An adaptive high-precision arc interpolation machining method and system

Abstract

The application discloses a kind of self-adapting high-precision arc interpolation processing method and system, belong to numerical control processing technical field, it aims at solving the core pain point of traditional arc interpolation poor adaptability, insufficient precision, lack of automatic compensation, linkage is not smooth.In this method, six core steps of core parameter definition entry, real-time data acquisition, dynamic parameter operation in loop, two-dimensional error compensation, arc interpolation execution, interference pre-judgment and loop termination are included;Supporting system is provided with six function modules such as parameter configuration, data acquisition, dynamic operation, realizes the automatic control of whole process of processing.The application adopts dynamic angle increment self-adaption, parameterized dynamic correction and tool wear automatic compensation core technology, can control the surface roughness of part within Ra≤1.6 μm, size deviation ≤±0.02mm, programming time is shortened by more than 90%, processing efficiency is improved by 30%, and is widely applicable to the arc profile processing scene of various numerical control equipment.

Description

Technical Field

[0001] This invention belongs to the field of CNC machining technology and relates to an adaptive high-precision circular interpolation machining method and system. Background Technology

[0002] In the current field of Computer Numerical Control (CNC) machining, circular interpolation is one of the core processes, and its performance directly determines the contour accuracy and surface quality of the machined parts. Currently, traditional circular interpolation macro programs mainly suffer from the following technical challenges:

[0003] Poor adaptability: When machining arcs of different radii, it is usually necessary to redesign or adjust the tool according to the fixed angle increment, or even rewrite the program. It cannot flexibly adapt to the machining needs of multiple specifications, which increases the programming workload and time cost.

[0004] Insufficient precision: When using fixed angle increments for interpolation, the chord height error between adjacent interpolation points increases in the machining of small radius arcs, resulting in poor surface roughness and making it difficult to meet the machining standards of high-precision parts.

[0005] Lack of automatic compensation: Tool wear during long-term use directly leads to dimensional deviations. Current technology lacks an effective online automatic compensation mechanism, requiring frequent manual calibration and machine downtime for inspection, which seriously affects the consistency and stability of machining.

[0006] Unstable linkage: In multi-axis linkage machining, speed fluctuations often occur at the junction of arc segments and straight segments due to unreasonable speed planning, which causes tool movement to stutter and increases the risk of overcutting or leaving tool marks on the parts.

[0007] The aforementioned problems severely restrict the efficiency and quality of CNC machining. Therefore, there is an urgent need for a circular interpolation technology solution that can balance "adaptive, high-precision, and stable linkage". Summary of the Invention

[0008] In view of the defects and shortcomings of the existing technology, the purpose of this invention is to provide an adaptive high-precision circular interpolation machining method and system to solve the problems of poor adaptability, insufficient accuracy, lack of automatic compensation and unstable linkage of traditional circular interpolation.

[0009] To achieve the above-mentioned technical effects, the technical solution adopted by the present invention is as follows: An adaptive high-precision circular interpolation machining method includes the following: S1 defines and inputs the core parameters of the machining process, including the initial radius. Target radius Initial radius increment Correction value Angle increment Z-axis starting position Z-axis termination position and Z-axis reference position ; S2, During the machining cycle, the dynamic status data of the tool and the position feedback data of the machine tool are synchronously collected at a preset frequency. The dynamic status data includes at least the real-time wear amount W of the tool, and the position feedback data includes at least the current actual Z-axis coordinate of the tool. and real-time radius measurement of the workpiece ; S3, in the current cutting cycle, based on the machining progress and initial radius increment. In addition to the collected dynamic state data, the Z-axis command coordinate of the current cycle is calculated in real time. and radius base value ; S4, combined with correction value Real-time tool wear W and real-time workpiece radius measurement values The real-time compensation amount is calculated. And through real-time compensation amount For the basic value of radius Make corrections to obtain the actual cutting radius for the current cycle. ; S5, according to the Z-axis command coordinates and actual cutting radius R e It generates and executes circular interpolation commands to control the tool to complete the cutting process of the current cycle; S6, based on Z-axis command coordinates and actual cutting radius R e Interference prediction is performed, and the processing endpoint is checked after each loop, i.e., the loop ends.

[0010] Preferably, S3 specifically includes: S31, the specific processing schedule is as follows: Calculate the current loop count N and the total loop count. The ratio of the two values ​​is used to determine the processing progress percentage P, which is then used as the processing progress percentage; where, , ; S32, based on the machining progress percentage P and the Z-axis starting position and Z-axis termination position Through linear interpolation formula Calculate the theoretical Z-axis coordinate Z for the current loop; combine this with the Z-axis reference position. Perform calibration to obtain the Z-axis command coordinates for the current cycle. The calibration formula is ; S33, based on the current loop count N and the actual radius increment used in the current loop. Calculate the current base radius value under the uncompensated state. The formula is Among them, the radius increment The initial value is the initial radius increment. ; S34, repeat S31~S33, compare the real-time collected dynamic status data with the preset threshold. If the threshold is exceeded, the radius increment ΔR of the next cycle is dynamically adjusted.

[0011] Preferably, S4 specifically includes: S41, the base radius value With correction value Add them together to get the radius after basic compensation. ; S42, the base radius value With the real-time radius measurement value of the workpiece Subtracting the two yields the real-time radius deviation of the workpiece. And through the real-time radius deviation of the workpiece Calculate the real-time compensation amount based on the real-time wear amount W of the cutting tool. ; S43, the radius after basic compensation With real-time compensation amount Add them together to get the actual cutting radius R of the current cycle. e .

[0012] Preferred, real-time compensation amount The calculation formula is as follows:

[0013] in, β The weighting coefficient is preset based on the characteristics of the processed material, and its value range is 0.5≤β≤1.0.

[0014] Preferably, the interference prediction in S6 specifically involves pausing machining if the safety distance S is less than a preset safety threshold, automatically adjusting the Z-axis feed sequence, recalculating the coordinates, and then re-executing the cutting; the calculation of the safety distance S is as follows: .

[0015] Preferably, the cycle termination in S6 specifically involves verifying the following two conditions after each cycle: (1) the actual cutting radius of the current cycle. Has the target radius been reached? And the error is ≤0.001mm; (2) Actual Z-axis coordinates Has the Z-axis end position been reached? The error must be ≤0.002mm; if both conditions are met, the machining cycle ends and the tool retracts to the safe plane; if not, return to S3 and repeat the cycle operation.

[0016] An adaptive high-precision circular interpolation machining system is provided for implementing the method disclosed in this application. The system specifically includes: Parameter configuration module: used to define and input the core parameters of the processing procedure; Data acquisition module: Used to synchronously acquire dynamic status data of the tool and position feedback data of the machine tool at a preset frequency during the machining cycle. The dynamic status data includes at least the real-time wear amount W of the tool, and the position feedback data includes at least the current actual Z-axis coordinate of the tool. and real-time radius measurement of the workpiece ; Dynamic calculation module: used to perform calculations based on machining progress and initial radius increment during the current cutting cycle. In addition to the collected dynamic state data, the Z-axis command coordinate of the current cycle is calculated in real time. and radius base value ; Compensation execution module: used to combine preset correction values And based on the real-time tool wear W and the real-time workpiece radius measurement value The calculated real-time compensation amount For the basic value of radius Make corrections to generate the actual cutting radius for the current cycle. ; Interpolation execution module: used to perform interpolation based on Z-axis command coordinates. and actual cutting radius R e It generates and executes circular interpolation commands to control the tool to complete the cutting process of the current cycle; Safety and Termination Module: Used to determine the Z-axis coordinates before executing interpolation commands. and actual cutting radius R e Interference prediction is performed, and the processing endpoint is checked after each cycle.

[0017] The above technical solution has the following beneficial effects: (1) The processing adaptability is greatly improved and the flexibility is high: It breaks through the limitations of traditional fixed angle increment and fixed tool parameters. It adopts parametric design and dynamic angle increment adaptive mechanism. Only the core parameters need to be modified to complete the processing of arcs with different radii and different specifications. There is no need to change the tool or rewrite the program. The programming time of a single part is shortened from the traditional 30 minutes to 2 minutes, and the changeover efficiency is improved by more than 90%. It can perfectly adapt to the flexible processing scenarios of multiple varieties and small batches.

[0018] (2) The machining accuracy is significantly improved and the surface quality is excellent: Through the dynamic parameter calculation within the cycle and the dual-dimensional error compensation mechanism, the cutting radius and tool coordinates are corrected in real time, which effectively solves the problem of large error in the chord height of small radius arc caused by fixed angle increment; through actual machining verification, the surface roughness of the part can be stably controlled within Ra≤1.6μm, and the optimal Ra≤1.2μm can be achieved. The dimensional deviation is controlled within ±0.02mm, and the optimal ±0.01mm can be achieved, which fully meets the machining standards of high precision parts.

[0019] (3) Strong automation compensation capability and good processing stability: It integrates online tool wear automatic compensation function, establishes wear compensation model by processing number statistics and real-time wear amount collection, automatically corrects the circular interpolation coordinate parameters, and offsets the wear error caused by long-term tool use. It does not require frequent manual stop calibration, which greatly reduces labor costs and downtime; at the same time, it ensures the consistency of part size in batch processing and significantly improves the yield rate.

[0020] (4) Optimization of linkage stability and improvement of processing efficiency: Through the synchronous optimization of Z-axis feed speed and trajectory smoothing, the speed fluctuation problem at the junction of arc segment and straight segment is solved. The tool movement is smooth and without stuttering throughout the entire process, effectively avoiding processing defects such as overcutting and tool mark residue. At the same time, dynamic parameter optimization reduces the invalid cutting stroke, and the overall processing time is shortened by more than 30% compared with the traditional method, which greatly improves the processing efficiency. Attached Figure Description

[0021] Figure 1 It is when the angle increment The processing simulation diagram is shown when the value is 8.6. Figure 2 It is when the angle increment When =1, process simulation diagram; Figure 3 When the angle increment Processing simulation diagram when =0.125; Figure 4 This is a simplified diagram of the normal processing procedure; Figure 5 This describes the state of the part after the first blade wears down. Figure 6 The processing status will not be corrected and will continue to be processed. Figure 7 It refers to the state where the chipped edge is not corrected and processing continues. Figure 8 This is a picture of the actual workpiece obtained from Example 1. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the embodiments. It should be noted that the following embodiments are only used to explain the present invention and are not intended to limit the scope of protection of the present invention. Any substitutions or modifications made by those skilled in the art based on the technical solutions of the present invention without inventive effort shall fall within the scope of protection of the present invention.

[0023] The adaptive high-precision circular interpolation machining method described in this invention achieves adaptive adjustment and high-precision control of circular interpolation by combining variable calculation and loop logic of macro programs with real-time data acquisition and two-dimensional compensation. It can be directly installed on machining centers and CNC milling machines of mainstream CNC systems such as FANUC and SIEMENS.

[0024] Example This embodiment discloses an adaptive high-precision circular interpolation machining method, including the following: S1, Define and input the core parameters of the processing, including the initial radius. Target radius Initial radius increment Correction value Angle increment Z-axis starting position Z-axis termination position and Z-axis reference position .

[0025] The relevant macro program in this embodiment is as follows: #1=80.3(tool radius / initial radius) ); #2=97. (Target radius) ); #3 = [#2 - #1] / 2 (Increment of initial radius) ); #4 = #3 - 0.1 (correction value) ); #7 = 0.125 (angle increment) ); #10 = -191.2 (Z-axis starting position) ); #11=#10-8.5 (Z-axis end position) ); #12=-169 (Z-axis reference position) ); The core parameters in this embodiment are as follows: initial radius The initial cutting radius at the start of machining is 8.35mm, corresponding to macro program #3=[#2-#1] / 2; Target radius The target radius of the finished product is 48.5mm (corresponding to a target diameter of φ97mm). Initial radius increment : 0.125mm (radial feed rate in a single cutting cycle); Correction value : 8.25mm (#3-0.1, used to compensate for machine tool geometric deviations and initial tool wear); Angle increment : 0.125° (Macro program #7, with built-in adaptive rule as described in the claims: the smaller the radius, the smaller the angle increment automatically). Z-axis starting position -191.2mm (Macro program #10); Z-axis termination position -199.7mm (Macro program #11=#10-8.5); Z-axis reference position -169.0mm (Macro program #12, coordinate calibration reference).

[0026] All core parameters are accurate to 0.001mm, and angles to 0.1°. After being entered through the CNC system's human-machine interface, the system automatically verifies the parameters: Confirm. > , ≠ Processing is allowed to begin after no logical exceptions are found.

[0027] S2, During the machining cycle, dynamic status data of the cutting tool and position feedback data of the machine tool are synchronously acquired at a preset frequency. The dynamic status data includes at least the real-time wear amount W of the cutting tool, and the position feedback data includes at least the current actual Z-axis coordinate of the cutting tool. and real-time radius measurement of the workpiece .

[0028] In this embodiment, the acquisition configuration is as follows: the acquisition frequency is set to 10ms / time, which is completely synchronized with the cutting cycle step; In this embodiment, a 3x standard deviation filtering algorithm is used to filter all collected data to remove abnormal fluctuations in vibration amplitude and load current, ensuring the validity of the data input to the calculation module.

[0029] S3, in the current cutting cycle, based on the machining progress and the initial radius increment... In addition to the collected dynamic state data, the Z-axis command coordinate of the current cycle is calculated in real time. and radius base value ; S3 specifically includes: S31, the specific processing progress is as follows: Calculate the current loop count N and the total loop count. The ratio of the two values ​​is used to determine the processing progress percentage P, which is then used as the processing progress and updated in real time with each cycle. in, , ; This embodiment The value is rounded to the nearest integer. S32, based on the machining progress percentage P and the Z-axis starting position and Z-axis termination position Through linear interpolation formula Calculate the theoretical Z-axis coordinate Z for the current loop; Combined with Z-axis reference position Perform calibration to obtain the Z-axis command coordinates for the current cycle. The calibration formula is This corresponds to the coordinate update logic of Z[#12+#10] in the macro program; S33, based on the current loop count N and the actual radius increment used in the current loop. Calculate the current base radius value under the uncompensated state. The formula is ; Among them, radius increment The initial value is the initial radius increment. ; Initial radius increment in this embodiment Take 0.125mm, which corresponds to the basic operation logic of #4 in the macro program; S34, repeat S31~S33, compare the real-time collected dynamic status data with the preset threshold. If the threshold is exceeded, the radius increment ΔR of the next cycle is dynamically adjusted.

[0030] In this embodiment, the vibration amplitude V of the workpiece is compared in real time with the preset threshold V0 = 0.05 mm. If V > V0 or the load exceeds the rated range, dynamic adjustment of the radius increment is triggered. The adjustment formula is ΔR′ = ΔR × (1 λ), where λ is 0.1~0.3; in this embodiment, the vibration amplitude is stable within 0.02mm during processing and does not exceed the threshold, and ΔR remains unchanged at 0.125mm.

[0031] S4, combined with correction value Real-time tool wear W and real-time workpiece radius measurement values The real-time compensation amount is calculated. And through the real-time compensation amount For the basic value of radius Make corrections to obtain the actual cutting radius for the current cycle. ; S4 specifically includes: S41, the base radius value With correction value Add them together to complete the basic compensation, and you will get the radius after basic compensation. This offsets the inherent geometric deviations of the machine tool and the initial wear of the cutting tool; S42, the base radius value With the real-time radius measurement value of the workpiece Subtracting the two yields the real-time radius deviation of the workpiece. And through the real-time radius deviation of the workpiece Calculate the real-time compensation amount based on the real-time wear amount W of the cutting tool. ; The real-time compensation amount The calculation formula is as follows:

[0032] in, β The weighting coefficients are preset based on the characteristics of the processed materials, and their values ​​range from 0.1 to 1. β ≤0.3, in this embodiment, for 45# steel workpieces, 0.2 is used; S43, the radius after basic compensation With real-time compensation amount Add them together to get the actual cutting radius R of the current cycle. e Simultaneously set a radius limit threshold (Rt±0.002mm) to avoid compensation exceeding tolerance; corresponding to #4=#4-#7 in the macro program. The radius dynamic correction logic of TAN[15°] is used to achieve real-time compensation in each cycle.

[0033] S5, according to the Z-axis command coordinate and actual cutting radius R e Generate and execute circular interpolation command G code, and simultaneously optimize the Z-axis feed speed: straight segment feed speed F300, circular segment feed speed F200, to achieve a smooth speed transition between the circular and straight segments, avoid speed fluctuations, and control the tool to complete the current cycle of cutting.

[0034] The interpolation trajectory strictly follows the following three-segment circular arc equation, which perfectly matches the interpolation logic of the claims: The equation of the first tangent arc is: (X) X0) 2 +(Y Y0) 2 =(R e / 2) 2The corresponding macro is G03X[301.+#4]R[#4 / 2]. The second equation for cutting a complete circle: (X) X0) 2 +(Y Y0) 2 =R e 2 The corresponding macro is G03I[-#4]. The equation of the third segment of the tangent arc is: (X) X0) 2 +(Y Y0) 2 =(R e / 2) 2 The corresponding macro program is G03X301.R[#4 / 2]; Where X0 is the X-axis coordinate of the center of the circle; Y0 is the current Y-axis position.

[0035] After each loop: Arc radius: R e =( -0.1)-n× ×\tanΘ (The radius gradually decreases with the cycle, and Θ is an angle) Θ represents Figure 4 15 degrees in the middle.

[0036] Where n is the number of iterations.

[0037] When the angle increment When the value is 8.6, process the simulation diagram, such as... Figure 1 When the angle increment When =1, process the simulation diagram, such as Figure 2 When the angle increment When the value is 0.125, the processing simulation diagram is shown, such as... Figure 3 .

[0038] In order to complete the product processing, we need to make #7 as small as possible.

[0039] S6, based on the Z-axis command coordinates and actual cutting radius R e Interference prediction is performed, and the processing endpoint is checked after each loop, i.e., the loop ends.

[0040] Specifically, the interference prediction in S6 means that if the safety distance S is less than the preset safety threshold, the machining is paused, the Z-axis feed sequence is automatically adjusted, the coordinates are recalculated, and then the cutting is performed. The safety distance S is calculated as follows: .

[0041] In S6, loop termination specifically involves checking the following two conditions after each iteration: (1) Actual cutting radius of the current cycle Has the target radius been reached? And the error is ≤0.001mm; (2) Actual Z-axis coordinates Has the Z-axis end position been reached? And the error is ≤0.002mm; If both conditions are met, the machining cycle ends and the tool retracts to the safe plane; if not, the cycle is repeated in S3.

[0042] When the cutting tool is functioning normally, a face milling cutter is used to machine deep cavity parts according to the method described in this embodiment. The machining result is as follows: Figure 4 When the cutting tool wears or chipps during machining, the machining of the first part becomes like this. Figure 5 When wear occurs, continue processing; otherwise, if not corrected... Figure 6 When chipping occurs, continuing processing without the corrective processing method disclosed in this embodiment will result in the following issues: Figure 7 .

Claims

1. An adaptive high-precision circular interpolation machining method, characterized in that, Including the following: S1, Define and input the core parameters of the processing, including the initial radius. Target radius Initial radius increment Correction value Angle increment Z-axis starting position Z-axis termination position and Z-axis reference position ; S2, During the machining cycle, dynamic status data of the cutting tool and position feedback data of the machine tool are synchronously acquired at a preset frequency. The dynamic status data includes at least the real-time wear amount W of the cutting tool, and the position feedback data includes at least the current actual Z-axis coordinate of the cutting tool. and real-time radius measurement of the workpiece ; S3, in the current cutting cycle, based on the machining progress and the initial radius increment... In addition to the collected dynamic state data, the Z-axis command coordinate of the current cycle is calculated in real time. and radius base value ; S4, combined with correction value Real-time tool wear W and real-time workpiece radius measurement values The real-time compensation amount is calculated. And through the real-time compensation amount For the basic value of radius Make corrections to obtain the actual cutting radius for the current cycle. ; S5, according to the Z-axis command coordinate and actual cutting radius R e It generates and executes circular interpolation commands to control the tool to complete the cutting process of the current cycle; S6, based on the Z-axis command coordinates and actual cutting radius R e Interference prediction is performed, and the processing endpoint is checked after each loop, i.e., the loop ends.

2. The adaptive high-precision circular interpolation machining method according to claim 1, characterized in that, S3 specifically includes: S31, the specific processing progress is as follows: Calculate the current loop count N and the total loop count. The ratio is used to determine the processing progress percentage P and is taken as the processing progress. in, , ; S32, based on the machining progress percentage P and the Z-axis starting position and Z-axis termination position Through linear interpolation formula Calculate the theoretical Z-axis coordinate Z for the current loop; Combined with Z-axis reference position Perform calibration to obtain the Z-axis command coordinates for the current cycle. The calibration formula is ; S33, based on the current loop count N and the actual radius increment used in the current loop. Calculate the current base radius value under the uncompensated state. The formula is ; Among them, radius increment The initial value is the initial radius increment. ; S34, repeat S31~S33, compare the real-time collected dynamic status data with the preset threshold. If the threshold is exceeded, the radius increment ΔR of the next cycle is dynamically adjusted.

3. The adaptive high-precision circular interpolation machining method according to claim 1, characterized in that, S4 specifically includes: S41, the base radius value With correction value Add them together to get the radius after basic compensation. ; S42, the base radius value With the real-time radius measurement value of the workpiece Subtracting the two yields the real-time radius deviation of the workpiece. And through the real-time radius deviation of the workpiece Calculate the real-time compensation amount based on the real-time wear amount W of the cutting tool. ; S43, the radius after basic compensation With real-time compensation amount Add them together to get the actual cutting radius R of the current cycle. e .

4. The adaptive high-precision circular interpolation machining method according to claim 3, characterized in that, The real-time compensation amount The calculation formula is as follows: in, β The weighting coefficient is preset based on the characteristics of the processed material, and its value range is 0.5≤β≤1.

0.

5. The adaptive high-precision circular interpolation machining method according to claim 1, characterized in that, Specifically, the interference prediction in S6 means that if the safety distance S is less than the preset safety threshold, the machining is paused, the Z-axis feed sequence is automatically adjusted, the coordinates are recalculated, and then the cutting is performed. The safety distance S is calculated as follows: .

6. The adaptive high-precision circular interpolation machining method according to claim 1, characterized in that, Specifically, the loop termination in S6 involves verifying the following two conditions after each loop iteration: (1) Actual cutting radius of the current cycle Has the target radius been reached? And the error is ≤0.001mm; (2) Actual Z-axis coordinates Has the Z-axis end position been reached? And the error is ≤0.002mm; If both conditions are met, the machining cycle ends and the tool retracts to the safe plane; if not, the cycle is repeated in S3.

7. An adaptive high-precision circular interpolation machining system, characterized in that, The system for implementing the method according to any one of claims 1 to 7 specifically comprises: Parameter configuration module: used to define and input the core parameters of the processing procedure; Data acquisition module: Used to synchronously acquire dynamic status data of the cutting tool and position feedback data of the machine tool at a preset frequency during the machining cycle. The dynamic status data includes at least the real-time wear amount W of the cutting tool, and the position feedback data includes at least the current actual Z-axis coordinate of the cutting tool. and real-time radius measurement of the workpiece ; Dynamic calculation module: used to calculate the initial radius increment based on the machining progress in the current cutting cycle. In addition to the collected dynamic state data, the Z-axis command coordinate of the current cycle is calculated in real time. and radius base value ; Compensation execution module: used to combine preset correction values And based on the real-time tool wear W and the real-time workpiece radius measurement value The calculated real-time compensation amount For the aforementioned basic radius value Make corrections to generate the actual cutting radius for the current cycle. ; Interpolation execution module: used to perform interpolation based on the Z-axis command coordinates. and actual cutting radius R e It generates and executes circular interpolation commands to control the tool to complete the cutting process of the current cycle; Safety and Termination Module: Used to determine the Z-axis command coordinates before executing the interpolation command. and actual cutting radius R e Interference prediction is performed, and the processing endpoint is checked after each cycle.

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