-directional steel joint model of the complex structure part containing the hollow cavity into g sub-feature structures, and perform finish machining and subtractive cutting on the formed part before the interference obstacles in the multi-directional steel joint model of the complex structure part containing the hollow cavity are additively formed, so as to determine the complete segmentation plan of the multi-directional steel joint model of the complex structure part containing the hollow cavity.

[0139] Step 6:

[0140] After the final segmentation plan of the complex structure part containing the hollow cavity is established, perform the complete process planning of the multi-directional steel joint model of the complex structure part containing the hollow cavity on the 2g processes of the g sub-feature structures of the multi-directional steel joint model of the complex structure part containing the hollow cavity obtained according to the initial order of additive and subtractive manufacturing processes, and form the complete process planning sequence set FullSeq, as shown in the following formula 9:

[0141]

[0142] In the formula, FullSeq refers to the complete process planning sequence set of the multi-directional steel joint model of the complex structure part containing the hollow cavity, INc DE is the additive process for the c-th sub-feature structure in the initial process sequence on the complex solid structure after solidification c m is the m-th sub-feature structure in the initial process sequence on the complex solid structure after solidification, k is the k-th sub-feature structure in the pre-planned process sequence of the hollow cavity, f is the number of sub-feature structures formed after feature segmentation of the complex solid structure after solidification, and HIN is the subtractive process for the c-th sub-feature structure in the initial process sequence on the complex solid structure after solidification d HDE is the additive process for the d-th sub-feature structure in the pre-planned process sequence of the hollow cavity d h is the number of sub-feature structures formed after feature segmentation of the hollow cavity, and HDE is the subtractive process for the d-th sub-feature structure in the pre-planned process sequence of the hollow cavity

[0143] After obtaining the complete process planning sequence set of the complex structure multi-directional steel joint model with a hollow cavity, check whether there is still interference and collision between the additive printing head and the subtractive cutting tool when performing additive and subtractive processes according to this complete process planning sequence. If there is interference and collision between the additive printing head and the subtractive cutting tool, then return to adjust the feature segmentation position according to the existing interference and collision situation between the additive printing head and the subtractive cutting tool until it is checked that there is no interference and collision between the additive printing head and the subtractive cutting tool when performing additive and subtractive processes according to this complete process sequence of the complex structure multi-directional steel joint model with a hollow cavity; if there is no interference and collision between the additive printing head and the subtractive cutting tool, adjust and merge the g sub-feature structures according to the feature segmentation position under the current plan to ensure the minimum number of segmentation times of the complex structure multi-directional steel joint model with a hollow cavity, then the final segmentation plan of the complex structure multi-directional steel joint model with a hollow cavity can be determined.

[0144] The number of times of switching the additive printing head and the subtractive cutting tool required for sorting the complete process planning sequence of the complex structure multi-directional steel joint model with a hollow cavity is Swithing·W, as shown in the following formula (10):

[0145] Swithing·W = 2g - 1 (10)

[0146] In the formula, Swithing·W is the number of times of switching the additive printing head and the subtractive cutting tool required for sorting the complete process planning sequence of the complex structure multi-directional steel joint model with a hollow cavity, and g is the number of sub-feature structures formed after feature segmentation of the complex structure multi-directional steel joint model with a hollow cavity.

[0147] On the premise of ensuring no interference and collision between the additive manufacturing head and the subtractive cutting tool, after adjusting and merging the g sub-feature structures according to the feature segmentation positions, the number of segmentation times of the multi-directional steel joint model of the complex structural part with a hollow cavity is minimized; the 2g processes of the obtained g sub-feature structures are reordered according to the adjusted and merged order of additive and subtractive manufacturing processes to form the final optimal process sequence set FullSeq* of the multi-directional steel joint model of the complex structural part with a hollow cavity, as shown in the following formula (11):

[0148]

[0149] In the formula, FullSeq* represents the final optimal process sequence set of the multi-directional steel joint model of the complex structural part with a hollow cavity, ZIN tu represents the u-th sub-feature process in the t-th additive process of the multi-directional steel joint model of the complex structural part with a hollow cavity, ZDE tu represents the u-th sub-feature process in the t-th subtractive process of the multi-directional steel joint model of the complex structural part with a hollow cavity, e 1 represents the original number of sub-features in the first additive process of the multi-directional steel joint model of the complex structural part with a hollow cavity, e l represents the original number of sub-features in the l-th additive process of the multi-directional steel joint model of the complex structural part with a hollow cavity, and g represents the number of sub-feature structures obtained after feature segmentation of the multi-directional steel joint model of the complex structural part with a hollow cavity;

[0150] The number of times of switching the additive manufacturing head and the subtractive cutting tool required for the final optimal process sequence sorting of the multi-directional steel joint model of the complex structural part with a hollow cavity is Swithing·W*, as shown in the following formula (12):

[0151] Swithing·W* = 21 - 1 (12)

[0152] In the formula, Swithing·W* represents the number of times of switching the additive manufacturing head and the subtractive cutting tool required for the final optimal process sequence sorting of the multi-directional steel joint model of the complex structural part with a hollow cavity, and l represents the number of groups of additive and subtractive processes in the final optimal process sequence sorting of the multi-directional steel joint model of the complex structural part with a hollow cavity, and l < g;

[0153] The final optimal process sequence sorting of the multi-directional steel joint model of the complex structural part with a hollow cavity is obtained to get the final optimal process plan, and the optimized additive and subtractive manufacturing process plan of the multi-directional steel joint model of the complex structural part with a hollow cavity is obtained, specifically as Figure 6as shown

[0154] To verify the effect of the method of the present invention, in this embodiment, the method of the present invention is compared with the existing method as follows:

[0155] 1. For the multi-directional steel joint model of a complex structural member with a hollow cavity, the number of process switching times for the two manufacturing mode methods by the existing additive and subtractive manufacturing in alternation is 19 times; the number of process switching times for the final optimal process plan of the multi-directional steel joint model of a complex structural member with a hollow cavity obtained by the method of the present invention is 7 times; it can be seen that the method of the present invention can significantly reduce the number of process switching times, thereby saving a large amount of preparation and tool change time consumed by process alternation and improving the process efficiency.

[0156] 2. The time taken for the optimal process plan of the hollow cavity by the method of the existing additive and subtractive manufacturing in alternation is 7 minutes, 20 seconds and 56 milliseconds, as specifically Figure 7 shown; the time taken for the optimal process plan of the hollow cavity by the method of the present invention is 4 minutes, 37 seconds and 29 milliseconds, as specifically Figure 8 shown. It can be seen that the time taken for the optimal process plan of the method of the present invention is significantly less than that of the existing method, and the efficiency is higher.

Claims

1. A method for planning the additive and subtractive manufacturing process of complex structural parts, characterized in that, it includes the following steps: S1: Solidify all the hollow cavities contained in the given complex structural part with hollow cavities; S2: On the solidified complex solid structural part, find the position of the interference and collision junction according to the interference and collision situation as the feature segmentation position, determine the overall segmentation scheme according to the feature segmentation position, and adjust and merge the feature segmentation positions to obtain the optimal process plan; S3: Divide all the hollow cavities contained in the given complex structural part with hollow cavities into two types: hollow cylinders and hollow spheres; S4: Conduct separate feature segmentation on these two types of hollow cavities, namely hollow cylinders and hollow spheres, adjust and merge the feature segmentation positions, determine the hollow cavity segmentation scheme, and realize the process pre-planning of the hollow cavities; S5: Merge the overall segmentation scheme and the hollow cavity segmentation scheme to obtain the complete segmentation scheme of the complex structural part with hollow cavities; S6: Based on the complete segmentation scheme, adjust and merge the execution order of the additive and subtractive manufacturing process sequence of the complex structural part with hollow cavities to reduce the switching times of the additive printing head and the subtractive cutting tool, and obtain the optimized additive and subtractive manufacturing process plan of the complex structural part with hollow cavities; Step S2 includes the following process: A1: On the solidified complex solid structural part, find the position of the interference and collision junction according to the interference and collision situation of the simulated additive printing head and subtractive cutting tool as the feature segmentation position, and divide the complex solid structural part into multiple sub-feature structures; A2: Sort the process sequences of the obtained multiple sub-feature structures to determine the overall segmentation scheme and adjust and merge the multiple sub-feature structures according to the feature segmentation position to ensure the minimum number of segmentation times of the complex solid structural part and obtain the optimal process plan; Step A1 is specifically: Conduct the accessibility evaluation of the additive printing head and subtractive cutting tool on the solidified complex solid structural part, analyze the interference and collision situation of the additive printing head and subtractive cutting tool on the solidified complex solid structural part according to the accessibility evaluation, find n interference and collisions, take the position of the interference and collision junction as the feature segmentation position, and divide the complex solid structural part into f sub-feature structures to perform finish machining and subtractive cutting on the formed part before the interference obstacles in the complex solid structural part are additively formed; Step A2 is specifically: A2-1: Sort the 2f processes of the obtained f sub-feature structures in the initial order of additive and subtractive manufacturing processing to form the initial process sequence set Pro·seq, as shown in the following formula (1): Pro·seq = {IN 1 , DE 1 , IN 2 , DE 2 , …, IN m , DE m , …, IN f , DE f | m = 1, 2, …, f} (1) Wherein, Pro·seq refers to the set of initial process sequences on the solidified complex solid structural part, IN c refers to the additive process of the c-th sub-feature structure in the initial process sequence on the solidified complex solid structural part, DE c refers to the subtractive process of the c-th sub-feature structure in the initial process sequence on the solidified complex solid structural part, m refers to the m-th sub-feature structure in the initial process sequence on the solidified complex solid structural part, and f is the number of sub-feature structures obtained after feature segmentation of the solidified complex solid structural part; A2-2: After obtaining the set of initial process sequences, check whether there are any interference and collision situations between the additive manufacturing print head and the subtractive manufacturing cutting tool when performing additive and subtractive manufacturing according to this initial process sequence. If there are interference and collision situations between the additive manufacturing print head and the subtractive manufacturing cutting tool, return to step A1 to adjust the feature segmentation position according to the existing interference and collision situations between the additive manufacturing print head and the subtractive manufacturing cutting tool until it is checked that there are no interference and collision situations between the additive manufacturing print head and the subtractive manufacturing cutting tool when performing additive and subtractive manufacturing according to this initial process sequence; If there are no interference and collision situations between the additive manufacturing print head and the subtractive manufacturing cutting tool, the overall segmentation plan can be determined. Under the current plan, adjust and merge the f sub-feature structures according to the feature segmentation position to ensure the minimum number of segmentation times for the complex solid structure part and obtain the optimal process plan; The method for obtaining the optimal process plan in step A2-2 is as follows: The number of times of switching the additive manufacturing print head and the subtractive manufacturing cutting tool required for the initial process sequence sorting is Swithing·T, as shown in the following formula 2: Swithing·T = 2f - 1 (2) In the formula, Swithing·T represents the number of times of switching the additive manufacturing print head and the subtractive manufacturing cutting tool required for the initial process sequence sorting, and f is the number of sub-feature structures obtained after the feature segmentation of the complex solid structure part after solidification; Under the condition of ensuring that there are no interference and collision situations between the additive manufacturing print head and the subtractive manufacturing cutting tool, adjust and merge the f sub-feature structures according to the feature segmentation position to ensure the minimum number of segmentation times for the complex solid structure part; Re-sort the 2f processes of the obtained f sub-feature structures according to the adjusted and merged order of additive and subtractive manufacturing processing sequence to form the optimal process sequence set Pro·seq*, as shown in the following formula 3: Wherein, Pro·seq* represents the set of optimal process sequences on the solidified complex solid structural member, IN ab represents the b-th sub-feature process in the a-th additive process of the solidified complex solid structural member, DE ab represents the b-th sub-feature process in the a-th subtractive process of the solidified complex solid structural member, p 1 represents the number of original sub-features in the first additive process of the solidified complex solid structural member, p i represents the number of original sub-features in the i-th additive process of the solidified complex solid structural member, and f is the number of sub-feature structures obtained after the feature segmentation of the solidified complex solid structural member; The number of times of switching the additive manufacturing print head and the subtractive manufacturing cutting tool required for the optimal process sequence sorting is Swithing·T*, as shown in the following formula 4: Swithing·T* = 2i - 1 (4) In the formula, Swithing·T* represents the number of times of switching the additive manufacturing print head and the subtractive manufacturing cutting tool required for the optimal process sequence sorting, and i is the number of groups of an additive process and a subtractive process in the optimal process sequence sorting, and i < f; Obtain the optimal process sequence sorting to ensure obtaining the optimal process plan; In step S4, the specific feature segmentation of the two hollow cavities of the hollow cylinder and the hollow sphere is as follows: Feature segmentation of a hollow cylinder: First, the hollow cylinder is vertically cut along the plane where the central axis of the hollow cylinder is located as the preliminary feature segmentation. At this time, two symmetrical parts are obtained. Select the half of the hollow cylinder that is close to the processing platform and perform additive manufacturing first. If the length of the hollow cylinder is short or the wall thickness of the hollow cylinder is thin, and there is no interference or collision when directly performing additive manufacturing on the other half of the hollow cylinder for subsequent additive manufacturing, then no further feature segmentation is required. If the length of the hollow cylinder is long or the wall thickness of the hollow cylinder is thick, and there is interference or collision when directly performing additive manufacturing on the other half of the hollow cylinder for subsequent additive manufacturing, then the other half of the hollow cylinder for subsequent additive manufacturing is further segmented by flat cutting according to the reach range of the tool, divided into equal-length cylinder segments, until there is no interference or collision when directly performing additive manufacturing on the other half of the hollow cylinder for subsequent additive manufacturing; Feature segmentation of a hollow sphere: The hollow sphere is segmented along the plane parallel to the processing platform and passing through the center of the sphere as the preliminary feature segmentation. At this time, two symmetrical hollow hemispheres are obtained. Select the half of the hollow hemisphere that is close to the processing platform and perform additive manufacturing first, and then the other hollow hemisphere for subsequent additive manufacturing is further segmented along the plane perpendicular to the hemisphere plane and passing through the central axis of the hollow hemisphere, dividing the other hollow hemisphere into two halves, which is 1 / 4 of the original hollow sphere; Step S6 is specifically as follows: After the final segmentation plan of the complex structural part with a hollow cavity is established, the 2g processes of the g sub-feature structures of the complex structural part with a hollow cavity obtained are planned for the complete process of the complex structural part with a hollow cavity in the order of the initial additive and subtractive manufacturing processing sequence, constituting the complete process planning sequence set FullSeq, as shown in the following formula 9: Wherein, FullSeq is the set of complete process planning sequences for complex structural parts containing hollow cavities, IN c is the additive process for the c-th sub-feature structure in the initial process sequence on the complex solid structural part after solidification, DE c is the subtractive process for the c-th sub-feature structure in the initial process sequence on the complex solid structural part after solidification, m is the m-th sub-feature structure in the initial process sequence on the complex solid structural part after solidification, k is the k-th sub-feature structure in the process pre-planning sequence for the hollow cavity, f is the number of sub-feature structures obtained after feature segmentation of the complex solid structural part after solidification, HIN d is the additive process for the d-th sub-feature structure in the process pre-planning sequence for the hollow cavity, HDE d is the subtractive process for the d-th sub-feature structure in the process pre-planning sequence for the hollow cavity, h is the number of sub-feature structures obtained after feature segmentation of the hollow cavity; After obtaining the complete process planning sequence set of the complex structural part with a hollow cavity, check whether there is still interference or collision between the additive manufacturing print head and the subtractive manufacturing cutting tool when performing additive manufacturing and subtractive manufacturing according to this complete process planning sequence. If there is interference or collision between the additive manufacturing print head and the subtractive manufacturing cutting tool, then return to the previous step and adjust the feature segmentation position according to the current interference or collision situation between the additive manufacturing print head and the subtractive manufacturing cutting tool until it is checked that there is no interference or collision between the additive manufacturing print head and the subtractive manufacturing cutting tool when performing additive manufacturing and subtractive manufacturing according to this complete process sequence of the complex structural part with a hollow cavity; If there is no interference or collision between the additive manufacturing print head and the subtractive manufacturing cutting tool, adjust and merge the g sub-feature structures according to the feature segmentation position under the current plan to ensure the minimum number of segmentation times of the complex structural part with a hollow cavity, then the final segmentation plan of the complex structural part with a hollow cavity can be determined; The number of times of switching the additive manufacturing print head and the subtractive manufacturing cutting tool required for sorting the complete process planning sequence of the complex structural part with a hollow cavity is Swithing·W, as shown in the following formula (10): Swithing·W = 2g - 1 (10) In the formula, Swithing·W refers to the number of times of switching the additive manufacturing head and the subtractive cutting tool required for sorting the complete process planning sequence of a complex structural part with a hollow cavity, and g refers to the number of sub-feature structures obtained after the feature segmentation of the complex structural part with a hollow cavity; On the premise of ensuring no interference and collision between the additive manufacturing head and the subtractive cutting tool, the g sub-feature structures are adjusted and merged according to the feature segmentation position to ensure the minimum number of segmentation times of the complex structural part with a hollow cavity; the 2g processes of the obtained g sub-feature structures are re-sorted according to the adjusted and merged order of additive and subtractive manufacturing processes to obtain the final optimal process sequence of the complex structural part with a hollow cavity, constituting the final optimal process sequence set FullSeq* of the complex structural part with a hollow cavity, as shown in the following formula (11): In the formula, FullSeq* represents the set of the final optimal process sequences of complex structural parts containing hollow cavities, and ZIN tu represents the u-th sub-feature process in the t-th additive manufacturing process of the complex structural part containing hollow cavities, and ZDE tu represents the u-th sub-feature process in the t-th subtractive manufacturing process of the complex structural part containing hollow cavities, and e 1 represents the number of original sub-features in the first additive manufacturing process of the complex structural part containing hollow cavities, and e l represents the number of original sub-features in the l-th additive manufacturing process of the complex structural part containing hollow cavities, and g represents the number of sub-feature structures after feature segmentation of the complex structural part containing hollow cavities; The number of times of switching the additive manufacturing head and the subtractive cutting tool required for the final optimal process sequence sorting of the complex structural part with a hollow cavity is Swithing·W*, as shown in the following formula (12): Swithing·W* = 2l - 1 (12) In the formula, Swithing·W* refers to the number of times of switching the additive manufacturing head and the subtractive cutting tool required for the final optimal process sequence sorting of the complex structural part with a hollow cavity, and l refers to the number of groups of additive and subtractive processes in the final optimal process sequence sorting of the complex structural part with a hollow cavity, and l < g; The final optimal process sequence sorting of the complex structural part with a hollow cavity is obtained to obtain the final optimal process planning, and the optimized additive and subtractive manufacturing process planning scheme of the complex structural part with a hollow cavity is obtained.

2. A method for planning the additive and subtractive manufacturing process of a complex structural part according to claim 1, characterized in that the method for determining the hollow cavity segmentation scheme in step S4 is as follows: According to the interference and collision situation still existing between the additive manufacturing head and the subtractive cutting tool simulated for the two hollow cavities, the position of the interference and collision junction is found as the further feature segmentation position, and each hollow cavity is segmented into h sub-feature structures, so as to perform finish machining and subtractive cutting on the formed part before the interference obstacle in each hollow cavity is additively formed, so as to determine the segmentation scheme of each hollow cavity.

3. A method for planning the additive and subtractive manufacturing process of a complex structural part according to claim 2, characterized in that the method for pre-planning the process of the hollow cavity in step S4 is as follows: The 2h processes of the h sub-feature structures of each obtained hollow cavity are pre-planned for the process of the hollow cavity according to the initial order of additive and subtractive manufacturing processes, constituting the process pre-planning sequence set Seq, as shown in the following formula (5): Seq = {HIN 1 , HDE 1 , HIN 2 , HDE 2 , …, HIN k , HDE k , …, HIN h , HDE h | k = 1, 2, …, h} (5) Wherein, Seq is a set of process pre-planning sequences representing the hollow cavity, and HIN d is the additive process of the d-th sub-feature structure in the process pre-planning sequence representing the hollow cavity, and HDE d is the subtractive process of the d-th sub-feature structure in the process pre-planning sequence representing the hollow cavity, k is the k-th sub-feature structure in the process pre-planning sequence representing the hollow cavity, and h is the number of sub-feature structures formed after the feature segmentation of the hollow cavity; After obtaining the set of pre-planned process sequences for the hollow cavity, check whether there is still interference and collision between the additive printing head and the subtractive cutting tool when additive and subtractive manufacturing are carried out according to this pre-planned process sequence. If there is interference and collision between the additive printing head and the subtractive cutting tool, go back to the previous step and adjust the feature segmentation position according to the existing interference and collision between the additive printing head and the subtractive cutting tool until it is checked that there is no interference and collision between the additive printing head and the subtractive cutting tool when additive and subtractive manufacturing are carried out according to this initial process sequence; If there is no interference and collision between the additive printing head and the subtractive cutting tool, each hollow cavity segmentation scheme can be determined. Under the current scheme, adjust and merge the h sub-feature structures according to the feature segmentation position to ensure the minimum number of segmentation times for each hollow cavity; The number of times of switching the additive printing head and the subtractive cutting tool required for sorting the pre-planned process sequence of the hollow cavity is Swithing·Y, as shown in the following formula (6): Swithing·Y=2h - 1 (6) In the formula, Swithing·Y represents the number of times of switching the additive printing head and the subtractive cutting tool required for sorting the pre-planned process sequence of the hollow cavity, and h is the number of sub-feature structures obtained after the hollow cavity is segmented by feature segmentation; Under the condition of ensuring no interference and collision between the additive printing head and the subtractive cutting tool, after adjusting and merging the h sub-feature structures according to the feature segmentation position to ensure the minimum number of segmentation times for each hollow cavity; re-sort the 2h processes of the obtained h sub-feature structures according to the adjusted and merged sequence of additive and subtractive manufacturing processing priorities to form the optimal process sequence set Seq* of the hollow cavity, as shown in the following formula (7): Wherein, Seq* is the set of optimal process sequences representing the hollow cavity, HIN rs is the s-th sub-feature process in the r-th additive process in the hollow cavity, HDE rs is the s-th sub-feature process in the r-th additive process in the hollow cavity, z 1 is the number of original sub-features in the first subtractive process in the hollow cavity, z j is the number of original sub-features in the j-th additive process in the hollow cavity, and h is the number of sub-feature structures obtained after feature segmentation of the hollow cavity; The number of times of switching the additive printing head and the subtractive cutting tool required for sorting the optimal process sequence of the hollow cavity is Swithing·Y*, as shown in the following formula 8: Swithing·Y*=2j - 1 (8) In the formula, Swithing·Y* represents the number of times of switching the additive printing head and the subtractive cutting tool required for sorting the optimal process sequence of the hollow cavity, and j is the number of groups of additive process and subtractive process in the optimal process sequence sorting of the hollow cavity, and j < h; Obtain the optimal process sequence sorting of the hollow cavity to ensure the optimal process planning.

4. A method for planning the additive and subtractive manufacturing process of a complex structural part according to claim 1, characterized in that the specific step S5 is as follows: Restore the solid structure part originally being a hollow cavity in the obtained overall segmentation scheme to a hollow cavity, substitute the obtained hollow cavity segmentation scheme, and perform merging, so as to divide the complex structural part containing the hollow cavity into g sub-feature structures, and perform finish machining and subtractive cutting on the formed part first before the interference obstacles in the complex structural part containing the hollow cavity are additively formed, so as to determine the complete segmentation scheme of the complex structural part containing the hollow cavity.

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