Method for material removal process replay based on operation log and parallel simulation of cutting forces

Abstract

The application discloses a material removal process replay and cutting force parallel simulation method based on an operation log, and belongs to the technical field of mechanical processing and computer-aided manufacturing. According to the total number of numerical control processing steps and a preset item capacity, a three-dimensional operation log system is initialized and a storage space is allocated. Then, the material removal operation parameters of a grid unit are recorded at a preset interval during the material removal process to form an operation record chain. Through log index positioning of the corresponding item, reverse material removal operation is performed, and an accurate target historical state is obtained through topological verification. Based on the sub-domain data, local cutting force is calculated and global cutting force curves are generated. The method provided by the application only records key operation parameters, dynamically allocates storage resources, and reduces storage overhead. Through log indexing and reverse operation, efficient and accurate state backtracking of any step is realized, the cutting force simulation efficiency is improved by combining parallel computing, and the problems of heavy storage burden, slow backtracking and low simulation efficiency of the traditional method are solved.

Description

Technical Field

[0001] This invention belongs to the field of machining and computer-aided manufacturing technology, and particularly relates to a method for replaying material removal process and parallel simulation of cutting force based on operation logs. Background Technology

[0002] Addressing the technical challenge of material removal state backtracking in CNC machining simulation, it is frequently necessary to return to historical machining states for analysis and verification during CNC machining process simulation. Traditional methods require storing a large number of intermediate state models, resulting in high storage costs and slow playback speeds. Current CNC machining simulation systems mainly suffer from the following problems in material removal and cutting force simulation: Full-state storage methods require saving the complete model for each simulation step, with storage costs increasing linearly with the number of simulation steps; checkpoint-based state recovery methods have low playback efficiency, requiring re-execution of all operations from the most recent checkpoint; existing methods struggle to support state backtracking accurate to any simulation step; and for long-term machining simulations of large and complex parts, cutting force simulation becomes a bottleneck in system performance. Summary of the Invention

[0003] The purpose of this invention is to provide a parallel simulation method for material removal process replay and cutting force based on operation logs, which solves the problems in the prior art, such as storage overhead increasing linearly with simulation steps; low playback efficiency requiring re-execution of all operations from the most recent checkpoint; and difficulty in supporting state backtracking accurate to arbitrary simulation steps.

[0004] To achieve the above objectives, this invention provides a method for parallel simulation of material removal process replay and cutting force based on operation logs, comprising the following steps:

[0005] S1. Initialize the 3D operation log system: Based on the total number of CNC machining steps num_nc_step and the preset entry capacity num_per_log, initialize the 3D operation log system tri_log and allocate storage space for log entries in the X, Y, and Z directions;

[0006] S2. 3D Operation Log Recording: During the material removal process, log recording is triggered at a preset interval of every num_per_log steps; all grid cell coordinates (i, j) of the dexel model in the X, Y, and Z directions of the current step are traversed; the material removal interval (t1, t2) in each grid cell is extracted; the parameters are written into the operation log of the corresponding direction according to the log entry structure to form a complete operation record chain;

[0007] S3, Intelligent Operation Replay: Receives the target backtracking step instruction, calculates the corresponding log entry range num_entry; calls the intelligent operation replay algorithm, reads the operation records in the X, Y, and Z directions in the order of the entries, and performs reverse material removal operation on each record (i, j, t1, t2), updating the dexel model in the corresponding direction; after completing the processing of all entries, ensures the consistency of the entity state through three-dimensional topology verification, and obtains the target historical state;

[0008] S4. Parallel Simulation of Cutting Force: For the target state obtained by replay, divide it into subdomains according to the machining area and generate parallel computing tasks; dynamically allocate tasks to each computing node and calculate local cutting forces based on the dexel data in the subdomain; summarize the calculation results of each computing node to generate the global cutting force curve of the target step and complete the simulation.

[0009] Preferably, the three-dimensional operation log system in S1 is used to structure and store the operation information of the material removal process. Its log hierarchy is a three-level structure of three-dimensional direction set - log entry - operation record. Specifically, the three-dimensional direction set tri_log contains independent logs in the X, Y and Z directions. The log of each direction, Operation_Log, consists of several log entries. Each log entry stores the operation record corresponding to num_per_log CNC machining steps. Each operation record contains the grid cell coordinates (i, j) and the material removal interval (t1, t2).

[0010] Preferably, the specific details of allocating log entry storage space in S1 for the X, Y, and Z directions are as follows:

[0011] Based on num_nc_step and num_per_log, calculate the total number of required log entries using the formula num_log=⌈num_nc_step / num_per_log⌉, and allocate equal amounts of log entry storage space in the X, Y, and Z directions according to this total number.

[0012] Preferably, before performing the reverse material removal operation on each record in S3, a log indexing step is also included. Based on the log entry range num_entry corresponding to the target backtracking step, all log entries within the range of num_entry are automatically located without traversing all historical log entries.

[0013] Preferably, the specific details of performing the reverse material removal operation on each record in S3 are as follows:

[0014] If the interval (t1, t2) completely covers a certain dexel segment (r1, r2), then delete that segment.

[0015] If the removed interval (t1, t2) only covers the left part of a certain dexel line segment (r1, r2), then modify the right boundary endpoint of the line segment to obtain a new line segment (r1, t2) to retain the unremoved part;

[0016] If the removed interval (t1, t2) only covers the right side of a certain dexel line segment (r1, r2), then modify the left boundary endpoint of the line segment to obtain a new line segment (t1, r2) to retain the unremoved part;

[0017] If the removed interval (t1, t2) is located in the middle of a dexel line segment (r1, r2), then the original line segment is divided into two segments, (r1, t1) and (t2, r2), and the uncovered part is retained.

[0018] Preferably, after obtaining the target historical state in S3, a replay result verification step is also included, the specific content of which is as follows:

[0019] The reconstructed target historical state is compared with the theoretical state corresponding to this step by geometric features, and the size deviation between the two is calculated. If the deviation is less than the preset accuracy threshold, the playback result is deemed valid; if the deviation is greater than or equal to the preset accuracy threshold, the log entries are reread and the reverse material removal operation is performed.

[0020] Preferably, the subdomain division rule in S4 based on the processing area is as follows:

[0021] Based on the grid cells (i, j) of the tri-dexel model, the grid is divided according to the continuous interval of grid coordinates in the X or Y direction to ensure that the difference in the number of grid cells contained in each subdomain does not exceed a preset threshold, thus avoiding computational load imbalance.

[0022] Preferably, in S4, the dynamic allocation of tasks to each computing node adopts a dynamic load balancing strategy, which distributes subdomain computing tasks to multiple computing nodes, and the nodes exchange boundary condition information through shared memory.

[0023] Preferably, the dexel data in the subdomain of S4 includes material removal amount, tool parameters and material properties. The local cutting force is calculated by empirical formulas or finite element methods, and finally the global cutting force is obtained by summing them up.

[0024] Preferably, the global cutting force curve includes the changing trends of the cutting force components in the X, Y, and Z directions with the machining steps.

[0025] Therefore, the present invention, employing the above method, has the following beneficial effects:

[0026] (1) Only key operation parameters for material removal are recorded, rather than the complete intermediate model, resulting in a small log file size; storage space is dynamically allocated, and the requirements are accurately calculated according to the processing steps and preset item capacity to avoid redundant occupation and get rid of the problem of storage overhead increasing linearly with the steps.

[0027] (2) The log indexing mechanism directly locates the target entry without traversing all records, greatly improving the backtracking speed; the reverse operation covers the entire scenario, and combined with three-dimensional topology verification and result verification, it ensures that the reconstruction of the historical state of any step is accurate and the deviation is controllable.

[0028] (3) Make full use of multi-node computing power to solve the performance bottleneck of simulation of large and complex parts.

[0029] The local cutting force is calculated based on the accurate replay of the state, and the results are aggregated to generate a global curve in multiple directions, balancing simulation efficiency and calculation accuracy.

[0030] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0031] Figure 1 This is a flowchart of the operation of the parallel simulation method for material removal process replay and cutting force based on operation logs according to the present invention.

[0032] Figure 2 This is a flowchart of the three-dimensional operation log recording process of the present invention;

[0033] Figure 3 This is a flowchart of the intelligent operation replay process of the present invention;

[0034] Figure 4 This is a flowchart of the parallel simulation of cutting force in this invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages disclosed in the embodiments of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are only used to explain the embodiments of the present invention and are not intended to limit the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of this application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout.

[0036] It should be noted that the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as a process, method, system, product, or server that includes a series of steps or units, not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or device.

[0037] The following is combined Figures 1-4 The embodiments of the present invention will be described in detail below.

[0038] Example 1

[0039] like Figure 1 As shown, this invention provides a parallel simulation method for material removal process replay and cutting force based on operation logs. First, a three-dimensional operation log system is initialized. Then, various operation parameters are recorded in real time during the material removal process. Finally, a rapid backtracking of the processing state is achieved through an operation replay mechanism. This system mainly includes three core functional modules: log initialization, operation recording, and state replay.

[0040] (1) Architecture of the three-dimensional operation log system:

[0041] A three-dimensional operation log system is used to structurally store key operational information in the material removal process, supporting multi-directional collaborative recording. Its architecture includes:

[0042] Log hierarchy: A three-level structure of "three-dimensional direction set - log entries - operation record" is adopted. Among them, the three-dimensional direction set (tri_log) contains independent logs for the X, Y, and Z directions; the log for each direction (Operation_Log) consists of several log entries; each entry stores a set of key parameters for the material removal operation.

[0043] Operation log parameters: Each operation log includes:

[0044] Spatial positioning information: dexel grid coordinates (i, j), identifying the two-dimensional grid cell where the operation is located;

[0045] Geometric feature information: Material removal interval (t1, t2) represents the range of line segments removed in the dexel line.

[0046] Dynamic storage mechanism: Based on the total number of CNC machining steps (num_nc_step) and the preset entry capacity (num_per_log), the required number of log entries is automatically calculated (num_log=⌈num_nc_step / num_per_log⌉), realizing dynamic allocation and efficient utilization of storage space.

[0047] (2) Intelligent operation replay algorithm:

[0048] like Figure 3 As shown, the intelligent operation replay algorithm, based on a three-dimensional operation log system, enables rapid reconstruction of any historical state. Its core components include:

[0049] Log indexing mechanism: Based on the target backtracking steps, the corresponding log entry range is automatically located without traversing the entire history, thus improving indexing efficiency.

[0050] Reverse material removal logic: For different material removal scenarios, execute the corresponding reverse operation:

[0051] Complete Coverage Scenario: If the removed interval (t1, t2) completely covers a certain dexel segment (r1, r2), then delete that segment.

[0052] Partial coverage scenarios:

[0053] If the removed interval (t1, t2) only covers the left part of a certain dexel line segment (r1, r2), then modify the right boundary endpoint of the line segment to obtain a new line segment (r1, t2) to retain the unremoved part;

[0054] If the removed interval (t1, t2) only covers the right side of a certain dexel line segment (r1, r2), then modify the left boundary endpoint of the line segment to obtain a new line segment (t1, r2) to retain the unremoved part;

[0055] Intermediate coverage scenario: If the removed interval (t1, t2) is located in the middle of a certain dexel line segment (r1, r2), then the original line segment is divided into two segments, namely (r1, t1) and (t2, r2), and the uncovered part is retained.

[0056] 3D Collaborative Replay: Simultaneously executes dexel model replay operations in the X, Y, and Z directions, and ensures the integrity of the 3D entity state through topological consistency verification.

[0057] (3) Parallel simulation algorithm for cutting force:

[0058] The parallel simulation algorithm for cutting forces, based on replayed historical states, enables efficient calculation of multi-step cutting forces, including:

[0059] State segmentation mechanism: The replayed 3D entity is divided into several subdomains according to the processing area, and each subdomain corresponds to an independent cutting force calculation task.

[0060] Parallel task scheduling: A dynamic load balancing strategy is adopted to distribute subdomain computing tasks to multiple computing nodes, and the nodes exchange boundary condition information through shared memory.

[0061] Cutting force calculation model: Each node calculates the local cutting force based on the amount of material removed within the subdomain (derived from the dexel line segment parameters), tool parameters, and material properties, using empirical formulas or finite element methods, and finally sums them up to obtain the global cutting force.

[0062] Specifically, the following steps are included:

[0063] S1. Initialization Phase:

[0064] Based on the total number of CNC machining steps (num_nc_step) and the preset entry capacity (num_per_log), initialize the three-dimensional operation log system (tri_log) and allocate log entry storage space for the X, Y, and Z directions;

[0065] Initialize the initial tri-dexel model of the part to be processed (containing dexel data in the three directions of dexel_x, dexel_y, and dexel_z).

[0066] S2, Operation Recording Stage:

[0067] like Figure 2 As shown, during the material removal process, log recording is triggered at preset intervals (every num_per_log steps):

[0068] Traverse all mesh elements (i, j) of the dexel model in the X, Y, and Z directions in the current step;

[0069] Extract the line segment parameters (t1, t2) of the material removal operation in each grid cell;

[0070] The parameters are written to the corresponding operation log according to the log entry structure, forming a complete operation record chain.

[0071] S3, Operation Replay Phase:

[0072] Receive the target backtracking step instruction and calculate the corresponding log entry range (num_entry=⌈target step / num_per_log⌉).

[0073] The intelligent operation replay algorithm is invoked to read the operation records in the X, Y, and Z directions in order of entry:

[0074] For each record (i, j, t1, t2), perform a reverse material removal operation and update the dexel model in the corresponding direction;

[0075] After all entries have been processed, the consistency of entity states is ensured through three-dimensional topology verification to obtain the target historical state.

[0076] S4. Parallel simulation stage of cutting force:

[0077] like Figure 4 As shown, the target state obtained from replay is divided into subdomains according to the processing area. Each subdomain is regarded as a thread, and parallel computing tasks are generated.

[0078] Tasks are dynamically allocated to computing nodes, and each node calculates the local cutting force based on the dexel data within its subdomain.

[0079] Summarize the calculation results of each node, generate the global cutting force curve for the target step, and complete the simulation.

[0080] Example 2

[0081] To verify the practicality and superiority of the technical solution of this invention, a cavity machining scenario was selected for simulation verification:

[0082] Processing object and task: Select a square material with dimensions of 106mm×95mm×24mm as the blank. The target processing task is cavity cutting. A cavity structure with dimensions of 101mm×90mm×20.25mm and a corner radius of 2.5mm needs to be processed on the blank to simulate the actual precision cavity processing requirements.

[0083] Simulation parameter settings: To balance display quality and operational accuracy, the sampling interval is set to 0.1mm to ensure accurate representation of details such as cavity fillets and sidewalls; tool selection... The 5mm ball end mill uses a helical downward cutting + circumferential cutting method for machining, which fully conforms to the actual cavity machining process specifications.

[0084] Simulation results and data: The total simulation time for complete material removal was 96.25s; the operation log storage file size was only 1.35MB, demonstrating significant storage advantages; by replaying the processing process using the operation log, the processing status after every 1000 analysis steps (log storage interval) can be accurately obtained, and the complete replay time is less than 0.1s, fully demonstrating the technical advantages of rapid backtracking.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A parallel simulation method for material removal process replay and cutting force based on operation logs, characterized in that, Includes the following steps: S1. Initialize the 3D operation log system: Based on the total number of CNC machining steps num_nc_step and the preset entry capacity num_per_log, initialize the 3D operation log system tri_log and allocate storage space for log entries in the X, Y, and Z directions; S2. 3D Operation Log Recording: During the material removal process, log recording is triggered at a preset interval of every num_per_log steps; all grid cell coordinates (i, j) of the dexel model in the X, Y, and Z directions of the current step are traversed; the material removal interval (t1, t2) in each grid cell is extracted; the parameters are written into the operation log of the corresponding direction according to the log entry structure to form a complete operation record chain; S3, Intelligent Operation Replay: Receives the target backtracking step instruction, calculates the corresponding log entry range num_entry; calls the intelligent operation replay algorithm, reads the operation records in the X, Y, and Z directions in the order of the entries, and performs reverse material removal operation on each record (i, j, t1, t2), updating the dexel model in the corresponding direction; after completing the processing of all entries, ensures the consistency of the entity state through three-dimensional topology verification, and obtains the target historical state; S4. Parallel Simulation of Cutting Force: For the replayed target state, divide it into subdomains according to the machining area and generate parallel computing tasks; dynamically allocate tasks to each computing node and calculate local cutting forces based on the dexel data in the subdomain; summarize the calculation results of each computing node to generate the global cutting force curve of the target step and complete the simulation. The specific details of performing the reverse material removal operation on each record in S3 are as follows: If the interval (t1, t2) completely covers a certain dexel segment (r1, r2), then delete that segment. If the removed interval (t1, t2) only covers the left part of a certain dexel line segment (r1, r2), then modify the right boundary endpoint of the line segment to obtain a new line segment (r1, t2) to retain the unremoved part; If the removed interval (t1, t2) only covers the right side of a certain dexel line segment (r1, r2), then modify the left boundary endpoint of the line segment to obtain a new line segment (t1, r2) to retain the unremoved part; If the removed interval (t1, t2) is located in the middle of a dexel line segment (r1, r2), then the original line segment is divided into two segments, (r1, t1) and (t2, r2), and the uncovered part is retained.

2. The parallel simulation method for material removal process replay and cutting force based on operation logs as described in claim 1, characterized in that: The three-dimensional operation log system in S1 is used to structure and store the operation information of the material removal process. Its log hierarchy is a three-level structure of three-dimensional direction set - log entry - operation record. Specifically, the three-dimensional direction set tri_log contains independent logs in the X, Y and Z directions. The log of each direction, Operation_Log, consists of several log entries. Each log entry stores the operation record corresponding to num_per_log CNC machining steps. Each operation record contains the grid cell coordinates (i, j) and the material removal interval (t1, t2).

3. The parallel simulation method for material removal process replay and cutting force based on operation logs according to claim 1, characterized in that, The specific details of allocating log entry storage space in S1 for the X, Y, and Z directions are as follows: Based on num_nc_step and num_per_log, calculate the total number of required log entries using the formula num_log=⌈num_nc_step / num_per_log⌉, and allocate equal amounts of log entry storage space in the X, Y, and Z directions according to this total number.

4. The parallel simulation method for material removal process replay and cutting force based on operation logs as described in claim 1, characterized in that: Before performing the reverse material removal operation on each record, S3 also includes a log indexing step. Based on the log entry range num_entry corresponding to the target backtracking step, all log entries within the range of num_entry are automatically located without traversing all historical log entries.

5. The parallel simulation method for material removal process replay and cutting force based on operation logs according to claim 1, characterized in that, After obtaining the target's historical state, S3 also includes a replay result verification step, the details of which are as follows: The reconstructed target historical state is compared with the theoretical state corresponding to this step by geometric features, and the size deviation between the two is calculated. If the deviation is less than the preset accuracy threshold, the playback result is deemed valid; if the deviation is greater than or equal to the preset accuracy threshold, the log entries are reread and the reverse material removal operation is performed.

6. The parallel simulation method for material removal process replay and cutting force based on operation logs according to claim 1, characterized in that, The subdomain division rules in S4 based on processing area are as follows: Based on the grid cells (i, j) of the tri-dexel model, the grid is divided according to the continuous interval of grid coordinates in the X or Y direction to ensure that the difference in the number of grid cells contained in each subdomain does not exceed a preset threshold, thus avoiding computational load imbalance.

7. The parallel simulation method for material removal process replay and cutting force based on operation logs according to claim 1, characterized in that: In S4, tasks are dynamically allocated to each computing node using a dynamic load balancing strategy. Subdomain computing tasks are distributed to multiple computing nodes, and the nodes exchange boundary condition information through shared memory.

8. The parallel simulation method for material removal process replay and cutting force based on operation logs according to claim 1, characterized in that, The dexel data within the S4 subdomain includes material removal amount, tool parameters, and material properties. Local cutting forces are calculated using empirical formulas or finite element methods, and the global cutting forces are finally obtained by summing them up.

9. The parallel simulation method for material removal process replay and cutting force based on operation logs according to claim 1, characterized in that: The global cutting force curve includes the trend of the cutting force components in the X, Y, and Z directions as a function of the machining steps.

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