A method and apparatus for deterministic reshaping of the inner wall of a metal cylindrical part

Abstract

The application discloses a certainty modification method and device for the inner wall of a metal cylindrical part, and the method comprises the following steps: measuring the multi-section roundness error data of the inner wall of the metal cylindrical part by using a roundness instrument, performing adaptive filtering processing, selecting a polishing wheel for certainty modification, setting processing parameters and obtaining a removal function; performing simulation processing in a process software by using the removal function and the multi-section roundness error data after adaptive filtering, ensuring that the polishing wheel and the processing parameters meet the requirements, whether the dynamic performance of a machine tool meets the requirements or not, so as to obtain an optimal removal function, combining the optimal removal function to perform certainty modification processing on the inner wall of the metal cylindrical part, and if the roundness error data does not meet the requirements after the processing is completed, iterative processing is continuously performed until the roundness error data meets the requirements. The application aims to overcome the limitation of the "error reflection" problem, improve the processing efficiency of the inner wall of the metal cylindrical part and improve the processing precision of the inner wall of the metal cylindrical part.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ultra-precision machining of the inner wall of a metal cylindrical part, and in particular to a deterministic reshaping method and device for the inner wall of a metal cylindrical part. BACKGROUND

[0002] Air and space high-end optical systems such as guided detection face extreme lightweight, extreme temperature conditions, extreme mechanical conditions and extreme optical performance requirements. Full aluminum optical systems can meet the above extreme use requirements due to their excellent characteristics such as optical-mechanical integration, thermalization, high resolution, large field of view, wide spectrum and lightweight, and have become an important direction for the development of detection and guidance optical systems internationally. With the development of spectral imaging and other detection needs, metal aluminum mirrors will be widely used in high-performance full aluminum optical systems of various equipment such as aerospace and unmanned platforms in the future, so the manufacturing equipment and manufacturing capacity of metal aluminum mirrors have broad market prospects. Metal aluminum mirrors require nanometer-level surface accuracy, and domestic ultra-precision gas static pressure spindles used for metal aluminum mirror turning cannot meet the machining accuracy requirements in terms of precision and stiffness performance. The roundness of the inner wall of the gas static pressure sliding bearing plays a very key role in the rotation accuracy performance of the spindle. How to achieve a bearing inner wall roundness of less than 0.3 microns to improve the rotation accuracy of the gas static pressure spindle has become a research hotspot in today's technology development.

[0003] Currently, high-precision machining of the inner wall of a metal cylindrical part faces severe technical challenges. Traditional machining processes mainly rely on turning and manual grinding processes. Although the turning process is efficient, its precision is difficult to meet the requirements of high-precision parts in the machining of large-size and heavy workpieces. The main problems include limited tool contact angle, large single-end clamping machining vibration, and "error replication" problems, which result in insufficient machining precision. At the same time, although manual grinding can achieve high machining precision, it is low in efficiency and highly dependent on the experience and skills of workers, which is uncertain and difficult to meet batch production requirements. In actual production, especially in batch production and complex inner wall shape machining, the limitations of traditional processes are more pronounced. For example, in deep hole inner wall machining, the machining space is narrow, and the tool contact angle and machining parameter adjustment range are limited, further exacerbating the machining difficulty. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a deterministic reshaping method and device for the inner wall of a metal cylindrical part, which overcomes the limitations of the "error replication" problem, improves the machining efficiency of the inner wall of a metal cylindrical part, and improves the machining precision of the inner wall of a metal cylindrical part.

[0005] To solve the above technical problems, the technical scheme adopted by the present application is as follows:

[0006] A method for deterministic modification of the inner wall of a metal cylindrical part, comprising the following steps:

[0007] 1) measuring the multi-section roundness error data of the inner wall of the metal cylindrical part using a roundness instrument;

[0008] 2) performing adaptive filtering processing on the measured multi-section roundness error data;

[0009] 3) selecting a deterministic modification polishing wheel according to the adaptive filtered multi-section roundness error data, setting the machining parameters of the polishing wheel and performing machining to obtain a removal function;

[0010] 4) performing simulation machining in the process software using the removal function and the adaptive filtered multi-section roundness error data, if the roundness after simulation machining does not meet the requirements, then jumping to step 3); otherwise, jumping to step 5);

[0011] 5) judging whether the dynamic performance of the machine tool meets the requirements, if not, then jumping to step 3); otherwise, jumping to step 6);

[0012] 6) combining the optimal removal function, the adaptive filtered multi-section roundness error data, using the process software to generate machining code, and importing the machining code into the machine tool to realize deterministic modification machining of the inner wall of the metal cylindrical part;

[0013] 7) measuring the roundness error data of the inner wall of the machined metal cylindrical part using the roundness instrument, if the roundness error data does not meet the requirements, then jumping to step 6); otherwise, ending and exiting.

[0014] Optionally, step 1) comprises: 1.1) calibrating a measurement starting point on the inner wall of the metal cylindrical part, which is also the machining starting point of the inner wall of the metal cylindrical part; 1.2) starting from the calibrated measurement starting point, using the roundness instrument to perform multiple roundness measurements based on a preset measurement interval of adjacent sections to obtain multi-section measurement data of the inner wall of the metal cylindrical part, the measurement interval of adjacent sections being 5-10 mm; 1.3) using the measurement software and process software of the roundness instrument to calculate the multi-section roundness error data of the inner wall of the metal cylindrical part based on the multi-section measurement data of the inner wall of the metal cylindrical part.

[0015] Optionally, the step 2) comprises: 2.1) decomposing the multi-section roundness error data into signals of multiple scales by using wavelet transform, and extracting frequency features of each scale, and performing power spectrum density analysis on the signals of each scale to extract error amplitudes of each scale; 2.2) taking the multi-section roundness error data, the frequency features and the error amplitudes as inputs, and using a pre-trained neural network machine learning model to predict an optimal filtering range T1, wherein the neural network machine learning model is pre-trained to establish a mapping relationship between the inputs of the multi-section roundness error data, the frequency features and the error amplitudes, and the output of the optimal filtering range T1; and 2.3) filtering the measured multi-section roundness error data by using the optimal filtering range T1 to filter out data exceeding the optimal filtering range T1.

[0016] Optionally, the step 3) comprises:

[0017] 3.1) converting the multi-section roundness error data after adaptive filtering from an original spatial domain signal to a frequency domain signal by performing fast Fourier transform processing;

[0018] 3.2) obtaining a specified proportion of frequencies with the largest amplitudes in the frequency domain signal as profile cutoff frequencies in the circumferential direction of the metal cylindrical part, and obtaining a ratio of the amplitude of each frequency component in the frequency domain signal to the maximum amplitude, and selecting a frequency with a ratio exceeding a preset threshold as a profile cutoff frequency in the axial direction of the metal cylindrical part;

[0019] 3.3) selecting diameters and widths of the deterministic modification polishing wheel according to a selection rule that the cutoff frequencies of the removal function made by the selected polishing wheel should be greater than and closest to the profile cutoff frequencies in the circumferential direction and the axial direction of the metal cylindrical part;

[0020] 3.4) setting machining parameters of the polishing wheel, machining according to the selected deterministic modification polishing wheel and the set machining parameters, measuring the inner wall of the machined metal cylindrical part by using a roundness instrument, and extracting a removal function.

[0021] Optionally, the machining parameters of the polishing wheel include part or all of a polishing wheel pressure, a sand belt update speed and a polishing wheel vibration frequency.

[0022] Optionally, the step 5) includes: using the pulse iteration method to calculate the residence time by using the process software, obtaining the residence time of each position of the C-axis spindle, Z-axis and X-axis; calculating the speed of the metal cylindrical part at the position of the shortest residence time of the C-axis spindle, Z-axis and X-axis, respectively, and comparing with the maximum movement speed of the C-axis spindle, Z-axis and X-axis of the machine tool, if the speed of the metal cylindrical part at the position of the shortest residence time of the C-axis spindle, Z-axis or X-axis exceeds the corresponding maximum movement speed, it is determined that the dynamic performance of the machine tool does not meet the requirements.

[0023] A deterministic modification device for applying the deterministic modification method of the inner wall of the metal cylindrical part, comprising a numerical control machine tool and a deterministic modification module arranged on the numerical control machine tool, the numerical control machine tool comprising a C-axis spindle and a movement adjusting mechanism, the C-axis spindle having an angle servo control function and being provided with a clamp for clamping and fixing the processed metal cylindrical part, the deterministic modification module comprising a vibration mechanism and a modification mechanism, the vibration mechanism being installed on the movement adjusting mechanism, and the modification mechanism being installed on the vibration mechanism.

[0024] Optionally, the movement adjusting mechanism comprises a cascade connected X-axis slide plate and Z-axis slide plate, the movement direction of the X-axis slide plate is perpendicular to the axis direction of the processed metal cylindrical part, and the movement direction of the Z-axis slide plate is parallel to the axis direction of the processed metal cylindrical part.

[0025] Optionally, the modification mechanism comprises a sand belt, a support, a polishing wheel and a sand belt driving mechanism, the sand belt is sleeved on the polishing wheel and the sand belt driving mechanism, the polishing wheel is installed on the support, and the support and the sand belt driving mechanism are installed on the vibration mechanism.

[0026] Optionally, the modification mechanism is further provided with one or more sand belt guide mechanisms, the sand belt guide mechanism comprises a pair of support arms and a guide rod installed between the pair of support arms, a rotatable sliding sleeve is sleeved on the guide rod to constrain the direction of the sand belt by the sliding sleeve to prevent the middle section of the sand belt from contacting the opening edge of the processed metal cylindrical part, and the pair of support arms are respectively fixedly installed on the support.

[0027] Compared with the prior art, the present application mainly has the following beneficial effects: the core advantage of the present application is that through intelligent data processing and adaptive machining control, the roundness precision of 0.3 microns of the inner wall of the metal cylindrical part is broken through, and a matching machining device is designed. Compared with the traditional turning and manual grinding process, the present application constructs a multi-dimensional error control system: (1) the present application proposes an adaptive filtering optimization method, which is expected to break through the problem that the machining precision and efficiency are limited by the fixed filtering range of the traditional method. The present application combines wavelet transform for frequency analysis and machine learning model for adaptive filtering optimization, and innovatively breaks through the dependence on fixed threshold and rules of the traditional method, realizing accurate and flexible adaptive selection of the filtering range; (2) the present application innovatively proposes a deterministic machining method and device based on the principle of "precision evolution", which can overcome the limitation of the motion precision of the machine tool in the traditional machining, and realize higher precision machining of the inner wall of the metal cylindrical part. For the problem of ultra-precision machining of the inner wall of the part in the field of mechanical machining, the present application innovatively proposes a deterministic removal regulation mechanism for the error high point / low point distribution of the inner wall of the metal cylindrical part, and designs a machining device coordinated with the vibration frequency, contact pressure and updating speed of the abrasive belt and other parameters, realizes the negative feedback regulation of the material removal rate and error characteristics, and reduces the roundness error from the industry average of 0.7 microns to the level of 0.25 microns. The technical breakthrough provides key technical support for the manufacturing of high-precision gas static pressure C-axis spindle, and shows important application value in the field of high-end equipment such as aerospace optical system. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is a basic flowchart of the embodiment method of the present application.

[0029] Figure 2 It is a three-dimensional top view of the removal function of the deterministic modification of the embodiment of the present application.

[0030] Figure 3 It is a three-dimensional top view of the removal function of the deterministic modification of the embodiment of the present application.

[0031] Figure 4 It is a three-dimensional top view of the removal function of the deterministic modification of the embodiment of the present application.

[0032] Figure 5 It is a three-dimensional top view of the removal function of the deterministic modification of the embodiment of the present application.

[0033] Figure 6 It is a three-dimensional top view of the removal function of the deterministic modification of the embodiment of the present application.

[0034] Figure 7A structure diagram for reshaping the inner wall of a metal cylindrical part according to an embodiment of the present application.

[0035] Fig. 1 is a structure diagram for reshaping the inner wall of a metal cylindrical part according to an embodiment of the present application. DETAILED DESCRIPTION

[0036] In order to make the person skilled in the art better understand the technical solutions of the present application, the technical solutions of the present application will be further described in detail below in combination with the drawings of the embodiments of the present application.

[0037] As shown in Fig. 1, the certainty reshaping method for the inner wall of the metal cylindrical part according to the present embodiment includes the following steps: Figure 1

[0038] 1) Measure the multi-section roundness error data of the inner wall of the metal cylindrical part using a roundness instrument;

[0039] 2) Perform adaptive filtering processing on the measured multi-section roundness error data;

[0040] 3) Select a polishing wheel for certainty reshaping according to the adaptive filtered multi-section roundness error data, set the machining parameters of the polishing wheel and perform machining to obtain a removal function;

[0041] 4) Perform simulation machining in a process software using the removal function and the adaptive filtered multi-section roundness error data, if the roundness after simulation machining does not meet the requirements, jump to step 3); otherwise, jump to step 5);

[0042] 5) Judge whether the dynamic performance of the machine tool meets the requirements, if not, jump to step 3); otherwise, jump to step 6);

[0043] 6) Combine the optimal removal function, the adaptive filtered multi-section roundness error data, and use the process software to generate machining code, and import the machining code into the machine tool to realize certainty reshaping machining of the inner wall of the metal cylindrical part;

[0044] 7) Measure the roundness error data of the machined inner wall of the metal cylindrical part using a roundness instrument, if the roundness error data does not meet the requirements, jump to step 6); otherwise, end and exit.

[0045] Step 1) of the present embodiment includes:

[0046] 1.1) Mark a measurement starting point on the inner wall of the metal cylindrical part, which is also the machining starting point of the inner wall of the metal cylindrical part;

[0047] ​1.2) Starting from the calibrated measurement origin point, multiple roundness measurements are performed by the roundness measuring instrument based on a preset measurement interval of adjacent sections to obtain multi-section measurement data of the inner wall of the metal cylindrical part, and the measurement interval of adjacent sections is 5-10 mm;

[0048] 1.3) The measurement software and process software of the roundness measuring instrument are used to calculate multi-section roundness error data of the inner wall of the metal cylindrical part according to the multi-section measurement data of the inner wall of the metal cylindrical part. In the process software, these data are processed to generate a cylindrical error topographic map of the inner wall of the metal cylindrical part to be machined.

[0049] The step 2) of the embodiment comprises:

[0050] 2.1) The multi-section roundness error data is decomposed into signals of multiple scales by wavelet transform, and frequency characteristics at each scale are extracted, and power spectral density analysis is performed on signals of each scale to extract error amplitudes at each scale;

[0051] 2.2) The multi-section roundness error data, frequency characteristics and error amplitudes thereof are input, and a pre-trained neural network machine learning model is used to predict an optimal filtering range T1, and the neural network machine learning model is pre-trained to establish a mapping relationship between the input multi-section roundness error data, frequency characteristics and error amplitudes thereof and the output optimal filtering range T1;

[0052] 2.3) The multi-section roundness error data obtained by measurement is filtered by the optimal filtering range T1, and data exceeding the optimal filtering range T1 is filtered out.

[0053] In step 2.1), the wavelet transform decomposition method used when the multi-section roundness error data is decomposed into signals of multiple scales is a known method, and therefore the implementation details are not described in detail. Wavelet transform can decompose error data into signals of multiple scales, which can capture both the details and overall trends of the signals, and can perform multi-scale analysis on the transformed signals to extract frequency characteristics at each scale, thereby providing data for filtering parameter optimization.

[0054] The neural network machine learning model in step 2.2) can adopt a required classifier as needed, and the multi-section roundness error data and its frequency characteristics and error amplitude are input into the neural network machine learning model, so that the optimal filtering range T1 can be predicted. In the training process of the neural network machine learning model, the model is trained through the continuously accumulated historical data, so that it can automatically generate the most suitable filtering range according to the input error data. After the model training is completed, the system automatically determines the appropriate filtering range T1 according to the error data. The range is dynamically adjusted based on the characteristics of the error data, and the filtering effect can be automatically optimized within the data preprocessing period before each processing. With the accumulation of error data, according to different machined surface shapes, the filtering range T1 will be closer and closer to the ideal filtering range T of the surface shape.

[0055] In this embodiment, step 3) includes:

[0056] 3.1) The multi-section roundness error data after adaptive filtering is converted from the original spatial domain signal to the frequency domain signal by performing fast Fourier transform (FFT) processing; by performing fast Fourier transform (FFT) processing on the inner wall shape error data of the metal cylindrical part, the original spatial domain signal can be converted to the frequency domain signal, and the energy distribution at different frequencies can be revealed;

[0057] 3.2) Obtain the specified proportion of frequencies with the maximum amplitude in the frequency domain signal as the profile cutoff frequency in the circumferential direction of the metal cylindrical part, for example, in order to determine the frequency most significant to the reshaping, the 10% of the frequencies with the maximum amplitude are selected in this embodiment, and these frequencies are taken as the profile cutoff frequency in the circumferential direction of the metal cylindrical part; obtain the ratio of the amplitude of each frequency component in the frequency domain signal to the maximum amplitude, and select the frequencies whose ratio exceeds the preset threshold as the profile cutoff frequency in the axial direction of the metal cylindrical part; in the frequency domain, the normalized amplitude spectrum of the shape error data in the circumferential direction, i.e. the ratio of the amplitude of each frequency component in the frequency domain signal to the maximum amplitude, is obtained, and by analyzing the amplitude spectrum, it can be identified which frequency component has a greater influence on the shape error of the part. Therefore, in this embodiment, the normalized amplitude spectrum of the shape error data in the axial direction, i.e. the ratio of the amplitude of each frequency component to the maximum amplitude, is obtained, the 10% of the frequencies with the maximum amplitude of the normalized amplitude spectrum are selected, and these frequencies are taken as the profile cutoff frequency in the axial direction of the metal cylindrical part;

[0058] 3.3) The diameter and width of the deterministic modification polishing wheel are selected according to the selected polishing wheel removal function cutoff frequency, which should be greater than and closest to the profile cutoff frequency of the metal cylindrical part in the circumferential and axial directions. The appropriate size of the polishing wheel is selected for removal function making, and the selection rule is that the removal function cutoff frequency made by the selected polishing wheel should be greater than and closest to the profile cutoff frequency of the metal cylindrical part in the circumferential and axial directions, so this step can be repeated. Under the same machining parameter conditions, different polishing wheel diameters and widths have different modification capabilities, which are specifically reflected in the cutoff frequency of the removal function made by the polishing wheel. The diameter and width of the polishing wheel are the key parameters affecting the modification capability of the removal function. The modification capability of the removal function can be represented by the normalized amplitude spectrum of the Fourier transform of the removal function. When the cutoff frequency of the removal function is higher than the cutoff frequency of the metal cylindrical part inner wall shape error data, the removal function can theoretically correct the shape error of the inner wall. The removal function with low cutoff frequency usually has high modification efficiency and is suitable for correcting macroscopic surface error with long wavelength; while the removal function with high cutoff frequency is suitable for correcting surface error in a wider frequency range;

[0059] 3.4) The machining parameters of the polishing wheel are set, and the metal cylindrical part inner wall is machined according to the selected deterministic modification polishing wheel and the set machining parameters. The machined metal cylindrical part inner wall is measured by using a roundness gauge, and the removal function is extracted. Figure 2 The three-dimensional top view of the deterministic modification removal function of this embodiment is determined, and the axial direction and the circumferential direction are marked in the figure.

[0060] The machining parameters of the polishing wheel in this embodiment include the polishing wheel pressure, the abrasive belt update speed and the polishing wheel vibration frequency (part or all of them can be included). The reasonable setting of these parameters can ensure that the contact state between the polishing wheel and the part inner wall is stable during the machining process, and the modification effect is optimal. The removal function is made by using the selected polishing wheel, and the normalized amplitude spectrum of the removal function in the axial and circumferential directions is obtained by using Fourier transform. The frequency corresponding to 10% of the maximum amplitude is taken as the cutoff frequency of the removal function in the axial and circumferential directions. When the cutoff frequency is higher than the profile cutoff frequency of the metal cylindrical part inner wall in the axial and circumferential directions, the reasonable diameter and width of the polishing wheel can be determined. Otherwise, the appropriate size of the polishing wheel needs to be selected again, and the removal function is made.

[0061] In step 4) of this embodiment, the extracted removal function is imported into the process software for simulation machining. If the simulation result cannot meet the precision requirement (roundness <0.3 μm), return to step 3) to reselect the diameter and width of the deterministic modification polishing wheel, and adjust the machining parameters, so as to improve the modification precision. If the precision meets the requirements, the next step is continued.

[0062] The step 5) of determining whether the dynamic performance of the machine tool meets the requirements in the embodiment includes: using the process software to solve the residence time by using the pulse iteration method to obtain the residence time of each position of the C-axis spindle, the Z-axis and the X-axis; calculating the speed of the metal cylindrical part at the position of the shortest residence time on the C-axis spindle, the Z-axis and the X-axis, respectively, and comparing it with the maximum movement speed of the C-axis spindle, the Z-axis and the X-axis of the machine tool, if the speed of the metal cylindrical part at the position of the shortest residence time on the C-axis spindle, the Z-axis or the X-axis exceeds the corresponding maximum movement speed, it is determined that the dynamic performance of the machine tool does not meet the requirements. If it does not meet the requirements, jump to step 3) to reselect the diameter and width of the deterministic modification polishing wheel, and adjust the processing parameters to increase the cutoff frequency of the removal function and reduce the modification efficiency; otherwise, jump to step 6).

[0063] In the embodiment, the topographic map of the deterministic modification removal function is as shown in Figure 2 In the case of fixed diameter and width of the polishing wheel, the size (length and width) of the removal function is mainly affected by the polishing wheel pressure, the belt update speed and the polishing wheel vibration frequency. Increasing the polishing wheel pressure, the belt update speed and the vibration frequency will cause the cutoff frequency of the removal function to increase, and vice versa. By adjusting the processing parameters, removal functions with different cutoff frequencies can be obtained, thereby having different modification capabilities. Under the condition that the cylinder pressure, vibration frequency and belt speed of the deterministic modification device are consistent, the size of the removal function made by different polishing wheel diameters is different: the smaller the diameter of the polishing wheel, the smaller the length of the removal function in the circumferential direction, which means that the circumferential cutoff frequency is higher, which can meet the modification needs of higher frequency in the circumferential direction; the smaller the width of the polishing wheel, the smaller the length of the removal function in the axial direction, which means that the axial cutoff frequency is higher, which can meet the modification needs of higher frequency in the axial direction; vice versa. However, due to the limitation of the dynamic performance of the machine tool, process software needs to be used for simulation processing, if the simulation result cannot meet the processing precision requirement, the appropriate polishing wheel diameter and width need to be reselected. At the same time, even if the appropriate polishing wheel diameter and width are determined through simulation, due to the existence of positioning errors and other factors in the actual processing process, the processing effect and the simulation result also have differences, so iterative processing is needed. After multiple processing, the cutoff frequency of the surface shape error will be higher, so a polishing wheel with smaller size needs to be selected to realize effective modification.

[0064] In step 6) of the embodiment, the optimal removal function and the multi-section roundness error data after adaptive filtering are combined, the process software is used to generate processing code, and the processing code is imported into the machine tool to realize the deterministic modification processing of the inner wall of the metal cylindrical part; the processing parameters are set to be consistent with the parameters for making the removal function, and the deterministic modification processing of the inner wall of the metal cylindrical part is completed.

[0065] In step 7 of the embodiment, the roundness error data of the inner wall of the processed metal cylindrical part is measured by using a roundness tester, and if the roundness error data does not meet the requirements, the step 6 is jumped to; otherwise, the process is ended and exited. Specifically, after processing, the shape error data of the inner wall of the metal cylindrical part is measured by using a roundness tester, and it is judged whether the roundness error of the inner wall of the processed metal cylindrical part is less than 0.3 μm, and if yes, the process is ended and exited.

[0066] In order to verify the certainty modification method of the inner wall of the metal cylindrical part, a metal cylindrical part processed by ultra-precision turning is selected in the embodiment, the inner wall diameter is 90 mm, and the length is 180 mm. The initial roundness error of the part is about 0.7 μm, the cylindricity error is 1.5 μm, and the three-dimensional error topography and cylindrical surface shape development diagram of the part are shown in Figure 3 and Figure 4 According to the method of the embodiment, the certainty modification removal function in the process software is used for simulation processing. After 67 minutes of modification, the final modification result is shown in Figure 5 , the cylindricity error converges to 0.9 μm, and the roundness error is reduced to an average of 0.25 μm. Considering that the machining accuracy of the current ultra-precision lathe can only reach a roundness error of 0.5 μm and a cylindricity error of 1.0-1.5 μm, it can be seen that the method adopted in the embodiment can realize the digital modification of the ultra-precision metal cylindrical part which cannot be achieved by traditional mechanical machining.

[0067] As shown in Figure 6 , the embodiment also provides a certainty modification device for applying the certainty modification method of the inner wall of the metal cylindrical part described above, which comprises a numerical control machine tool and a certainty modification module arranged on the numerical control machine tool. The numerical control machine tool comprises a C-axis spindle 1 and a motion adjusting mechanism, the C-axis spindle 1 has an angle servo control function, and a clamp for clamping and fixing a processed metal cylindrical part 2 is arranged on the C-axis spindle 1. The certainty modification module comprises a vibration mechanism and a modification mechanism, the vibration mechanism is installed on the motion adjusting mechanism, and the modification mechanism is installed on the vibration mechanism.

[0068] In the embodiment, the motion adjusting mechanism comprises a cascade connected X-axis slide plate and Z-axis slide plate, the motion direction of the X-axis slide plate is perpendicular to the axis direction of the processed metal cylindrical part 2, and the motion direction of the Z-axis slide plate is parallel to the axis direction of the processed metal cylindrical part 2.

[0069] As shown in Figure 6 and Figure 7As shown, the shaping mechanism in this embodiment includes a sanding belt 3, a bracket 4, a polishing wheel 5 and a sanding belt driving mechanism. The sanding belt 3 is sleeved on the polishing wheel 5 and the sanding belt driving mechanism. The polishing wheel 5 is installed on the bracket 4. The bracket 4 and the sanding belt driving mechanism are installed on the vibration mechanism. The sanding belt 3 is sleeved on the polishing wheel 5 so that the surface of the polishing wheel 5 is covered with the sanding belt 3. The polishing wheel 5 is in contact with the inner wall of the metal cylindrical part 2 being processed. During the processing, the deterministic shaping module 4 is fed along the Z axis, and the sanding belt 3 shears and removes the metal inner wall material under the applied pressure. Through the C-axis spindle 1 (the C-axis direction is as shown in FIG. Figure 7 The linkage between the Z-axis (indicated by the curved arrow in the figure) and the Z-axis enables quantitative removal of different locations on the inner wall of the processed metal cylindrical part 2 (the lifting and pressing indicated by the straight arrows in the figure are used to adjust the removal amount), thereby completing the deterministic shaping of the entire inner wall surface of the processed metal cylindrical part 2. In addition, the deterministic shaping module is equipped with an abrasive belt drive mechanism to ensure the stability of shear removal efficiency.

[0070] like Figure 6 As shown, in order to increase the processing depth of the shaping mechanism and prevent the middle section of the abrasive belt from contacting the opening edge of the metal cylindrical part being processed when processing a deeper metal cylindrical part 2, the shaping mechanism in this embodiment is further provided with one or more abrasive belt guide mechanisms (specifically two in this embodiment, located on the entry and exit sides of the abrasive belt 3, respectively). The abrasive belt guide mechanism includes a pair of support arms 6 and a guide rod 7 mounted between the pair of support arms 6. The guide rod 7 is provided with a rotatable sliding sleeve to constrain the direction of the abrasive belt 3 through the sliding sleeve to prevent the middle section of the abrasive belt 3 from contacting the opening edge of the metal cylindrical part being processed. The pair of support arms 6 are respectively mounted and fixed on the bracket 4. As an optional embodiment, a bearing can be installed between the sliding sleeve and the guide rod to improve the stability and reliability of the sliding sleeve's rotation, thereby improving the shaping quality of the abrasive belt 3.

[0071] In summary, the embodiment proposes a deterministic reshaping method for the inner wall of a metal cylindrical part, and designs a device that can realize the machining of the inner wall of a metal cylindrical part. The method uses a sand belt vibration grinding method to remove material, breaking through the limitations of the "error reflection" problem. This method achieves efficient removal through the self-selecting abrasive particles and vibration motion of the sand belt, while avoiding the surface sintering and peeling problems that are easily caused by traditional grinding methods. By precisely controlling the machining time and grinding pressure of each position on the surface through the numerical control system, quantitative removal and high-precision machining are achieved. This method not only overcomes the low efficiency and uncertainty of traditional manual grinding, but also significantly improves the machining precision and greatly improves the inner wall roundness, achieving high-precision machining of 0.3μm level. In addition, through the flexible deformation of the sand belt and the precise control of the numerical control system, this embodiment can adapt to various complex machining requirements, significantly improving the machining efficiency and product consistency. This innovative method provides a new solution for the efficient and high-precision machining of the inner wall of a metal cylindrical part, with important engineering practice value and broad application prospects, especially in the fields of high-precision part machining such as aerospace, automobile manufacturing, and precision instruments, which can significantly improve the product machining quality, reduce production costs, and has important popularization value.

[0072] The above is only the preferred embodiment of the present application, and the protection scope of the present application is not limited to the above-mentioned embodiments. Any technical solutions falling within the scope of the present application should be considered within the protection scope of the present application. It should be noted that for ordinary technical personnel in the technical field, some improvements and refinements without departing from the principles of the present application should also be considered within the protection scope of the present application.

Claims

1. A deterministic shaping method for the inner wall of a metal cylindrical part, characterized in that: The steps include: 1) Use a roundness tester to measure the roundness error data of multiple sections of the inner wall of a metal cylindrical part; 2) Adaptive filtering is performed on the measured multi-section roundness error data; 3) Selecting a deterministically modified polishing wheel based on the multi-section roundness error data after adaptive filtering, setting the polishing wheel processing parameters, and performing processing to obtain a removal function; 4) Use the multi-section roundness error data after the removal function and adaptive filtering to simulate the processing in the process software. If the roundness after the simulation does not meet the requirements, jump to step 3); Otherwise, go to step 5); 5) Determine whether the dynamic performance of the machine tool meets the requirements. If not, jump to step 3); otherwise, jump to step 6); 6) Combining the optimal removal function and the multi-section roundness error data after adaptive filtering, the process software is used to generate machining codes, which are then imported into the machine tool to achieve deterministic shaping of the inner wall of the metal cylindrical part; 7) Use a roundness tester to measure the roundness error data of the inner wall of the processed metal cylindrical part. If the roundness error data does not meet the requirements, jump to step 6); otherwise, end and exit; Step 2) includes: 2.1) decomposing the multi-section roundness error data into signals of multiple scales using wavelet transform, extracting the frequency characteristics at each scale respectively, and performing power spectral density analysis on the signals at each scale to extract the error amplitude at each scale; 2.2) taking the multi-section roundness error data and its frequency characteristics and error amplitude as input, and using a pre-trained neural network machine learning model to predict an optimal filtering range T1, wherein the neural network machine learning model is pre-trained to establish a mapping relationship between the input multi-section roundness error data and its frequency characteristics and error amplitude, and the output optimal filtering range T1; 2.3) filtering the measured multi-section roundness error data using the optimal filtering range T1, and filtering out data exceeding the optimal filtering range T1; Step 3) includes: 3.1) Converting the multi-section roundness error data after adaptive filtering from the original spatial domain signal into the frequency domain signal by performing fast Fourier transform processing; 3.2) Obtain the frequency with the maximum amplitude in the frequency domain signal at a specified ratio as the cutoff frequency of the profile in the circumferential direction of the metal cylindrical part; obtain the ratio of the amplitude of each frequency component in the frequency domain signal to the maximum amplitude, and select the frequency at which this ratio exceeds a preset threshold as the cutoff frequency of the profile in the axial direction of the metal cylindrical part; 3.3) Selecting the diameter and width of the deterministically modified polishing wheel based on the rule that the removal function cutoff frequency of the selected polishing wheel should be greater than and closest to the profile cutoff frequency of the metal cylindrical part in the circumferential and axial directions; 3.4) Set the polishing wheel processing parameters, perform processing according to the selected deterministic polishing wheel and the set processing parameters, use a roundness meter to measure the inner wall of the processed metal cylindrical part, and extract the removal function.

2. The deterministic shaping method for the inner wall of a metal cylindrical part according to claim 1, characterized in that: Step 1) includes: 1.1) calibrating a measurement starting point on the inner wall of the metal cylindrical part, and the measurement starting point also serves as a processing starting point for the inner wall of the metal cylindrical part; 1.2) starting from the calibrated measurement starting point, using a roundness meter to perform multiple roundness measurements based on a preset measurement spacing between adjacent sections to obtain multi-section measurement data of the inner wall of the metal cylindrical part, wherein the measurement spacing between adjacent sections is 5 to 10 mm; 1.3) using the measurement software and process software of the roundness meter to calculate the multi-section roundness error data of the inner wall of the metal cylindrical part based on the multi-section measurement data of the inner wall of the metal cylindrical part.

3. The deterministic shaping method for the inner wall of a metal cylindrical part according to claim 1, characterized in that: The processing parameters of the polishing wheel include part or all of the polishing wheel pressure, the sand belt renewal speed and the polishing wheel vibration frequency.

4. The deterministic shaping method for the inner wall of a metal cylindrical part according to claim 1, characterized in that: In step 5), determining whether the dynamic performance of the machine tool meets the requirements includes: using the process software to use the pulse iteration method to solve the dwell time to obtain the dwell time of each position of the C-axis spindle, Z-axis and X-axis; calculating the speed of the metal cylindrical part at the position with the shortest dwell time on the C-axis spindle, Z-axis and X-axis respectively, and comparing it with the maximum movement speed of the C-axis spindle, Z-axis and X-axis of the machine tool. If the speed of the metal cylindrical part at the position with the shortest dwell time on the C-axis spindle, Z-axis or X-axis exceeds the corresponding maximum movement speed, it is determined that the dynamic performance of the machine tool does not meet the requirements.

5. A deterministic shaping device for applying the deterministic shaping method for the inner wall of a metal cylindrical part according to any one of claims 1 to 4, characterized in that: The invention comprises a numerical control machine tool and a deterministic shaping module arranged on the numerical control machine tool, wherein the numerical control machine tool comprises a C-axis spindle (1) and a motion adjustment mechanism, wherein the C-axis spindle (1) has an angle servo control function and a fixture for clamping and fixing a processed metal cylindrical part (2) is provided on the C-axis spindle (1), and the deterministic shaping module comprises a vibration mechanism and a shaping mechanism, wherein the vibration mechanism is mounted on the motion adjustment mechanism, and the shaping mechanism is mounted on the vibration mechanism.

6. The deterministic shaping device according to claim 5, characterized in that: The motion adjustment mechanism comprises an X-axis slide and a Z-axis slide connected in cascade, wherein the motion direction of the X-axis slide is perpendicular to the axial direction of the processed metal cylindrical part (2), and the motion direction of the Z-axis slide is parallel to the axial direction of the processed metal cylindrical part (2).

7. The deterministic shaping device according to claim 5, characterized in that: The shaping mechanism comprises an abrasive belt (3), a bracket (4), a polishing wheel (5) and an abrasive belt driving mechanism, wherein the abrasive belt (3) is sleeved on the polishing wheel (5) and the abrasive belt driving mechanism, the polishing wheel (5) is mounted on the bracket (4), and the bracket (4) and the abrasive belt driving mechanism are mounted on the vibration mechanism.

8. The deterministic shaping device according to claim 7, characterized in that: The shaping mechanism is further provided with one or more abrasive belt guiding mechanisms, the abrasive belt guiding mechanisms comprising a pair of support arms (6) and a guide rod (7) mounted between the pair of support arms (6), the guide rod (7) being provided with a rotatable sliding sleeve to constrain the direction of the abrasive belt (3) through the sliding sleeve to prevent the middle section of the abrasive belt (3) from contacting the opening edge of the processed metal cylindrical part (2), and the pair of support arms (6) being respectively mounted and fixed on the bracket (4).

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