A quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy

Abstract

This invention discloses a quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy, comprising the following steps: S1, collecting initial data to obtain first data; S2, unifying the data units in the first data to obtain second data; S3, using the least squares method to fit the second data to obtain the fitting result: logarithmically transforming the vibration velocity and machining accuracy data, and fitting with a quadratic polynomial; S4, obtaining the expression for the relationship between vibration velocity and machining accuracy. Compared with the prior art, this invention, based on existing standards, relevant design data, and vibration test data, through statistical analysis, establishes a relationship between machine tool machining accuracy and environmental vibration requirements on the basis of data fitting. This allows designers to determine the root mean square value of the site's environmental vibration velocity based on the accuracy conditions of the production process during the planning, design, and use stages, and to rationally arrange the production line and corresponding anti-micro-vibration technologies.

Description

Technical Field

[0001] This invention relates to the field of vibration analysis technology in machine tool processing, and in particular to a quantitative analysis method for the relationship between environmental vibration and machine tool processing accuracy. Background Technology

[0002] If a cutting machine tool is subjected to vibration during machining, it will disrupt the normal cutting process, affecting machining quality and production efficiency, and in severe cases, even the service life of the equipment or cutting tools. Machine tool vibration problems can generally be divided into three categories: (1) environmental vibration; (2) idling vibration; and (3) cutting vibration. For the first category, environmental vibration, it is necessary to address it through vibration control technology in construction engineering. However, the second and third categories of vibration problems require solutions in terms of equipment and processes. The impact of environmental vibration on machining accuracy is as follows: Figure 1 As shown.

[0003] In 2013 and 2015, my country successively formulated the "Permissible Vibration Standard for Building Engineering" GB50868-2013 and the "Technical Specification for Anti-vibration Engineering of Electronic Industry" GB 51076-2015, which made some specific provisions on the requirements for environmental vibration during machine tool processing, especially the anti-vibration control of precision machining equipment.

[0004] Most of these standards use frequency domain vibration velocity as the evaluation index and provide some corresponding machining accuracy conditions. However, these vibration prevention standards, as well as anti-micro-vibration standards, only specify some numerical tables and do not establish a relationship between machine tool machining accuracy and anti-micro-vibration requirements.

[0005] As is well known, environmental vibration has a significant impact on machining accuracy. In the planning, design, construction, and use of engineering projects, it is necessary to determine the degree of impact of vibration on machining accuracy in order to facilitate engineering treatment. In construction projects involving precision instruments and equipment, which require anti-vibration control, designers face several challenges: (1) Given the precision requirements of the equipment, it is necessary to understand the limitations imposed by site vibration. (2) Given the site vibration conditions, how to assess the impact of vibration on precision equipment. Generally, the anti-vibration requirements for the site are provided by the equipment manufacturer. However, during the planning and design phases of engineering projects, the equipment is often not yet ordered, and the requirements for different equipment may vary. Therefore, in many situations, it is impossible to obtain anti-vibration data for the equipment, making it impossible to conduct normal anti-vibration control design. Summary of the Invention

[0006] The purpose of this invention is to provide a quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy. This method enables designers to determine the required root mean square value of site environmental vibration velocity based on the accuracy conditions of the production process during the planning and design stages, and to rationally arrange the production line and corresponding anti-micro-vibration technology measures.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy includes the following steps:

[0009] S1. Collect initial data to obtain the first data, wherein the initial data includes:

[0010] (1) Standards related to machining accuracy and environmental vibration;

[0011] (2) Design data on machining accuracy and environmental vibration provided by the equipment manufacturer;

[0012] (3) Data on machining accuracy or error and environmental vibration from machining equipment manuals and textbooks;

[0013] (4) The test results of the field vibration test, including data on environmental vibration and processing accuracy;

[0014] S2. Unify the data units in the first data to obtain the second data:

[0015] (1) For environmental vibration data, vibration displacement and vibration acceleration need to be converted into vibration velocity, and peak value and amplitude need to be uniformly converted into root mean square value of vibration velocity.

[0016] (2) Perform collaborative processing on the relevant machining accuracy data to convert machining errors into dimensional errors;

[0017] S3. Use the least squares method to fit the second data to obtain the fitting result: logarithmically transform the vibration velocity and processing accuracy data, and then use a quadratic polynomial to fit the data.

[0018] S4. Obtain the expression for the relationship between vibration velocity and machining accuracy:

[0019] Fitting Formula 1:

[0020]

[0021] In the formula: To meet the machining accuracy requirements of cutting machine tools, ;

[0022] The root mean square value of the vibration velocity in the 1 / 3 octave band. ;

[0023] To calculate the coefficients, when hour, ;when hour, ;

[0024] To calculate the coefficients, when hour, ;when hour, ;

[0025] To calculate the coefficients, when hour, ;when hour, ;

[0026] Fitting Formula 2:

[0027]

[0028] In the formula: To meet the machining accuracy requirements of cutting machine tools, ;

[0029] The root mean square value of the vibration velocity in the 1 / 3 octave band. ;

[0030] To calculate the coefficients, ;

[0031] To calculate the coefficients, ;

[0032] To calculate the coefficients, .

[0033] Applicable frequency range: 1Hz~100Hz;

[0034] Range of root mean square vibration velocity values: ;

[0035] Corresponding machining accuracy requirements range: .

[0036] Preferably, the process of processing the environmental vibration data in step S2 is as follows:

[0037] 1) For frequency domain data, vibration displacement can be converted into vibration velocity using the following formula:

[0038]

[0039] In the formula: The center frequency of the i-th third octave band is Hz;

[0040] The root mean square value of the vibration displacement corresponding to the center frequency of the i-th third octave band.

[0041] The root mean square value of the vibration velocity corresponding to the center frequency of the i-th third octave band.

[0042] 2) For frequency domain data, vibration acceleration is converted to vibration velocity using the following formula:

[0043]

[0044] In the formula: The root mean square value of the vibration acceleration corresponding to the center frequency of the i-th third octave band.

[0045] 3) For the peak vibration velocity at one-third octave band Calculate using the following formula:

[0046] .

[0047] Preferably, in step S2, the machining accuracy data is processed collaboratively according to the following procedure: the tolerance values ​​among dimensional tolerance (IT), form tolerance (Tf), positional tolerance, and surface roughness (Ra) are in the following order: dimensional tolerance > form tolerance > positional tolerance > surface roughness.

[0048] 1) When the form tolerance is 60% of the dimensional tolerance, Ra≤0.05IT;

[0049] 2) When the form tolerance is 40% of the dimensional tolerance, Ra≤0.025IT;

[0050] 3) When the form tolerance is 25% of the dimensional tolerance, Ra≤0.012IT;

[0051] 4) When the form tolerance is less than 25% of the dimensional tolerance, Ra≤0.15Tf.

[0052] Preferably, in step S3, the data on vibration velocity and machining accuracy in the table below are used for fitting:

[0053] .

[0054] Preferably, the standards mentioned in step S1 include ISO 10816, VDI 2038-2013, DIN 4150, ISO2631-1, etc.

[0055] This invention also provides an application of a quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy, used for anti-micro-vibration control design in the early stages of a proposed mechanical and electronic plant construction project:

[0056] (1) After the process requirements are determined, the applicability of the vibration environment of the proposed site is evaluated by using the fitting formula under the condition of known processing accuracy.

[0057] (2) Given the vibration environment conditions of the proposed construction site, the applicability of the process layout scheme is evaluated using the fitting formula;

[0058] (3) If the above two assessments do not meet the process requirements, the fitting results shall be used as the basis for taking vibration control measures and the vibration control level shall be determined.

[0059] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0060] Based on existing standards, relevant design data, and vibration test data, statistical analysis was conducted, and a relationship between machine tool machining accuracy and environmental vibration requirements was established through data fitting. This allows designers to determine the root mean square value of site environmental vibration velocity based on the accuracy conditions of the production process at each stage of planning, design, and use, and to rationally arrange production lines and corresponding anti-micro-vibration technical measures, thereby determining a reasonable construction plan. Attached Figure Description

[0061] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0062] Figure 1 This is a schematic diagram illustrating the impact of environmental vibration on machining accuracy in the background technology.

[0063] Figure 2 This is a flowchart of a quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy disclosed in this invention;

[0064] Figure 3 This is a schematic diagram of the fitting results in step 1 of the present invention;

[0065] Figure 4 This is a schematic diagram showing the comparison of vibration test results before and after vibration isolation treatment in Example 2. Detailed Implementation

[0066] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0067] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0068] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0069] Example 1

[0070] Reference Figure 2 This invention discloses a quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy, comprising the following steps:

[0071] S1. Collect initial data to obtain the first data, wherein the initial data includes:

[0072] (1) Relevant standards for machining accuracy and environmental vibration, including: ISO 10816, VDI 2038-2013, DIN4150, ISO 2631-1, etc.;

[0073] (2) Design data on machining accuracy and environmental vibration provided by the equipment manufacturer;

[0074] (3) Data on machining accuracy or error and environmental vibration from machining equipment manuals and textbooks;

[0075] (4) Test results of field vibration test, including data on environmental vibration and processing accuracy.

[0076] S2. Unify the data units in the first data to obtain the second data:

[0077] (1) For environmental vibration data, vibration displacement and vibration acceleration need to be converted into vibration velocity, and peak value and amplitude need to be converted into root mean square value of vibration velocity.

[0078] 1) For frequency domain data, vibration displacement can be converted into vibration velocity using the following formula:

[0079]

[0080] In the formula: The center frequency of the i-th third octave band is Hz;

[0081] The root mean square value of the vibration displacement corresponding to the center frequency of the i-th third octave band.

[0082] It is the root mean square value of the vibration velocity corresponding to the center frequency of the i-th third octave band.

[0083] 2) For frequency domain data, vibration acceleration can be converted into vibration velocity using the following formula:

[0084]

[0085] In the formula: It is the root mean square value of the vibration acceleration corresponding to the center frequency of the i-th third octave band.

[0086] 3) For the peak vibration velocity at one-third octave band It can be calculated using the following formula:

[0087] .

[0088] (2) Collaboratively process the relevant machining accuracy data to convert machining errors into dimensional errors. Generally, the tolerance values ​​among dimensional tolerance (IT), form tolerance (Tf), positional tolerance, and surface roughness (Ra) are: dimensional tolerance > form tolerance > positional tolerance > surface roughness.

[0089] 1) When the form tolerance is 60% of the dimensional tolerance (medium relative geometric accuracy), Ra≤0.05IT;

[0090] 2) When the form tolerance is 40% of the dimensional tolerance (higher relative geometric accuracy), Ra≤0.025IT;

[0091] 3) When the form tolerance is 25% of the dimensional tolerance (high relative geometric accuracy), Ra≤0.012IT;

[0092] 4) When the form tolerance is less than 25% of the dimensional tolerance (ultra-high relative geometric accuracy), Ra≤0.15Tf.

[0093] S3. Use the least squares method to fit the second data and obtain the fitting results: According to the table below, logarithmically transform the vibration velocity and processing accuracy data and use a quadratic polynomial for fitting.

[0094]

[0095] The fitting results are as follows Figure 3 As shown, the relationship between vibration velocity and machining accuracy is illustrated. The horizontal axis represents the octave band coordinates of the root mean square value of the environmental vibration velocity, with units of... The vertical axis represents the machining accuracy in a logarithmic coordinate system with base 10, and the unit is... .

[0096] S4. Obtain the expression for the relationship between vibration velocity and machining accuracy:

[0097] Fitting Formula 1:

[0098]

[0099] In the formula: To meet the machining accuracy requirements of cutting machine tools, ;

[0100] The root mean square value of the vibration velocity in the 1 / 3 octave band. .

[0101] To calculate the coefficients, when hour, ;when hour, ;

[0102] To calculate the coefficients, when hour, ;when hour, ;

[0103] To calculate the coefficients, when hour, ;when hour, ;

[0104] Fitting Formula 2:

[0105]

[0106] In the formula: To meet the machining accuracy requirements of cutting machine tools, ;

[0107] The root mean square value of the vibration velocity in the 1 / 3 octave band. ;

[0108] To calculate the coefficients, ;

[0109] To calculate the coefficients, ;

[0110] To calculate the coefficients, .

[0111] Applicable frequency range: 1Hz~100Hz;

[0112] Range of root mean square vibration velocity values: ;

[0113] Corresponding machining accuracy requirements range: .

[0114] This invention also discloses the application of a quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy, used in the initial stage of a proposed mechanical and electronic plant project for anti-micro-vibration control design:

[0115] (1) Once the process requirements are determined, under the condition of known processing accuracy, the applicability of the vibration environment of the proposed site can be evaluated by using the fitting formula;

[0116] (2) Given the vibration environment conditions of the proposed construction site, the applicability of the process layout scheme can be evaluated using the fitting formula;

[0117] (3) If the above two assessments do not meet the process requirements, the fitting results can be used as the basis for taking vibration control measures and the vibration control level can be determined.

[0118] Based on statistical analysis, this invention establishes the relationship between environmental vibration and machine tool machining accuracy. Through the above two fitting formulas, designers can determine the root mean square value of site environmental vibration velocity according to the accuracy conditions of the production process at various stages such as planning, design and use, so as to reasonably arrange the production line and corresponding anti-micro-vibration technology measures, and thus determine a reasonable construction plan.

[0119] Example 2

[0120] For example, a CNC machine tool is located in a machining workshop. There is a vibration device in a separate area of ​​the workshop, 32 meters away in a straight line. The vibration of the CNC machine tool's foundation is significant, affecting the machining accuracy of the machine tool's finishing operations. On-site vibration measurements show that the root mean square value of the vibration velocity is... The vibration exceeded the national standard Class I vibration isolation requirements and did not meet the process requirements. The user requested vibration control measures. Using the fitting formula of this invention, it can be deduced that using vibration isolation technology on the main vibration source equipment (the aforementioned vibration equipment) with a vibration isolation efficiency of 40% can meet the process requirements and the machining accuracy requirements of the machine tool.

[0121] Vibration isolation measures were implemented on the vibration source equipment, effectively improving the vibration environment of the CNC machine tool (results are shown in Table 1). Vibration velocity... It dropped to 44.72 This ensures the normal operation of the machine tool. Table 1 compares the analysis results before and after vibration isolation treatment. The vibration isolation efficiency is 48%. After vibration isolation treatment, the machining accuracy of the machine tool's finishing process is improved by approximately [percentage missing]. The accuracy of the analysis results differed significantly from the pre- and post-treatment test results provided by the user's quality inspection department. The results are consistent. Figure 4 The test data before and after vibration isolation treatment show that the vibration speed of the CNC machine tool has decreased significantly after the treatment.

[0122] Table 1. Comparison of Tests and Analyses Before and After Treatment

[0123]

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy, characterized in that, Includes the following steps: S1. Collect initial data to obtain the first data, wherein the initial data includes: (1) Standards related to machining accuracy and environmental vibration; (2) Design data on machining accuracy and environmental vibration provided by the equipment manufacturer; (3) Data on machining accuracy or error and environmental vibration from machining equipment manuals and textbooks; (4) The test results of the field vibration test, including data on environmental vibration and processing accuracy; S2. Unify the data units of the first data to obtain the second data: (1) For environmental vibration data, vibration displacement and vibration acceleration need to be converted into vibration velocity, and peak value and amplitude need to be uniformly converted into root mean square value of vibration velocity. (2) Perform collaborative processing on the relevant machining accuracy data to convert machining errors into dimensional errors; S3. Use the least squares method to fit the second data to obtain the fitting result: logarithmically transform the vibration velocity and processing accuracy data, and then use a quadratic polynomial to fit the data. S4. Obtain the expression for the relationship between vibration velocity and machining accuracy: Fitting Formula 1: , In the formula: To meet the machining accuracy requirements of cutting machine tools, ; The root mean square value of the vibration velocity in the 1 / 3 octave band. ; To calculate the coefficients, when hour, ;when hour, ; To calculate the coefficients, when hour, ;when hour, ; To calculate the coefficients, when hour, ;when hour, ; Fitting Formula 2: , In the formula: To meet the machining accuracy requirements of cutting machine tools, ; The root mean square value of the vibration velocity in the 1 / 3 octave band. ; To calculate the coefficients, ; To calculate the coefficients, ; To calculate the coefficients, ; Applicable frequency range: 1Hz~100Hz; Range of root mean square vibration velocity values: ; Corresponding machining accuracy requirements range: .

2. The quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy according to claim 1, characterized in that, In step S2, the process of processing the environmental vibration data is as follows: 1) For frequency domain data, vibration displacement can be converted into vibration velocity using the following formula: ， In the formula: The center frequency of the i-th third octave band is Hz; The root mean square value of the vibration displacement corresponding to the center frequency of the i-th third octave band. The root mean square value of the vibration velocity corresponding to the center frequency of the i-th third octave band. 2) For frequency domain data, vibration acceleration is converted to vibration velocity using the following formula: ， In the formula: The root mean square value of the vibration acceleration corresponding to the center frequency of the i-th third octave band. 3) For the peak vibration velocity at one-third octave band Calculate using the following formula: 。 3. The quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy according to claim 1, characterized in that, In step S2, the machining accuracy data is processed collaboratively according to the following procedure: the tolerance values ​​among dimensional tolerance (IT), form tolerance (Tf), positional tolerance, and surface roughness (Ra) are in the following order: dimensional tolerance > form tolerance > positional tolerance > surface roughness. 1) When the form tolerance is 60% of the dimensional tolerance, Ra≤0.05IT; 2) When the form tolerance is 40% of the dimensional tolerance, Ra≤0.025IT; 3) When the form tolerance is 25% of the dimensional tolerance, Ra≤0.012IT; 4) When the form tolerance is less than 25% of the dimensional tolerance, Ra≤0.15Tf.

4. The quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy according to claim 1, characterized in that, The standards mentioned in step S1 include ISO 10816, VDI 2038-2013, DIN 4150, and ISO 2631-1.

5. The application of the quantitative analysis method for the relationship between environmental vibration and machine tool machining accuracy according to any one of claims 1-4, characterized in that, Used for anti-micro-vibration control design in the early stages of a proposed mechanical and electronic plant construction project: (1) After the process requirements are determined, the applicability of the vibration environment of the proposed site is evaluated by using the fitting formula under the condition of known processing accuracy. (2) Given the vibration environment conditions of the proposed construction site, the applicability of the process layout scheme is evaluated using the fitting formula; (3) If the above two assessments do not meet the process requirements, the fitting results shall be used as the basis for taking vibration control measures and the vibration control level shall be determined.

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