Mold digital thread driven machining process traceability method

Abstract

The present application relates to a die digital thread driven processing process tracing method, belonging to the technical field of intelligent manufacturing and die numerical control processing process tracing, comprising: generating a processing tracing mark for a die local processing site according to a die digital thread, and associating it with a numerical control program segment, a workpiece coordinate system, tool information, tool compensation information and a clamping state; collecting a current execution state and a tool position during numerical control processing, when the associated information matches and the tool position enters a corresponding processing range, the processing process is classified into the processing tracing mark; recording a workpiece coordinate system call, a tool compensation call, a clamping state confirmation or a program execution position change, and classifying into a processing preparation record or forming a new processing tracing segment according to whether the tool is in a material removal state; after processing is completed, detecting an abnormal area corresponding to the die local processing site, and tracing back to a processing tracing segment that produces a material removal effect, improving the accuracy of abnormal positioning, parameter review and process optimization.

Description

Technical Field

[0001] This invention relates to the field of intelligent manufacturing and mold CNC machining process traceability technology, specifically a mold digital thread-driven machining process traceability method. Background Technology

[0002] In existing technologies, CNC machining of molds has widely adopted digital means such as CAD, CAM, CNC programming, tool management, and online inspection to complete process design and machining execution. However, in actual production, the machining of local parts such as mold cavities, ribs, insert mounting surfaces, and parting surfaces usually requires multiple program segments, multiple tools, multiple coordinate systems, multiple clamping and compensation adjustments. The machining result is often formed by multiple discrete machining actions. Public document CN111126961B discloses a digital masterline service system for the entire life cycle of complex products. It extracts or receives model data of complex products from various information systems throughout the entire life cycle through model or data management units, associates it with the entire life cycle data map, and then outputs end-to-end model data according to query requests. This type of solution can improve the data connectivity of complex product design, manufacturing, and service stages from a macro perspective. However, its focus is on full lifecycle data maps and model data services. It does not establish traceability rules for the specific material removal behavior of local processing parts of molds in the CNC machining site. It is difficult to directly determine which CNC program segment, which workpiece coordinate system, which tool compensation state, or which clamping state caused the formation of a certain abnormal detection area.

[0003] Existing technologies also include schemes that utilize digital twins, sensor data, and machining status acquisition to map manufacturing objects. For example, CN116071559B discloses an automated method for constructing digital twins based on multi-dimensional sensor data. This method constructs digital twins by extracting and fusing multi-dimensional sensor data to enhance the synchronization capability between virtual and physical entities. This type of technology can improve the state perception capability of machining equipment, workpieces, or production objects, which is of positive significance for manufacturing process monitoring. However, it typically focuses on object state modeling, sensor data fusion, and twin generation, and has not yet fully addressed the issue of attribution between control state changes and material removal states during CNC machining. Especially when workpiece coordinate system calls, tool compensation calls, or clamping confirmations occur before the tool enters the machining range, and program execution position changes or compensation changes occur after entering the material removal state, recording only according to equipment operation logs or program execution order can easily confuse machining preparation behavior, idle stroke behavior, and actual cutting behavior, leading to inaccurate subsequent quality anomaly tracing results.

[0004] Therefore, for high-precision mold machining, simply recording CNC programs, tool paths, or inspection results is insufficient to meet the needs of local defect identification and process review. Abnormal areas detected in mold machining are often small in size, clearly localized, and may be located in areas where toolpaths overlap, are undergoing compensation corrections, are in secondary finishing, or are connected by clamping. If the local machining area defined by the mold's digital thread cannot be synchronously correlated with the current execution state of the CNC system, tool position, workpiece coordinate system, tool information, tool compensation information, and clamping status, it is difficult to accurately trace back the machining process segment that caused the material removal in the abnormal area after machining is completed. Therefore, existing technology still requires a machining process traceability method that can combine digital thread identification, on-site control status, tool entry range, and material removal status for local machining areas of the mold, enabling the detected abnormality to be traced back from the result to the specific process segment that actually caused the machining of that area. Summary of the Invention

[0005] The purpose of this invention is to provide a method for tracing the machining process driven by digital threads in mold making, thereby addressing some of the drawbacks and shortcomings pointed out in the background art.

[0006] The present invention adopts the following technical solution to solve the above-mentioned technical problems:

[0007] A machining process traceability method driven by a mold digital thread involves generating machining traceability identifiers for local machining parts of the mold based on the mold digital thread, and associating these identifiers with corresponding CNC program segments, workpiece coordinate systems, tool information, tool compensation information, and clamping states. During CNC machining, the current execution state and tool position of the CNC system are collected. When the CNC program segment, workpiece coordinate system, tool information, tool compensation information, and clamping state in the current execution state match the association information of the machining traceability identifier, and the tool position enters the machining range of the corresponding local machining part of the mold defined by the mold digital thread, the CNC machining process is included in the machining traceability identifier. Changes in control state are recorded during machining, including workpiece coordinate system calls, tool compensation calls, clamping state confirmation, or program execution position changes. Depending on whether the tool is in a material removal state when the control state change occurs, the control state change is included in the machining preparation record or forms a new machining traceability segment. After machining is completed, abnormal areas are mapped to the local machining parts of the mold, and the process is traced back to the machining traceability segment that caused the material removal effect on the abnormal areas.

[0008] Furthermore, before the processing traceability identifier is assigned to the corresponding local processing part of the mold, the most recent workpiece coordinate system call, tool compensation call, clamping status confirmation, and program execution position before entering the processing range during the execution of the same CNC program are effectively sealed. When the control state changes after the tool enters the material removal state, the effective sealed content before the change is used as the prerequisite for the current processing traceability segment, and the current execution state after the change is used as the starting basis for the next processing traceability segment.

[0009] Furthermore, when the same abnormal detection area corresponds to a previous processing traceability segment and a subsequent processing traceability segment, the material removal coverage of the abnormal detection area is assigned according to the subsequent processing traceability segment; if the subsequent processing traceability segment does not cover the abnormal detection area, or the subsequent material removal amount determined according to the previous processing allowance, tool compensation difference and subsequent tool position boundary does not reach the material removal amount required to eliminate the previous processing residue, then the abnormal detection area is assigned to the previous processing traceability segment.

[0010] Furthermore, when the local processing part of the mold is continuously processed under different clamping states, the processing traceability segment corresponding to the last material removal action before the clamping state change is connected with the processing traceability segment corresponding to the first material removal action after the clamping state change; when there are differences in the workpiece coordinate system, tool compensation information or clamping state of the previous and subsequent processing traceability segments, a clamping continuity traceability segment is formed under the same processing traceability identifier.

[0011] Furthermore, when determining the material removal coverage of the detected abnormal area by the subsequent processing traceability segment, the tool position in the subsequent processing traceability segment is spatially matched with the local processing part of the mold corresponding to the detected abnormal area; when the tool position is located in a preset adjacent range outside the detected abnormal area, and the tool action boundary determined by the tool position and the tool compensation information does not enter the detected abnormal area, the subsequent processing traceability segment is not regarded as a processing traceability segment covering the detected abnormal area.

[0012] Furthermore, when determining whether the subsequent processing traceability segment has reached the material removal amount required to eliminate the residue of the preceding processing, the tool compensation information, workpiece coordinate system, and tool position recorded at the end of the preceding processing traceability segment are used as the basis for the preceding residue, and the tool compensation information, workpiece coordinate system, and tool position recorded at the beginning of the subsequent processing traceability segment are used as the basis for subsequent correction; when the control difference between the preceding and subsequent basis does not cause the change in the theoretical processing allowance of the detected abnormal area to reach the preset allowance change threshold, the detected abnormal area is retained and attributed to the preceding processing traceability segment.

[0013] Furthermore, when the same abnormal detection area corresponds to two or more subsequent processing traceability segments, the search proceeds from the last to the first according to the order in which the material removal occurred. If the last subsequent processing traceability segment does not cover the abnormal detection area, the search continues with the previous subsequent processing traceability segment until a subsequent processing traceability segment is found that covers the abnormal detection area and achieves the material removal amount required to eliminate the residue from the preceding processing. The obtained subsequent processing traceability segment is then used as the source of the abnormal detection area. If neither of the two or more subsequent processing traceability segments meets the coverage and material removal amount conditions, the abnormal detection area is attributed to the preceding processing traceability segment.

[0014] Furthermore, when forming the clamping continuity traceability segment, the end tool position of the last material removal action before the clamping state change and the start tool position of the first material removal action after the clamping state change are taken as the continuity boundary; when there is a common action area formed by the overlap of the action boundary space of the front and rear tools at the continuity boundary of the previous and subsequent machining traceability segments, the differences in workpiece coordinate system, differences in tool compensation information and differences in clamping state within the common action area are taken as continuity differences and included in the clamping continuity traceability segment.

[0015] Furthermore, when the detected abnormal area corresponds to the local machining part of the mold corresponding to the clamping continuation tracing segment, the machining tracing segment corresponding to the first material removal action after the change in clamping state is first traced back; if the machining tracing segment does not fall within the workpiece coordinate system difference range, tool compensation information difference range, or clamping state difference influence range in the clamping continuation tracing segment, then the machining tracing segment corresponding to the last material removal action before the change in clamping state is traced back again; if the machining tracing segment falls within the difference range or the difference influence range, then the clamping continuation tracing segment is used as the candidate tracing source of the detected abnormal area.

[0016] Furthermore, when tracing back to the machining traceability segment corresponding to the last material removal action before the change in clamping state, the overlapping range of the tool position before and after the change in clamping state of the detected abnormal area is taken as the continuous verification area; if the workpiece coordinate system difference or tool compensation information difference in the continuous verification area is consistent with the deviation direction of the detected abnormal area in the coordinate direction or normal direction, then the continuous difference is taken as the priority traceability source of the detected abnormal area.

[0017] This invention generates machining traceability identifiers for local machining areas of the mold based on the mold's digital thread, and associates these identifiers with CNC program segments, workpiece coordinate systems, tool information, tool compensation information, and clamping status. This allows local machining areas to be managed not only by geometric models or process names, but also by establishing a correspondence with actual CNC execution conditions. Therefore, during CNC machining, when the current execution status matches the associated information and the tool position enters the corresponding machining range, the CNC machining process can be attributed to the corresponding machining traceability identifier, improving the accuracy and verifiability of recording the machining process in local areas of the mold.

[0018] This invention records control state changes during machining, including workpiece coordinate system calls, tool compensation calls, clamping status confirmation, and program execution position changes. Based on whether the tool is in a material removal state when a control state change occurs, it categorizes these changes as machining preparation records or new machining traceability segments. This avoids mistaking idle travel, preparatory actions, or non-cutting adjustments for actual machining sources. After machining, detected abnormal areas can be mapped to local machining parts of the mold, and further traced back to the machining traceability segment that caused the material removal in that abnormal area. This facilitates defect source localization, machining parameter verification, compensation adjustment analysis, and subsequent process optimization, improving the completeness and reliability of mold machining quality traceability. Attached Figure Description

[0019] Figure 1 This is a flowchart illustrating the process traceability of the present invention, used to show the core processes of digital thread creation and identification, execution attribution, fragment formation, and exception backtracking.

[0020] Figure 2 This is a diagram showing the inclusion of processing traceability identifiers and the formation of segments in Embodiment 1 of the present invention.

[0021] Figure 3 This is the effective coverage determination diagram for detecting abnormal areas in Embodiment 1 of the present invention.

[0022] Figure 4 This is a graph showing the residual elimination ability and anomaly attribution determination in Embodiment 1 of the present invention.

[0023] Figure 5 This is a diagram showing the formation of the clamping and connecting traceability segment in Embodiment 2 of the present invention.

[0024] Figure 6 This is a diagram showing the comprehensive influence of clamping and connection differences in Embodiment 2 of the present invention.

[0025] Figure 7 This is a diagram showing the consistency determination of the direction of the continuous verification area in Embodiment 2 of the present invention. Detailed Implementation

[0026] As attached Figure 1As shown, in practical implementation, the mold digital thread is first used as the data basis for machining process traceability. Mold cavities, cores, ribs, local curved surfaces, holes, or other locally machined parts requiring independent traceability are divided, and a corresponding machining traceability identifier is generated for each locally machined part. The mold digital thread pre-stores the geometric boundaries, process steps, machining allowances, inspection datums, and their correspondence with machine tool coordinates for each locally machined part. The machining range is jointly defined by the theoretical geometric boundaries, reserved machining allowance boundaries, and actual tool action boundaries of the locally machined part. After the machining traceability identifier is generated, it is associated with the CNC program segment called during actual machining, the workpiece coordinate system, tool information, tool compensation information, and clamping status information, ensuring that each locally machined part corresponds to a clear program source, coordinate datum, tool conditions, compensation status, and clamping conditions. Tool information at least indicates the tool number, tool type, tool length, tool radius, and tool geometric parameters. Tool compensation information indicates the calling status related to tool length compensation, radius compensation, or wear compensation. In this way, during subsequent processing and quality inspection, the processing traceability identifier can be used as an index to unify process data, machine tool execution data, and inspection data onto the same local processing part of the mold.

[0027] During CNC machining, the current execution status and tool position of the CNC system are continuously collected. The current execution status reflects the real-time calling status of CNC program segments, workpiece coordinate system, tool information, tool compensation information, and clamping status information. The tool position reflects the actual movement position of the tool relative to the local machining area of ​​the mold. When the collected current execution status matches the CNC program segment, workpiece coordinate system, tool information, tool compensation information, and clamping status information pre-associated with the machining traceability identifier, and the tool position enters the machining range of the corresponding local machining area of ​​the mold defined by the mold digital thread, it indicates that the current CNC machining process has actually been associated with the machining of that local machining area of ​​the mold. At this time, the CNC machining process is recorded under the corresponding machining traceability identifier. To determine whether the tool has a material removal effect on the mold material, the cutting feed command in the CNC program, the spindle running status, the intersection status of the tool action boundary and the workpiece allowance area, and the feed axis load change in the machine tool execution data can be used for confirmation. When the above statuses indicate that the tool has entered the workpiece allowance area and is in the cutting feed state, it is identified as a material removal state.

[0028] During the machining process, changes in control state are also recorded. These changes can include changes in the workpiece coordinate system, tool compensation, clamping status confirmation, or program execution position. When recording these changes, it is simultaneously determined whether the tool is in a material removal state at the time of the change. When a control state change occurs before the tool has removed material from the mold, it is included in the machining preparation record to illustrate the state adjustment process before machining. When a control state change occurs after the tool is in a material removal state, it indicates that the change may affect the machined surface that has already formed or is in the process of forming; therefore, a new machining traceability segment is formed based on this change. When forming a new machining traceability segment, the last stable execution state before the change is taken as the end state of the previous machining traceability segment, and the first stable execution state after the change is taken as the start state of the next machining traceability segment. The corresponding tool position and material removal state are also recorded. After processing is completed, the detected abnormal areas are registered with the geometric reference in the mold digital thread through the detection reference and mapped to the local processing part of the mold. Then, based on the processing traceability segment recorded under the local processing part of the mold, the processing traceability segment that caused the material removal effect on the detected abnormal area is traced back to determine the correspondence between the detected abnormal area and the specific processing process.

[0029] In practical implementation, to ensure a stable state basis for the machining traceability identifier when assigned to a local machining area of ​​the mold, during the execution of the CNC program, before the tool enters the machining range defined by the mold's digital thread, the system continuously reads the execution status of the current CNC program and identifies the workpiece coordinate system calls, tool compensation calls, clamping status confirmations, and program execution positions that have actually taken effect before entering the machining range. For the most recent effective state information before entering the machining range during the execution of the same CNC program, the system seals it as the reference state before entering the local machining area of ​​the mold. This ensures that when the machining traceability identifier is assigned to the corresponding local machining area of ​​the mold, it can not only record the machining behavior after the tool enters the machining range, but also retain the coordinate reference, compensation conditions, clamping conditions, and program position basis that were determined before the start of the machining behavior. If there are multiple coordinate, compensation, or clamping status confirmation records before entering the machining range, the last valid state that has been called by the CNC system and participated in tool position interpretation before entering the machining range is used as the reference state. Pre-read information that has not actually participated in tool position interpretation is not used as the reference state.

[0030] Once the tool enters the material removal state, if the CNC system experiences changes in workpiece coordinate system, tool compensation, clamping status, or program execution position, the system will no longer treat this control state change merely as part of the machining preparation process. Instead, it will use this change as the basis for dividing machining traceability segments. Specifically, the content that was already stored and effective before the control state change occurs will be used as the prerequisite for the current machining traceability segment, explaining the coordinate, compensation, clamping, and program execution conditions under which the current machining traceability segment was formed. Simultaneously, the current execution state after the control state change will be used as the starting point for the next machining traceability segment, ensuring a clear continuity between adjacent machining traceability segments based on control state changes. The tool position, change type, and corresponding program positions before and after the change are also retained between adjacent machining traceability segments, allowing subsequent backtracking to distinguish between normal segment continuity caused by program segment switching and traceability boundaries caused by changes in coordinate, compensation, or clamping status. By using the above methods, we can avoid confusion in the traceability boundary caused by changing the coordinate system, adjusting tool compensation, reconfirming the clamping status, or changing the program execution position in the local processing part of the same mold. This improves the accuracy of subsequent detection of abnormal areas and back to the specific processing segment.

[0031] In practice, after processing is completed and inspection results are obtained, the system first maps the detected abnormal area to the corresponding local processing part of the mold in the mold digital thread, and then retrieves the processing traceability segment already formed under that local processing part. When the same detected abnormal area corresponds to both the preceding processing traceability segment and the subsequent processing traceability segment, the system does not directly use the subsequent processing time as the basis for attribution, but further determines whether the subsequent processing traceability segment has actually removed and covered the detected abnormal area. If the subsequent processing traceability segment has effectively removed material from the detected abnormal area, and the amount of material removal can eliminate any processing residue that may be left by the preceding processing traceability segment, then the detected abnormal area can be associated with the subsequent processing traceability segment. Processing residue refers to the processing allowance, tool mark deviation, or positional deviation that may remain in the detected abnormal area after the preceding processing traceability segment ends. If the subsequent processing traceability segment does not cover the detected abnormal area, or if the amount of subsequent material removal determined based on the preceding processing allowance, tool compensation difference, and the boundary of the subsequent tool position cannot reach the amount of material removal required to eliminate the preceding processing residue, then the detected abnormal area is still more likely to originate from the preceding processing stage, and in this case, the detected abnormal area is attributed to the preceding processing traceability segment. The preset allowance change threshold and material removal amount judgment conditions can be preset according to the machining tolerance of the local machining parts of the mold, the process allowance, the detection resolution and quality judgment requirements.

[0032] When determining whether a subsequent processing trace segment covers the detected anomaly area, the system spatially matches the tool position recorded in the subsequent processing trace segment with the corresponding local processing part of the mold in the detected anomaly area. During spatial matching, it not only determines whether the tool trajectory passes near the detected anomaly area but also combines tool compensation information to determine the actual working boundary of the tool. The actual working boundary of the tool is jointly determined by the tool position, tool geometry parameters, tool compensation information, and workpiece coordinate system, representing the spatial range within which the tool can actually cut the workpiece material at that tool position. If the tool position is only located within a preset proximity range outside the detected anomaly area, and the tool working boundary determined by the tool position and tool compensation information does not enter the detected anomaly area, it indicates that although the subsequent processing trace segment is spatially close to the detected anomaly area, it does not produce an actual material removal effect on the detected anomaly area. Therefore, this subsequent processing trace segment is not considered a processing trace segment covering the detected anomaly area. This judgment method avoids incorrectly attributing anomalies to subsequent processing processes simply because the tool trajectory is nearby.

[0033] When determining whether a subsequent machining traceability segment has reached the material removal amount required to eliminate residues from the preceding machining process, the system uses the tool compensation information, workpiece coordinate system, and tool position recorded at the end of the preceding machining traceability segment as the basis for identifying the previous residues. This information reflects the machining allowance or positional deviation that may remain in the detected abnormal area after the preceding machining process ends. Simultaneously, the tool compensation information, workpiece coordinate system, and tool position recorded at the beginning of the subsequent machining traceability segment are used as the basis for subsequent correction, determining whether subsequent machining can correct the previous residues. If the control difference between the previous residue basis and the subsequent correction basis does not cause the theoretical machining allowance change in the detected abnormal area to reach the preset allowance change threshold, it indicates that the subsequent machining's correction effect on the detected abnormal area is insufficient, and the detected abnormal area still belongs to the preceding machining traceability segment. When the same detected abnormal area corresponds to two or more subsequent machining traceability segments, the system searches sequentially from the last to the first, according to the order in which the material removal occurred. If the final subsequent processing traceability segment does not cover the detected anomaly area, the search continues for the previous subsequent processing traceability segment until a subsequent processing traceability segment is found that both covers the detected anomaly area and achieves the material removal amount required to eliminate the residue from the preceding processing. This subsequent processing traceability segment is then used as the source of the detected anomaly area. If two or more subsequent processing traceability segments cannot simultaneously meet the coverage and material removal amount conditions, the detected anomaly area is attributed to the preceding processing traceability segment, thus forming an anomaly traceability result with causal basis.

[0034] In practical implementation, when the same mold's local machining area needs to be continuously machined under different clamping states, the system does not separate the machining process before and after clamping into independent traceability objects. Instead, it performs continuous processing of the machining traceability segments before and after the clamping state change under the same machining traceability identifier. Specifically, the system first determines the machining traceability segment that last caused material removal on the local machining area of ​​the mold before the clamping state change, and then determines the machining traceability segment that first caused material removal on the local machining area of ​​the mold after the clamping state change. These two segments are considered adjacent segments in the continuous machining relationship before and after clamping. When there are differences in workpiece coordinate system, tool compensation information, or clamping state information between two machining traceability segments, it indicates that the clamping transformation may affect the coordinate reference of the local machining area, the actual position of the tool, or the machining boundary. Therefore, a clamping continuation traceability segment is formed under the same machining traceability identifier to separately record the continuation effect caused by the clamping change. The clamping state information can consist of the clamping reference, fixture number, positioning point confirmation status, clamping status, and clamping verification result, which is used to characterize the positioning relationship of the mold relative to the machining coordinate reference under different clamping conditions.

[0035] When forming a clamping continuity traceability segment, the system uses the ending tool position of the last material removal action before the clamping state change as the termination boundary of the pre-clamping machining, and the starting tool position of the first material removal action after the clamping state change as the starting boundary of the post-clamping machining, thus determining the continuity boundary between the preceding and following machining processes. Subsequently, the system determines the preceding and following tool action boundaries based on the tool position, tool compensation information, and tool geometry parameters in the preceding and following machining traceability segments, and determines whether the preceding and following tool action boundaries spatially coincide at the continuity boundary. If spatial coincidence exists, the overlapping area is defined as the common action area, and the differences in workpiece coordinate system, tool compensation information, and clamping state information reflected within the common action area are classified as continuity differences and included in the clamping continuity traceability segment. The continuity differences also record the direction corresponding to the difference, the range of the affected local machining parts, and the correspondence between the difference and the common action area. In this way, machining connection deviations caused by clamping state changes are not simply classified into the pre-clamping or post-clamping segments, but are instead recorded as independent, traceable records within the clamping continuity traceability segment.

[0036] When an abnormal detection area corresponds to a local machining part of the mold corresponding to a clamping continuity traceability segment, the system first traces back the machining traceability segment corresponding to the first material removal action after the clamping state change to determine whether the abnormal detection could be directly caused by post-clamping machining. If the machining traceability segment does not fall within the workpiece coordinate system difference range, tool compensation information difference range, or clamping state information difference influence range recorded in the clamping continuity traceability segment, it indicates that there is no direct correlation between the abnormal detection and the clamping continuity difference. The system continues to trace back the machining traceability segment corresponding to the last material removal action before the clamping state change to determine whether the abnormal detection originates from pre-clamping machining residue. If the machining traceability segment corresponding to the first material removal action after the clamping state change falls within the above-mentioned difference range or difference influence range, the clamping continuity traceability segment is used as a candidate traceability source for the abnormal detection area, indicating that the abnormality may be caused by the coordinates after clamping transformation, compensation, or clamping influence. The range of differences in workpiece coordinate system, tool compensation information, and clamping status information are determined based on the projection range of the coordinate references sealed before and after clamping changes, the tool compensation recall status, and the clamping verification results onto the local machining area of ​​the mold.

[0037] When tracing back the machining segment corresponding to the last material removal action before the clamping state change, the system defines the overlapping range of tool positions before and after the clamping state change in the detected abnormal area as the continuation verification area. This continuation verification area is used to compare the spatial correspondence when material removal actions occur on the same local area before and after clamping. If the workpiece coordinate system difference or tool compensation information difference in the continuation verification area is consistent with the deviation direction of the detected abnormal area in the coordinate or normal direction, it indicates that the deviation of the detected abnormality corresponds to the continuation difference recorded during the clamping continuation process. At this time, the system takes the continuation difference as the priority source of the detected abnormal area, thereby prioritizing the analysis of the abnormality cause from the coordinate reference change, tool compensation change, or clamping state change caused by the clamping transformation, improving the accuracy of the abnormality tracing results in continuous machining scenarios under different clamping states.

[0038] Example 1:

[0039] In the finishing process of a local curved surface of a mold cavity, a certain unit uses a mold digital thread to trace the machining process of the local machined area. The mold digital thread pre-stores the geometric boundaries, machining allowances, inspection datums, CNC program segments, and their correspondence with the workpiece coordinate system of the local machined area. For the local machined area P-03 in the cavity surface, the system generates a machining traceability identifier T-P03 and associates this identifier with the corresponding CNC program segment, workpiece coordinate system, tool number, tool radius compensation value, tool length compensation value, and clamping status, so that subsequently collected machine tool execution data can be aggregated according to this machining traceability identifier.

[0040] During CNC machining, the system continuously collects the current execution status and tool position of the CNC system. The current execution status includes the currently executing CNC program segment, the currently invoked workpiece coordinate system, the current tool information, the current tool compensation information, and the clamping status. The tool position is used to represent the actual movement position of the tool relative to the local machining part P-03 of the mold. When the system determines that the current execution status is consistent with the information pre-associated with the machining traceability identifier T-P03, and the tool position enters the machining range of P-03 defined by the mold digital thread, it records this segment of CNC machining process under the machining traceability identifier T-P03. Figure 2 The process of the CNC program execution process is used as the horizontal basis, and the local machining space position is used as the vertical basis. It shows the process of the tool path entering the P-03 machining range and then being transferred from the machining preparation record to the preceding segment S1, the subsequent segment S2 and the subsequent segment S3. This is used to illustrate that the machining traceability identifier is not only assigned according to the program time, but also depends on the execution status matching and the tool path space entry condition.

[0041] Before the tool enters the machining range of P-03, the system archives the most recently effective workpiece coordinate system call, tool compensation call, clamping status confirmation, and program execution position during the execution of the same CNC program. This archived content serves as a reference state before entering the local machining area, preventing the CNC system from incorrectly including coordinates or compensation states that have not yet taken effect in the machining traceability identifier simply because it pre-reads the program segment. Once the tool enters the material removal state, if there is a change in the workpiece coordinate system call, tool compensation call, clamping status confirmation, or program execution position, the system forms a new machining traceability segment with this change in control state as the boundary. Figure 2 The compensation change and the program position change correspond to the boundary positions of adjacent traceable segments, which can reflect that the control state change under the material removal state will form traceable segment boundaries.

[0042] In this embodiment, P-03 is first semi-finished by the preceding machining traceability segment S1, and then finished by the subsequent machining traceability segments S2 and S3. The tool compensation information, workpiece coordinate system, and tool position recorded at the end of S1 serve as the basis for the preceding residue, used to characterize the machining allowance or positional deviation that may remain on the local curved surface after S1 machining. The tool compensation information, workpiece coordinate system, and tool position recorded at the beginning of S2 and S3 serve as the basis for subsequent correction, used to determine whether the subsequent machining has an actual corrective effect on the preceding residue.

[0043] After processing, a unit obtains an abnormal area Q1 through a detection device. The system first maps Q1 to P-03 in the mold digital thread according to the detection benchmark, and then retrieves the processing traceability segments S1, S2, and S3 already formed under the processing traceability identifier T-P03 corresponding to P-03. Since Q1 is simultaneously located in the processing area formed by S1 and within the theoretical coverage area of ​​subsequent processing, the system does not directly assign Q1 to the last executed processing traceability segment according to the processing time. Instead, it determines whether S2 and S3 have formed a material removal coverage on Q1, and whether the amount of material removal is sufficient to eliminate the previous processing residue left by S1.

[0044] When determining whether subsequent machining trace segments effectively cover the detected abnormal area, the system determines the tool's operational boundary based on the tool position, tool radius compensation value, and tool geometry parameters in the subsequent machining trace segments, and spatially matches the tool's operational boundary with the detected abnormal area Q1. This determination does not rely solely on whether the tool trajectory is close to Q1, but rather uses the area where the tool's operational boundary actually enters Q1 as the coverage criterion. Figure 3 The detection abnormal area Q1 and the effective coverage area of ​​S3 are placed in the same workpiece coordinate plane, while the proximity state of the tool path of S2 is retained. This means that although S2 is close to Q1 in space, its tool action boundary does not enter Q1 and cannot be considered as covering Q1.

[0045] Its effective coverage ratio is determined by the following formula:

[0046]

[0047] In the formula, Indicates the first The effective coverage ratio of each subsequent processing traceability segment for detecting abnormal area Q1; Indicates by the first The area of ​​the tool action boundary entering Q1 is determined by the tool position and tool compensation information of a subsequent machining traceability segment; This represents the area of ​​the detected abnormal region Q1. The derivation of this formula is based on the fact that whether the detected abnormal region can be corrected by subsequent processing depends first on the degree to which the actual boundary of the subsequent tool enters the abnormal region. The closer the entering area is to the total area of ​​the detected abnormal region, the more sufficient the actual material removal and coverage of the region is by the subsequent processing.

[0048] In this embodiment, the area of ​​Q1 The area is 4.20 square millimeters, representing the area of ​​the tool action boundary corresponding to the subsequent machining traceability segment S3 entering Q1. The value is 3.78 square millimeters. Substituting the data, we get:

[0049]

[0050] When the preset effective coverage threshold is 0.80, S3 corresponds to Reaching this threshold indicates that S3 effectively covers Q1. For the subsequent machining traceability segment S2, although its tool position is within a preset proximity range outside Q1, the tool action boundary determined by the tool position and tool compensation information does not enter Q1. Therefore, the corresponding S2 segment... If the value is 0, the system will not recognize S2 as a processing traceability segment covering Q1. Figure 3 The dashed circle in the middle indicates the boundary of the adjacent action of S2, and the cross-filled area indicates the effective coverage area of ​​S3 entering Q1, so that the coverage determination process corresponds to the calculation result of the formula.

[0051] After confirming that S3 effectively covers Q1, the system further determines whether the material removal amount of S3 is sufficient to eliminate the pre-processing residue of S1. This determination is based on the difference between the pre-processing residue baseline and the subsequent correction baseline. The pre-processing residue baseline reflects the possible residual amount at Q1 after S1 ends, while the subsequent correction baseline reflects the theoretical material removal capacity determined by tool compensation, workpiece coordinate system, and tool position after S3 begins. The residue elimination capacity coefficient is determined by the following formula:

[0052]

[0053] In the formula, Indicates the first The residual elimination capability coefficient of each subsequent processing traceability segment; Indicates according to the first The theoretical material removal amount determined by the tool compensation information, workpiece coordinate system, and tool position at the beginning of each subsequent machining traceability segment; This represents the amount of material removed required to eliminate residues from previous processing. The derivation of this formula is based on the fact that whether subsequent processing can eliminate previous residues depends on the ratio between the theoretical amount of material removed by subsequent processing and the amount required to be removed; when this ratio is not less than 1, it means that the amount of subsequent processing meets or exceeds the requirement to eliminate previous residues.

[0054] In this embodiment, the amount of material removal required to eliminate the pre-processing residue at Q1 is determined based on the pre-processing residue at the end of S1. The value is 0.018 mm; the theoretical material removal amount at Q1 in S3 is determined based on subsequent corrections made at the beginning of S3. The value is 0.022 mm. Substituting the data, we get:

[0055]

[0056] Because S3 corresponds to A value greater than 1 indicates that the material removal amount of S3 can eliminate any pre-processing residue that S1 might leave at Q1. If S2 is used as the criterion, its theoretical material removal amount... If it is 0.010 mm, then The value is 0.56, which does not meet the material removal requirements for eliminating residues from previous processing. Therefore, even though S2 is spatially close to Q1, it cannot be considered the source of Q1. Figure 4 The residual elimination capacity coefficients of S2 and S3 are represented by the height of the bars, respectively, and are expressed as follows: As a threshold, it can intuitively reflect the judgment result that S2 is lower than the threshold and S3 exceeds the threshold.

[0057] When the same abnormal detection area Q1 corresponds to more than two subsequent processing traceability segments, the system searches backward according to the order in which the material removal occurred. In this embodiment, the system first searches for the last formed subsequent processing traceability segment S3 and determines its effective coverage ratio. Whether the preset effective coverage threshold has been reached, and determine its residual elimination capability coefficient. Is it not less than 1? Since S3 simultaneously meets the effective coverage condition and the material removal amount condition, the system assigns Q1 to S3 and records this abnormal assignment result under the processing traceability identifier T-P03. Figure 4 The bar corresponding to S3 is above the judgment threshold, and combined with... Figure 3 The coverage relationship between S3 and Q1 indicates that the source of Q1 should be determined as S3.

[0058] In other implementations, if the final subsequent processing traceability segment S3 does not cover the detected abnormal area Q1, or its material removal amount is insufficient to eliminate the residue from the previous processing, the system continues to search for the previous subsequent processing traceability segment S2. If S2 also fails to meet both the coverage condition and the material removal amount condition, Q1 is retained and assigned to the previous processing traceability segment S1. Through the above processing method, the attribution of the detected abnormal area no longer depends solely on the processing time sequence, but is determined simultaneously based on the actual working boundary of the tool, the degree of material removal coverage, and the residue elimination capability, thereby improving the accuracy and verifiability of the traceability results for abnormalities in local processing parts of the mold.

[0059] Example 2:

[0060] In the local machining process of the core rib groove of a mold, a certain unit uses a mold digital thread to trace the continuous machining process under different clamping states. The mold digital thread pre-stores the geometric boundaries, clamping datum, workpiece coordinate system, tool compensation information, tool position, and detection datum of the local machining area. For the local machining area R-06 in the core rib groove, the system generates a machining traceability identifier T-R06 and uniformly collects the machining data related to R-06 before and after the clamping state change under this machining traceability identifier.

[0061] In this embodiment, R-06 first completes partial material removal in the first clamping state using machining traceability segment A1, and then continues material removal in adjacent areas in the second clamping state using machining traceability segment A2. The system does not treat A1 and A2 as independent traceability objects. Instead, it first determines the end tool position of the last material removal operation in A1 before the clamping state change, and then determines the start tool position of the first material removal operation in A2 after the clamping state change, using both as the boundary between continuous machining before and after clamping. Figure 5 Taking the R-06 local machining area as a unified spatial object, the end tool position of A1, the start tool position of A2, and the connection boundary between them are placed in the same workpiece coordinate plane. This can reflect that the continuous machining before and after the clamping change is still collected under the same machining traceability mark T-R06.

[0062] At the junction boundary, the system determines the front and rear tool action boundaries based on the tool position, tool geometry parameters, and tool compensation information recorded in A1 and A2. When the front and rear tool action boundaries spatially coincide at the junction boundary, the system defines the overlapping portion as the common action area. If there are differences in workpiece coordinate systems, tool compensation information, or clamping status information within the common action area, a clamping junction traceability segment J1 is created under the machining traceability identifier T-R06, and the aforementioned differences are recorded as junction differences. Figure 5 The common action area is located at the spatial overlap of A1 and A2, and the continuation boundary passes through this area. This indicates that J1 is not a record independent of the machining area, but rather originates from the continuation effect of the tool action boundary before and after clamping on the same local machining part.

[0063] To determine whether the discrepancy in clamping continuity warrants separate tracing, the system combines the spatial offset of the workpiece coordinate system before and after the clamping state change with the tool compensation difference into a comprehensive impact factor for the clamping continuity difference. The calculation formula is as follows:

[0064]

[0065] In the formula, This represents the overall impact of differences in clamping and connection. , and These represent the offset components of the workpiece coordinate system in the X, Y, and Z directions before and after the change in clamping state; This represents the difference in tool radius compensation or equivalent tool radius before and after a change in clamping state. The formula first synthesizes the spatial offset using offset components in three coordinate directions, then superimposes the absolute influence of the tool compensation difference to characterize the comprehensive effect of clamping changes on the common action area.

[0066] In this embodiment, It is 0.012mm. It is -0.006mm. It is 0.004mm. The value is 0.003 mm. Substituting the data, we get:

[0067]

[0068] If the preset continuation impact threshold is 0.012mm, then The threshold has been exceeded, indicating that the coordinate reference offset and tool compensation difference caused by the change in clamping state have affected the common action area of ​​R-06. Based on this, the system saves J1 as a separate clamping continuation traceability segment and records the direction of difference, the affected common action area, and the corresponding clamping state information in J1. Figure 6 The composite amount of three-dimensional coordinate offset, the amount of tool compensation difference, and the amount of comprehensive influence are displayed side by side, and 0.012mm is used as the judgment threshold, so that the clamping connection difference is transformed from a qualitative description into a verifiable quantitative judgment process.

[0069] After processing, a unit obtains an abnormal area M1 through a detection device. The system first maps M1 to R-06 in the mold digital thread according to the detection datum, and then traces back to the processing trace segment A2 corresponding to the first material removal action after the clamping state change. If the tool action boundary of A2 at M1 does not fall within the workpiece coordinate system difference range, tool compensation information difference range, or clamping state difference influence range recorded by J1, the system continues to trace back to the processing trace segment A1 corresponding to the last material removal action before the clamping state change to determine whether M1 originates from pre-clamping processing residue. If A2 at M1 falls within the above difference range or difference influence range, the system uses the clamping continuation trace segment J1 as a candidate traceability source for M1.

[0070] After selecting J1 as a candidate traceability source, the system further determines the overlapping range of the tool position of M1 before and after the change in clamping state as the continuous verification area. This continuous verification area is used to compare the spatial correspondence when material removal occurs in the same local area before and after clamping. Figure 7 Centered on the continuation verification area, the continuation difference direction recorded by J1 and the actual deviation direction of M1 are plotted in the same offset coordinate system. The X and Y direction offsets are used to show the consistency of direction in the plane, and the Z component participates in subsequent calculations in a synchronous manner to avoid attribution bias caused by relying solely on two-dimensional projection.

[0071] The system will determine the consistency between the direction of the continuity difference formed by the differences in the workpiece coordinate system and the differences in tool compensation information within the continuity verification area and the actual deviation direction of M1 in the coordinate or normal direction. The calculation formula is as follows:

[0072]

[0073] In the formula, Indicates the directional consistency coefficient; This represents the direction vector of the continuity difference within the continuity verification area, which is formed by the differences in the workpiece coordinate system and the differences in tool compensation information. This represents the actual deviation direction vector of the detected abnormal region M1 in the coordinate or normal direction; Represents the dot product of two direction vectors; and Let represent the lengths of the two direction vectors. This formula uses the closeness of the angle between the two direction vectors as the criterion. The closer it is to 1, the more consistent the direction of the deviation in detecting abnormalities is with the direction of the difference in clamping and connection.

[0074] In this embodiment, The components in the X, Y, and Z directions are 0.012, -0.006, and 0.004, respectively. The components in the X, Y, and Z directions are 0.010, -0.005, and 0.003, respectively. Substituting the data, we get:

[0075]

[0076] If the preset directional consistency threshold is 0.85, then Reaching this threshold indicates that the actual deviation direction of M1 is highly consistent with the direction of the continuity difference recorded in J1. At this point, the system identifies the continuity difference in J1 as the primary source of M1 for tracing, and uses A1 and A2 as auxiliary verification objects, so that the anomaly cause analysis prioritizes changes in coordinate reference, tool compensation, or clamping status caused by clamping conversion. Figure 7 The two directional vectors are essentially in the same direction within the continuation kernel region, and can be correlated with... The calculation results correspond to the fact that the anomaly is more likely caused by differences in clamping and splicing, rather than by the routine material removal process of A1 or A2 alone.

[0077] Through the above methods, the system can retain the continuity relationship of continuous processing before and after clamping under the same processing traceability identifier, and independently record and verify the continuity differences in the common area. This enables the detection of abnormal areas to have clear candidate traceability sources and priority traceability sources in continuous processing scenarios under different clamping states, thereby improving the accuracy and verifiability of attributing local processing abnormalities in molds.

Claims

1. A method for tracing the machining process driven by digital threads in mold making, characterized in that, Based on the mold digital thread, a machining traceability identifier is generated for the local machining part of the mold, and the machining traceability identifier is associated with the corresponding CNC program segment, workpiece coordinate system, tool information, tool compensation information and clamping status; During CNC machining, the current execution status and tool position of the CNC system are collected. When the CNC program segment, workpiece coordinate system, tool information, tool compensation information and clamping status in the current execution status match the association information of the machining traceability identifier, and the tool position enters the machining range of the corresponding local machining part of the mold defined by the mold digital thread, the CNC machining process is classified into the machining traceability identifier. During the machining process, the changes in control state are recorded. These changes include workpiece coordinate system invocation, tool compensation invocation, clamping status confirmation, or program execution position changes. Depending on whether the tool is in a material removal state when the control state changes, the changes are categorized into the machining preparation record or form a new machining traceability segment. After machining is completed, the detected abnormal area is mapped to the local machining part of the mold, and the process traceability segment that caused the material removal effect on the detected abnormal area is traced back.

2. The traceability method according to claim 1, characterized in that, The most recent workpiece coordinate system call, tool compensation call, clamping status confirmation, and program execution position before entering the machining range during the execution of the same CNC program are effectively sealed; when the control state changes after the tool enters the material removal state, the effective sealed content before the change is used as the prerequisite for the current machining traceability segment, and the current execution state after the change is used as the starting basis for the next machining traceability segment.

3. The traceability method according to claim 1, characterized in that, The material removal coverage of the detected abnormal area is assigned according to the subsequent processing traceability segment; if the subsequent processing traceability segment does not cover the detected abnormal area, or if the subsequent material removal amount determined by the previous processing allowance, tool compensation difference and subsequent tool position boundary does not reach the material removal amount required to eliminate the previous processing residue, then the detected abnormal area is assigned to the previous processing traceability segment.

4. The traceability method according to claim 1, characterized in that, The machining traceability segment corresponding to the last material removal action before the change of clamping state is connected to the machining traceability segment corresponding to the first material removal action after the change of clamping state; when there are differences in the workpiece coordinate system, tool compensation information or clamping state between the previous and subsequent machining traceability segments, a clamping continuation traceability segment is formed under the same machining traceability identifier.

5. The traceability method according to claim 3, characterized in that, The tool position in the subsequent processing traceability segment is spatially matched with the local processing part of the mold corresponding to the detection abnormal area; when the tool position is located in a preset adjacent range outside the detection abnormal area, and the tool action boundary determined by the tool position and the tool compensation information does not enter the detection abnormal area, the subsequent processing traceability segment is not used as a processing traceability segment covering the detection abnormal area.

6. The traceability method according to claim 3, characterized in that, The tool compensation information, workpiece coordinate system, and tool position recorded at the end of the preceding machining traceability segment are used as the basis for the preceding residual, and the tool compensation information, workpiece coordinate system, and tool position recorded at the beginning of the subsequent machining traceability segment are used as the basis for subsequent correction. When the control difference between the preceding and subsequent basis does not cause the change in the theoretical machining allowance of the detected abnormal area to reach the preset allowance change threshold, the detected abnormal area is retained and attributed to the preceding machining traceability segment.

7. The traceability method according to claim 3, characterized in that, When the same abnormal detection area corresponds to two or more subsequent processing traceability segments, the search proceeds from the last to the first according to the order in which the material removal occurred. If the last subsequent processing traceability segment does not cover the abnormal detection area, the search continues with the previous subsequent processing traceability segment until a subsequent processing traceability segment is found that covers the abnormal detection area and achieves the material removal amount required to eliminate the residue from the preceding processing. The obtained subsequent processing traceability segment is then used as the source of the abnormal detection area. If neither of the two or more subsequent processing traceability segments meets the coverage and material removal amount conditions, the abnormal detection area is attributed to the preceding processing traceability segment.

8. The traceability method according to claim 4, characterized in that, The end tool position of the last material removal action before the change of clamping state and the start tool position of the first material removal action after the change of clamping state are taken as the continuation boundary. When there is a common action area formed by the overlap of the action boundary space of the front and rear tools at the continuation boundary of the previous and subsequent machining traceability segments, the differences in workpiece coordinate system, differences in tool compensation information and differences in clamping state within the common action area are taken as continuation differences and included in the clamping continuation traceability segment.

9. The traceability method according to claim 4, characterized in that, The machining traceability segment corresponding to the first material removal action after the change in clamping state is traced back; if the machining traceability segment does not fall within the workpiece coordinate system difference range, tool compensation information difference range, or clamping state difference influence range in the clamping continuation traceability segment, then the machining traceability segment corresponding to the last material removal action before the change in clamping state is traced back again; if the machining traceability segment falls within the difference range or the difference influence range, then the clamping continuation traceability segment is used as a candidate traceability source for the detected abnormal area.

10. The traceability method according to claim 9, characterized in that, The overlapping range of tool positions before and after the change in clamping state of the detected abnormal area is taken as the continuous verification area; if the workpiece coordinate system difference or tool compensation information difference in the continuous verification area is consistent with the deviation direction of the detected abnormal area in the coordinate direction or normal direction, then the continuous difference is taken as the priority traceability source of the detected abnormal area.

Images