A method and system for compensating for a profiled part

Abstract

The application provides a compensation machining method for a special-shaped machining part, and comprises the following steps: S1, placing the special-shaped machining part on a self-adaptive flexible clamp for preliminary fixation, and collecting current actual position coordinates of the special-shaped machining part in real time by using photoelectric detection equipment; S2, comparing the current actual position coordinates with target position coordinates preset in a numerical control system, calculating position error, and performing automatic compensation of the position error in the system to correct a machining reference; and S3, collecting vibration signals in a cutting process in real time by using a vibration detection sensor during machining. Through real-time data collection and feedback by using photoelectric equipment and position error compensation in the system, the application solves the problem that the special-shaped part is difficult to be accurately positioned, and improves repeated positioning accuracy by more than 50%.

Description

Technical Field

[0001] This invention relates to the field of machining and manufacturing technology, and in particular to a compensation machining method and system for irregularly shaped machined parts. Background Technology

[0002] In modern machining and manufacturing, with the development of aerospace, automotive, and medical device industries, the demand for machining irregularly shaped parts (such as blades, curved structural components, and irregular shells) is increasing. Existing technologies present the following technical problems in machining irregularly shaped parts:

[0003] Due to their irregular shape, irregularly shaped parts are difficult to position precisely using traditional mechanical fixtures. The datum for each clamping is deviated, resulting in low repeatability and high scrap rate.

[0004] When machining irregularly shaped parts by turning or milling, the asymmetrical force points make them prone to deformation. At the same time, fluctuations in cutting force can cause vibrations in the cutting tools and machine tools, which not only affect tool life but also severely reduce the surface quality and contour of the parts.

[0005] Existing CNC machining mostly uses fixed cutting parameters, which cannot be dynamically adjusted according to the real-time vibration state during the machining process. This results in poor machining quality in the vibration-prone area and low machining efficiency in the stable area. To address this, a compensation machining method and system for irregularly shaped parts is proposed. Summary of the Invention

[0006] In view of this, embodiments of the present invention provide a compensation processing method and system for irregularly shaped processed parts to solve or alleviate the technical problems existing in the prior art, and at least provide a beneficial option.

[0007] The technical solution of this invention is implemented as follows: a compensation processing method for irregularly shaped machined parts, comprising the following steps: S1. The irregularly shaped machining part is initially fixed on the adaptive flexible fixture, and the current actual position coordinates of the irregularly shaped machining part are collected in real time using photoelectric detection equipment; S2. Compare the current actual position coordinates with the preset target position coordinates in the CNC system, calculate the position error, and automatically compensate for the position error in the system to correct the machining reference. S3. During the machining process, vibration signals during the cutting process are collected in real time using vibration detection sensors; S4. Based on the amplitude of the collected vibration signal, determine whether it exceeds the preset vibration threshold. If it does, dynamically adjust the three cutting elements, namely cutting speed, feed rate and cutting depth, to reduce the cutting force until the amplitude of the vibration signal falls back to a safe range.

[0008] In some embodiments, the algorithm formula for automatic position error compensation in S2 is as follows: in, This is the position error vector. These are the actual position coordinates collected by the photoelectric detection equipment. Preset the target location coordinates for the system. The actual machining coordinates after compensation. For compensation coefficient, The value ranges from 0.8 to 1.2.

[0009] In some embodiments, the specific algorithm formula for dynamically adjusting the three cutting elements in S4 is as follows: Let the current vibration amplitude be The preset vibration threshold is ,when At that time, a dynamic adjustment factor is introduced. : Adjusted cutting speed feed rate Cutting depth ; in, The cutting sensitivity coefficient is preset for the system. , and These are the cutting speed, feed rate, and depth of cut before adjustment.

[0010] A compensation machining system for irregularly shaped machined parts, used to implement the compensation machining method described in any of the above claims, the system comprising: Positioning and clamping module for securing irregularly shaped machined parts, including adaptive flexible clamps; The position detection and compensation module includes photoelectric detection equipment, which is used to collect the position coordinates of the component in real time and feed them back to the CNC system. The CNC system then calculates the position error and compensates for the coordinates. The vibration detection module includes a vibration detection sensor installed near the spindle or tool to collect vibration signals during the machining process in real time. The dynamic adjustment control module is communicatively connected to the vibration detection module and the CNC system, and is used to dynamically calculate and issue adjustment commands for the three cutting elements based on the vibration signal.

[0011] In some embodiments, the photoelectric detection device is a laser displacement sensor or a machine vision camera, used to acquire the three-dimensional spatial coordinates of feature points of irregularly shaped processed parts.

[0012] In some embodiments, the vibration detection sensor is a triaxial accelerometer, and the dynamic adjustment control module has an embedded fuzzy PID controller for smoothly outputting the adjustment amounts of the three cutting elements.

[0013] In some embodiments, when the position detection and compensation module acquires feature points of irregularly shaped processed parts, it employs a multi-feature point spatial fitting algorithm to extract at least three reference feature points that are not on the same straight line, and calculates the overall deflection angle error by constructing a spatial coordinate system matrix to achieve attitude compensation in three-dimensional space.

[0014] In some embodiments, the adaptive flexible clamp includes a base, a plurality of pneumatic / hydraulic adaptive support columns arranged in an array, and a fine-tuning locking mechanism; The support column is equipped with a pressure sensor, which automatically expands and contracts to fit the irregular part according to its surface shape during the clamping process, and is rigidly fixed by a fine-tuning locking mechanism after fitting into place.

[0015] In some embodiments, before executing S4, the dynamic adjustment control module is further configured to adaptively set the preset vibration threshold based on the current tool overhang length and the hardness coefficient of the workpiece. The calculation formula is as follows: in As the standard benchmark threshold, This is a factor affecting the tool overhang length. This is a factor affecting material hardness.

[0016] In some embodiments, the vibration detection module and the dynamic adjustment control module transmit data in real time via industrial Ethernet. The cutting three-element adjustment commands calculated by the dynamic adjustment control module are sent to the machine tool CNC system through a high-speed I / O interface, with a command response cycle of less than 5 milliseconds.

[0017] In some embodiments, the positioning method for irregularly shaped parts is first addressed.

[0018] An adaptive flexible fixture is used to initially fix irregularly shaped parts, and photoelectric equipment is used for real-time data acquisition and feedback. The system compares the actual acquired coordinates with the target coordinates and automatically compensates for positional errors, thereby significantly improving the repeatability of the parts.

[0019] Secondly, a vibration detection mechanism is introduced during the processing.

[0020] By monitoring the cutting vibration status in real time through sensors, when the vibration amplitude exceeds the threshold, the system dynamically adjusts the cutting force and the three cutting elements (cutting speed, feed rate, and depth of cut) to effectively suppress vibration and deformation and improve machining quality.

[0021] The embodiments of the present invention have the following advantages due to the adoption of the above technical solutions: I. This invention solves the problem of inaccurate positioning of irregularly shaped parts by real-time data acquisition and feedback from photoelectric equipment and performs position error compensation in the system, thereby improving the repeatability accuracy by more than 50%.

[0022] Second, by dynamically adjusting the three cutting elements, this invention effectively avoids part deformation caused by excessive local cutting force, suppresses cutting vibration, and significantly improves the surface quality and contour of the machined parts.

[0023] Third, by maintaining normal or optimized cutting parameters in areas with less vibration and dynamically reducing parameters only in areas prone to vibration, this invention improves overall machining efficiency by about 20% compared to traditional conservative machining throughout the entire process.

[0024] The above overview is for illustrative purposes only and is not intended to be limiting in any way. Detailed Implementation

[0025] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention.

[0026] It is important to note that terms such as "first," "second," "symmetric," "array," "set in," and "set with" are used only to distinguish between descriptive and positional descriptions and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, features specified with terms such as "first" or "symmetric" may explicitly or implicitly include one or more of that feature; similarly, when the quantity of certain features is not limited by words such as "two" or "three," it should be noted that such features also explicitly or implicitly include one or more features.

[0027] In this invention, unless otherwise explicitly specified and limited, terms such as “installation,” “connection,” and “fixation” should be interpreted broadly; for example, they can be fixed connections, detachable connections, or integral moldings; they can be mechanical connections, direct connections, welding, or indirect connections through an intermediate medium; they can be internal connections between two components or the interaction between two components.

[0028] This invention provides a compensation machining method for irregularly shaped machined parts, comprising the following steps: S1. The irregularly shaped machining part is initially fixed on the adaptive flexible fixture, and the current actual position coordinates of the irregularly shaped machining part are collected in real time using photoelectric detection equipment; S2. Compare the current actual position coordinates with the preset target position coordinates in the CNC system, calculate the position error, and automatically compensate for the position error in the system to correct the machining datum. S3. During the machining process, vibration signals during the cutting process are collected in real time using vibration detection sensors; S4. Based on the amplitude of the collected vibration signal, determine whether it exceeds the preset vibration threshold. If it does, dynamically adjust the three cutting elements, namely cutting speed, feed rate and cutting depth, to reduce the cutting force until the amplitude of the vibration signal falls back to a safe range.

[0029] In this embodiment, the specific algorithm formula for automatic position error compensation in S2 is as follows: in, This is the position error vector. These are the actual position coordinates collected by the photoelectric detection equipment. Preset the target location coordinates for the system. The actual machining coordinates after compensation. For compensation coefficient, The value ranges from 0.8 to 1.2.

[0030] In this embodiment, the specific algorithm formula for dynamically adjusting the three cutting elements in S4 is as follows: Let the current vibration amplitude be The preset vibration threshold is ,when At that time, a dynamic adjustment factor is introduced. : Adjusted cutting speed feed rate Cutting depth ; in, The cutting sensitivity coefficient is preset for the system. , and These are the cutting speed, feed rate, and depth of cut before adjustment.

[0031] A compensation machining system for irregularly shaped machined parts, used to implement any of the above-mentioned compensation machining methods, the system comprising: Positioning and clamping module for securing irregularly shaped machined parts, including adaptive flexible clamps; The position detection and compensation module includes photoelectric detection equipment, which is used to collect the position coordinates of the component in real time and feed them back to the CNC system. The CNC system then calculates the position error and compensates for the coordinates. The vibration detection module includes a vibration detection sensor installed near the spindle or tool to collect vibration signals during the machining process in real time. The dynamic adjustment control module communicates with the vibration detection module and the CNC system to dynamically calculate and issue adjustment commands for the three cutting elements based on the vibration signal.

[0032] In this embodiment, the photoelectric detection device is specifically a laser displacement sensor or a machine vision camera, used to acquire the three-dimensional spatial coordinates of feature points of irregularly shaped processed parts.

[0033] In this embodiment, the vibration detection sensor is a triaxial accelerometer, and the dynamic adjustment control module has an embedded fuzzy PID controller for smoothing the output of the adjustment amounts of the three cutting elements.

[0034] In this embodiment, specifically, when the position detection and compensation module acquires the feature points of the irregularly shaped processed parts, it adopts a multi-feature point spatial fitting algorithm to extract at least three reference feature points that are not on the same straight line, and calculates the overall deflection angle error by constructing a spatial coordinate system matrix to achieve attitude compensation in three-dimensional space.

[0035] In this embodiment, the adaptive flexible fixture specifically includes a base, multiple pneumatic / hydraulic adaptive support columns arranged in an array, and a fine-tuning locking mechanism. The support column has an integrated pressure sensor that automatically expands and contracts to fit the irregularly shaped parts during the clamping process, and is rigidly fixed by a fine-tuning locking mechanism after fitting into place.

[0036] In this embodiment, specifically, before executing S4, the dynamic adjustment control module is also configured to adaptively set a preset vibration threshold based on the current tool overhang length and the hardness coefficient of the workpiece. The calculation formula is as follows: in As the standard benchmark threshold, This is a factor affecting the tool overhang length. This is a factor affecting material hardness.

[0037] In this embodiment, the vibration detection module and the dynamic adjustment control module transmit data in real time via industrial Ethernet. The cutting three-element adjustment commands calculated by the dynamic adjustment control module are sent to the machine tool CNC system through a high-speed I / O interface, with a command response cycle of less than 5 milliseconds.

[0038] Example 1 Take the milling process of an irregularly shaped titanium alloy blade as an example.

[0039] The blade is placed on a flexible fixture, and a laser displacement sensor mounted next to the machine tool spindle is used to scan three reference feature points of the blade to obtain the current actual position coordinates. .

[0040] The system's preset target location coordinates are .

[0041] The system calculates the position error vector: To ensure the smoothness of compensation, a compensation coefficient is set. .

[0042] The system automatically corrects the coordinate origin of subsequent machining programs to: This step eliminates the reference offset caused by manual clamping, enabling high-precision machining.

[0043] Example 2 In the processing of Example 1, a triaxial accelerometer is installed on the spindle to collect vibration signals in real time.

[0044] Set preset vibration threshold .

[0045] When the milling cutter enters the thin-walled region at the edge of the blade, the vibration amplitude... Rise to .

[0046] because The system triggers a dynamic adjustment mechanism to set the cutting sensitivity coefficient. .

[0047] Calculate the dynamic adjustment factor: Assume the initial cutting parameters are: cutting speed feed rate Cutting depth .

[0048] The adjusted parameters are: After parameter adjustment, the cutting force decreased significantly, and the vibration amplitude decreased. It fell back to [a certain value] within 0.5 seconds. The system resumes steady-state processing.

[0049] The vibration returned to normal when the tool left the thin-walled region and entered the thick-walled region. The parameters are automatically restored to the preset value, ensuring processing efficiency.

[0050] In this embodiment, specifically, the experimental data comparison... A comparison was made between processing the same batch of irregularly shaped blades using traditional fixed-parameter processing and processing using the system of this invention.

[0051] Five core evaluation indicators were selected, and the experimental statistics are shown in the table below: Comparison table of experimental data between traditional processing methods and the processing method of this invention In the table, repeatability error and contour error are in mm; surface roughness is in μm; single-piece machining time is in min; and tool wear is in mm.

[0052] As can be seen from the comparison table of experimental data between the traditional machining method and the machining method of the present invention, the compensation machining system of the present invention reduces the repeatability error by about 70%, the surface roughness by about 50%, and the contour accuracy by a significant margin. At the same time, the machining efficiency is increased by about 15.7%, and tool wear is also effectively controlled.

[0053] In this embodiment, specifically, by acquiring and feeding back real-time data from photoelectric devices, a position error model is established in the CNC system and automatic coordinate compensation is performed to solve the problem of difficult positioning of irregular parts.

[0054] Based on real-time vibration detection, an adjustment factor algorithm containing a logarithmic function is used to dynamically adjust the square terms of cutting speed, feed rate, and depth of cut to achieve smooth suppression of cutting force, balancing machining quality and efficiency.

[0055] The combination of adaptive flexible fixtures and multi-feature point fitting technology ensures stable clamping and precise compensation of irregular parts in spatial posture.

[0056] 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 person skilled in the art can easily conceive of various variations or substitutions within the technical scope disclosed in the present invention, and these should all 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 compensation machining method for irregularly shaped machined parts, characterized in that, Includes the following steps: S1. The irregularly shaped machining part is initially fixed on the adaptive flexible fixture, and the current actual position coordinates of the irregularly shaped machining part are collected in real time using photoelectric detection equipment; S2. Compare the current actual position coordinates with the preset target position coordinates in the CNC system, calculate the position error, and automatically compensate for the position error in the system to correct the machining reference. S3. During the machining process, vibration signals during the cutting process are collected in real time using vibration detection sensors; S4. Based on the amplitude of the collected vibration signal, determine whether it exceeds the preset vibration threshold. If it does, dynamically adjust the three cutting elements, namely cutting speed, feed rate and cutting depth, to reduce the cutting force until the amplitude of the vibration signal falls back to a safe range.

2. The compensation machining method for irregularly shaped machined parts according to claim 1, characterized in that, The algorithm formula for automatic position error compensation in S2 is as follows: in, This is the position error vector. These are the actual position coordinates collected by the photoelectric detection equipment. Preset the target location coordinates for the system. The actual machining coordinates after compensation. For compensation coefficient, The value ranges from 0.8 to 1.

2.

3. The compensation machining method for irregularly shaped machined parts according to claim 1, characterized in that, The specific algorithm formula for dynamically adjusting the three cutting elements in S4 is as follows: Let the current vibration amplitude be The preset vibration threshold is ,when At that time, a dynamic adjustment factor is introduced. : Adjusted cutting speed feed rate Cutting depth ; in, The cutting sensitivity coefficient is preset for the system. , and These are the cutting speed, feed rate, and depth of cut before adjustment.

4. A compensation machining system for irregularly shaped machined parts, characterized in that, The system for implementing the compensation processing method according to any one of claims 1-3, the system comprising: Positioning and clamping module for securing irregularly shaped machined parts, including adaptive flexible clamps; The position detection and compensation module includes photoelectric detection equipment, which is used to collect the position coordinates of the component in real time and feed them back to the CNC system. The CNC system then calculates the position error and compensates for the coordinates. The vibration detection module includes a vibration detection sensor installed near the spindle or tool to collect vibration signals during the machining process in real time. The dynamic adjustment control module is communicatively connected to the vibration detection module and the CNC system, and is used to dynamically calculate and issue adjustment commands for the three cutting elements based on the vibration signal.

5. The compensation machining system for irregularly shaped machined parts according to claim 4, characterized in that, The photoelectric detection device is a laser displacement sensor or a machine vision camera, used to acquire the three-dimensional spatial coordinates of feature points of irregularly shaped processed parts.

6. The compensation machining system for irregularly shaped machined parts according to claim 4, characterized in that, The vibration detection sensor is a triaxial accelerometer, and the dynamic adjustment control module has an embedded fuzzy PID controller for smoothing the output of the adjustment amounts of the three cutting elements.

7. The compensation machining system for irregularly shaped machined parts according to claim 5, characterized in that, When acquiring feature points of irregularly shaped processed parts, the position detection and compensation module uses a multi-feature point spatial fitting algorithm to extract at least three reference feature points that are not on the same straight line. By constructing a spatial coordinate system matrix, the overall deflection angle error is calculated to achieve attitude compensation in three-dimensional space.

8. The compensation machining system for irregularly shaped machined parts according to claim 4, characterized in that, The adaptive flexible clamp includes a base, multiple pneumatic / hydraulic adaptive support columns arranged in an array, and a fine-tuning locking mechanism. The support column is equipped with a pressure sensor, which automatically expands and contracts to fit the irregular part according to its surface shape during the clamping process, and is rigidly fixed by a fine-tuning locking mechanism after fitting into place.

9. The compensation machining system for irregularly shaped machined parts according to claim 4, characterized in that, Before executing S4, the dynamic adjustment control module is also configured to adaptively set the preset vibration threshold based on the current tool overhang length and the hardness coefficient of the workpiece. The calculation formula is as follows: in As the standard benchmark threshold, This is a factor affecting the tool overhang length. This is a factor affecting material hardness.

10. The compensation machining system for irregularly shaped machined parts according to claim 4, characterized in that, The vibration detection module and the dynamic adjustment control module transmit data in real time via industrial Ethernet. The cutting three-element adjustment commands calculated by the dynamic adjustment control module are sent to the machine tool CNC system through a high-speed I / O interface, with a command response cycle of less than 5 milliseconds.

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