Construction method of process datum and unified datum collaborative standardization in CNC machining

Abstract

The application provides a construction method of process reference and unified reference coordination standardization in CNC machining, comprising the following steps: S1, machining part classification and reference present situation investigation; S2, reference problem identification and analysis; S3, reference selection rule making; S4, standard process reference library construction; S5, reference precision and error control; S6, reference and production whole factor coordination. The reference system of "unified reference as the main, process reference as the auxiliary, whole process coordination control" is established, the reference unification of design, process, machining and testing is realized, and the machining precision stability, production change efficiency and management standardization level are improved.

Description

Technical Field

[0001] This invention relates to the fields of intelligent manufacturing and CNC machining technology, and in particular to a method for constructing a collaborative standardization of process references and unified references in CNC machining. Background Technology

[0002] Currently, as the manufacturing industry transforms towards flexibility and intelligence, intelligent flexible processing lines have become the core equipment for processing precision parts in small batches of various varieties.

[0003] In existing technologies, in multi-variety, small-batch CNC machining production, especially in scenarios involving multiple customer drawings, the design datums of different machined parts often differ. Traditional production models commonly suffer from chaotic datum management. (1) The unified benchmark and the process benchmark are disconnected, and there is a lack of standardized construction process, which leads to the inconsistency of design benchmark, process benchmark and measurement benchmark. Frequent switching of benchmark between processes generates cumulative error and large fluctuations in the machining accuracy of parts. (2) The selection of references relies too much on the operator's experience. The selection of references for the same type of parts is not uniform. Fixtures and programs cannot be reused, the changeover time is long, and the production efficiency is low. (3) Lack of quantitative benchmark accuracy and error control standards, unstable benchmark accuracy, and inability to support intelligent production processes such as automated loading and unloading and automatic detection.

[0004] Therefore, there is an urgent need to develop a construction method that can achieve unified benchmark and process benchmark collaborative standardization and closed-loop management of the entire process to solve the above pain points. Summary of the Invention

[0005] The purpose of this invention is to provide a method for constructing a collaborative standardization of process datum and unified datum in CNC machining, aiming to solve or at least partially solve the shortcomings of the above-mentioned background technology. By establishing a datum system of "unified datum as the main standard, process datum as the auxiliary standard, and collaborative control of the whole process", it realizes the datum unification of design, process, machining, and inspection, and improves the stability of machining accuracy, production changeover efficiency and management standardization level.

[0006] This invention provides a method for constructing a collaborative standardization mechanism between process datum and unified datum in CNC machining, comprising the following steps: S1. Classification of Machining Parts and Survey of Current Status of Standards: All machining parts are classified according to structural type, and all machining processes of the machining parts are sorted out. The process standards and sources of standards for each machining process are recorded to form a list of current status of process standards. Among them, process standards include positioning standards, clamping standards, and measurement standards. S2. Identification and Analysis of Benchmark Problems: Based on benchmark problems, compare the design benchmarks of the workpiece design drawings to identify benchmark problems existing in the process benchmarks, and analyze the root causes of benchmark problems; S3. Formulate reference selection rules: Based on the reference problem, combined with the machining capabilities of CNC production line equipment and the design drawings of the machined parts, formulate unified and mandatory rough reference selection rules, fine reference selection rules and auxiliary reference setting rules for the entire production line, forming a general specification for process reference selection; S4. Construct a standard process benchmark library: Select general specifications based on process benchmarks, and for typical structural parts and their design drawings, first determine a unified benchmark that runs through the entire process and coincides with the design benchmark of the part, and then confirm the process benchmark for each processing step to form a standard process benchmark library. S5. Reference accuracy and error control: Based on the standard process reference library, reference accuracy control indicators and error control measures are set for the unified reference and each process reference to form a reference accuracy and error control specification. S6. Coordination of benchmarks and all production elements: Based on unified benchmarks and process benchmarks, ensure that the benchmarks of process documents, drawings and models, tooling fixtures, CNC programs and inspection specifications are consistent, forming a unified benchmark system for the entire process.

[0007] Furthermore, the structural types include shafts, discs, flanges, housings, and supports.

[0008] Furthermore, in step S3, the specific rules for selecting the rough reference include: giving priority to non-machined surfaces of the workpiece as the rough reference; giving priority to surfaces of the workpiece with large area, good rigidity, and small deformation; ensuring uniform allowance on important machined surfaces of the workpiece; the rough reference can only be used once; and prohibiting the use of gates, risers, flash, and severely damaged areas as the rough reference.

[0009] Furthermore, in step S3, the specific rules for selecting the precision datum include: the precision datum should preferentially adopt the design datum of the design drawing of the workpiece; the selection of the process datum for each machining process should follow the principle of datum unification to reduce datum conversion; for the datum surface, the precision datum should be easy to clamp, position, measure and tool set, and should not interfere with the tool or fixture.

[0010] Furthermore, in step S3, the rules for setting auxiliary references specifically include: auxiliary references are only added when the design references are not suitable for clamping or machining; auxiliary references must be clearly marked on the design drawings and process documents of the machined parts; the structure of auxiliary references is simple and easy to machine, does not affect the function, strength and assembly requirements of the parts, and can be retained or removed as needed after machining is completed.

[0011] Furthermore, in step S5, the specific aspects of datum accuracy and error control include: positioning error control: positioning error ≤ 1 / 3 of the corresponding dimensional tolerance; repeat clamping error control: quantifying the repeat clamping error in each processing step; datum conversion control: if datum conversion is necessary, dimensional chain calculation and error verification must be completed.

[0012] Furthermore, in step S6, the coordination between the benchmark and the entire production process specifically includes the following sub-steps: S61. Unified process document benchmarks: Mark the process benchmarks and benchmark sources for each processing step in the process documents; S62. Unified datum for drawings and models: Use unified datum symbols to mark the datum position and accuracy requirements of the process datum on the design drawings of the machined parts; S63. Unified tooling and fixture datum: The positioning surfaces, support surfaces, and positioning pins of tooling and fixtures shall be designed and optimized according to a unified datum. S64. Unified CNC program reference: The workpiece coordinate system, tool setting point, and reference point are established according to a unified reference, and a standardized program template is compiled to embed the unified reference into the CNC program; S65. Unified Inspection Standards and Standards: The inspection standards for testing methods and instruments shall be consistent with the process standards. S66. Establish a unified benchmark system covering the entire process of design, technology, processing, and inspection.

[0013] Furthermore, after completing step S6, pilot verification and effect evaluation are carried out: typical structural processed parts are selected to verify the effectiveness of the unified benchmark system for the entire process, and after optimization and improvement, a scalable solution is formed.

[0014] Furthermore, after completing pilot verification and effect evaluation, the standard process benchmark library will be dynamically iterated: a dynamic maintenance mechanism for the standard process benchmark library and a benchmark adaptation mechanism based on drawings will be established to continuously optimize the unified benchmark system for the entire process.

[0015] Furthermore, a data exchange channel is established between the standard process datum library and the enterprise's geometric feature library. The datum surface, datum hole, and center hole used in the unified datum all come from the geometric feature library.

[0016] This invention provides a method for constructing a standardized system for process datum and unified datum in CNC machining. It establishes a unified datum that coincides with the design datum as the core line of the entire process. Simultaneously, it prioritizes the reuse of the unified datum for each process datum, introducing auxiliary datums only when necessary and strictly controlling errors. This fundamentally reduces errors caused by datum conversion, thereby improving the stability of machining accuracy. By deeply embedding the relationship between the unified datum and process datum into all production elements such as process documents, drawings, models, tooling, CNC programs, and inspection specifications, a unified datum system is constructed for the entire process. This achieves a standardized operation mode of "one-time positioning, full process reuse," increasing the reuse rate of tooling and programs for similar machined parts, thereby shortening changeover time and improving production efficiency. Furthermore, by establishing a standardized datum management system led by the unified datum and implemented collaboratively with process datums, it replaces the non-standard datum selection mode that relies on personal experience, reducing the need for customized design and manufacturing of special fixtures and improving the level of standardization in production management. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a flowchart of a method for constructing a collaborative standardization of process datum and unified datum in CNC machining according to the present invention. Detailed Implementation

[0019] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. Based on the description of the present invention, all other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of the present invention.

[0020] Unless otherwise explicitly specified and limited, the terms "setup," "installation," and "connection" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms based on the specific circumstances.

[0021] The terms “upper,” “lower,” “left,” “right,” “front,” “back,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use. They are only for the convenience of description and simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0022] The terms “first,” “second,” “third,” etc., are used merely to distinguish elements with similar properties, not to indicate or imply relative importance or a specific order.

[0023] The terms “include,” “comprising,” or any other variation thereof are intended to cover non-exclusive inclusion, which includes not only the elements listed but also other elements not expressly listed.

[0024] This invention provides a method for constructing a collaborative standardization mechanism between process datum and unified datum in CNC machining, comprising the following steps: S1. Classification and Current Status Survey of Processed Parts: All processed parts are classified according to structural type, and all processing steps of the processed parts are reviewed. The process references and reference sources for each processing step are recorded to form a current status list of process references. Among them, process references include positioning references, clamping references, and measurement references. Structural types include shafts, discs, flanges, boxes, and brackets.

[0025] S2. Benchmark Problem Identification and Analysis: Based on the current status list of process benchmarks and comparing it with the design benchmarks of the workpiece design drawings, identify benchmark problems existing in the process benchmarks. These problems include inconsistent benchmarks, frequent errors caused by inter-process benchmarks, unstable benchmark accuracy, and benchmark selection relying on experience without unified standards. Analyze the root causes of benchmark problems from four dimensions: process, tooling, operation, and management.

[0026] S3. Formulate reference selection rules: Based on the reference problem, combined with the machining capabilities of CNC production line equipment and the design drawings of the machined parts, formulate unified and mandatory rough reference selection rules, fine reference selection rules and auxiliary reference setting rules for the entire production line, forming a general specification for process reference selection.

[0027] Furthermore, the specific rules for selecting the coarse datum include: (1) The non-machined surface of the workpiece should be used as the rough reference.

[0028] (2) Prioritize the use of surfaces with large area, good rigidity and small deformation in the processed parts.

[0029] (3) Ensure that the allowance on the important machining surfaces of the workpiece is uniform.

[0030] (4) The coarse reference should be used only once and should not be reused to avoid cumulative error.

[0031] (5) It is forbidden to use gates, risers, flash, or severely damaged areas as rough reference.

[0032] Furthermore, the specific rules for selecting precise benchmarks include: (1) The design datum of the machining part should be used first.

[0033] (2) The selection of process reference for each processing step follows the principle of reference unification to reduce reference conversion.

[0034] (3) For the reference surface, the precision reference should be easy to clamp, position, measure and set the tool, and should not interfere with the tool or fixture.

[0035] (4) For the reference surface, it is necessary to clarify the uniform accuracy requirements such as flatness and roughness of the precision reference.

[0036] Furthermore, the auxiliary benchmark setting rules specifically include: (1) Auxiliary datum is only added when the design datum is not suitable for clamping or machining.

[0037] (2) Auxiliary references must be clearly marked in the design drawings and process documents of the workpiece.

[0038] (3) The auxiliary reference has a simple structure and is easy to process. It does not affect the function, strength and assembly requirements of the parts, and can be retained or removed as needed after processing.

[0039] S4. Construct a standard process benchmark library: Select general specifications based on process benchmarks, and for typical structural parts and their design drawings, first determine a unified benchmark that runs through the entire process and coincides with the design benchmark of the part, and then confirm the process benchmark for each processing step to form a reusable standard process benchmark library.

[0040] S5. Reference accuracy and error control: Based on the standard process reference library, reference accuracy control indicators and error control measures are set for the unified reference and each process reference, forming a reference accuracy and error control specification.

[0041] In step S5, the specific aspects of reference accuracy and error control include: (1) Positioning error control: The positioning error is less than 1 / 3 of the corresponding dimensional tolerance.

[0042] (2) Control of repeated clamping error: Quantify the repeated clamping error in each processing step. For example, the repeated clamping error in key processes is ≤0.005mm, and the repeated clamping error in ordinary processes is ≤0.01mm.

[0043] (3) Reference conversion control: If reference conversion is necessary, dimensional chain calculation and error verification must be completed.

[0044] S6. Coordination of benchmarks and the entire production process: Based on unified benchmarks and process benchmarks, ensure that the benchmarks of process documents, drawings and models, tooling fixtures, CNC programs and inspection specifications are consistent, forming a unified benchmark system for the entire process.

[0045] In step S6, the coordination between the benchmark and the entire production process specifically includes the following sub-steps: S61. Unified process document benchmarks: Mark the process benchmarks and benchmark sources for each processing step in the process documents.

[0046] S62. Unified datum for drawings and models: Use unified datum symbols to mark the datum position and accuracy requirements of the process datum on the design drawings of the machined parts.

[0047] S63. Unified tooling and fixture datum: The positioning surfaces, support surfaces, and positioning pins of tooling and fixtures shall be designed and optimized according to a unified datum.

[0048] S64. Unified CNC program reference: The workpiece coordinate system, tool setting point, and reference point are established according to a unified reference, a standardized program template is compiled, and the unified reference is embedded into the CNC program.

[0049] S65. Unified Inspection Standards and Benchmarks: The inspection standards for testing methods and instruments shall be consistent with the process standards.

[0050] S66. Establish a unified benchmark system covering the entire process of design, technology, processing, and inspection.

[0051] S7. Conduct pilot verification and effect evaluation: Select typical structural processing parts to verify the effectiveness of the whole process benchmark unified system, and optimize and improve it to form a scalable solution.

[0052] More specifically, pilot verification and effectiveness evaluation include the following sub-steps: S71. Pilot Project Selection: Select typical structural processed parts as pilot projects; S72. Standardized pilot operation: Processing and production are carried out based on a unified benchmark system for the entire process, and key technical indicators of processed parts are collected in real time. Key technical indicators include processing accuracy, benchmark offset, processing efficiency, and quality pass rate. S73. Implementation effect comparison: Compare the key technical indicators before and after the pilot implementation, analyze the impact of benchmark unification on the key technical indicators of processed parts, and evaluate the implementation effect of benchmark unification. S74. Root cause analysis and optimization: Collect problems such as reference offset, non-standard operation, and insufficient fixture compatibility that occur during the pilot operation, conduct analysis, and carry out targeted optimization; S75. Verification Results: Generate a pilot verification report on process benchmark standardization, clarifying the pilot conclusions, optimization measures, and recommendations for promotion and application.

[0053] S8. Dynamic iteration of the standard process benchmark library: Establish a dynamic maintenance mechanism for the standard process benchmark library and a benchmark adaptation mechanism based on drawings to continuously optimize the unified benchmark system for the entire process.

[0054] More specifically, the dynamic iteration of the standard process benchmark library includes the following sub-steps: S81. Dynamic Maintenance: Review the implementation of benchmark unification, dynamically update benchmark standards and supporting documents in conjunction with the introduction of new processed parts, equipment updates, changes in customer drawings and production process optimization needs, establish a rapid feedback and handling mechanism for benchmark issues, and promptly resolve benchmark issues that arise during production. S82. Adapt to unified standards according to drawings: Regularly review the design standards of different customers' design drawings, optimize the unified standard scheme, and promote its application after customer confirmation.

[0055] Furthermore, a standard process benchmark library is established to interact with the enterprise's geometric feature library. The benchmark surfaces, benchmark holes, and center holes used for the unified benchmark all come from the geometric feature library. When the geometric feature library is updated, the standard process benchmark library is updated synchronously; when the standard process benchmark library is adjusted, the geometric feature library is optimized in reverse, realizing a closed-loop collaboration between feature standardization and benchmark standardization, ensuring that the design, processing, and benchmark selection of geometric features remain consistent.

[0056] As described above, this invention provides a method for constructing a standardized system for process datum and unified datum in CNC machining. By identifying a unified datum that coincides with the design datum as the core line of the entire process, and prioritizing the reuse of the unified datum for each process, auxiliary datums are introduced only when necessary, with strict error control. This fundamentally reduces errors caused by datum conversion, thereby improving the stability of machining accuracy. Furthermore, by deeply embedding the relationship between the unified datum and process datum into all production elements such as process documents, drawings, models, tooling, CNC programs, and inspection specifications, a unified datum system for the entire process is constructed. This achieves a standardized operation mode of "one-time positioning, full process reuse," increasing the reuse rate of tooling and programs for similar machined parts, thereby shortening changeover time and improving production efficiency. Finally, by establishing a standardized datum management system led by the unified datum and implemented collaboratively with the process datum, the non-standard datum selection mode relying on personal experience is replaced, reducing the need for customized design and manufacturing of special fixtures, and improving the level of standardization in production management.

[0057] The present invention will be further described in detail below with reference to specific embodiments.

[0058] This embodiment focuses on the core drive shaft of a smart flexible processing line with a monthly output of 5,000 pieces. The dimensions of the drive shaft are φ30×200mm, and the design reference of the design drawings is the axis centerline.

[0059] S1. Classification and baseline status survey of processed parts (1) Structure type: Shaft-type machined parts.

[0060] (2) The processing steps are as follows: blanking, rough turning of both ends, drilling of A-type center hole, rough turning of outer circle, finish turning of outer circle, milling of 8mm flat keyway, grinding of outer circle, deburring, and three-coordinate inspection.

[0061] The above processing steps constitute a complete precision machining process for the φ30×200mm drive shaft, from raw material blank to qualified finished product. Each step is interconnected, and the underlying logic is consistent throughout. The specific processing steps are as follows: Cutting: Cut the φ32mm steel bar into blanks of about 202mm. Using the outer circle of the blank as a reference, use a steel ruler to control the length. Only the blank preparation is completed.

[0062] Rough turning of both ends: The blank outer circle is held by a three-jaw chuck, and both ends are turned to ensure that the end faces are parallel. The total length is adjusted to 200.5mm, and the total length is controlled by a vernier caliper.

[0063] Drilling Type A Center Holes: The blank outer diameter is held by a three-jaw chuck, and the two ends are drilled to drill the Type A φ3.15 center holes according to GB / T145 standards.

[0064] Rough turning of the outer diameter: The blank outer diameter is clamped at one end by a three-jaw chuck, and the φ32mm blank is turned to φ30.5mm, leaving a finishing allowance. The outer diameter is measured with a micrometer.

[0065] Finish turning of the outer diameter: The outer diameter is rough turned by clamping one end with a three-jaw chuck, and the A-type center hole at the other end is held by the tailstock center. Turn to φ30h6, leaving a grinding allowance. The outer diameter is measured with a micrometer.

[0066] Milling 8mm flat keyway: V-block supports and precision machine the outer diameter, pressure plate fixes the workpiece, mill a standard 8mm flat keyway, the keyway width is checked with a keyway plug gauge, and the depth is measured with a vernier caliper.

[0067] Grinding the outer diameter: Hold the A-type center holes at both ends with two centers and grind to φ30h6 (-0.013 / -0.025) to ensure accuracy and surface roughness. The outer diameter is measured with a micrometer.

[0068] Deburring: Use a hand clamp to hold the outer circle and remove burrs and flash.

[0069] Coordinate measuring machine (CMM) inspection: A general-purpose fixture is used to clamp the outer circle and the outer circle generatrix is ​​used as the measurement datum to inspect key dimensions and geometric tolerances, and to determine whether they are qualified or unqualified.

[0070] (3) The current status list of process benchmarks is shown in Table 1.

[0071] Table 1:

[0072] S2. Benchmark Problem Identification and Analysis (1) Identifying the benchmark problem Inconsistent datum: The design datum is the centerline, but the original process involves four datum conversions (conversion of the blank outer circle to rough turning of the outer circle, conversion of rough turning of the outer circle to finish turning of the outer circle, conversion of finish turning of the outer circle to the center hole, and conversion of the center hole to the outer circle surface), with a cumulative error of 0.02-0.03mm, which directly leads to out-of-tolerance coaxiality of the outer circle (design requirement ≤0.01mm, actual maximum 0.035mm).

[0073] The rough datum is reused three times in processes 2, 3, and 4. Because the roundness error of the blank itself is amplified, the outer wall thickness of the outer circle is uneven.

[0074] The accuracy of the reference surface is not controlled: the contact rate of the conical surface of the A-type center hole is only 50%-60%, and there is no unified testing standard, which causes unstable positioning when grinding the outer circle.

[0075] (2) Root cause analysis At the process level: A unified benchmark system for the entire process has not been established, and the selection of benchmarks relies on the personal experience of process engineers, resulting in a lack of standardized procedures.

[0076] Tooling: The fixtures lack standardized reference interfaces, and the positioning references of the fixtures in different processes are inconsistent, making it impossible to reuse them across processes.

[0077] At the management level: there are no benchmark accuracy control standards, and the quality of the benchmark surface is not included in the mandatory inspection process.

[0078] S3. Establish benchmark selection rules Based on the aforementioned benchmark issues, and considering the machining capabilities of the four three-axis BF-V8 and two four-axis BF-850V machining centers on the production line (spindle speed 12000rpm, positioning accuracy 0.003 / 300mm), specific benchmark selection rules for shaft-type machined parts are formulated: (1) Rules for selecting coarse datum: The outer circle of the blank is used as the sole rough reference, and it is used only once in processes 2 and 3. The rough reference clamping length is ≥30mm to ensure clamping rigidity and avoid vibration during machining; The blank end face, gate marks, and areas of dent damage must not be used as rough references; (2) Rules for selecting precision benchmarks: The A-type φ3.15 center holes at both ends are uniformly used as the precision datum for all processes, and they completely coincide with the design datum (axis centerline); The contact rate of the conical surface of the central hole is ≥80%, the circular runout is ≤0.003mm, and the surface roughness Ra is ≤1.6μm; All subsequent processes must prioritize the use of the center hole for positioning, and it is forbidden to arbitrarily change the reference. (3) Rules for setting auxiliary benchmarks Only when the shaft length-to-diameter ratio is greater than 10, it is permissible to add one auxiliary datum in the middle for auxiliary support. This auxiliary datum is only used to increase rigidity and does not participate in positioning. It shall be removed after machining is completed. The position of this auxiliary datum must be clearly marked in the process document and error verification shall be performed.

[0079] S4. Establish standard process benchmarks for shaft-type machining parts. (1) Determine a unified datum: Coinciding with the design datum, determine "the A-type φ3.15 center holes at both ends" as the unified datum for the entire process of the drive shaft, and name it Datum A. The geometric parameters and tolerance requirements of this unified datum are completely consistent with the corresponding geometric features in the company's geometric feature library.

[0080] (2) Determine the process benchmark for each process, as shown in Table 2.

[0081] Table 2:

[0082] It should be noted that: Process 2 (rough turning of both end faces) and Process 3 (drilling A-type center holes) are completed consecutively under the same three-jaw chuck clamping, without loosening the clamp or realigning. Therefore, the rough datum of the "outer diameter of the blank" is only used once, strictly adhering to the principle that "the rough datum can only be used once." These two processes jointly complete the machining of datum A (A-type center holes at both ends). After Process 3 is completed, all subsequent processes fully reuse datum A. There is only one datum conversion (converting the outer diameter of the blank to the A-type center holes at both ends) throughout the entire process, and the accuracy and stability of the datum system are not affected. In addition, in intelligent flexible production lines, Process 2 and Process 3 can be combined into one process.

[0083] S5. Reference Accuracy and Error Control (1) Unified benchmark accuracy control Center hole machining: A carbide A-type φ3.15 center drill was used, with a spindle speed of S=1500rpm and a feed rate of F=0.1mm / r. After machining, the hole was ground.

[0084] Center hole inspection: The contact rate of the conical surface is ≥80% when tested by the coloring method, and the circular runout is ≤0.003mm when tested by the dial indicator. Any unqualified center holes must be reworked.

[0085] Center hole protection: Wear a dust cap during processing and use a special center hole bracket during transportation to avoid bumps and damage.

[0086] (2) Error Quantification and Control Positioning error: The tolerance of the outer circle φ30h6 is 0.013mm, and the positioning error is ≤0.004mm.

[0087] Repeat clamping error: ≤0.005mm for critical processes (finish turning, grinding of outer diameter), ≤0.01mm for ordinary processes.

[0088] Reference conversion error: Only one reference conversion (from the outer circle of the blank to the center holes of type A at both ends), conversion error ≤0.01mm.

[0089] S6. Coordination of Benchmarks and All Factors of Production S61. Unified process document benchmarks: All process documents clearly indicate "Benchmark A: φ3.15 center hole of type A at both ends", process document number: GY-ZL-2026-001, and establish a digital association with the standard process benchmark library.

[0090] S62. Unified reference between drawings and model: In 2D drawings, the reference symbol "A" is used to mark the center holes at both ends to clarify the accuracy requirements; in 3D models, a reference coordinate system is established, with the origin set at the center of the right end face (coinciding with reference A).

[0091] S63. Standardized tooling and fixtures: The two-center fixture with BT40 tool holders is used uniformly and is compatible with all CNC machine tools on the production line; the fixture positioning accuracy is ≤0.002mm and the accuracy is calibrated once a month.

[0092] S64. Unified CNC program benchmark: The benchmark verification code is embedded in the program template to automatically detect the positioning accuracy of the A-type center hole. If an abnormality occurs, the machining will be paused and an alarm will be triggered.

[0093] S65. Unified Inspection Standards and Benchmarks: The coordinate measuring machine (CMM) program uses benchmark A as the measurement benchmark and automatically generates inspection reports; the first piece inspection must first check the accuracy of benchmark A, and only after it passes the test can mass production begin.

[0094] S66. Establish a unified benchmark system covering the entire process of design, technology, processing, and inspection.

[0095] S67. Digital Binding of Intelligent Manufacturing Control System: Establish a benchmark information archive in the intelligent manufacturing control system and bind it with the information of parts, fixtures, programs and tools. The system automatically verifies whether the benchmark of each process meets the unified benchmark requirements. If there is an abnormality, an alarm is triggered and processing is prohibited.

[0096] S7. Pilot verification and effect evaluation: Three batches of the above-mentioned drive shafts, totaling 150 pieces, were produced continuously. Core data such as processing accuracy, production efficiency, and quality indicators were collected in real time. The comparison of the effects before and after the pilot is shown in Table 3.

[0097] Table 3:

[0098] S8, Dynamic Iteration of Standard Process Benchmark The benchmark scheme for the drive shaft is incorporated into the company's standard process benchmark library as the benchmark design template for all shaft-type machined parts, and is enforced and promoted to all 28 types of shaft-type parts on the production line, achieving 100% reuse of fixtures and programs.

[0099] Dynamic maintenance: Review the benchmark execution status every quarter, and establish an auxiliary benchmark standard for the new growth axis (φ20×300mm) in March 2026; establish a benchmark issue feedback mechanism, and operators can submit benchmark anomalies through the intelligent manufacturing control system, which will respond and handle them within 24 hours.

[0100] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for constructing a collaborative standardization mechanism between process datum and unified datum in CNC machining, characterized in that, Includes the following steps: S1. Classification of Processed Parts and Survey of Current Status of Standards: All processed parts are classified according to structural type, and all processing steps of the processed parts are sorted out. The process standards and sources of standards for each processing step are recorded to form a list of current status of process standards. The process standards include positioning standards, clamping standards, and measurement standards. S2. Reference Problem Identification and Analysis: Based on the reference problem, compare it with the design reference of the design drawing of the workpiece, identify the reference problem existing in the process reference, and analyze the root cause of the reference problem; S3. Formulate reference selection rules: Based on the reference problem, combined with the processing capabilities of the CNC production line equipment and the design drawings of the processed parts, formulate unified and mandatory coarse reference selection rules, fine reference selection rules and auxiliary reference setting rules for the entire production line, forming a general specification for process reference selection; S4. Construct a standard process benchmark library: Based on the process benchmark, select general specifications, and for the typical structure of the processed part and in conjunction with its design drawings, first determine a unified benchmark that runs through the entire process and coincides with the design benchmark of the processed part, and then confirm the process benchmark for each of the processing processes to form a standard process benchmark library. S5. Reference accuracy and error control: Based on the standard process reference library, reference accuracy control indicators and error control measures are set for the unified reference and each process reference to form a reference accuracy and error control specification. S6. Coordination of benchmarks and all production elements: Based on the unified benchmarks and the process benchmarks, ensure that the benchmarks of process documents, drawings and models, tooling fixtures, CNC programs and inspection specifications are consistent, forming a unified benchmark system for the entire process.

2. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 1, characterized in that, The structural types include shafts, discs, flanges, housings, and brackets.

3. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 1, characterized in that, In step S3, the coarse reference selection rules specifically include: The unmachined surface of the workpiece is preferred as the rough reference. Surfaces with large area, good rigidity, and small deformation in the processed parts should be selected preferentially. Ensure that the allowance on the important machined surfaces of the workpiece is uniform; The coarse benchmark can only be used once; It is prohibited to use gates, risers, flash, or severely damaged areas as the rough reference.

4. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 1, characterized in that, In step S3, the specific rules for selecting the precision reference include: The precision reference shall preferably be the design reference of the design drawings of the workpiece; The selection of the process reference for each of the aforementioned processing steps follows the principle of reference unification to reduce reference conversion; For the reference surface, the precision reference surface should be easy to clamp, position, measure and tool set, and should not interfere with the tool or fixture.

5. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 1, characterized in that, In step S3, the auxiliary reference setting rules specifically include: The auxiliary reference is added only when the design reference is not suitable for clamping or machining; The auxiliary reference must be clearly marked on the design drawings of the workpiece and the process documents; The auxiliary reference has a simple structure and is easy to manufacture. It does not affect the function, strength and assembly requirements of the parts, and can be retained or removed as needed after the manufacturing is completed.

6. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 1, characterized in that, In step S5, the specific aspects of the reference accuracy and error control include: Positioning error control: Positioning error ≤ 1 / 3 of the corresponding dimensional tolerance; Repeat clamping error control: quantify the repeat clamping error in each of the aforementioned processing steps; Reference conversion control: If reference conversion is necessary, dimensional chain calculation and error verification must be completed.

7. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 1, characterized in that, In step S6, the coordination between the benchmark and the entire production process specifically includes the following sub-steps: S61. Standardization of process document benchmarks: The process benchmarks and benchmark sources for each processing step shall be marked in the process documents; S62. Unified datum for drawings and models: The datum position and accuracy requirements of the process datum are marked using unified datum symbols on the design drawings of the processed parts; S63. Unified tooling and fixture datum: The positioning surfaces, support surfaces, and positioning pins of tooling and fixtures shall be designed and optimized according to the aforementioned unified datum. S64. Unified CNC program benchmark: The workpiece coordinate system, tool setting point, and reference point are established according to the unified benchmark, and a standardized program template is compiled, embedding the unified benchmark into the CNC program; S65. Unified Inspection Standards and Standards: The inspection standards for testing methods and instruments shall be consistent with the process standards. S66. Establish a unified benchmark system covering the entire process of design, technology, processing, and inspection.

8. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 1, characterized in that, After completing step S6, pilot verification and effect evaluation are carried out: the effectiveness of the whole process benchmark unified system is verified by selecting the processed parts with typical structures, and after optimization and improvement, a scalable solution is formed.

9. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 8, characterized in that, After completing the pilot verification and effect evaluation, the standard process benchmark library is dynamically iterated: the standard process benchmark library is dynamically maintained and the benchmark is adapted according to the diagram to continuously optimize the unified benchmark system of the whole process.

10. The method for constructing a collaborative standardization system for process datum and unified datum in CNC machining as described in claim 1, characterized in that, The standard process reference library establishes a data interaction channel with the enterprise's geometric feature library, wherein the reference surface, reference hole, and center hole used in the unified reference all come from the geometric feature library.

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